Journal articles on the topic 'Arid zone plants'
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1
Jain, Satish C., B. Pancholi, R. Singh, and R. Jain. "Pharmacognostical studies of important arid zone plants." Revista Brasileira de Farmacognosia 20, no. 5 (November 2010): 659–65. http://dx.doi.org/10.1590/s0102-695x2010005000023.
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Francois, L. E. "Salinity effects on four arid zone plants." Journal of Arid Environments 11, no. 1 (July 1986): 103–9. http://dx.doi.org/10.1016/s0140-1963(18)31315-6.
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Lewis, Megan. "Spectral characterization of Australian arid zone plants." Canadian Journal of Remote Sensing 28, no. 2 (January 2002): 219–30. http://dx.doi.org/10.5589/m02-023.
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Simpson, B. S., V. Bulone, S. J. Semple, G. W. Booker, R. A. McKinnon, and P. Weinstein. "Arid awakening: new opportunities for Australian plant natural product research." Rangeland Journal 38, no. 5 (2016): 467. http://dx.doi.org/10.1071/rj16004.
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The importance of plants and other natural reserves as sources for biologically important compounds, particularly for application in food and medicine, is undeniable. Herein we provide a historical context of the major scientific research programs conducted in Australia that have been aimed at discovering novel bioactive natural products from terrestrial plants. Generally speaking, the main approaches used to guide the discovery of novel bioactive compounds from natural resources have included random, ethnobotanical and chemotaxonomic strategies. Previous Australian plant natural product research campaigns appear to have lacked the use of a fourth strategy with equally high potential, namely the ecologically guided approach. In addition, many large studies have sampled plant material predominantly from tropical regions of Australia, even though arid and semi-arid zones make up 70% of mainland Australia. Therefore, plants growing in arid zone environments, which are exposed to different external stressors (e.g. low rainfall, high ultraviolet exposure) compared with tropical flora, remain an untapped reservoir of potentially novel bioactive compounds. Research of Australian arid zone plants that is ecologically guided creates a new opportunity for the discovery of novel bioactive compounds from plants (and potentially other biota) for application in health care, food and agricultural industries.
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Jain, SC, B. Pancholi, R. Singh, and R. Jain. "Antibacterial and antifungal potential of some arid zone plants." Indian Journal of Pharmaceutical Sciences 72, no. 4 (2010): 510. http://dx.doi.org/10.4103/0250-474x.73939.
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Bona, Elisa, Nadia Massa, Omrane Toumatia, Giorgia Novello, Patrizia Cesaro, Valeria Todeschini, Lara Boatti, et al. "Climatic Zone and Soil Properties Determine the Biodiversity of the Soil Bacterial Communities Associated to Native Plants from Desert Areas of North-Central Algeria." Microorganisms 9, no. 7 (June 23, 2021): 1359. http://dx.doi.org/10.3390/microorganisms9071359.
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Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a “holobiont”. In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species.
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Rathore, Mala. "Leaf Protein Concentrate as Food Supplement from Arid Zone Plants." Journal of Dietary Supplements 7, no. 2 (May 2010): 97–103. http://dx.doi.org/10.3109/19390211003766777.
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BIDINGER, F. R., O. P. YADAV, and E. WELTZIEN RATTUNDE. "GENETIC IMPROVEMENT OF PEARL MILLET FOR THE ARID ZONE OF NORTHWESTERN INDIA: LESSONS FROM TWO DECADES OF COLLABORATIVE ICRISAT-ICAR RESEARCH." Experimental Agriculture 45, no. 1 (January 2009): 107–15. http://dx.doi.org/10.1017/s0014479708007059.
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SUMMARYThe arid zone of northwestern India is a unique adaptation zone for crop plants because of its pervasive severe moisture stress and high temperatures. Pearl millet (Pennisetum glaucum) is a major cereal in this zone as it represents approximately 25% of the total acreage of the crop in the country. Pearl millet hybrid cultivars, which have gained widespread acceptance from farmers elsewhere in the country, have not been adopted in the arid zone. Farmers continue to sow their traditional landraces because the yield advantage of current hybrids is not expressed in this zone, and the risk of failure in poor years with the hybrids is unacceptably high. The International Crops Research Institute for the Semi-Arid Tropics and the Indian Council of Agricultural Research have been collaborating to understand the unique nature of pearl millet in the arid zone since the late 1980s. This collaboration has produced a better understanding of how arid zone farmers manage their germplasm, of the unique features of this invaluable resource and of a range of ways of using this germplasm to produce well-adapted new varieties and hybrids that will meet the requirements of the farmers of the arid zone. It has been shown that new cultivars for the arid zone need to be based on parental materials, including traditional landraces that are specifically adapted to the arid zone. This paper summarizes the main lessons of nearly 20 years of this collaborative research.
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Rakhimov, Tulkin, Ikram Yusupov, and Zafar Boirov. "Influence of Industrial Emissions on Morphological Signs of Leaves of Greening Plants." Natural Systems and Resources, no. 2 (October 2020): 26–32. http://dx.doi.org/10.15688/nsr.jvolsu.2020.2.3.
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Currently, studies of the industrial environment and related theoretical and applied environmental problems are undoubtedly relevant. Therefore, the indicators of environmental monitoring of greening tree species are the main indicators of the ecological situation in the industrial zones of the arid zone of the South of Uzbekistan. The article investigates the effect of SO2 on the morphometric index of leaf blades of some planted trees. Based on the information collected, a morphometric indicator of leaf blades and its relationship with the concentration of sulfur in the atmosphere are provided. Based on the changes in morphological and anatomical and some biological indicators, the degree of stability of greening species is revealed. The results obtained can be used in monitoring green spaces of industrial regions, as well as for predicting the effects of environmental pollution. The research results can serve as a scientific basis for the selection and regionalization of tree species for landscaping the industrial centers of the arid zone. According to our observations, changes in signs towards xeromorphy show a direct relationship with gas resistance, because these indicators depend on the structural features of the leaf blade. In particular, xeromorphic signs are the following: a decrease in the leaf blade, an increase in pubescence, an increase in the number of stomata per mm2, length of venation, etc. We recommend using ash for landscaping streets and parks in the arid zone. Due to the high decorative and drought-resistant properties, they should be used in group, linear, alley, as well as mixed plantings. Considering gas resistance, drought resistance, as well as salt tolerance of elm and quince, we recommend using them for landscaping industrial regions, as well as for planting shelterbelts. In large industrial centers, we recommend using maple, ash and elm for landscaping, as they have more resistant signs to toxicants, in particular to sulphurous anhydride. The analysis of the obtained research data allows stating that there is a relationship between the concentration of sulphurous anhydride and the morphometric indicators of leaf blades of greening trees in industrial zones
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Schweingruber, Fritz Hans. "Anatomical Characteristics and Ecological Trends in the Xylem and Phloem of Brassicaceae and Resedacae." IAWA Journal 27, no. 4 (2006): 419–42. http://dx.doi.org/10.1163/22941932-90000164.
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The xylem and phloem of Brassicaceae (116 and 82 species respectively) and the xylem of Resedaceae (8 species) from arid, subtropical and temperate regions in Western Europe and North America is described and analysed, compared with taxonomic classifications, and assigned to their ecological range. The xylem of different life forms (herbaceous plants, dwarf shrubs and shrubs) of both families consists of libriform fibres and short, narrow vessels that are 20–50 μm in diameter and have alternate vestured pits and simple perforations. The axial parenchyma is paratracheal and, in most species, the ray cells are exclusively upright or square. Very few Brassicaceae species have helical thickening on the vessel walls, and crystals in fibres. The xylem anatomy of Resedaceae is in general very similar to that of the Brassicaceae. Vestured pits occur only in one species of Resedaceae.Brassicaceae show clear ecological trends: annual rings are usually distinct, except in arid and subtropical lowland zones; semi-ring-porosity decreases from the alpine zone to the hill zone at lower altitude. Plants with numerous narrow vessels are mainly found in the alpine zone. Xylem without rays is mainly present in plants growing in the Alps, both at low and high altitudes. The reaction wood of the Brassicaceae consists primarily of thick-walled fibres, whereas that of the Resedaceae contains gelatinous fibres. The frequency of sclereids in Brassicaceae bark is an indicator of ecological differences: sclereids are rare in plants from the alpine zone and frequent in plants from all other ecotones.
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Davies, S. J. J. F., and S. A. Kenny. "The ages and fecundity of some arid-zone plants in Western Australia." Rangeland Journal 35, no. 4 (2013): 455. http://dx.doi.org/10.1071/rj12112.
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Since 1960, 22 species of individually marked, arid-zone perennial plants in the Murchison District and Gibson Desert of Western Australia have been monitored for flowering, fecundity, and survival. The age to which individual species survive was determined in terms of half-life, i.e. the time elapsed for half of the marked sample to die. The estimates ranged from 6.5 to 535 years. Phenology was recorded by observing whether the plants carried buds, flowers, fruits, or any combination of these, or were sterile. Fecundity of each species was measured by recording each year the percentage of the sample trees that carried fruit, by collecting seeds in trays placed beneath the plants and by counting the pods produced by some species. Fecundity was related to seasonal rainfall, most species responding positively to summer rainfall. The concept of mast years, as utilised in the northern hemisphere, was applied to recorded fecundities and some evidence was found that, after a year of high fecundity, the plants responded less vigorously to conditions of high rainfall than they did in the previous year of high rainfall. This suggests that, in years when fecundity is high, it diminishes the resources available within the plants to respond to heavy rainfall the following year or reduces the soil nutrients available to them.
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Dedkov, Viktor P., Elena V. Danzhalova, Sergey N. Tkachenko, S. Khadbaatar, E. Ariunbold, Peter D. Gunin, and Sergey N. Bazha. "The Influence Of Vegetation On Reflected Solar Radiation In Arid And Extra-Arid Zone Of Mongolian Gobi." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 13, no. 4 (December 31, 2020): 72–80. http://dx.doi.org/10.24057/2071-9388-2020-91.
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Vegetation cover has a noticeable effect on surface reflectivity and local microclimate in arid areas of Mongolian Gobi. Over the past decades, various shrub species (Haloxylon ammodendron and Calligonum mongolicum) have appeared on the previously unvegetated hamada. The climatic consequences of bush encroachment are still poorly understood. Using the experimental data, this article estimates the reflectance of plants dominating in Mongolia’s dry steppe, desert-steppe, and desert ecosystems. The average values of the total reflection coefficient at visible and infrared wavelengths range from 19.7% ± 1.4% to 20.1% ± 1.7% in plants growing in desert-steppe ecosystems, and from 25.0% ± 0.9% to 24.8% ± 1.5% on the bare surface. The difference between the reflectance of vegetated and unvegetated surfaces reaches 5%. Therefore, in daylight hours, the vegetated day surface loses less solar energy than the non-vegetated surface does. This phenomenon may be defined as a quasi- or secondary greenhouse effect – in daylight hours, solar energy is retained on the surface by vegetation and this contributes to the temperature increase. Such an impulse, which seems to be insignificantly small at first glance, triggers a series of climatic variations leading to a change in the structure of the radiation and heat balance as well as the climate not only in the desert-steppe and desert ecosystems but also in Central Asia as a whole. All this may explain the 1.2-2.3°C increase in air temperatures in the Gobi observed over the last 25 years.
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Reid, N., and RT Lange. "Host Specificity, Dispersion and Persistence Through Drought of Two Arid Zone Mistletoes." Australian Journal of Botany 36, no. 3 (1988): 299. http://dx.doi.org/10.1071/bt9880299.
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In the Whyalla region of South Australia, the loranthaceous mistletoe Amyema quandang (Lindl.) Tiegh. is virtually host-specific to Acacia papyrocarpa Benth., whereas Lysiana exocarpi (Behr.) Tiegh. (Loranthaceae) frequently parasitises 12 species in seven families, and less commonly infects seven other species. Amyema quandang is contagiously distributed with respect to Acacia papyrocarpa, larger trees supporting higher numbers of mistletoes. Host branch diameter (HBD) is assumed to index the age of individual mistletoes of Amyema quandang since seedlings only establish on thin host branches. The age distribution of A. quandang is skewed towards young plants since almost half the population para- sitises host branches Ͱ4 15 mm in diameter, within the range infected by seedlings. HBD is correlated with canopy size and the number of haustorial branches. The proportion of reproductive mistletoes increases with HBD and hyperparasitic L. exocarpi are confined to older plants of A. quandang with HBD Ͱ5 31 mm. As a result of the severe drought in 1982, 25% of large plants of A. quandang lost one or two main haustorial branches and suffered reductions in canopy volume, but only 4% died; by contrast, 31% of large L. exocarpi died and a further 19% lost most of their foliage. In the A. quandang population as a whole, recruitment balanced mortality (19%) over a 40 month period, but in the L. exocarpi popu- lation recruitment compensated for only half the mortality. None of the xerophytic shrub and tree hosts of either mistletoe died.
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Blackwell, M. "AMENITY HORTICULTURE AND THE USE OF AUSTRALIAN NATIVE PLANTS IN ARID ZONE ENVIRONMENTS." Acta Horticulturae, no. 454 (February 1998): 263–72. http://dx.doi.org/10.17660/actahortic.1998.454.30.
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Kumar, G. Phani, Raj Kumar, and O. P. Chaurasia. "Conservation Status of Medicinal Plants in Ladakh: Cold Arid Zone of Trans-Himalayas." Research Journal of Medicinal Plant 5, no. 6 (June 1, 2011): 685–94. http://dx.doi.org/10.3923/rjmp.2011.685.694.
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Russell, Hugh, and Hal Gurgenci. "Improving the performance of arid-zone geothermal power plants using seasonal heat storage." Geothermics 51 (July 2014): 337–43. http://dx.doi.org/10.1016/j.geothermics.2014.03.006.
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Steinberg, Spencer, and Vernon Hodge. "Copper Complexation by Dissolved Organic Matter in arid Soils: A Voltametric Study." Environments 5, no. 11 (November 20, 2018): 125. http://dx.doi.org/10.3390/environments5110125.
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A voltammetric method was used to estimate the complexing capacity of water extracts from both desert soils sampled at the root zone of creosote and salt cedar plants, and in soils from interspace or background regions where no vegetative influence was apparent. The copper complexing capacity of water extracts of these desert soils was influenced by contact time and pH. In soils from the root zones of creosote and salt cedar plant, copper complexation capacities at pH 8 were from 5 µM to 60 µM after five min contact periods, while 18 h contact periods yielded copper complexation capacities of 40 µM–80 µM. Soils with no vegetative influence had copper complexing capacities of less the 2 µM. The copper complexing capacities of these soils are well correlated with the concentration of organic carbon in the water extract (r2 = 0.86). The abundance of soluble organic matter in the root zone of desert shrubs has the potential to control the solution speciation of Cu2+. The formation of soluble complexes should also have an important influence on the plant uptake and transport of copper, as well as other heavy metals in the root zones of desert shrubs and beyond.
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Curtis, Ellen M., Andrea Leigh, and Scott Rayburg. "Relationships among leaf traits of Australian arid zone plants: alternative modes of thermal protection." Australian Journal of Botany 60, no. 6 (2012): 471. http://dx.doi.org/10.1071/bt11284.
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Despite the importance of leaf traits that protect against critically high leaf temperatures, relationships among such traits have not been investigated. Further, while some leaf trait relationships are well documented across biomes, little is known about such associations within a biome. This study investigated relationships between nine leaf traits that protect leaves against excessively high temperatures in 95 Australian arid zone species. Seven morphological traits were measured: leaf area, length, width, thickness, leaf mass per area, water content, and an inverse measure of pendulousness. Two spectral properties were measured: reflectance of visible and near-infrared radiation. Three key findings emerged: (1) leaf pendulousness increased with leaf size and leaf mass per area, the former relationship suggesting that pendulousness affords thermal protection when leaves are large; (2) leaf mass per area increased with thickness and decreased with water content, indicating alternative means for protection through increasing thermal mass; (3) spectral reflectance increased with leaf mass per area and thickness and decreased with water content. The consistent co-variation of thermal protective traits with leaf mass per area, a trait not usually associated with thermal protection, suggests that these traits fall along the leaf economics spectrum, with leaf longevity increasing through protection not only against structural damage but also against heat stress.
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Belitskaya, M. N., I. R. Gribust, E. E. Nefed’eva, O. S. Filimonova, and M. A. Golovanova. "The phyllophagous of woody plants of genus Ulmus in protective plantings of arid zone." IOP Conference Series: Earth and Environmental Science 115 (January 2018): 012015. http://dx.doi.org/10.1088/1755-1315/115/1/012015.
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Sharma, G., H. N. Verma, and R. Sharma. "Evaluation of Plant Growth Promoting Rhizobacterial Activity in Soil Samples of Arid Zone Plants." Proceedings of the National Academy of Sciences, India Section B: Biological Sciences 83, no. 1 (March 2013): 91–95. http://dx.doi.org/10.1007/s40011-012-0034-0.
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Sharma, G., H. N. Verma, and R. Sharma. "RAPD Analysis to Study Metagenome Diversity in Soil Microbial Community of Arid Zone Plants." Proceedings of the National Academy of Sciences, India Section B: Biological Sciences 83, no. 2 (April 10, 2013): 135–39. http://dx.doi.org/10.1007/s40011-012-0041-1.
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Norman, P., R. Denham, and M. J. Calvert. "Life histories of two arid-zone shrubs change with differences in habitat, grazing and climate." Rangeland Journal 36, no. 3 (2014): 249. http://dx.doi.org/10.1071/rj14003.
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Shrubs are an important component of vegetation throughout the world. They are particularly significant in semiarid environments where they can dominate, driving ecosystem structure and functioning, and shaping land use. Life-history information was derived for Eremophila sturtii R.Br. and Dodonaea viscosa subsp. angustissima J.G.West, two widespread and common shrubs of semiarid eastern Australia. Plants growing under background climatic conditions took between 2 and 4 years to become established, attained the capacity to reproduce sexually at between 10 and 12 years, were in a sexually reproductive stage for between 17 and 28 years and lived an average maximum of 33–40 years. Under background climatic conditions between 70 and 80% of plants that entered the juvenile stage survived to sexual maturity while under severe drought this proportion fell to between 40 and 60%. Juvenile plants, particularly of E. sturtii, experienced the highest mortality under background conditions while, when exposed to severe drought, older plants, particularly D. viscosa subsp. angustissima in the intermediate stage, experienced the greatest increase in mortality, dying at more than twice the background rate. The high survival rates of E. sturtii and D. viscosa subsp. angustissima shown here, even under extreme drought conditions and in grazed- and ungrazed areas, help to explain why these shrub species have been observed to dominate vegetation in large areas of eastern Australia.
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Kuznetsova, I., N. Azovtseva, and A. Bondarev. "NORMS OF CHANGE OF PHYSICAL PROPERTIES OF SOILS OF STEPPE, ARID AND SEMI-DESERT ZONES OF EUROPEAN RUSSIAN TERRITORIES." Dokuchaev Soil Bulletin, no. 67 (June 30, 2011): 3–19. http://dx.doi.org/10.19047/0136-1694-2011-67-3-19.
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Norms of change of physical properties of arable land have been developed chernozems of steppe, chestnut soils of dry-steppe and light-chestnut soils of desert steppe zones of the European territory of Russia depending on the nature of anthropogenic impact. The limits of optimum, admissible and critical values of physical properties of these soils for growth and development of plants are established. For each zone, expert estimates of the distribution of soil areas with optimal, acceptable and critical values of the basic physical properties of soils are given. The greatest differences are observed in the density and structural composition of soils of different soil-climatic zones. In the steppe zone, soils with optimal values of arable layer density prevail among ordinary chernozems (1.0 - 1.2 g/cm3); among pre-Caucasian and southern chernozems - with values of 1.25-1.35 g/cm3. Among the chestnut soils of the dry-steppe zone the most common are the differences in the permissible values equilibrium density (1.30-1.40 g/cm3); in the desert steppe zone light chestnut soils with permissible (1.35- 1.45 g/cm3) and critical values (>1.45 g/cm3) of the equilibrium density. In the arable layer of soils of each separate zone agrophysical properties are significantly reduced by agrotechnical measures and close requirements of crops cultivated in the zone. Norms of change of physical properties can serve as a guide for assessing the current physical condition of arable soils and a basic basis for the development of regional fertility conservation and reproduction systems of the soil.
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Bhattarai, Shandesh, Ram P. Chaudhary, Cassandra L. Quave, and Robin SL Taylor. "The use of medicinal plants in the trans-himalayan arid zone of Mustang district, Nepal." Journal of Ethnobiology and Ethnomedicine 6, no. 1 (2010): 14. http://dx.doi.org/10.1186/1746-4269-6-14.
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Khassanov, O. Kh, T. Rachimova, and S. F. Tadzhiev. "Biological characteristics of newly cultivated fodder plants for pastures of the arid zone in Uzbekistan." Genetic Resources and Crop Evolution 41, no. 3 (1994): 125–31. http://dx.doi.org/10.1007/bf00051629.
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Forrest, Cairo N., David G. Roberts, Andrew J. Denham, and David J. Ayre. "Isolation and Lack of Potential Mates may Threaten an Endangered Arid-Zone Acacia." Journal of Heredity 110, no. 6 (July 18, 2019): 738–45. http://dx.doi.org/10.1093/jhered/esz043.
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Abstract Clonality may provide reproductive assurance for many threatened plants while limiting sexual reproductive success either through energetic tradeoffs or because clones are self-incompatible. Most stands of the Australian arid-zone plant Acacia carneorum, flower annually but low seed set and an absence of sexual recruitment now suggest that this species and other, important arid-zone ecosystem engineers may have low genotypic diversity. Indeed, our recent landscape-scale genetic study revealed that stands are typically monoclonal, with genets usually separated by kilometers. An inability to set sexually produced seed or a lack of genetically diverse mates may explain almost system-wide reproductive failure. Here, using microsatellite markers, we genotyped 100 seeds from a rare fruiting stand (Middle-Camp), together with all adult plants within it and its 4 neighboring stands (up to 5 km distant). As expected, all stands surveyed were monoclonal. However, the Middle-Camp seeds were generated sexually. Comparing seed genotypes with the single Middle-Camp genotype and those of genets from neighboring and other regional stands (n = 26), revealed that 73 seeds were sired by the Middle-Camp genet. Within these Middle-Camp seeds we detected 19 genotypes in proportions consistent with self-fertilization of that genet. For the remaining 27 seeds, comprising 8 different genotypes, paternity was assigned to the nearest neighboring stands Mallee and Mallee-West, approximately 1 km distant. Ironically, given this species’ vast geographic range, a small number of stands with reproductively compatible near neighbors may provide the only sources of novel genotypes.
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Brown, RF. "Defoliation regrowth and dry matter partitioning in the two arid zone grasses, Aristida armata and Thyridolepis mitchelliana." Australian Journal of Agricultural Research 38, no. 5 (1987): 881. http://dx.doi.org/10.1071/ar9870881.
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Plants of the desirable rangeland grass, Thyridolepis mitchelliana, and its undesirable companion, Aristida armata, were defoliated at various ages, and their subsequent regrowth and seed production compared with that of intact plants. Young plants of T. mitchelliana, but not A. armata, often failed to survive severe defoliation. Seed production by A. armata greatly exceeded that of T. mitchelliana and was much less affected by defoliation. In both defoliated and intact plants, the proportion of dry matter in inflorescences was several times greater for A. armata than T. mitchelliana, but the reverse occurred with leaf production. Root growth was little affected by defoliation, and there was no evidence of export of root material to support tops regrowth. Total plant production of both species was unaffected by the loss of half the tops, but was depressed by more severe defoliation. The differences between the two species in their reaction to defoliation seem sufficient to explain the displacement of T. mitchelliana by A. armata which followed the introduction of domestic livestock. Under grazing, A. armata is likely to have a reproductive advantage, and the implications of this for pasture management are examined.
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Martin, Chris A., and John M. Ruter. "Growth and Foliar Nutrient Concentrations of Crape Myrtle in Response to Disparate Climate and Fertilizer Placement in Large Nursery Containers." Journal of Environmental Horticulture 14, no. 1 (March 1, 1996): 9–12. http://dx.doi.org/10.24266/0738-2898-14.1.9.
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Abstract A study was replicated in different climates [central Arizona (arid, Sonoran desert) and southwestern Georgia (humid, temperate)] to evaluate effects of controlled-release fertilizer placement in a bark-based container substrate on growth and foliar nutrient concentrations of Lagerstroemia indica L. × L. fauriei Koehne ‘Muskogee’ in large (#7) containers. Plants in Arizona were smaller with higher shoot-to-root ratios and higher levels of N, K, P, Fe, and Cu and lower levels ofCa and Zn in foliage compared with plants in Georgia. Differences in meteorological factors such as higher maximum and minimum temperatures and solar radiation, lower rainfall, and higher container root-zone temperatures, leachate electrical conductivity and nitrate concentrations were coincident with the smaller size and higher foliar nutrient concentration of Arizona plants. Fertilizer placed at the north exposure of container substrate increased plant size in Arizona. However, compared with growth of plants in Georgia, fertilizer placement at the north exposure in Arizona was not enough to entirely alleviate size inhibition caused by the arid Sonoran desert climate.
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Esechie, H. A. "Effect of planting density on growth and yield of irrigated maize (Zea mays) in the Batinah Coast region of Oman." Journal of Agricultural Science 119, no. 2 (October 1992): 165–69. http://dx.doi.org/10.1017/s0021859600014076.
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SUMMARYField studies were conducted in 1989 and 1990 to investigate the effect of planting density on growth and yield of maize under irrigation in the Batinah Coast region, an arid zone in the Sultanate of Oman. Two maize cultivars, Eperon and Challenger, were grown at three densities (24000, 48000 and 74000 plants/ha). Grain yield was highest at 48000 plants/ha. Leaf area index (LAI) increased with increase in plant density but was not related to grain yield. Lodging was highly correlated with shelling percentage.
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Wilson, JR, and JB Hacker. "Comparative digestibility and anatomy of some sympatric C3 and C4 arid zone grasses." Australian Journal of Agricultural Research 38, no. 2 (1987): 287. http://dx.doi.org/10.1071/ar9870287.
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The importance of C4 (panicoid) and C3 (festucoid) leaf anatomy to differences in in vitro dry matter digestibility (DMD) of grasses was assessed using two Australian summer-growing arid zone C4 grasses, Cymbopogon obtectus and Digitaria brownii, and two C3 grasses, Thyridolepis mitcheiliana and Monochather paradoxa. Seed of these sympatric species was collected from a 400 m2 area near Charleville, Qld. Thus the usual problem of confounding C4 and C3 type with species of different environmental adaptation was avoided in this study. Proportions of tissue types in leaf cross sections and DMD were measured for plants grown in a glasshouse under summer (� water stress) or winter ( - stress) conditions. Differences in tissue proportions due to C4 and C3 leaf anatomy were greater than those induced by growth conditions. C4 leaves consistently had less mesophyll and more of the less-digestible epidermis, bundle sheath, sclerenchyma and vascular tissues. Water-stress resulted in leaves with an increased proportion of mesophyll, but differences in tissue proportions between summer- and winter-grown leaves were small. Species were divided into fast (D. brownii and 7, mitchelliana) and slow (C. obtectus and M. paradoxa) leaf development groups for comparison of DMD. Within each group the C3 species consistently had the highest leaf DMD, but across groups the difference of 18-27 days in time to develop a new leaf sometimes overrode the advantage to DMD of the C3 anatomy. Stem DMD did not differ consistently between C4 and C3 species. The DMD was highest for water-stressed material, and higher in winter- than summer-grown plants. The anatomy associated with either C4 tropical or C3 temperate grass genera clearly contributes to difference in DMD between leaves, but variation in DMD associated with leaf age or environment was only in part attributable to differences in tissue proporxions.
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Cole, Kenneth L., and Geng-Wu Liu. "Holocene Paleoecology of an Estuary on Santa Rosa Island, California." Quaternary Research 41, no. 3 (May 1994): 326–35. http://dx.doi.org/10.1006/qres.1994.1037.
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AbstractThe middle to late Holocene history and early Anglo-European settlement impacts on Santa Rosa Island, California, were studied through the analysis of sediments in a small estuarine marsh. A 5.4-m-long sediment core produced a stratigraphic and pollen record spanning the last 5200 yr. Three major zones are distinguishable in the core. The lowermost zone (5200 to 3250 yr B.P.) represents a time of arid climate with predominantly marine sediment input and high Chenopodiaceae and Ambrosia pollen values. The intermediate zone (3250 yr B.P. to 1800 A.D.) is characterized by greater fresh water input and high values for Asteraceae and Cyperaceae pollen and charcoal particles. The uppermost zone (1800 A.D. to present) documents the unprecedented erosion, sedimentation, and vegetation change that resulted from the introduction of large exotic herbivores and exotic plants to the island during Anglo-European settlement. The identification of pollen grains of Torrey Pine (Pinus torreyana) documents the persistence of this endemic species on the island throughout the middle to late Holocene.
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Bessonova, Valentina, and Tetiana Yusypiva. "Physiological Parameters of the State of Pinus Pallasiana D. Don in different Forest-Growth Conditions in Ravine Viyskovyi." Ekológia (Bratislava) 40, no. 2 (June 1, 2021): 137–44. http://dx.doi.org/10.2478/eko-2021-0016.
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Abstract The influence of different forest-growth conditions on the ecological and physiological parameters of Pinus pallasiana D. Don plants growing in anti-erosion planting is investigated. The experimental sites are located in the thalweg (test area 1) and on the slope of southern exposure in the lower, middle, and upper parts (test areas 2–4) of Ravine Viyskovyi (steppe zone of Ukraine). Forest-growth conditions are clay-loam soil (CL2) (mesophilic, fresh soil), СL1–2 (xeromesophilic, rather fresh), СL1 (mesoxerophilic, somewhat dry or semi-arid), and СL0–1 (xerophilic, arid) correspondently. It was shown that the growth rates of trees, the growth rate of lateral (scaffold) branches in length and thickness, needle-packing coefficient, and needle surface area of annual shoots are maximal in P. pallasianа in the thalweg in conditions of the best water supply and minimal in arid and semi-arid conditions of growth. The research revealed that the highest content of total water in the needles is characteristic of plants of fresh forest plant conditions and the smallest in arid and semi-arid areas (test areas 3 and 4), which is consistent with the forest-vegetation conditions. Sufficient contents of potassium, calcium, and magnesium in all areas and phosphorus in three areas except the middle part of the slope were found in the needles of P. pallasianа. However, insufficient content of nitrogen was found in the needles, especially in the trees of the middle part of the slope, which, together with low water supply, could cause the most significant slowdown in the growth of P. pallasianа plants precisely on this experimental site. A correlation was established between the indices of plant growth and the content of water and nutrients.
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Kumar, Amit, Monideepa Mitra, Bhupendra S. Adhikari, and Gopal S. Rawat. "Flora of Niti Valley: a cold arid region of Nanda Devi Biosphere Reserve, Western Himalaya, India." Check List 12, no. 1 (January 6, 2016): 1824. http://dx.doi.org/10.15560/12.1.1824.
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Located in the extended buffer zone of Nanda Devi Biosphere Reserve in Western Himalaya, Niti valley represents a cold arid region. The reserve has been extensively surveyed in terms of floral diversity by various workers, albeit highly confined to the core zones. The current survey recorded 495 species belonging to 267 genera and 73 families of vascular plants through systematic collection in the years 2011, 2012 and 2014. Of the recorded species, 383 were dicots, 93 monocots, 9 pteridophytes and 10 gymnosperms. Asteraceae was most diverse family (32 genera with 58 species), followed by Poaceae (22 genera with 41 species), Lamiaceae (15 genera with 19 species) Fabaceae (14 genera with 22 species), Brassicaceae (12 genera with 12 species) and Rosaceae (11 genera with 36 species). The present survey also updates the existing flora of Nanda Devi Biosphere Reserve (801 species) with addition of 167 species. This study reveals that the Niti valley forms a transition zone, as the floral elements have affinity with Trans as well as Greater Himalaya.
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Davies, S. J. J. F., S. A. Kenny, and T. F. M. Walsh. "The population dynamics of some arid zone plants during 46 years of grazing on Mileura Station, Western Australia." Rangeland Journal 37, no. 4 (2015): 367. http://dx.doi.org/10.1071/rj15016.
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Grazed quadrats were monitored on Mileura Station, Western Australia from 1967 to 2013 in order to study the population dynamics of the perennial plants in two of the land systems on the property. Counts of plants on four quadrats at each of 10 sites were made in 1967, 1976, 1990 and 2013, and individual plants were traced for the first three samplings. Five sites were on the Sherwood land system and five on the Belele land system. The results indicated that the populations of some species in the mulga shrubland increased steadily over the 46 years of the study whereas the populations of other species, especially the small, short-lived shrubs, fluctuated over this period. A reduction in stocking rate from 1976 to 1990 was associated with an increase in the population of perennial plants; the total numbers for the 1976 count were 1506 compared with 2102 in 1990. Mean summer rainfall increased between 1990 and 2013 and this increase may have been associated with the recruitment. Overall, the study showed that commercial stocking, although at a lower rate than that recommended by the Western Australian Department of Agriculture, was compatible with increases in the populations of the perennial components of mulga shrubland in this region.
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Curtis, Ellen M., John Gollan, Brad R. Murray, and Andrea Leigh. "Native microhabitats better predict tolerance to warming than latitudinal macro-climatic variables in arid-zone plants." Journal of Biogeography 43, no. 6 (March 3, 2016): 1156–65. http://dx.doi.org/10.1111/jbi.12713.
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Wagner, A., D. A. Devitt, B. Bird, R. Jasoni, and J. A. Arnone III. "Response of Four Shrub Species to Different Water Source Components in an Arid Environment." Environment and Natural Resources Research 8, no. 3 (September 29, 2018): 166. http://dx.doi.org/10.5539/enrr.v8n3p166.
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Shrubland species in the Great Basin (USA) depend on soil water recharged from precipitation and/or groundwater for survival and growth. Climate warming and possible basin water diversion could alter the amount and timing of water availability to these plants. The objective of this study was to quantify the extent to which each of four co-occurring shrub species, big sage [Artemisia tridentata], rabbitbrush [Ericameria nauseosus], greasewood [Sarcobatus vermiculatus] and shadscale [Atriplex confertifolia)) acquired water from different sources (precipitation, soil vadose zone and/or groundwater) during a growing season. Soil salinity increased linearly with depth over the upper 1.5 m of soil, with salinity ranging from 0.84 to 31.70 dSm-1 in saturation extracts (R2=0.78, p<0.001). Changes in soil water both with depth and time during the growing period indicated that all species accessed soil water from precipitation recharge. Evapotranspiration totals for the growing period exceeded total precipitation by 137 mm, indicating that plants also used water stored deeper within the vadose zone and/or from groundwater (particularly) by the phreatophyte greasewood. Delta18O in the soil solution declined linearly with depth over the upper 100 cm (R2=0.80, p<0.001). Delta18O values in greasewood corresponded closely to Delta18O values measured deeper in the vadose zone and groundwater. Output from a mixing model indicated a decrease in groundwater reliance for greasewood from 30% in July to 2% in September, with a major shift to deeper soil water in the vadose zone (180 cm depth) (38% in July to 97% in September). Our data suggested that the four shrub species at our site were able to coexist because of their different spatial, temporal, and physiological uses of available soil water, reflecting possible water resource partitioning based on differences in response to precipitation, ability to extract water at deeper depths and variable tolerance to elevated levels of soil salinity to access groundwater.
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Belitskaya, Maria, and Irina Gribust. "Dendrofagous in the forest reclamation complexes with the participation of introduced tree species in arid zone conditions." SOCIALNO-ECOLOGICHESKIE TECHNOLOGII 9, no. 3 (2019): 343–61. http://dx.doi.org/10.31862/2500-2961-2019-9-3-343-361.
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The problem of optimization of ecological conditions of urbanized and agricultural areas of the arid zone is especially urgent nowadays. Severe forest conditions make it necessary to optimize the environment due to the protective plantations of different types and ecological categories. The use of woody plants unusual for a given area as part of multifunctional stands is one of the main methods for increasing the ecological capacity of the territory, changing the structure and population of insects. The study was conducted in Volgograd, Samara and Rostov regions. By the degree of biotic potential accumulation among the trees adapted in the arid region, plants of the Ulmaceae, Rosaceae and Fabaceae families are distinguished. The introduction of woody vegetation into new territories is also accompanied by the penetration of alien species of pests. Currently, among the phyllophages of woody plants used in landscaping various landscapes, there are invader insects. In urban areas, these species are particularly closely associated with Robinia pseudoacacia L. The most numerous as part of the pests of assimilation apparatus of this plant are Obolodiplosis robiniae (Haldeman, 1847) and Nematus tibialis (Neuman, 1837). Dissemination of Robinia by these insects in the protective forest plantations varies greatly. In the roadside forest plantations and the agroforest plantations in the composition of dendroflora the species of the family Ulmaceae are predominant. Among the invasive species that appeared in them is Aproceros leucopoda (Takeuchi, 1939); in these stands, it almost completely destroys the elm foliage. In the crowns of trees of recreational landscaping, single individuals of this species are found. Among the dendrophages of the stands of urbanized and forest-agrarian landscapes, open-living leaf-eating insects giving outbreaks of mass reproduction (Xanthogaleruca luteola, Dicranura ulmi, Cladius ulmi, Aproceros leucopoda) stand out. Wide spread and increase in the number is observed in Obolodiplosis robiniae and Fenusa ulmi.
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Beudel, Saskia, and Margo Daly. "Gallant Desert Flora: Olive Pink’s Australian Arid Regions Flora Reserve." Historical Records of Australian Science 25, no. 2 (2014): 227. http://dx.doi.org/10.1071/hr14016.
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In the mid-1950s Olive Pink campaigned to have an area of land in Alice Springs set aside as a flora reserve. In 1956 the area was gazetted as the Australian Arid Regions Flora Reserve, with Pink appointed as honorary curator. Although Pink was not a professional horticulturalist or botanist, she established a garden that marked itself out from contemporary gardens, such as Maranoa Gardens and the Australian National Botanic Gardens, which were similarly committed to showcasing indigenous Australian plants. Pink's approach was pioneering in that she aimed to create a collection of plants selected by a delineated ‘climatic zone' and geographic area rather than drawn from all parts of the continent. This article argues that Pink developed a distinctive form of horticultural work informed by her passion for and close artistic observation of desert flora; her long experience establishing and maintaining gardens under central Australian ecological conditions; along with her anthropological insight into Indigenous knowledge of flora gained through her studies with Arrernte and Warlpiri people. Today we might recognize the principles that informed Pink's garden through the concepts of ‘water-wise gardens' and environmental sustainability practices.
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Li, Shuaishuai, Jiahua Zhang, Sha Zhang, Yun Bai, Dan Cao, Tiantian Cheng, Zhongtai Sun, Qi Liu, and Til Prasad Pangali Sharma. "Impacts of Future Climate Changes on Spatio-Temporal Distribution of Terrestrial Ecosystems over China." Sustainability 13, no. 6 (March 10, 2021): 3049. http://dx.doi.org/10.3390/su13063049.
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Understanding the response of terrestrial ecosystems to future climate changes would substantially contribute to the scientific assessment of vegetation–climate interactions. Here, the spatiotemporal distribution and dynamics of vegetation in China were projected and compared based on comprehensive sequential classification system (CSCS) model under representative concentration pathway (RCP) RCP2.6, RCP4.5, and RCP8.5 scenarios, and five sensitivity levels were proposed. The results show that the CSCS model performs well in simulating vegetation distribution. The number of vegetation types would increase from 36 to 40. Frigid–perhumid rain tundra and alpine meadow are the most distributed vegetation types, with an area of more than 78.45 × 104 km2, whereas there are no climate conditions suitable for tropical–extra-arid tropical desert in China. Some plants would benefit from climate changes to a certain extent. Warm temperate–arid warm temperate zone semidesert would expand by more than 1.82% by the 2080s. A continuous expansion of more than 18.81 × 104 km2 and northward shift of more than 124.93 km in tropical forest would occur across all three scenarios. However, some ecosystems would experience inevitable changes. More than 1.33% of cool temperate–extra-arid temperate zone desert would continuously shrink. Five sensitivity levels present an interphase distribution. More extreme scenarios would result in wider ecosystem responses. The evolutionary trend from cold–arid vegetation to warm–wet vegetation is a prominent feature despite the variability in ecosystem responses to climate changes.
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Guzmán-Mendoza, Rafael, Gabriela Castaño-Meneses, and José Alejandro Zavala-Hurtado. "Foraging Activity and Trophic Spectrum of Red AntPogonomyrmex barbatusSmith, 1858, in Productivity-Contrasted Microenvironments." Psyche: A Journal of Entomology 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/942737.
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Foraging strategies can be influenced by many factors such as abundance, availability, and toxicity of the resources. In arid zones, the distribution and productivity of plants also act as additional factors that affect foraging strategies. Twenty colonies ofPogonomyrmex barbatusants were studied in an arid zone of central Mexico to evaluate the trophic niche breadth in two sites with contrasting productivities in terms of their diversity and amount of resources during two seasons. The results suggest that when the resources are abundant as in the rainy season, the trophic niche breadth is reduced in sites with high productivity and, in the same sites, the trophic niche breadth increases when the resources are limited as in the dry season. In contrast, the trophic niche breadth is similar in both conditions of resource availability (i.e., rainy and dry seasons) at sites with low productivity. During the dry season, populations ofP. barbatusshowed a similar foraging behavior in sites with high and low productivity. Thus, the particular characteristics of a site can significantly affect the foraging strategies of the ants in those environments.
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Whitney, Kenneth D. "Evidence for simple genetic control of a fruit-colour polymorphism in Acacia ligulata." Australian Journal of Botany 53, no. 4 (2005): 363. http://dx.doi.org/10.1071/bt04157.
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Fruit-colour polymorphisms are common in nature, but their genetic bases have rarely been examined in wild species. Here, I report on controlled crosses in Acacia ligulata A.Cunn. ex Benth., an Australian arid-zone shrub with a red–yellow–orange aril colour polymorphism. The evidence is consistent with 1-locus, 2-allele control of red v. yellow phenotypes; these phenotypes comprise 98.7% of the adult plants in nature. At this proposed r locus, yellow is dominant to red. Evidence concerning the rare orange morph is limited, but is consistent with models in which orange is produced by either (a) a third allele at the r locus or (b) modification by a second locus. Simple genetic architecture for ecologically relevant traits, such as fruit colour, should aid in linking ecological processes such as frugivory and seed dispersal to the evolutionary trajectories of plant populations.
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Zahra, Noreen. "Phenotypic Plasticity for Growth and Nutrient Uptake in Milk Thistle under Salt Stress: Modulatory Role of Soil Supplementations with Plant Growth Promoters." International Journal of Agriculture and Biology 25, no. 03 (March 1, 2021): 692–700. http://dx.doi.org/10.17957/ijab/15.1718.
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Salinity stress negatively affects key physiological phenomena in plants while plants show great variability and respond differentially for tolerance to salt stress. Usually, nutrients imbalances affect specific plant tissues and physiological processes which are requisite for normal plant growth and development. The aim of this two-year (2017 and 2018) simulated field study was to investigate phenotypic plasticity for growth, relative leaf water content (RLWC) and nutrient status in milk thistle [Silybum marianum (L.) Gaertn.] ecotypes and the potential role of soil supplementation with pre-optimized levels of plant growth promoters (PGPs) in modulating these attributes under control and salinity (12 dS/m) stress. Four ecotypes of milk thistle were collected from three ecologically distinct zones including Faisalabad (FSD) and Kalar Kahar (KK) – semi-arid zone, Gujranwala (GUJ) – hot semi-arid zone and Quetta (QTA) – cool semi-arid zone. The studied nutrients were nitrate-N, phosphate-P, sulfate-S, sodium (Na), potassium (K) and calcium (Ca). The soil supplemented PGPs, applied with irrigation water, were ascorbic acid (AsA), thiourea (TU) and moringa leaf extract (MLE) at 250 μM, 500 μM and 3%, respectively of soil moisture content at field capacity. Results indicated that soil supplementation of PGPs in the field conditions is a feasible approach for enhancing nutrient uptake of milk thistle ecotypes under salt stress, while the effect of salinity stress restricted the uptake of the studied nutrients and caused their imbalance. Although the salinity stress reduced shoot and root dry matter, RLWC and restricted the uptake of these nutrients irrespective of ecotypes, the levels of nitrate-N, phosphate-P, K, sulfate-S, Ca, and RWC contents increased more with the soil supplementation of AsA followed by MLE as compared to other soil supplements in both the study years. Among the ecotypes, QTA followed by KK and FSD ecotypes gained more dry weight with greater leaf RWC and higher tissue nutrient contents due to PGPs under salt stress. The principal component analysis and correlation data revealed the existence of distinct phenotypic plasticity in the milk thistle ecotypes for nutrient acquisition with soil supplementation of PGPs under salinity stress. To conclude, ecotypes from QTA and KK were more promising than the others while AsA and MLE were better soil supplements in improving shoot and root nutrients under salt stress. © 2021 Friends Science Publishers
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Ranieri, E. "Hydraulics of sub-superficial flow constructed wetlands in semi arid climate conditions." Water Science and Technology 47, no. 7-8 (April 1, 2003): 49–55. http://dx.doi.org/10.2166/wst.2003.0670.
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This paper reports the evaluation of the hydraulics of two constructed wetland (cws) plants located in Apulia (the South Eastern Italy region characterized by semi arid climate conditions). These fields were planted with Phragmites australis hydrophytes and are supplied with local secondary wastewater municipal treatment plant effluent. Each plant - Kickuth Root-Zone method based - covers an area of approx. 2,000 m2. The evapotranspiration phenomenon has been evaluated within perforated tubes fixed to the field bottom and very high values - up to 40 mm/d - were found. Hydraulic conductivity has been evaluated by in situ measurements at different field points. Hydraulic gradients and the piezometric curve within the field are also reported.
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Irmak, Suat, Ali T. Mohammed, William Kranz, C. D. Yonts, and Simon van Donk. "Irrigation-Yield Production Functions and Irrigation Water Use Efficiency Response of Drought-Tolerant and Non-Drought-Tolerant Maize Hybrids under Different Irrigation Levels, Population Densities, and Environments." Sustainability 12, no. 1 (January 2, 2020): 358. http://dx.doi.org/10.3390/su12010358.
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Irrigation-yield production functions (IYPFs), irrigation water use efficiency (IWUE), and grain production per unit of applied irrigation of non-drought-tolerant (NDT) and drought-tolerant (DT) maize (Zea mays L.) hybrids were quantified in four locations with different climates in Nebraska [Concord (sub-humid), Clay Center (transition zone between sub-humid and semi-arid); North Platte (semi-arid); and, Scottsbluff (semi-arid)] during three growing seasons (2010, 2011, and 2012) at three irrigation levels (fully-irrigated treatment (FIT), early cut-off (ECOT), and rainfed (RFT)) under two plant population densities (PPDs) (low-PPD; 59,300 plants ha−1; and, high-PPD, 84,000 plants ha−1). Overall, DT hybrids’ performance was superior to NDT hybrid at RFT, ECT, and FIT conditions, as confirmed by the yield response, IYPF and IWUE when all locations, years, and PPDs were averaged. The yield response to water was greater with the high-PPD than the low-PPD in most cases. The magnitude of the highest yields for DT hybrids ranged from 7.3 (low-PPD) to 8.5% (high-PPD) under RFT, 3.7 (low-PPD) to 9.6% (high-PPD) under ECOT, and 3.9% (high-PPD) under FIT higher than NDT hybrid. Relatively, DT hybrids can resist drought-stress conditions longer than NDT hybrid with fewer penalties in yield reduction and maintain comparable or even higher yield production at non-stress-water conditions.
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Wright, Boyd R., and Peter J. Clarke. "Germination biologies and seedbank dynamics of Acacia shrubs in the Western Desert: implications for fire season impacts on recruitment." Australian Journal of Botany 66, no. 3 (2018): 278. http://dx.doi.org/10.1071/bt18003.
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In arid Australia, fires in different seasons often result in markedly different recruitment rates of woody plants, and this can have important and long-lasting impacts on post-fire community structure and composition. The current study investigated ecological mechanisms behind this effect in four widespread arid Acacia species: Acacia aptaneura, Maslin & J.E.Reid Acacia kempeana F.Muell., Acacia maitlandii F.Muell. and Acacia melleodora Pedley. Specifically, the study examined whether increased recruitment after summer compared with winter burning relates to (1) higher soil temperatures during summer fires having increased capacity to overcome dormancy of seeds with heat-stimulated germination; (2) warmer soil temperature conditions after summer fires providing more favourable incubation temperatures for germination; and/or (3) summer fires coinciding with seasonal fluxes in seedbank densities, which may occur in response to granivory and/or rapid rates of seed deterioration after dispersal. Results supported hypotheses (1) and (2), as germination of all species responded positively to heat shock and warmer incubation temperatures. Some support was also demonstrated for hypothesis (3), as seedbank densities were shown to fluctuate seasonally, most likely in response to strong granivory. This multi-species study provides insights into mechanisms behind enhanced shrub recruitment after arid zone summer fires; and reinforces the notion that season of burn can be a strong determinant of regeneration trajectories of woody plants after fire.
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MIGHRI, HEDI, AHMED AKROUT, JOSEPH CASANOVA, FELIX TOMI, and MOHAMED NEFFATI. "IMPACT OF SEASON AND HARVEST FREQUENCY ON BIOMASS AND ESSENTIAL OIL YIELDS OF ARTEMISIA HERBA-ALBA CULTIVATED IN SOUTHERN TUNISIA." Experimental Agriculture 45, no. 4 (August 27, 2009): 499–508. http://dx.doi.org/10.1017/s0014479709990445.
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SUMMARYArtemisia herba-alba Asso has been successfully cultivated in the Tunisian arid zone. However, information regarding the effects of the harvest frequency on its biomass and essential oil yields is very limited. In this study, the effects of three different frequencies of harvesting the upper half of the A. herba-alba plant tuft were compared. The harvest treatments were: harvesting the same individual plants at the flowering stage annually; harvesting the same individual plants at the full vegetative growth stage annually and harvesting the same individual plants every six months. Statistical analyses indicated that all properties studied were affected by the harvest frequency. Essential oil yield, depended both on the dry biomass and its essential oil content, and was significantly higher from plants harvested annually at the flowering stage than the other two treatments. The composition of the β- and α-thujone-rich oils did not vary throughout the experimental period.
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Grebennikov, Vadim, Ivan Shipilov, and Olesya Khonina. "Photosynthetic activity and agro-energy efficiency of growing perennial grasses under different modes of use of the grass stand." Agrarian Bulletin of the 198, no. 7 (July 31, 2020): 2–11. http://dx.doi.org/10.32417/1997-4868-2020-198-7-2-11.
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Abstract. The purpose of research is to study the adaptability and stability of new varieties and species of perennial grasses under different modes of use of grass (hay, pasture), aimed at reducing the dependence of their productivity on fluctuations in agrometeorological conditions in the arid zone. The research is based on the methods of designing grasslands adapted to extreme conditions of the arid zone and capable of withstanding temperature, water, and coenotic stresses due to morphophysiological reactions of plants. Results and practical significance. The most productive eco-plastic grass mixtures of new varieties of perennial legumes and grasses that are necessary for creating agrophytocenoses for target use have been identified. Correlative relationships of the productivity level of the species and variety with the physiological parameters of plants were established. The role of the phytocenotic factor that characterizes the relationship of plants in different modes of use of grass (haymaking, pasture) is determined and patterns in the dynamics of accumulation of crop biomass by grass mixtures of different botanical composition are established. The highest biomass on average for 4 years was formed by crops in the mode of haymaking use of grass (alfalfa + wheat grass + brome + sainfoin + melilot – 3.07 t/ha of dry matter). For pasture use, on average, over 4 years, the highest productivity was provided by a grass mixture – alfalfa + fairway + brome + wheatgrass + festulolium + sainfoin + melilot with a collection of 1.5 t/ha of dry matter and 9.6 GJ/ha of exchange energy for a net energy income of 8.7 GJ/ha. Scientific novelty. For the first time for the conditions of the dry-steppe zone, an adaptive approach to the creation of productive stands of perennial grass mixtures with the participation of new varieties and species of legumes and grasses, revealing the mechanism of plant interaction based on the developed optical structure of phytocenosis in different modes of forage use (haymaking, pasture), is proposed.
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Mehalaine, S., O. Belfadel, T. Menasria, and A. Messaili. "Chemical Composition and Antibacterial Activity of Essential Oils of Three Medicinal Plants from Algerian Semi-Arid Climatic Zone." Phytothérapie 16, S1 (December 2018): S155—S163. http://dx.doi.org/10.3166/phyto-2019-0150.
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The present study was carried out to determine, for the first time, the chemical composition and antibacterial activity of essential oils derived from the aerial parts of three aromatic plants Thymus algeriensis Boiss & Reut, Rosmarinus officinalis L., and Salvia officinalis L. growing under semiarid conditions. The essential oils were chemically analyzed and identified by gas chromatography (GC) and GC/ mass spectrometry (GC/MS) and their antimicrobial activity was individually evaluated against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using both agar disk diffusion and agar dilution methods. The major constituents of Thymus algeriensis essential oil were identified as camphor (13.62%), 1,8-cineol (6.00%), borneol (5.74%), viridiflorol (4.00%), and linalool (3.93%). For Rosmarinus officinalis essential oil, 48 compounds were characterized, of which the main constituents were camphor (17.09%), Z-β-ocimene (10.88%), isoborneol (9.68%), α-bisabolol (7.89%), and borneol (5.11%). While, Salvia officinalis essential oil was characterized by β-thujone (16.44%), followed by viridiflorol (10.93%), camphor (8.99%), 1,8-cineol (8.11%), trans-caryophyllene (5.85%), and α-humulene (4.69%) as the major components. Notably, results from antibacterial screening indicated that Thymus algeriensis and Salvia officinalis essential oils exhibited a strong inhibitory effect against both Escherichia coli and Staphylococcus aureus compared to Rosmarinus officinalis essential oil. Further, less activity was recorded against Pseudomonas aeruginosa for the three tested essential oils.
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Schmidt-Lebuhn, Alexander N., and Kiarrah J. Smith. "From the desert it came: evolution of the Australian paper daisy genus Leucochrysum (Asteraceae, Gnaphalieae)." Australian Systematic Botany 29, no. 3 (2016): 176. http://dx.doi.org/10.1071/sb16012.
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Present patterns of diversity in the Australian flora have been shaped by increasing seasonality since the Eocene, and by pronounced aridification in the past 3 million years. Arid-zone plants are commonly hypothesised to be the products of radiations of ancestrally temperate or coastal lineages, as in the case of the everlasting paper daisy tribe Gnaphalieae (Asteraceae). However, these inferences are often based on higher-level phylogenies, whereas evolutionary processes in the Australian Gnaphalieae have rarely been studied at the species level. Here, we reconstructed the phylogeny and biogeographic history of the small, but ecologically diverse, paper daisy genus Leucochrysum, to examine recent habitat shifts and character changes, at the same time exploring the feasibility of using amplicon sequencing of low-copy nuclear gene regions to resolve phylogenetic relationships in Australian Gnaphalieae. On the balance of evidence, outgroup comparison and ancestral-area reconstruction support an ancestral range in the arid zone with subsequent diversification towards the south-east, demonstrating a complex evolutionary history with a re-colonisation of temperate areas. Low amplification success rates suggest that methods other than amplicon sequencing of currently available primers will be more promising for molecular phylogenetic work at a larger scale.
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Chesterfield, CJ, and RF Parsons. "Regeneration of Three Tree Species in Arid South-Eastern Australia." Australian Journal of Botany 33, no. 6 (1985): 715. http://dx.doi.org/10.1071/bt9850715.
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Grazing effects by introduced mammals on tree seedlings in the arid zone have caused concern for the long-term future of some tree species. This was investigated by measuring stem girths of Casuarina cristata Miq., Heterodendrum oleifoliurn Desf. and Myoporum platycarpum R.Br. in arid-zone wood- lands. Episodic seedling regeneration of Myoporum is inferred following series of wet years in the 1950s and 1970s. Although young Myoporum plants appear unpalatable to stock, regeneration may be sup- pressed by rabbit-grazing in some areas. Almost no Heterodendrurn seedlings were found but suckering was common after burning and clearing. This species is highly palatable to grazing mammals and suckers may grow to safety above the browse line only where stock are absent. Evidence for recent Casuarina seedling regeneration was limited to one cohort, on a site that had been flooded. While suckers can be found locally where surface roots become exposed, suckering appears insufficient to perpetuate many Casuarina stands. Mammal-grazing seems important in strongly limiting regeneration. While Casuarina and Heterodendrum stand densities decline due to natural senescence and occasional fire, the only species regenerating into gaps is Myoporum. There is concern for the future of Casuarina and Heterodendrum, given their widespread failure to regenerate despite the wettest 3 years ever recorded, in 1973-75. On pastoral land, at least 10 years without stock-grazing might be needed for successful regeneration of Heterodendrurn. In reserves, some nature conservation programs for woodlands might require virtual eradication of all exotic mammalian herbivores, including goats.