Letteratura scientifica selezionata sul tema "Sporophore formation"

The present experiment was conducted to identify the best organic amendment on the growth and yield of five species of oyster mushrooms viz.,Pleurotus florida, P. sajor-caju, P. eous, P. tuber-regium and Hypsizygus ulmarius by using organic amendments like rice bran, dry azolla, Neem cake, vermiwash and dry biogas slurry at three different concentrations. The effect of organic amendments on the number of days for sporophore formation, number and weight of sporophores varied according to the mushroom species. Results revealed that except dry biogas slurry, all organic amendments had superior effect in reducing number of days for sporophore formation, increasing the number of sporophores and yield. Effect of organic amendments on the yield of oyster mushrooms showed that all organic amendments except dry biogas slurry performed well with more number and weight of sporophores. The number of days for sporophore formation varied between 16.5 to 20.8 days in P. eous, 19.5 to 39 days in P. tuber-regium and 17.5 to 36.8 days in H. ulmarius. In P. florida and P. eous highest yield of 350.3g and 379g, respectively obtained from paddy straw amended with 1 per cent Neem cake. P. sajor-caju gave the maximum yield of 405.3g in 5 per cent rice bran. The maximum yield of 134.8g was recorded in P. tuber-regium when treated with 4 per cent rice bran whereas paddy straw amended with 6 per cent dry azolla gave highest yield of 218.3g in H. ulmarius.

The present investigation was conducted to study the effect of various growth regulators and micronutrients on growth and yield of Pleurotus sajor-caju. Results of the research explicitly indicated that the growth regulators and micronutrients experimented at different concentrations, targeting at stimulating growth and sporophore yield of Pleurotus sajor-caju, displayed significantly diverse response to in vitro colony diameter of the fungus, days required for spawn run, pinhead formation, first harvest of sporophores, yield of sporophores and biological efficiency. However, among the growth regulators used, gibberellic acid (GA) @ 20 and 15 ppm significantly improved the colony diameter (90 and 89.98 mm) in in vitro study; reduced the period required for spawn running (13 and 13.5 days), pinhead formation (16 and 16.5), and first harvest (18.5 and 19); augmented the total sporophore yield (858.25 and 855 g/kg dry substrate) and biological efficiency (85.83 and 85.5%). Mixture of micronutrients was ineffective in augmenting the foregoing traits. From the present investigation it is concluded that, spraying of gibberellic acid at 20 and 15 ppm concentrations on cultivation substrate, at the time of spawning, is highly beneficial for obtaining maximum yield of Pleurotus sajor-caju.

Wall development during primary spore formation, discharge, and germination of Entomophthorales is emphasized in ultrastructural studies of Conidiobolus, Entomophaga, Neozygites, and Erynia. In the fungi examined, spore and sporophore walls consist of a thick, electron-translucent inner layer and a thin, electron-dense outer layer. During spore formation, cytoplasm of the supporting sporophore cell migrates into the spore initial. As the former cell empties, a septum develops. Discharge is caused by inversion of the papillum, which lacks the electron-dense layer. Only in Erynia did the two spore wall layers separate upon impact. Intracytoplasmic organization of the primary spore is typical of the Zygomycotina; the morphology of organelles was characteristic of species, whereas nuclear ultrastructure was consistent within genera. Conidiobolus nuclei have a prominent nucleolus that lacks heterochromatin, in contrast with the other genera where large patches of heterochromatin were observed. Upon germination, no rupture of the spore outer layer was observed other than at points of germ tube emergence. The germ tube wall was continuous with the inner spore wall layer. The results are discussed in reference to Entomophthorales taxonomy and definition of the terms conidium and monosporous sporangiolum.

Objective: Fungi are heterotrophs and are involved in decomposition, nutrient cycling and nutrient transport, and are indispensable for achieving sustainable development. Mushrooms are the fungi with a distinctive fruiting body. Mushrooms are produced all over the world. In India, Punjab is the leading mushroom growing state. Mushrooms are rich sources of proteins, vitamins and minerals. Different types of immunoceuticals like lentinan, schizophyllan, active hexose correlated compound (AHCC) etc. have also been prepared from various mushrooms. The present review work highlights important observations in the area of mushroom. Methods: This review also shows that how several factors affect the fruiting body formation of mushrooms, which includes physiological (composition of culture media) and environmental factors (light, temperature, salinity, etc.). There are different factors like light, temperature etc. which affects the fruiting body development.Results: It has been found that, light has positive effects on hyphal aggregation and fruiting body maturation. It has been found that in oyster mushroom, light is essential for both normal expansion of pileus and in spore formation. It has been found that length of Stipe and the diameter of cap decreases with an increase in the concentration of CO2. Also, there is a range of temperature within which sporophore development occurs. The composition of media affects the growth of mushrooms too. It’s important to maintain a balance between carbon and nitrogen sources for induction of the fruiting body.Conclusion: There are different environmental factors affecting the fruiting body development of mushrooms. Hence, by adjusting various factors like temperature, light, media composition production of mushrooms can be increased.

Grape berries become resistant to powdery mildew early in development and are nearly immune to infection within 4 weeks after bloom. In this study, ontogenic resistance did not reduce attachment, germination, or appressorium formation of Uncinula necator on 3- to 4-week-old berries of Vitis vinifera ‘Chardonnay’ or 3-week-old berries of V. labruscana ‘Concord’. Pathogen ingress halted at the cuticle before formation of a penetration pore. As berries aged, hyphal elongation and colony growth slowed until finally no secondary hyphae formed on fully resistant berries. More appressoria formed per unit of hyphal length as berries aged, indicating that failure to penetrate older berries led to increased attempts to penetrate resistant fruit. Additionally, hyphae within the colonies began to die as berries aged. Finally, the number of degree-hours between germination and sporulation of the colony (latent period) increased and sporophore density decreased with berry age at time of inoculation. Thus, ontogenic resistance both slows, and eventually halts disease development on grape berries, and limits the likelihood of spread by reducing absolute supply of conidia and delaying their formation. It furthermore has a consistent, stable, and predictable impact on grape powdery mildew and operates in a similar fashion and to a similar degree in both V. labruscana and V. vinifera, although at a slightly earlier phenological stage in V. labruscana.

The preference of a particular strain to a specific substrate in shiitake mushroom was investigated. The effect of different genotypes (DMRO-34, DMRO-23, DMRO-327 and DMRO-388s), substrates (sawdust and wheat straw) and their interactions were found highly significant for yield and yield attributing factors. Strain DMRO-388s recorded the highest bio-efficiency (85.63%) on saw dust (SD) and the strain DMRO-327 with 53.02% on wheat straw (WS). The mycelial colonization was rapid on SD, while the sporophore formation was found earlier on WS. Breakdown of phenolic compounds in the substrate was found much higher in WS particularly with strain DMRO-327. Ability of the strains to degrade lignin content was found higher by the strain DMRO-388s (58.78%) in SD. Hemicellulose concentration decreased in both the substrates with each passing growth stage and it was found much rapid with DMRO-388s after spawn run stage. Of the substrates used, SD gave higher yield over the WS. But the earliness of fruiting on WS can economize the cost of shiitake cultivation as it is cheap and abundantly available.

ABSTRACT Mannases have industrial uses in food and pulp industries, and their regulation may influence development of the mushrooms of commercially important basidiomycetes. We expressed an Agaricus bisporus cel4 cDNA, which encodes a mannanase, inSaccharomyces cerevisiae and Pichia pastoris. CEL4 had no detectable activity on cellulose or xylan. This gene is the first isolated from this economically important fungus to encode a mannanase. P. pastoris secreted about three times more CEL4 than S. cerevisiae. The removal of the cellulose-binding domain of CEL4 lowered the secreted specific activity by P. pastoris by approximately 97%. The genomic sequence ofcel4 was isolated by screening a cosmid library of A. bisporus C54-carb8. The open reading frame was interrupted by 12 introns. The level of extracellular CEL4 increases dramatically at the postharvest stage in compost extracts of A. bisporus fruiting cultures. In laboratory liquid cultures ofA. bisporus, the activity of CEL4 detected in the culture filtrate reached a maximum after 21 days. The levels of CEL4 broadly mirrored the levels of enzyme activity. In the Solka floc-bound mycelium, CEL4 protein showed a maximum after 2 to 3 weeks of culture and then declined. Changes in CEL4 activity during fruiting-body development suggest that hemicellulose utilization plays an important role in sporophore formation. The availability of the cloned gene will further studies of compost decomposition and the extracellular enzymes that fungi deploy in this process.

Abstract The fossil record of Marsilea is challenging to assess, due in part to unreliable reports and conflicting opinions regarding the proper application of the names Marsilea and Marsileaceaephyllum to fossil leaves and leaflets similar to those of modern Marsilea. Specimens examined for this study include material assigned to Marsileaceaephyllum johnhallii, purportedly the oldest fossil record of a Marsilea-like sporophyte from the Lower Cretaceous of the Dakota Formation, Kansas, U.S.A.; leaves and leaf whorls of the extinct aquatic angiosperm Fortuna from several Late Cretaceous and Paleocene localities in western North America; and leaves and leaflets resembling Marsilea from the Eocene Green River Formation, Colorado and Utah, U.S.A. Literature on the fossil record of Marsilea was also reviewed. As a result, several taxonomic changes are proposed. Marsileaceaephyllum johnhallii is reinterpreted as an aquatic angiosperm that shares some architectural features with the genus Fortuna, although Marsileaceaephyllum is here maintained as a distinct genus with an emended diagnosis; under this reinterpretation, the name Marsileaceaephyllum can no longer be applied to sporophyte organs with affinities to Marsileaceae. Three valid fossil Marsilea species are recognized on the basis of sporophyte material that includes characteristic quadrifoliolate leaves and reticulate-veined leaflets: Marsilea campanica (J. Kvaček & Herman) Hermsen, comb. nov., from the Upper Cretaceous Grünbach Formation, Austria; Marsilea mascogos Estrada-Ruiz et al., from the Upper Cretaceous Olmos Formation, Mexico; and Marsilea sprungerorum Hermsen, sp. nov., from the Eocene Green River Formation, U.S.A. The species are distinguished from one another based on leaflet dimensions. Leaves from the Eocene Wasatch Formation, U.S.A., are transferred from Marsileaceaephyllum back to Marsilea, although not assigned to a fossil species. Finally, an occurrence of Marsilea from the Oligocene of Ethiopia is reassigned to Salvinia. A critical evaluation of the fossil record of Marsilea thus indicates that (1) the oldest fossil marsileaceous sporophytes bearing Marsilea-like leaves are from the Campanian; (2) only four credible records of sporophyte material attributable to Marsilea are known; and (3) the oldest dispersed Marsilea spores are known from the Oligocene.

Sporophyte production in Sphagnum was followed annually in 80 permanent 1-m2 plots at the bog expanse of a pristine mire during 1993–1999 and in 60 plots in peat pits abandoned 50 years ago during 1996–1999 in east central Sweden. The nine most abundant Sphagnum species produced sporophytes, with mean annual production ranging from 0.64 to 20 sporophytes/dm2 of cover among species. An estimated mean of 16 million Sphagnum spores/m2 mire area was produced annually at both mires. At the pristine mire, sporophyte production was positively related to the amount of precipitation the previous summer, suggesting that gametangium formation is especially sensitive to summer droughts. At the wetter peat pits, the amount of precipitation during spring in the year of sporophyte formation appeared more important, probably by positively affecting male gamete dispersal and fertilization. Larger patches had a higher probability of producing sporophytes at least once, showing areas with both sexes present among dioecious species, and thus giving an indication of clone size. Only slight differences in sporophyte production were found between the two mires, apart from effects of hydrological conditions and patch size. This indicates numerous colonizations at the peat pits. Summer droughts affected sporophyte maturation negatively by drying out sporophytes prematurely. Spore release phenology differed among species by up to a month and lasted from the beginning of July until the end of August. The early timing of spore dispersal in the most drought-sensitive, lawn-inhabiting sphagna should reduce the risk of sporophytes drying out prematurely during summer droughts.Key words: bryophyte, long-term study, mire, model, sexual reproduction, strategy.

This thesis focuses on the edible fungus Lepista (Pied Bleu or Wood Blewit). Factors affecting its potential commercial cultivation were explored and a contribution to knowledge of the morphology and cultivation of Australian species of Lepista has been made. Australian collections of Lepista were made within a 200 km zone of Sydney. A study of the morphology and taxonomic species of these collections was undertaken. Intra- and inter-fertility crosses were completed with French L. nuda and L. sordida to determine genetic relationships and biological species. Suitable substrates for agar medium, spawn production and cultivation were explored. The response to temperature of French and Australian Lepista in vitro, and Australian Lepista under cultivation, using cold shock, was observed. The effect of modified atmosphere exchanges per hour, CO2 levels, and cold shock during the cultivation cycle and sporophore production were investigated. A genebank of Australian Lepista was established. Three species of Lepista were found in Australia : L. nuda, L. sordida and L. saeva. Two other groups of Lepista were identified. The use of A. bisporus compost appeared to be optimal for experimental and commercial applications. Australian isolates of Lepista tolerate higher temperatures than French isolates, and grew at double the rate of the French at all temperatures except 5 degrees centigrade. The length of the spawn run was reduced from 43-58 days to 12-16 days with introduced CO2 of 9,000-11,000 ppm, but an erratic cyclic pattern of net CO2 production occurred which could only be stabilised by increasing ventilation. This initial cyclic pattern appeared to inhibit subsequent sporophore formation.
Doctor of Philosophy (PhD)

This thesis focuses on the edible fungus Lepista (Pied Bleu or Wood Blewit). Factors affecting its potential commercial cultivation were explored and a contribution to knowledge of the morphology and cultivation of Australian species of Lepista has been made. Australian collections of Lepista were made within a 200 km zone of Sydney. A study of the morphology and taxonomic species of these collections was undertaken. Intra- and inter-fertility crosses were completed with French L. nuda and L. sordida to determine genetic relationships and biological species. Suitable substrates for agar medium, spawn production and cultivation were explored. The response to temperature of French and Australian Lepista in vitro, and Australian Lepista under cultivation, using cold shock, was observed. The effect of modified atmosphere exchanges per hour, CO2 levels, and cold shock during the cultivation cycle and sporophore production were investigated. A genebank of Australian Lepista was established. Three species of Lepista were found in Australia : L. nuda, L. sordida and L. saeva. Two other groups of Lepista were identified. The use of A. bisporus compost appeared to be optimal for experimental and commercial applications. Australian isolates of Lepista tolerate higher temperatures than French isolates, and grew at double the rate of the French at all temperatures except 5 degrees centigrade. The length of the spawn run was reduced from 43-58 days to 12-16 days with introduced CO2 of 9,000-11,000 ppm, but an erratic cyclic pattern of net CO2 production occurred which could only be stabilised by increasing ventilation. This initial cyclic pattern appeared to inhibit subsequent sporophore formation.

The common peat moss, Sphagnum, is able to explosively disperse its spores by producing a vortex ring from a pressurized sporophyte to carry a cloud of spores to heights over 15 cm where the turbulent boundary layer can lift and carry them indefinitely. While vortex ring production is fairly common in the animal kingdom (e.g. squid, jellyfish, and the human heart), this is the first report of vortex rings generated by a plant. In other cases of biologically created vortex rings, it has been observed that vortices are produced with a maximum formation number of L/D = 4, where L is the length of the piston stroke and D is the diameter of the outlet. At this optimal formation number, the circulation and thus impulse of the vortex ring is maximized just as the ring is pinched off. In the current study, we modeled this dispersal phenomenon for the first time using ANSYS FLUENT 17.2. The spore capsule at the time of burst was approximated as a cylinder with a thin cylindrical cap attached to it. They were then placed inside a very large domain representing the air in which the expulsion was modeled. Due to the symmetry of our model about the central axis, we performed a 2D axisymmetric simulation. Also, due the complexity of the fluid domain as a result of the capsule-cap interface, as well as the need for a dynamic mesh for simulating the motion of the cap, first a mesh study was performed to generate an efficient mesh in order to make simulations computationally cost-effective. The domain was discretized using triangular elements and the mesh was refined at the capsule-cap interface to accurately capture the ring vortices formed by the expulsed cap. The dispersal was modeled using a transient simulation by setting a pressure difference between inside of the capsule and the surrounding atmospheric air. Pressure and vorticity contours were recorded at different time instances. Our simulation results were interpreted and compared to high-speed video data of sporophyte expulsions to deduce the pressure within the capsule upon dispersal, as well as the formation number of resulting vortex rings. Vorticity contours predicted by our model were in agreement with the experimental results. We hypothesized that the vortex rings from Sphagnum are sub-optimal since a slower vortex bubble would carry spores more effectively than a faster one.

Arabidopsis mutants that we have isolated, encode for fertilization-independent endosperm (fie), fertilization-independent seed2 (fis2) and medea (mea) genes, act in the female gametophyte and allow endosperm to develop without fertilization when mutated. We cloned the FIE and MEA genes and showed that they encode WD and SET domain polycomb (Pc G) proteins, respectively. Homologous proteins of FIE and MEA in other organisms are known to regulate gene transcription by modulating chromatin structure. Based on our results, we proposed a model whereby both FIE and MEA interact to suppress transcription of regulatory genes. These genes are transcribed only at proper developmental stages, as in the central cell of the female gametophyte after fertilization, thus activating endosperm development. To test our model, the following questions were addressed: What is the Composition and Function of the Polycomb Complex? Molecular, biochemical, genetic and genomic approaches were offered to identify members of the complex, analyze their interactions, and understand their function. What is the Temporal and Spatial Pattern of Polycomb Proteins Accumulation? The use of transgenic plants expressing tagged FIE and MEA polypeptides as well as specific antibodies were proposed to localize the endogenous polycomb complex. How is Polycomb Protein Activity Controlled? To understand the molecular mechanism controlling the accumulation of FIE protein, transgenic plants as well as molecular approaches were proposed to determine whether FIE is regulated at the translational or posttranslational levels. The objectives of our research program have been accomplished and the results obtained exceeded our expectation. Our results reveal that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms (Publication 1). Moreover our data show that FIE has additional functions besides controlling the development of the female gametophyte. Using transgenic lines in which FIE was not expressed or the protein level was reduced during different developmental stages enabled us for the first time to explore FIE function during sporophyte development (Publication 2 and 3). Our results are consistent with the hypothesis that FIE, a single copy gene in the Arabidopsis genome, represses multiple developmental pathways (i.e., endosperm, embryogenesis, shot formation and flowering). Furthermore, we identified FIE target genes, including key transcription factors known to promote flowering (AG and LFY) as well as shoot and leaf formation (KNAT1) (Publication 2 and 3), thus demonstrating that in plants, as in mammals and insects, PcG proteins control expression of homeobox genes. Using the Yeast two hybrid system and pull-down assays we demonstrated that FIE protein interact with MEA via the N-terminal region (Publication 1). Moreover, CURLY LEAF protein, an additional member of the SET domain family interacts with FIE as well. The overlapping expression patterns of FIE, with ether MEA or CLF and their common mutant phenotypes, demonstrate the versatility of FIE function. FIE association with different SET domain polycomb proteins, results in differential regulation of gene expression throughout the plant life cycle (Publication 3). In vitro interaction assays we have recently performed demonstrated that FIE interacts with the cell cycle regulatory component Retinobalsoma protein (pRb) (Publication 4). These results illuminate the potential mechanism by which FIE may restrain embryo sac central cell division, at least partly, through interaction with, and suppression of pRb-regulated genes. The results of this program generated new information about the initiation of reproductive development and expanded our understanding of how PcG proteins regulate developmental programs along the plant life cycle. The tools and information obtained in this program will lead to novel strategies which will allow to mange crop plants and to increase crop production.