Most aspects of microspore culture protocol have the capacity to cause stress to microspores, hence, less stressful treatments might be required to avoid deleterious effects. In stressed plants, polyamines and trehalo...Most aspects of microspore culture protocol have the capacity to cause stress to microspores, hence, less stressful treatments might be required to avoid deleterious effects. In stressed plants, polyamines and trehalose can act as compatible solutes or osmoprotectants by stabilizing proteins and biological membranes. To improve green plant regeneration in wheat microspore culture, this study assessed the effects of polyamines (putrecine, spermidine, spermine) and trehalose on androgenic response namely embryogenesis, green plant regeneration and ploidy of green plants regenerated in three spring wheat genotypes. Microspores of the genotypes produced significant numbers of embryos and green plants among polyamine treatments but trehalose had no effect (P ≤ 0.05). Polyamine treatments for 30 min generally produced more green plants per 100 microspores than the 60 min treatments in all three genotypes. At least three out of twelve polyamine treatments in each genotype improved the production of double haploid plants and seed setting in regenerants. Wheat genotype, concentration and duration of polyamine treatment had significant impact on embryogenesis and regeneration of green plants in this study. The study also showed that polyamines could be used to accelerate cultivar development in wheat breeding.展开更多
Leaf traits, structure and water status of Conocarpus lancifolius, a Combretaceae were investigated under semi-arid conditions. The leaf traits examined included leaf area and thickness, stomatal distribution, sclerop...Leaf traits, structure and water status of Conocarpus lancifolius, a Combretaceae were investigated under semi-arid conditions. The leaf traits examined included leaf area and thickness, stomatal distribution, sclerophylly, succulence and relative water content. Additionally, the types of secretory structures, histochemistry of trichomes, and chemical nature of the cuticlular waxes were evaluated. Leaves showed xerophytic characteristics including a high degree of sclerophylly, thick cuticle and outer epidermal cell wall, low relative water content and high trichome density on younger leaves. The species has two types of trichomes;a secretory, short-stalked capitate trichome and a non-secretory trichome with a bulbous base and a pointed tip. The leaves also have a pair of extrafloral nectaries on both sides of the distal end of the petiole, 3-4 pairs near the leaf apex and two secretory ducts or cavities on mature leaves that secreted polysaccharides, epicuticlar waxes and polyphenols. Compared to young leaves mature leaves had almost 3 times total cuticular wax deposit or load. The most abundant fatty acids were palmitic, stearic, nondecanoic, behenic and arachidic acids. The leaf traits and structures are discussed in relation to semi-arid habitat.展开更多
Aqueous leaf extract and pulverized leaf tissue were tested for allelopathic effects on seed germination, seedling growth traits and net photosynthesis of corn (Zea mays L.) and bean (Vigna sinensis L.) The chemical c...Aqueous leaf extract and pulverized leaf tissue were tested for allelopathic effects on seed germination, seedling growth traits and net photosynthesis of corn (Zea mays L.) and bean (Vigna sinensis L.) The chemical constituents of the leaf extract were determined by GC-MS and the efficacy of the leaf extract to control some soil-borne fungal pathogens was also evaluated. The leaf extract inhibited germination, radicle and plumule lengths, root and shoot growth, chlorophyll content, photosynthesis and nutrient uptake in both crops. In corn and bean plants growth inhibition was proportional to the concentrations of the extracts (2.5% - 7.5%). Seed germination was associated with water uptake and the solute potential of the extracts. Leaf extracts also reduced of chlorophyll content, and stressed photosynthetic function by reducing photochemical efficiency (Fv/Fm) and electron transport rate (ETR) of PS II in corn and bean plants. Corn was more tolerant to the leaf extract than bean plants. The GC-MS analysis detected thirty one and thirty three compounds in winter and summer leaf extracts, respectively. The majority was phenolic compounds. Mycelia growth of Fusarium oxysporum f. sp. lycopersicon, Sclerotinia sclerotiorum, and Rhizoctonia solani was inhibited and in 10% extract the fungi died. The extract however, had no effect on Trichoderma harzianum. Leaf extract of C. lancifolius exhibited both herbicidal and fungicidal properties but cannot be recommended for biological control of soil borne fungal plant pathogens because it has the potential to physiologically stress or damage cultivated plants or crops.展开更多
文摘Most aspects of microspore culture protocol have the capacity to cause stress to microspores, hence, less stressful treatments might be required to avoid deleterious effects. In stressed plants, polyamines and trehalose can act as compatible solutes or osmoprotectants by stabilizing proteins and biological membranes. To improve green plant regeneration in wheat microspore culture, this study assessed the effects of polyamines (putrecine, spermidine, spermine) and trehalose on androgenic response namely embryogenesis, green plant regeneration and ploidy of green plants regenerated in three spring wheat genotypes. Microspores of the genotypes produced significant numbers of embryos and green plants among polyamine treatments but trehalose had no effect (P ≤ 0.05). Polyamine treatments for 30 min generally produced more green plants per 100 microspores than the 60 min treatments in all three genotypes. At least three out of twelve polyamine treatments in each genotype improved the production of double haploid plants and seed setting in regenerants. Wheat genotype, concentration and duration of polyamine treatment had significant impact on embryogenesis and regeneration of green plants in this study. The study also showed that polyamines could be used to accelerate cultivar development in wheat breeding.
文摘Leaf traits, structure and water status of Conocarpus lancifolius, a Combretaceae were investigated under semi-arid conditions. The leaf traits examined included leaf area and thickness, stomatal distribution, sclerophylly, succulence and relative water content. Additionally, the types of secretory structures, histochemistry of trichomes, and chemical nature of the cuticlular waxes were evaluated. Leaves showed xerophytic characteristics including a high degree of sclerophylly, thick cuticle and outer epidermal cell wall, low relative water content and high trichome density on younger leaves. The species has two types of trichomes;a secretory, short-stalked capitate trichome and a non-secretory trichome with a bulbous base and a pointed tip. The leaves also have a pair of extrafloral nectaries on both sides of the distal end of the petiole, 3-4 pairs near the leaf apex and two secretory ducts or cavities on mature leaves that secreted polysaccharides, epicuticlar waxes and polyphenols. Compared to young leaves mature leaves had almost 3 times total cuticular wax deposit or load. The most abundant fatty acids were palmitic, stearic, nondecanoic, behenic and arachidic acids. The leaf traits and structures are discussed in relation to semi-arid habitat.
文摘Aqueous leaf extract and pulverized leaf tissue were tested for allelopathic effects on seed germination, seedling growth traits and net photosynthesis of corn (Zea mays L.) and bean (Vigna sinensis L.) The chemical constituents of the leaf extract were determined by GC-MS and the efficacy of the leaf extract to control some soil-borne fungal pathogens was also evaluated. The leaf extract inhibited germination, radicle and plumule lengths, root and shoot growth, chlorophyll content, photosynthesis and nutrient uptake in both crops. In corn and bean plants growth inhibition was proportional to the concentrations of the extracts (2.5% - 7.5%). Seed germination was associated with water uptake and the solute potential of the extracts. Leaf extracts also reduced of chlorophyll content, and stressed photosynthetic function by reducing photochemical efficiency (Fv/Fm) and electron transport rate (ETR) of PS II in corn and bean plants. Corn was more tolerant to the leaf extract than bean plants. The GC-MS analysis detected thirty one and thirty three compounds in winter and summer leaf extracts, respectively. The majority was phenolic compounds. Mycelia growth of Fusarium oxysporum f. sp. lycopersicon, Sclerotinia sclerotiorum, and Rhizoctonia solani was inhibited and in 10% extract the fungi died. The extract however, had no effect on Trichoderma harzianum. Leaf extract of C. lancifolius exhibited both herbicidal and fungicidal properties but cannot be recommended for biological control of soil borne fungal plant pathogens because it has the potential to physiologically stress or damage cultivated plants or crops.
