Dissertationen zum Thema „Plant“

Today, obesity has become the number one concern of kids and teens. About one in three Americans are overweight or obese. This in part is due to the consumption of highly commercialized and processed foods that lack the essential nutrients in maintaining a healthy weight in addition to normal cholesterol and blood pressure levels. Studies have shown that eating habits are learned early in life and are carried on throughout the rest of their lives. As children grow older into their adolescent years, they are more aware of their eating habits and have gained more autonomy in regards to food choices.

Plant-based foods have shown to drastically improve the overall health of individuals with high cholesterol, high blood pressure, and excess weight.

Power Plant is a facility that intends offer plant-based nutritional services in the form of informative lectures, interactive workshops, one-on-one nutritional guidance by appointment, with access to peer-mentors for additional support and guidance. Power Plant will dedicate their services to the Whittier Union high school district, surrounding community colleges, and universities in the Los Angeles County area.

Power Plant’s unique program design, physician referrals and the critical need of our generations to come, are all factors that will contribute to its success in the Los Angeles County community and for years to come.

Thesis (D. Sc.)--Faculty of Science, University of Adelaide, 1990.
Published works [representing] original research conducted during the various phases of [his] academic development--Pref. Includes bibliographical references.

Revised; Originally Published: 2000
8 pp.
Whether you are beginning a new landscape or renovating an existing one, planning ahead can prevent many problems. The majority of maintenance requirements and plant problems result from either selecting the wrong kind of plant for a location or planting an inferior specimen of the selected plant type. In other words, there are two decisions to be made: ▪ What species, or kind, of tree are you going to buy — an oak, pine, mesquite, or acacia? ▪ Assuming you decide on an oak, which one in the row of oaks at the nursery are you going to buy? The first decision is called Plant Selection and the second is Selecting Plants. Our goal is to install the right plant in the right place. This publication will cover the factors involved in making good decisions to achieve this goal.

8 pp.
The majority of maintenance requirements and plant problems result from either selecting the wrong kind of plant for a location or from planting an inferior specimen of the selected plant type. The first decision is called Plant Selection and the second one is Selecting Plants. This publication covers the factors involved in making good decisions to install the right plant in the right place.

En aquesta tesi presento quatre capítols, en els quals es discuteix com diferents espècies subarbustives interactuen amb plantes coexistents, sota règims variables d’estrès. Aquesta recerca ha estat centrada en ecosistemes de gran valor ambiental, ecològic i de conservació, i alhora sensibles als canvis ambientals, en quatre regions distintes situades en zones de latitud o altitud elevades. Per ordre latitudinal, els ecosistemes estudiats han estat: 1) el límit supraforestal dels Pirineus Centrals, situats en una zona temperada; 2) el gradient de successió primària d’un ecosistema situat en una zona boreal, a Finlàndia,; 3) el límit supraforestal situat a la zona subàrtica de Lapònia; i 4) la tundra situada en una zona de l’alt àrtic, al nord‐est de Grenlàndia . Els dos primers capítols es basen en una aproximació experimental i se centren en investigar com els subarbustos més comuns trobats prop del límit supraforestal interactuen amb plançons d’arbres de les espècies que formen el límit del bosc en dos ambients contrastats, i.e. el límit supraforestal subàrtic, i el límit supraforestal dels Pirineus Centrals. A més, donat que els arbres que viuen prop del límit de distribució són molt sensibles als canvis ambientals , especialment a l’augment de temperatures durant l’estació de creixement (Körner 2003), també s’ha investigat com podrien afectar el creixement dels plançons d’arbre i la seva supervivència al llarg de l’ecotò, diferents escenaris de canvis ambientals. El primer capítol es titula ‘Les interaccions arbre‐arbust i els canvis ambientals dirigeixen la dinàmica supraforestal a la zona subàrtica’, i s’hi exposa l’experiment de tres anys de durada que es va executar al ‘Parc Nacional d’Abisko’, en els Scandes subàrtics, al nord de Suècia; les plantes estudiades varen ser plançons de Betula pubescens i el subarbust Vaccinium myrtillus. En aquest estudi es va certificar la importància de les interaccions arbust‐arbre, tant facilitatives com competitives, com a elements clau en la dinàmica supraforestal subàrtica. A més, vàrem demostrar que la gran sensibilitat dels plançons a l’escalfament tenia fortes implicacions per la dinàmica supraforestal, tenint en compte l’escenari previst d’augment de temperatures en latituds elevades. També es va observar que les interaccions complexes entre arbusts i herbívors són claus per preveure canvis futurs. El segon capítol es titula ‘Els plançons d’arbres situats als límits supraforestals Pirinencs i subàrtics mostren respostes semblants a la presència d'arbustos i a les simulacions de canvis ambientals’. Aquí es presenta una comparació entre els resultats de l’experiment presentat en el primer capítol i els obtinguts en un experiment paral∙lel dut a terme durant un període de temps semblant prop del límit supraforestal en el ‘Parc Natural de l’Alt Pirineu’, als Pirineus Centrals catalans. Aquest experiment es va basar en el mateix disseny factorial que l’anterior estudi, però amb diferents espècies (i.e. plançons de l’arbre Pinus uncinata i l’arbust Rhododendron ferrugineum). Segons ens consta, és el primer estudi que avalua experimentalment les respostes de les plantes vers diferents escenaris ambientals en un ecosistema d’alta muntanya als Pirineus. En aquest capítol es presenten alguns mecanismes que ajudaran a comprendre la variabilitat recentment observada de les respostes locals de límits supraforestals de zones temperades i subàrtiques com a resultat del clima canviant, i també identifiquem alguns paral∙lelismes que poden utilitzar‐se per generalitzar les respostes a gran escala dels límits supraforestals al canvi climàtic. El tercer capítol se centra en els efectes d’un subarbust dominant (i.e. Empetrum nigrum) en plançons de Pinus sylvestris al llarg del gradient de successió primària en un ecosistema boreal en una illa emergent de la badia de Bòtnia, a Finlàndia. Aquest capítol s’anomena ‘Un arbust ericoide exerceix la doble funció de reclutar pins i els seus simbionts fúngics al llarg d’un gradient de successió primària’. Aquí hem mostrat que els efectes facilitadors i competidors dels subarbustos determinen fortament l’establiment de plançons i la seva colonització fúngica al llarg d’aquest gradient de successió. Segons ens consta, aquests són els primers resultats que demostren que un arbust ericoide micorrízic pot millorar tant el desenvolupament de l’arbre hoste ectomicorrízic com el dels simbionts fúngics de l’arbre. L’estudi presentat al quart capítol es va realitzar al llarg d’un gradient de nivositat en un ecosistema extrem de tundra àrtica al ‘Parc Nacional del nord‐est de Grenlàndia’, el Parc Nacional més gran del món. El capítol es titula ‘Interaccions vegetals i composició de la vegetació àrtica al llarg d’un gradient de nivositat al nord‐est de Grenlàndia’. Aquest ecosistema és probablement el més sensible i fràgil de tots els ecosistemes estudiats en aquesta tesi, donat que s’espera que a la costa est de Grenlàndia s’hi esdevinguin canvis substancials en el clima com a resultat de canvis destacables en els règims de precipitació de neu i de les temperatures (Brown i Mote 2009). Aquí es va avaluar la riquesa d’espècies de plantes, així com els patrons d’establiment i composició de diverses formes de creixement existents en comunitats vegetals àrtiques associades a una variació de la cobertura de neu durant els mesos d’hivern. Aquest estudi ajudarà a preveure la diversitat potencial i els canvis en la vegetació a la zona de l’alt Àrtic, si els règims de precipitació de neu canvien en el futur com es preveu.
In this thesis I present four chapters, and in all of them I discuss how dwarf shrubs interact with co‐occurring plants under varying regimes of stress. This research involved ecosystems of great environmental, nature conservation and ecological value, yet highly sensitive to environmental changes, in four contrasting cold regions at high altitude or high latitude. Following a latitudinal order, the selected ecosystems were: 1) a temperate alpine treeline in the Central Pyrenees; 2) a primary succession gradient in a boreal ecosystem in Finland; 3) a subarctic alpine treeline in Lapland; and 4) a high‐arctic tundra in north‐eastern Greenland. The first two chapters are based on an experimental approach and focus on how shrubs commonly found near the treeline interact with tree seedlings of treelineforming species in two contrasting environments, i.e. in a subarctic forest‐tundra ecotone in Lapland, northern Sweden, and in a more southern, temperate forestalpine pasture ecotone in the Central Pyrenees. In addition, since trees living near their limit of distribution are very sensitive to environmental changes, especially to increased temperature during the growing season (Körner 2003), we also assessed how distinct environmental change scenarios may affect tree seedling growth and survival across the ecotone. The first chapter is entitled ‘Shrub‐tree interactions and environmental changes drive treeline dynamics in the Subarctic’, where we explain the three‐year‐long experiment performed in the Abisko National Park, in the subarctic Scandes, Northern Sweden; the species studied were Betula pubescens tree seedlings and the shrub Vaccinium myrtillus. In this study we showed the importance of facilitative and competitive shrub‐tree interactions as drivers of subarctic treeline dynamics. Furthermore, we demonstrated that the great sensitivity of tree seedlings to warming had strong implications for treeline dynamics under the predicted warmer scenario at high latitudes, and we identified that complex interactions between shrubs and herbivores are critical to predicting future changes. The second chapter is entitled ‘Similar tree seedling responses to shrubs and to simulated environmental changes at Pyrenean and subarctic treelines’. Here we presented a comparison between the results obtained in the experiment presented in the first chapter and those obtained in a parallel experiment performed during a similar period near the treeline in the Alt Pirineu Natural Park, in the Central Pyrenees, Catalonia. This experiment was based on the same factorial design but with different species (i.e. Pinus uncinata tree seedlings and the shrub Rhododendron ferrugineum). To our knowledge, it is the first study which experimentally tests the responses of plants to distinct environmental scenarios in a high mountain ecosystem in the Pyrenees. In this chapter we presented some mechanisms for understanding the recently observed variability of local responses of both subarctic and alpine treelines to currently changing climate while identifying some commonalities that can be used to generalise large scale response of treelines to climate warming. The third chapter focuses on the effects of a dominant dwarf shrub (i.e. Empetrum nigrum) on Pinus sylvestris tree seedlings along a primary succession within a boreal ecosystem on an uplifting island in Bothnian Bay, Finland. This chapter is called ‘An ericoid shrub plays a dual role in recruiting both pines and their fungal symbionts along primary succession gradients’. Here we showed that facilitative and competitive effects of shrubs markedly determined tree seedling establishment and their fungal colonisation along this succession gradient, but in this chapter we did not relate these findings to any environmental changes. As far as we know, we presented the first finding that an ericoid mycorrhizal shrub may enhance both the performance of the ectomycorrhizal host tree and the tree’s fungal symbionts. The study presented in the fourth chapter was performed along a snow‐depth gradient in an extreme arctic tundra ecosystem in the Northeast Greenland National Park, the largest national park in the world. The chapter is entitled ‘Plant interactions and higharctic vegetation composition along a snow‐depth gradient in NE Greenland’. This ecosystem is probably the most sensitive and fragile among the ecosystems studied in this thesis as the eastern coast of Greenland is expected to experience substantial changes in climate due to marked changes in snow precipitation and temperature regimes (Brown and Mote 2009). Here we assessed plant species richness, establishment and composition patterns in distinct growth forms occurring in common arctic plant communities associated with varying snow‐depth during the winter season. This study will help to predict potential diversity and vegetation changes in the high Arctic if snow precipitation regime changes in the future as anticipated.

26 pp.
Geographically, Arizona can be divided roughly into four areas, southwest, central, southeast, and northern. These regions correspond with four climatic zones, allowing a large and diverse number of plants to be grown for landscaping purposes. But, interestingly, in this desert environment many of the parasitic diseases in landscape plants are caused by a limited number of plant pathogens. This publication discusses some of those diseases that are sufficiently important to the urban plants in all areas Arizona.

This research explored fate of organic contaminants in aquatic plant systems through (i) experimental development of relationships to describe sorption, uptake and enzymatic processing of contaminants by plants and inhibition of aquatic plants by contaminants and (ii) incorporation of experimental relationships into a conceptual model which describes contaminant fate in aquatic plant systems. This study focused on interactions of aquatic plants L. minor and M. aquaticum with halogenated phenols. 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4-dichlorophenol (2,4-DCP) are precursors for the highly toxic and heavily applied herbicides 2,4,5-T and 2,4-D and were examined in detail. Chlorophenols are generally resistant to microbial degradation, a property which may limit microbial remediation options as effective alternatives for clean up of contaminated sites. Relationships for fundamental interactions between plants and contaminants that dictate uptake, enzymatic processing and sequestration of contaminants by aquatic plants were established. An assay which quantified production of oxygen by plants was developed to quantify plant metabolic activity and inhibition. Uptake of chlorinated phenols depended on plant activity and aqueous phase concentration of contaminant in the protonated form. Therefore, plant activity, contaminant pKa and media pH were established as critical parameters controlling rate of contaminant uptake. A conceptual model was developed which incorporated plant activity and inhibition into a mathematical description of uptake of organic contaminants by aquatic plants. The conceptual model was parameterized using experimental data delineating effect of plant activity, inhibition and speciation on contaminant uptake and the model was verified using independently gathered data. Experimentation with radio-labeled chlorinated phenols established that contaminants were sequestered internal to plants by plant enzymatic processing. 19F NMR was established as a technique to quantify transformation and conjugation products internal to plants and contaminant assimilation by plants and demonstrated that multiple metabolites containing the parent compound were present and quantifiable internal to plants. Finally, fate of plant-sequestered contaminants in an anaerobic bioassay was examined using Desulfitobacterium sp. strain Viet1. The results of this study address the role of aquatic plants in sequestration of contaminants in surface waters that indicate the potential and limitations of use of aquatic plants in natural and engineered treatment systems.

Two phytochrome-like gene fragments have been isolated using a degenerate PCR strategy from the fern Pteridium aquilinum (bracken). Both share a high degree of similarity with each other and to previously isolated phytochromes. In an attempt to isolate larger phytochrome gene fragments and full length phytochrome genes a cDNA library was constructed from light-grown young bracken fronds. The library was screened with one of the bracken phytochrome fragments. The low level of abundance of phytochrome message, however, hindered the isolation of phytochrome genes from the cDNA library. The high degree of sequence homology between lower and high plant phytochromes has led to speculation on whether or not lower plant phytochromes can be functional in higher plants. This speculation can be addressed by expressing the lower plant phytochromes transgenically in higher plants and assaying for biological function. Arabidopsis thaliana ecotype Landsberg erecta has been transformed using an Agrobacterium mediated root explant transformation system with a phytochrome-like gene isolated from the fern Anemia phyllitidis. The phytochrome gene, PHY3 was placed under the control of a double 35S cauliflower mosaic virus (CaMV) promoter. A second construct has also been used to transform Arabidopsis containing the NH2-terminal half of Anemia PHY3 gene fused to the C-terminal half of oat PHYA. This construct was also attached to a CaMV promoter. Expression of these two constructs causes a reduction in sensitivity of the seedlings to continuous FR. This decreased sensitivity results in a long hypocotyl phenotype under FR, a reduction in anthocyanin production in FR and an inability of FR to block greening. The transgenic lines, however, showed a WT response to VLF light. It is apparent that the expression of the Anemia PHY3 gene is, in some way, interfering with the normal transduction of the phyA signalling pathway. The interference is restricted to the FR HIR.

The breakdown of the traditional rigid distinction between ‘hunter-gatherers’ and ‘farmers’ has lead to increased interest into the different types of human-plant relationships that existed in hunter-gatherer and early farming societies during the Mesolithic-Neolithic transition. This thesis assesses the scale and nature of human-plant exploitation in Mesolithic and Neolithic Scotland. Following Zvelebil (1994), several plant exploitation models are tested using palaeobotanical evidence: 1) opportunistic and incidental wild plant use; 2) systematic and intensive wild plant use; 3) wild plant food management, husbandry or cultivation; 4) the cultivation of domestic plants. It is concluded that wild plant exploitation was most probably systematic and intensive in Mesolithic Scotland, but there is no clear-cut evidence to substantiate the suggestion that Mesolithic hunter-gatherers managed wild plants. The relative importance of wild and domestic plants in the Neolithic economy is difficult to establish due to differences in the deposition, preservation, recovery and recording of cereals and wild plants. However, the importance of agriculture in the economy appears to have varied considerably between different sites and areas. In the Northern Isles and Outer Hebrides, settled agricultural communities were present and wild plant collection was insignificant. In contrast, a mixed plant subsistence economy based on both wild plant collection and cereal cultivation was probably the predominant subsistence strategy in mainland Scotland, though it appears that some apparently contemporary groups cultivated cereals on a large-scale, and others primarily focused on the collection of wild plants. The absence of cereals in assemblages from the Inner Hebrides and the West coast mainland suggests a greater degree of continuity in Mesolithic and Neolithic subsistence strategies in this area than elsewhere in Scotland. Differences in the importance of arable agriculture in each region may reflect the density of settlement in the Mesolithic and the natural availability of wild resources in the environment.

Recent preliminary data have suggested that microbe-to-plant signals, and plant internal signals elicited by microbial signals, affect aspects of plant physiology, development and growth. The reported research investigated the responses of plants to signal compounds of microbial and plant origin, such as lipo-chitooligosaccharides (LCOs - signal molecules in rhizobia-legume associations), chitin and chitosan (present in fungal cell walls), and phenolic compounds (salicylic acid, acetylsalicylic acid and gentisic acid - internal signals in plants, often affected by signals from microbes). Phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) are key enzymes of the phenylpropanoid pathway. Oligomers of chitin and chitosan increased the activities of both PAL and TAL in soybean leaves. The degree of increase was dependent on oligomer chain length and time after treatment. LCO [Nod Bj V (C18:1 , MeFuc)] was isolated from Bradyrhizobium japonicum strain 532C. When Arabidopsis thaliana plants were grown for two weeks on agar containing this LCO (10-8M) or chitin pentamer (10-4 M), they had greater root length, root diameter, root surface area and number of root tips than control plants. Chitosan (tetramer and pentamer) did not have this effect. Chitin and chitosan were also tested for effects on corn and soybean photosynthetic rates and growth. High molecular weight chitosan generally reduced photosynthetic rates, but did not reduce the growth of corn or soybean. However, foliar application of 10-6 M LCO to corn leaves increased photosynthetic rates (up to 36%). Foliar application of lumichrome (10-5 and 10-6 M), a breakdown product of riboflavin produced by some rhizosphere bacteria, to corn (C4 plant) and soybean (C3 plant) increased photosynthetic rates (up to 6%). Foliar application of lumichrome (10-5 M) increased soybean leaf area and shoot dry weight. Foliar application of SA, acetyl salicylic acid (ASA) and gentisic acid (GT

Plant microRNAs have been shown to have important roles in regulating diverse processes ranging from reproductive development to stress response. In the first two chapters, I focus on miRNA diversity in Aquilegia studying both anciently evolved broadly conserved and rapidly evolving species specific miRNAs. In chapter one, I utilize Aquilegia's critical phylogenetic position between the well developed models Arabidopsis thaliana and Oryza sativa to study the evolution of ancient miRNAs across the angiosperms. In chapter two, I utilize smallRNA high-throughput sequencing to annotate Aquilegia specific miRNAs and, in the process, uncover the novel regulation of a floral homeotic gene by an Aquilegia-specific miRNA. In chapter three, I look at the tissue specific development of miRNA regulation in the bioenergetically relevant model organism Populus trichocarpa. High-throughput smallRNA sequencing from four diverse tissue sets including leaves, xylem, mechanically treated xylem, and pooled vegetative and reproductive tissues were analyzed, revealing a total of 155 previously unannotated miRNAs, most of which are P. trichocarpa specific. Expanding on my work with the petal identity pathway, I turned a broader analysis of Aquilegia petal spurs. Petal spurs are the distinguishing characteristic of Aquilegia and are argued to be a key innovation in the adaptive radiation of the genus. In the fourth chapter, I explore the cellular basis of extreme spur length diversity in the genus and find that a single parameter, cell shape, can explain this morphological range. Next, I seek to describe the cellular patterns that give rise to a spur primoridia from an initially flat laminar petal and find that spur initiation is characterized by concentrated, prolonged, and oriented cell divisions. Inspired by this quantitative analysis of growth, chapter five looks at the mechanisms of shape change in cucumber tendrils. I find that anisotropic contraction of a multi-layered gelatinous fiber ribbon explains coiling in cucumbers. Surprisingly, we discover that tendrils display twistless-overwinding when pulled and exhibit an unforeseen force-extension response as a result. These results provide the design basis for twistless springs with tunable mechanical responses and serve as a clear example of how the biological systems can inspire applied mechanical designs.

Protein farnesyltransferase (FTase, E. C. 2.5.1.21) post-translationally modifies regulatory proteins involved in controlling cell growth, division, and differentiation. Recently, a cDNA clone (PsFTb) encoding a pea (Pisum sativum) FTase b subunit was isolated. Initial studies led to the hypothesis that FTase plays a role in the regulation of plant cell division. To gain insight into FTase function in plants, a detailed study of the expression pattern of FTase genes was carried out. A cDNA (NgFTb) encoding the b subunit of tobacco FTase was cloned from a Nicotiana glutinosa cDNA library to initiate studies in tobacco. In tobacco BY-2 suspension culture, levels of NgFTb mRNA and FTase activity transiently increased at the early log phase of cell growth and rapidly declined before cells entered stationary phase. These data, along with inhibitor studies in the BY-2 system, support our hypothesis. To understand the expression and regulation of pea FTase subunit genes, 5'-upstream sequences of both pea FTase subunit genes (PsFTb and PsFTa) were cloned from a pea genomic library. The 5'-upstream sequence (~2 kb) of PsFTa was fused to GUS (b-glucuronidase) and GFP (green fluorescent protein) reporter genes and introduced into tobacco plants. This 2 kb upstream region appears insufficient to provide PsFTa promoter function. On the other hand, 3.2 kb of PsFTb 5'-upstream sequence expressed as a PsFTb:GUS construct is fully functional in transgenic tobacco plants. GUS expression was most prominent in actively growing cells supporting FTase involvement in plant cell cycle control. GUS activity was also found in mature and imbibed embryos but not premature embryos, consistent with the role of FTase in abscisic acid (ABA) signaling. An unexpected pattern of GUS activity, not correlated with dividing cells or ABA signaling, was also observed in the transgenic plants. GUS activity was detected in vascular bundles adjacent to actively-growing tissues and in regions that connect two organs, e.g., junctions between stems and leaf petioles, cotyledons and hypocotyls, roots and hypocotyls. Auxin promotes PsFTb expression while light and sucrose inhibit expression. These spatial and temporal expression patterns strongly suggest that FTase has a broader role associated with regulation of nutrient transportation or allocation in plants.
Ph. D.

As the global population rises, the demand for food increases which underscores a need for improvement in food security. Disease pressures are a major concern surrounding sustainable agriculture. Static crop populations, containing little to no genetic diversity, are vulnerable to diverse pathogen populations. Wild relatives of crop plants are a reservoir for new disease resistance traits that can be introgressed into cultivated crops. The identification of novel disease resistance is of paramount importance because pathogen co-evolution is not only defeating current resistance genes (R genes) but chemical controls as well. Phytophthora sojae (P. sojae), the causal agent of Phytophthora root and stem rot disease, reduces soybean harvests worldwide. We developed an approach to screen for new R genes that recognize core effectors from P. sojae. We expect R genes identified by these screens to be durable because P. sojae requires core effectors for virulence. We utilized effector-based screening to probe Glycine soja germplasm with core RXLR effectors from P. sojae to search for novel R genes. We developed segregating populations from crosses of P. sojae resistant G. soja germplasm with susceptible G. max cultivar Williams to determine inheritance of potential R genes in germplasm that responded to core effectors. We are using marker assisted breeding to map disease resistance traits in recombinant inbred (RI) lines. To better understand pathosystems, we examined host resistance and susceptibility using bioinformatics. We analyzed the interaction between Arabidopsis thaliana ecotype Col-0 and Hyaloperonospora arabidopsidis isolate Emwa1 using a publicly available RNA time-course experiment. We describe a new algorithm to sort genes into time-point specific clusters using activation and repression parameters. Gene ontology annotations were used to identify defense genes with unique expression profiles, and A. thaliana null mutants for these genes were significantly more susceptible to Emwa1 than wild-type. We plan to use these tools to rapidly identify and guide introgression of durable disease resistance into crop species.
Ph. D.

The hexagons on a pineapple contrast with the ribs observed, for example, on pumpkins or saguaro cacti. This dissertation demonstrates how these various configurations, and also the related patterns of phyllotaxis (the arrangement of leaves into whorls or spirals) can be understood as the energy-minimizing buckling pattern of a compressed shell (the plant's tunica) on an elastic foundation. The key new idea is that the elastic energy is minimized by special triads or sequences of triads of periodic deformations whose local wavevectors add to zero. Although triad configurations arise from a variety of microscopic mechanisms in natural and laboratory systems, we show that the particular choices of wavevectors that are observed on plants arise in a nontrivial way from properties specific to a mechanical model. Furthermore, the theory predicts correlations between types of phyllotaxis and shapes of plant surface configurations and suggests experiments that can further test the mechanical theory of plant pattern formation. The dissertation concludes with a derivation of Cross-Newell equations governing pattern formation far from onset in nonisotropic systems and in systems with hexagonal planforms.

The "POWER - PLANT" deals with the rehabilitation of the former Central Power Conversion and Dale Schoeller (Nejedly I and III) in the village Libušín Mine. Will be newly designed for building the power plant technology with progressive fluidized bed boiler to biomass steam turbine with an output of 7 MW and absorption (trigeneration) unit producing heat, cooling and electricity, which also will function as a cooler primary circuits. The source of water for the power plant will not only former mining pit Nejedlý I which is currently flooded drinking water at about 12 ° C. This system uses high efficiency embedded fuel (biomass), which is ultimately required less. A greater proportion of electricity generated and part of the heat will be distributed to the public network. In most areas will be proposed publicly accessible greenhouses of steel-aluminum construction filled ETFE foil forming the heat insulating membrane filled with air. The reason is to create conditions for the cultivation of tropical and subtropical plants. Greenhouses will be connected to the absorption unit power (underground meanders through which water will circulate), the ventilation shaft mine and mine water - therefore it will be possible to manage the conditions of the internal environment of the building without the influence of the season and especially without mounting other technological devices. It will provide for cooperation with the absorption unit for cooling the primary circuit - therefore eliminating the need for cooling towers or fans. The project will build a detached departments of the Faculty of Mechanical Engineering in Prague - Institute of progressive technologies and systems for energy and the Faculty of Agronomy and Natural Resources CULS. The reason is to allow students and scientists actively and in practice mainly participate in the operation and especially the development of the issue. The public in the area besides themselves open to the greenhouses indoor and outdoor thermal swimming. Part of the entrance hall is a bistro and foremost lecture hall. The aim is decentralized botanical-energy complex of buildings that produce electricity, heat, cooling, and biomass, and creating recreational, educational and research conditions.

The goals of this thesis are to create a comprehensive business plan manual from various business plan frameworks and to clarify project documentation necessary for the commencement of the biomass power plant. The theoretical part serves to the reader as a manual, how to write a business plan. In each section the thesis lists necessary questions to be answered, the theory and the recommendations what to include in the business plan. The practical part represents a complete business plan of the development and op-eration of the biomass power plant with focus on the political analysis, key resources and financial analysis. In the end of the thesis the investment decision criteria are pre-sented together with the risks analysis, providing a solid information base upon which a potential investor can decide, whether to invest into the project.

This thesis examines Greater Melbourne’s indigenous plants movement from the 1930s to the early twenty first century. It demonstrates the important scientific and educational role of the public intellectual, Professor John Turner, and of the Melbourne University Botany School which he led for thirty five years. The case study of the movement within the City of Sandringham and its successor the City of Bayside reveals how the inhabitants of an urbanised are responded to threats to the indigenous trees and wildflowers of their neighbourhood, stimulating botanists to assist them and using political means in order to achieve their conservation objectives. The thesis draws upon a range of local archives, conservation literature and private papers.

Differing plant canopy structures between the sexes of the dioecious Cannomois congesta (Restionaceae) were found to be the result of the destructive pre-dispersal seed predation methods used by the four-striped grass mouse (Rhabdomys). Mature, reproductive culms on female plants were felled down (mid way along the culm) in large numbers by Rhabdomys in order for it to access the seeds held terminally on culms. Male plants were largely unaffected due to their lack of seeds. Seeds acquired through culm-felling by Rhabdomys were all eaten shortly after their discovery, leading to significant seed mortality each year and reducing the rate of seed dispersal by ants (myrmecochory). I studied the physiological effects of culm-felling by Rhabdomys in C. congesta. Firstly I investigated nutrient resorption from senescing culms and considered the effects of reproductive effort (higher in females) and sex-specific nutrient losses. I found that nutrient resorption from mature culms was highly efficient in both sexes. Culm-felling by Rhabdomys lead to the loss of pre-senescent culm tissue in females and therefore lead to the loss of a significant proportion of potentially resorbed nutrients. Nutrient resorption was found not to be flexible as a strategy to compensate for higher reproductive costs/nutrient-losses in females. This was possibly due to nutrient resorption occurring near is physiological maximum. Plant photosynthetic performance was also investigated using stable isotopes and gas exchange and was found to be similar in both C. congesta sexes throughout the year. The influence of culm-felling by Rhabdomys on female micro-climate also did not appear to have a significant influence on photosynthetic performance between sexes. There was a general lack of evidence to suggest compensatory physiological changes or reductions in fitness (photosynthetic capacity/growth/reproduction) in females due to higher reproductive costs/nutrient-losses. The lack of physiological differences and the fact that females supported a greater number of culms relative to males suggested that other compensatory mechanisms could exist. Phenological differences were discovered and could be important in allowing flexibility between sexes to best use available resources for their specific sexual requirements. Another possibility is that compensatory growth occurred in females at the cost of rhizome-stored nutrients. This has been shown to occur in graminoids after high levels of herbivory (Bryant et al 1983).

The conserved metabolites, oleic acid (18:1), a major monounsaturated fatty acid (FA), and glycerol-3-phosphate (G3P) are obligatory precursors of glycerolipid biosynthesis in plants. In Arabidopsis, the SSI2-encoded SACPD is the major isoform that contributes to 18:1 biosynthesis. Signaling induced upon reduction in oleic acid (18:1) levels not only upregulates salicylic acid (SA)-mediated responses but also inhibits jasmonic acid (JA)- inducible defenses. I examined the transcription profile of ssi2 plants and identified two transcription factors, WRKY50 and WRKY51. Although the ssi2 wrky50 and ssi2 wrky51 plants were constitutively upregulated in SA-derived signaling, they were restored in JAdependent defense signaling. Not only did these plants show JA-inducible PDF1.2 expression, but they were also restored for basal resistance to the necrotrophic pathogen, Botrytis cinerea. Overall, my results show that the WRKY50 and WRKY51 proteins mediate both SA- and low 18:1-dependent repression of JA signaling in Arabidopsis plants. My studies also show that cellular G3P levels are important for plant defense to necrotrophic pathogens. I showed that G3P levels are induced in Arabidopsis in response to the necrotrophic fungal pathogen B. cinerea. G3P-dependant induction of basal defense is not via the activities of other defense-related hormones such as SA, JA or the phytoalexin camalexin. Arabidopsis mutants unable to accumulate G3P (gly1, gli1) showed enhanced susceptibility to B. cinerea. Previous studies in our lab identified acyl-carrier protein 4 (ACP4), a component of FA and lipid biosynthesis, as an important regulator of plant systemic immunity. ACP4 mutant plants were defective in systemic acquired resistance (SAR) because they contained a defective cuticle. I further investigated the role of the plant cuticle in SAR by studying the involvement of long-chain acyl-CoA synthetases (LACS), a gene family involved in long-chain FA and cuticle biosynthesis, in SAR. In all, eight lacs mutants (lacs1, lacs2, lacs3, lacs4, lacs6, lacs7, lacs8, lacs9) were isolated and characterized. Six mutants were compromised in SAR. Together, my studies show that the various LACS isoforms contribute differentially to both cuticle formation and systemic immunity in Arabidopsis.

Cynipid gall formation is achieved by the intimate insect-plant interaction where by cynipid wasps redirect host plant development to form novel structures to protect and nourish the developing larva. To investigate the molecular mechanisms involved in this interaction, and extend our understanding of plant development, four approaches were taken. 1) A PCR based approach to search for genes to known signalling molecules: chitiooligosaccharides, or Nod factors, that control nodulation in the Rhizobia-legume interaction. PCR analysis was used to investigate the presence of the nodC gene in the cynipid gall wasp genome,h owever, no nodC-like sequencesw ere found. 2) SDS-PAGE analysis was carried out to compare inner-gall and non-gall protein signatures, demonstrating the variation between gall and non-gall tissue, and also that the protein signatures of inner-gall tissues vary between gall species. N-terminal sequencing and western blot analysis lead to the identification of a number of innergall proteins such as protein disulphide isomerase (PDI), formate dehydrogenase (FDH) and putative biotin carboxyl carrier protein (BCCP), involved in the synthesis of lipids in seeds. Analysis of the temporal and spatial expression of the putative BCCP revealed expression to be concentrated in the inner-gall cells throughout development, in all the gall species tested. 3) Cytological analysis of the inner-gall tissue was carried out throughout development of several gall species to investigate differences in their patterns of development and cytological characteristics of the inner-gall tissue, with many inner-gall cells being polytene. 4) A gall formation bioassay, to enable the activity of possible signals involved in gall formation to be tested, was developed. Rose callus tissue was used as a test tissue and the cynipid larval extract was exposed to this as a source of the active molecules. The induction of proteins in the callus after exposure to the larval extract was used as a molecular marker for activity. The polytene characteristic and the possible expression of seed proteins, suggest that seed developmental pathways may be used during gall formation.

Il controllo delle fitopatie è un tema molto importante nell’agricoltura moderna: da un lato si vede il bisogno di mantenere alto, ed anzi incrementare, il livello produttivo delle colture; dall’altro vi è una forte spinta verso la riduzione di input in agricoltura per ottenere una maggiore sostenibilità dei processi produttivi. In questo scenario, il controllo biologico, o biocontrollo, dei patogeni può essere un valido strumento per raggiungere entrambi gli obbiettivi. Nel presente lavoro di tesi è stata valutata la capacità di 7 diversi ceppi batterici, precedentemente isolati da piante di melo e vite, di essere agenti di biocontrollo e di promozione della crescita. I diversi saggi condotti nell’ambito di questo studio hanno incluso prove in vitro, in vivo, in planta, ed in silico per caratterizzare le potenzialità di questi ceppi, ottenendo i risultati di seguito riassunti: capacità di inibire la crescita miceliare di ascomycota e basidiomycota in vitro; capacità di ridurre la colonizzazione da parte di Botrytis cinerea in vivo su bacche di pomodoro; capacità di promuovere la crescita e di ridurre l’incidenza di Pseudomonas syringae e Cymbidium Ringspot Virus su piante di peperone in planta; identificazione di tratti genetici noti e di possibile nuovo interesse per il biocontrollo dall’analisi in silico dei genomi dei ceppi. In conclusione, questo studio non ha solo caratterizzato l’effetto di 7 ceppi candidati agenti di biocontrollo, ma ha indagato sui loro meccanismi d’azione, ponendo le basi per ulteriori studi atti a definire con maggior precisione i meccanismi molecolari alla base del biocontrollo al fine di identificare nuovi strumenti per un’agricoltura moderna e sostenibile.
The control of plant diseases is a very important topic in modern agriculture: on one hand, there is the necessity to maintain a high production level, and even to achieve higher production of crops; on the other, there is a strong drive towards the reduction of inputs in agriculture in order to achieve more sustainable productive processes. In this scenario, biological control, or biocontrol, of pathogens can be a helpful tool to achieve both objectives. In this thesis work the ability of 7 different bacterial strains, previously isolated from apple trees and grapevine plants, to act as biocontrol and plant-growth promoting agents was evaluated. Different assays were carried out in this study, including in vitro, in vivo, in planta, and in silico assays carried out to characterize the potential of these strains, achieving the results summarized as follows: ability to inhibit mycelial growth of ascomycota and basidiomycota in vitro: ability to reduce colonization by Botrytis cinerea in vivo on tomato berries: ability to promote growth and reduce the incidence of Pseudomonas syringae and Cymbidium Ringspot Virus on pepper plants during in planta assays; identification of known and possibly novel genetic traits for biocontrol from the in silico analysis of the genomes of the strains. In conclusion, this study has not only characterized the effect of 7 candidate biocontrol strains, but has investigated their mechanisms of action, paving the road for further studies aimed at defining more precisely the fine molecular mechanisms at the base of biocontrol and to identify new tools for a modern and sustainable agriculture.

Previous studies have shown that: (1) plant defensive compounds may have medicinal properties; and (2) defensive compounds present in aposematic insects are often sequestered from their host-plant(s). This study addresses whether aposematic insects can be used as guides to detect plants containing medicinally-active compounds. First, ten tropical medicinally-active plants and ten non-active plants, selected using previous ICBG bioassay results, were observed regularly to determine their insect populations. Aposematic insects were found more frequently on active than non-active plants ( X2=8.167, P=0.01). Second, three aposematic insects feeding on Tithonia diversifolia were examined chemically to determine the fate of the plant's pharmaceutically-active compounds. They were not found to sequester or excrete these compounds. Therefore, using aposematic insects could increase the likelihood of finding plants with medicinally-active compounds; however, these insects may not necessarily utilize these compounds for defensive purposes. The underlying basis for this significant association between aposematic insects and medicinally-active plants requires further investigation.

Responses of rice to plant growth regulators on germination and seedling growth under NaCl salinity were studied to identify possible means of increasing salinity tolerance. Gibberellic acid (GA) promoted germination processes and a-amylase activity and increased plumule but reduced radicle growth after emergence. GA partitioned more metabolites towards the plumule than the radicle. Chlormequat (CCC) showed no beneficial effects and abscisic acid (ABA) inhibited germination under saline conditions. Overall there was no large difference in the performance of three rice varieties, BR29, IR8 and Pokkali in germination. Artificially aged seeds showed increased sensitivity to salinity and GA produced similar effects on germination of artificially aged rice seeds as on unaged seeds. Seed pre-treatment with GA was as effective in promoting germination under saline conditions as applying GA in the germination media. GA with low Ca promoted germination and plumule growth as well as radicle growth. GA increased plant height and fresh weight of seedlings under saline conditions, however it did not show a large positive effect on rice seedlings. CCC had no beneficial effects on rice seedlings. ABA showed possible beneficial effects on rice seedlings as it reduced Na+ uptake and increased K+ and Ca2+ uptake. GA in combination with ABA appeared to adapt rice plants better to saline conditions. GA in combination with low Ca also promoted rice growth under saline conditions.

As electricity production from renewable sources increases, higher flexibility is required by fossil fuel generation to cope with the inherent fluctuations of solar and wind power. This results in shorter operating cycles and steeper ramps for the turbines, and more uncertainty for the operators. This thesis work applies mathematical optimization and statistical learning to improve the economic dispatch of a combined cycle power plant composed by two separate blocks of two gas turbines and one steam turbine. The goal is to minimize the input fuel to the gas turbines while respecting a series of constraints related to the demand the plant faces, power generation limits etc. This is achieved through the creation of a mathematical model of the plant that regulates how the plant can operate. The model is then optimized to reduce fuel consumption at a minimum. Machine learning techniques have been applied to sensor data from the plant itself to realistically simulate the behavior of the turbines. Input-Output curves have been obtained for power and exhaust heat generation of all the turbines using ordinary least squares on monthly data with a ten minutes sampling rate. The model is cross-validated and proven statistically valid. The optimization problem is formulated through generalized disjunctive programming in the form of a mixed-integer linear problem (MILP) and solved using a branch-and-bound algorithm. The output of the model is a one-week dispatch, in fifteen minutes intervals, carried out for two months in total. Lower fuel consumption is achieved using the optimization model, with a weekly reduction of fuel consumed in the range of 2-4%. A sensitivity analysis and a correlation matrix are used to highlights the demand and the maximum available capacity as critical parameters. Results show that the most efficient machines (alternatively, the ones with highest available capacity) should be operated at maximum load while still striving for an efficient utilization of the exhaust gas.
När elproduktionen från förnybara källor ökar krävs högre flexibilitet av fossil bränsleproduktion för att hantera fluktuationerna från sol- och vindkraft. Detta resulterar i kortare driftscykler och brantare ramper för turbinerna och mer osäkerhet för operatörerna. Detta avhandlingsarbete tillämpar matematisk optimering och statistisk inlärning för att förbättra det ekonomiska utnyttjandet av en kombicykel i ett kraftverk som består av två separata block med två gasturbiner och en ångturbin. Målet är att minimera bränsleförbrukningen hos gasturbinerna samtidigt som man tar hänsyn till en serie av villkor relaterade till efterfrågan som anläggningen står inför, kraftproduktionsbegränsningar etc. Detta uppnås genom skapandet av en matematisk modell för anläggningen som reglerar hur anläggningen kan fungera. Modellen är sedan optimerad för minsta möjliga bränsleförbrukning. Maskinteknik har använts på sensor data från själva anläggningen för att realistiskt simulera turbinernas beteende. In och utdata kurvor har erhållits för kraftproduktion och avgasvärmeproduktion med hjälp av ordinary least squares (OLS) med månads data och med en tio minuters samplingshastighet. Modellen är korsvaliderad och bevisad statistiskt giltig. Optimeringsproblemet formuleras genom en generaliserad disjunktiv programmering i form av ett mixed-integer linear problem (MILP) och löses med hjälp av en Branch-and-Bound algoritm. Resultatet från modellen är en veckas värden, med femton minuters intervall, totalt i två månader. Lägre bränsleförbrukning uppnås med hjälp av optimeringsmodellen, med en vecka minskad bränsleförbrukning i intervallet 2-4%. En känslighetsanalys och en korrelationsmatris används för att visa efterfrågan och den maximala tillgängliga kapaciteten som kritiska parametrar. Resultaten visar att de mest effektiva maskinerna (alternativt de med högsta tillgängliga kapacitet) bör drivas med maximal belastning medan de fortfarande strävar efter ett effektivt utnyttjande av avgaserna.

Aging of ray parenchyma cells from the young sap-wood to recently formed heartwood was studied in single stems of Pinus banksiana Lamb., Picea mariana (Mill.) B.S.P., Abies balsamea (L.) Mill, and Populus tremuloides Michx. Season, radial location of cell within sapwood, and cell location vertically within a ray at a given radius were considered as factors which might influence the aging process. A 12 mm increment core was extracted at breast height, from the north aspect of a tree of each species in May and July for moisture content determination. Another set of cores from the south aspect of the same trees was collected in May, June, July, August, October, and November or December. These cores were used to investigate the physiological and cytological properties of living sapwood ray parenchyma cells. Qualitative and quantitative observations were made of the status of ray cells both with light and transmission electron microscopy in order to draw inferences concerning the sapwood/heartwood transformation from the aging of sapwood ray parenchyma cells. The sapwood moisture content of the three conifers studied was higher than that of heartwood, whereas in Populus tremuloides it was lower than that of heartwood. The sapwood moisture content in May was consistently greater than in July. Vitality of the sapwood ray parenchyma cells expressed by a new nuclear elongation index decreased from the outer sapwood towards the heartwood. The survival rate of the cells decreased curvilinearly from the middle sapwood towards the heartwood. At a given sapwood increment, a greater percentage of dead ray parenchyma cells was found among the marginal cells than among the central cells of a ray. No statistically significant difference was found between the vitality of the marginal and central cells, nor between any two contiguous sampling periods with exceptions in Pinus banksiana and Picea mariana between two contiguous sampling periods from July to December. No typical pattern for the distribution of lipid content was found. The pattern of starch distribution displayed significant species, radial, vertical and seasonal variation and showed two general patterns across the sapwood. Pattern A described a decreasing trend from the outer sapwood towards the inner sapwood. Pattern B was characterized by a relatively low starch content both in the outer as well as the inner sapwood. The starch content in Populus tremuloides and the lipid content in Pinus banksiana and Picea mariana displayed no statistically significant difference between marginal and central ray cells. The majority of ray parenchyma cells showed a statistically significant difference between two contiguous sampling periods in starch and lipid contents. There was no inverse relationship between the starch and lipid content over the growing season studied. Young ray parenchyma cells were rich in chromatin and cytoplasm which contained numerous cell organelles. These cells were characterized by amyloplasts which possessed one or more elongated starch granules with thylakoids and osmiophilic globuli, numerous small lipid droplets and mostly rod-like mitochondria. In contrast, aged ray parenchyma cells featured an aggregated, dense nucleus and cytoplasm which contained few cell organelles. These aged cells possessed enlarged swollen starch granules, large lipid droplets or lumps with two staining densities, round shaped mitochondria with inconspicuous cristae and a rough/broken plasmalemma. Some heartwood substances originated from the lipid lumps which appeared frequently in dying ray cells. Based on microscopic observations and measurements of the loss of vitality of ray parenchyma cells, a declining survival rate, the disintegration of cell organelles and the origin of heartwood substances from lipid lumps, it can be concluded that heartwood formation is largely associated with the death of sapwood ray parenchyma cells. The death of these cells is due to the passage of time.
Forestry, Faculty of
Graduate

Title from PDF of title page (University of Missouri--Columbia, viewed on February 24, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Dale Blevins. Vita. Includes bibliographical references.

Le traitement photodynamique antimicrobien (acronyme anglais APDT) est apparu comme une solution alternative pour lutter contre les microorganismes multi-résistants. Cette méthode basée sur l'utilisation de photosensibilisateurs dont les porphyrines, fonctionne aussi contre les agents pathogènes des plantes ce qui nous a conduit à proposer une approche de type APDT dans le domaine de l’agriculture. Au cours de ce travail de thèse, nous nous sommes intéressés au côté « vert » de la mise en place de cette approche en réalisant une étude approfondie sur des plantules de deux espèces végétales: Arabidopsis thaliana et Lycopersicum esculentum (tomate) et sur une suspension cellulaire de tabac (TBY-2). Des porphyrines anioniques et cationiques hydrosolubles ont été testées. Nous avons montré qu’aucune de ces porphyrines testées à forte concentration (⩾ 80 μM) n’était cytotoxique à l’obscurité sur les plantules ou la suspension. Par contre sous photopériode (16h), les porphyrines cationiques testées à faible concentration (3,5 μM) se sont révélées létales pour les plantules d’Arabidopsis alors qu’elles n’ont fait que ralentir la croissance des plantules de tomate. Etonnamment, les porphyrines anioniques même testées à forte concentration n’ont pas (ou très peu) induit d’altérations de croissance des plantules. Cette situation se trouve inversée dans les cellules TBY-2 qui sont beaucoup plus sensibles aux porphyrines anioniques photoactivées qui induisent leur mort par apoptose. Ce modèle cellulaire nous a permis de comprendre i) les mécanismes d'interaction porphyrines anioniques avec la paroi cellulaire et ii) quels mécanismes étaient mis en place dans les cellules en réponse au stress photodynamique. En conclusion, ces études préliminaires sur le végétal laissent sérieusement entrevoir la possibilité de développer l’APDT en agriculture ciblée aux pathogènes de plantes et sans effet notable sur les plantes d’intérêt agronomique et les microorganismes du sol
Antimicrobial photodynamic treatment (APDT) has emerged as an alternative modality to strive against multidrug-resistant microorganisms. This method, based on the use of photosensitizers including porphyrins, has also shown substantial efficiency to kill plant pathogens. This led us to propose an APDT approach in the field of agriculture. During this thesis work, we were interested in the "green" side of this approach. Thus, we performed an in-depth study on two plant species: Arabidopsis thaliana and Lycopersicum esculentum (tomato) and on Tobacco Bright Yellow-2 suspension culture (TBY-2 cells) using anionic and cationic water-soluble porphyrins. We have shown that none of these porphyrins tested at high concentration (⩾ 80 μM) was cytotoxic on plantlets or suspension cells under dark conditions. On the other hand, the cationic porphyrins tested at low concentration (3.5 μM) were lethal for Arabidopsis while they only slowed the growth of tomato plantlets under 16 h photoperiod. Surprisingly, the same anionic porphyrins tested at high concentrations did not induce growth alterations of both plantlets. This situation is reversed in TBY-2 cells, which are much more sensitive to photoactivated anionic porphyrins that induce apoptosis-like cell death. TBY-2 cells allowed to understand i) the interactions of anionic porphyrins with the cell wall and ii) the induced cellular and molecular mechanisms in response to photodynamic stress. In conclusion, these preliminary studies on the plants and plant cells suggest the possibility of developing APDT in agriculture. It will be targeted to plant pathogens without any side effects on plants of agronomic interest and soil microorganisms

Aphids are economically important phloem-feeding insects that cause loss in plant productivity worldwide. This occurs through the removal of photoassimilates and the vectoring of hundreds of plant viruses. Plants possess a complex immune system in order to defend themselves from a range of pathogens including bacteria and fungi. I aimed to discover if this immune system was also involved in defence against aphids. I found that aphids have proteins that trigger plant immune responses. The aphid Myzus persicae contains several protein elicitors with varying molecular weights. These proteins are perceived by the plants Nicotiana benthamiana and Arabidopsis thaliana. In A. thaliana the perception of a 3 to 10 kDa elicitor fraction requires the leucine-rich repeat receptor-like kinase (LRR-RLK) BAK1, as a mutant in this gene was deficient in immune responses activated by this elicitor. Plant recognition of the elicitor is unlikely to depend on a single non-arginine-asparate (non-RD) RLK. In addition, aphids possess the means to modulate the plant immune response. I helped to identify three aphid effectors that modulate plant processes. I then investigated the role of one of these effectors, a M. persicae chemosensory protein (CSP) known as Mp10, in suppressing the immune responses triggered by the aphid elicitors. Mp10 is likely to disrupt the function of plant genes near the top of the immune signalling cascade in N. benthamiana in order to suppress elicitor-triggered immunity. Surprisingly, the homologs of this CSP in other aphids also show the same ability to suppress plant immune responses, suggesting an important role for Mp10 in plant-aphid interactions. This is the first report of a role for elicitor recognition by plants in aphid defence, the use of plant cell surface receptors to detect insects, and aphids’ attempts to suppress plant immunity.

A two year study was conducted to determine the optimum timing of the initial post plant irrigation using leaf water potential (LWP) measurements. A short - season Upland cotton (Gossvpium hirsutum L.), variety DPL 20, was planted on 19 April 1993 and 15 April 1994 at the Marana Agricultural Center on a Pima clay loam (Typic Torrifluvent) soil. Treatments, designated Tl , 72, and T3, were such that the initial post plant irrigation would be applied when the midday LWP of the uppermost, fully- developed leaf exposed to full sunlight measured -15, -19, and -23 bars, respectively. All treatments received the same irrigation regime following the initial post plant irrigation. Basic plant measurements, including plant height, mainstem node number, fruit retention, number of nodes above the uppermost white bloom, fresh bloom count within a 166 -ft1 area, and percent canopy cover, were taken weekly from each plot. Soil -water data was collected at 10 inch depth increments, to a depth of 60 in. , from access tubes located in each experimental unit. Yields were 1112, 1095, and 977 lbs lint/acre in 1993 and 1082, 1035, and 964 lbs lint /acre in 1994 for T1, 72, and T3, respectively. Yields were reduced when the midday LWP was allowed to fall below -19 bars, however, reduction was significant (P 5 0.05) only in 1993. At the time of the initial post plant irrigation for each treatment, approximately 83, 62, and 32 % of the total plant available water was present in the upper 60 in. of the soil profile for Ti, 72, and T3, respectively.

Bioactive chemicals are described as dietary components that affect people who consume those substances in their physiological as well as cellular function. Flavonoids, anthocyanins, tannins, berets, carotenoids, plant sterols and glucosinolates are all included. These may well be present most often in fruits and vegetables; offer anti - oxidant, anti-inflammatory but also antiviral activities; and therefore, can shield humans toward chronic disorders and metabolism. These favorable effects empower researchers to create novel functional foods containing prospective protective and healthful. Cardiovascular disease is the cardiac or blood vessel dysfunctional action. An inadequate heart and blood vessel function boosts the heart attack risk, heart failure, sudden death, stroke and heart rhythm disorders, resulting to diminished standard of health and a shorter life expectancy. Plant tissue culture is an effective venue for the generation of secondary metabolites along with its diverse implications. Diverse plant- based strategies including such callus or suspension cultivation are utilized generally in the synthesis of secondary plant metabolites. Several novel approaches which aim to have a rather significant and neglected influence on secondary metabolite synthesis.