Plant physiology

About: Plant physiology is a research topic. Over the lifetime, 1537 publications have been published within this topic receiving 72038 citations.

Nitrogen manipulation affects leaf senescence during late seed filling in soybean

Abstract: It is known that soybean plants store nitrogen during vegetative growth stage, and then remobilize it to the seeds during seed filling. This nitrogen remobilization is assumed to induce leaf senescence. The objective of this study was to investigate whether the manipulation of nitrogen availability could affect leaf senescence during seed filling. Soybean variety Fukuyutaka was grown in the side-opened vinyl house in 2014 and 2015 in Saga University, Japan. The plants were sufficiently watered with the solution containing 100 mg L−1 nitrogen and other nutrients before starting the treatments. The nutrient solution with different nitrogen concentrations (5–800 mg L−1) was applied to the plants from R6 (full-seed) to R7 (physiological maturity) stages. Parallel to the progress of plant senescence after R6 stage, the leaf-SPAD value, leaf nitrogen and soluble protein contents decreased gradually in control plants (100 mg L−1 nitrogen); however, these parameters did not change in higher nitrogen concentration treatments, whereas decreased quickly in lower nitrogen treatments. Therefore, the leaves and stems in higher nitrogen treatments remained green even at harvest time when the whole plant senesced in control and lower nitrogen treatments. The relative expression of an autophagy gene, GmATG8c, which is associated with nitrogen remobilization, showed the lower the nitrogen availability the earlier the up-regulation. The present results revealed that the shortage of nitrogen could stimulate the leaf senescence, while increasing soil nitrogen availability could delay even stop the leaf senescence, indicating that the nitrogen availability could be a key regulating factor of monocarpic senescence in soybean.

Comparison of effects of bacterial strains differing in their ability to synthesize cytokinins on growth and cytokinin content in wheat plants

Abstract: The content of cytokinins and pigments together with the morphological parameters and fresh weight were estimated in durum wheat (Triticum durum Desf.) plants 2–4 days after introduction into their rhizosphere of an aliquot of Bacillus suspension using the strains that differed in their ability of producing cytokinins. The experiments were performed under laboratory conditions at the optimum light intensity and mineral nutrition. Inoculation with microorganisms incapable to synthesize cytokinins did not affect the total cytokinin content in the wheat plants, whereas the presence of cytokinin-producing microorganisms in the rhizosphere was accompanied by a considerable increase in the total cytokinin content and the accumulation of individual hormones. On the second day after inoculation, a dramatic increase in zeatin riboside and zeatin O-glucoside contents was observed in the roots, and at the next day the accumulation of zeatin riboside and zeatin was registered in the shoots of treated plants. The increase in cytokinin content promoted plant growth (the increased leaf length and width and a faster accumulation of plant fresh and dry weight). Plant treatment with a substance obtained from microorganisms incapable to synthesize hormones resulted in the insignificant growth stimulation. Plant treatment with a substance obtained from cytokinin-producing microorganisms increased leaf chlorophyll content; in this case, the level of chlorophylls was comparable to that observed in the plants treated with a synthetic cytokinin benzyladenine. The role of cytokinins of microbial origin as a factor providing for growth-stimulating effect of bacteria on plants is discussed.

Ultraviolet-C mediated physiological and ultrastructural alterations in Juncus effusus L. shoots

Abstract: Increased ultraviolet radiations intruding on the earth pose a serious threat to the unadapted plants. Due to the ecological and economic significance of mat rush (Juncus effusus L.), an in vitro experiment was conducted to unveil the toxic effects of ultraviolet radiation (UV-C) on its physiology and ultrastructure. The basal culm segments of plant were used for in vitro treatments of UV-C with different exposure times (15, 30 and 45 min). The treated segments were first transferred to 1/2 strength MS media and then shifted to soil-perlite mixture for further growth. With increasing exposure time to UV-C, there was significant reduction in plant growth and biomass, and increased activities of antioxidant enzymes. Physiological and ultrastructural alterations were observed in the shoots of UV-treated plants. These plants exhibited significant reduction in chlorophyll contents and noticeable modifications at the ultra-cellular levels. Cell and chloroplast size reduced greatly, and there was appearance of higher amounts of plastoglobuli in chloroplasts resulting in disruption of thylakoid integrity. The functional and ultrastructural alterations in the stressed plants suggest a potential hazard of UV-C radiation on this aquatic flora and thus the ecosystem. The study further explores that UV-C radiations trigger these modifications mainly by damaging the chloroplast.

Alterations in growth and metabolism of potato plants by calcium deficiency

Abstract: Experiment in water culture was conducted to evaluate the calcium deficiency symptoms and their cause inSolanum tuberosum L var Chandramukhi Meristematic regions at stem and roots were severely affected and ultimately ceased to grow Plants remained stunted with few and smaller tubers Reducing sugar, non-reducing sugar and starch accumulated more in the leaves and stems and less in roots and tubers of calcium deficient plants Deficiency caused decrease in protein nitrogen, RNA, DNA and increase in soluble nitrogen in all the plant parts Potassium, phosphorus, calcium and sodium contents were lower and magnesium content higher in the deficient plant, than that of the healthy ones Morphological symptoms of calcium deficiency can be established by ionic balance and accumulation of oxalic acid in potato plants