Plant physiology

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

Role of cytokinin and salicylic acid in plant growth at low temperatures

Abstract: Low temperature restrains plant growth by inhibiting the cell cycle, and phytohormones play important roles in this case; however, the molecular mechanisms whereby phytohormones affect growth at low temperature are largely unknown. When grown at 23, 16, 10, and 4°C, we found that Arabidopsis thaliana could develop with normal morphology, but needed a prolonged period of cultivation. By screening mutants, we could implicate cytokinin and salicylic acid. At 4°C, both amp1 plants, which have an increased level of cytokinin, and wild-type plants treated with exogenous cytokinin, displayed relative growth rates greater than control by increasing total cell number. Additionally, transgenic NahG plants, which have lower salicylic acid content, grew faster than wild-type accompanied by larger cells. Expression of C-repeat binding transcription factors (CBFs), that mediate cold acclimation by stimulation of the expression of cold-inducible genes, was similar in all tested genotypes. Thus CBF expression did not correlate with the observed enhanced growth in mutants. The improved growth coincided with elevated expression of CYCD3;1, especially in NahG plants. At 4°C, enhanced endoreduplication took responsibility for larger cells in NahG plants, while enhanced cell division was observed in amp1 plants.

Plant Responses to High CO2 Concentration in the Atmosphere

Abstract: The impact of continuous rise in ambient CO2 concentration (AC) in the atmosphere on different facets of growth of crop plants is assessed. The effects of CO2 enrichment (EC) on plant growth, C3 and C4 photosynthesis, source-sink ratio, partitioning and translocation of metabolites, photosynthetic enzymes, respiratory rate, leaf area index, stomatal conductance (q s ), transpiration rate, biomass production and water use efficiency are reviewed. The CO2 fertilization effects are studied in both short-term (open top chambers) and long-term experiments. Long-term experiments suggest that ribulose-1,5-bisphosphate carboxylase is inactivated at high CO2 concentrations. Also g s is lowered. One of the conspicuous effects of EC is the closure of stomata in C3 plants. Photosystem (PS) 2 electron transport is more affected than PS1. Starch is the immediate product accumulated in the leaf of C3 plants. The “CO2 fertilization effect” does not confer any great advantage even in C3 plants.

Formation of Anthocyanins in Plants

Abstract: DISTINCT lines of investigation converge on the problem of the formation of antho-cyanins in plants, our information being derived from studies in plant physiology, in genetics and in the organic chemistry of the pigments and related members of the flavan group. Anthocyanins are frequently produced when photo-synthetic activity at the site of eventual pigmentation is diminished through seasonal changes or various kinds of injuries to the plant (mechanical, fungus disease, etc.). Under such conditions, carbohydrates and other synthetic products tend to accumulate as the result of interference with the translocation currents. Abundant nutriment favours anthocyanin formation, which can, in many cases, be accelerated by artificial feeding with sugars.

Sugar beet extract acts as a natural bio-stimulant for physio-biochemical attributes in water stressed wheat (Triticum aestivum L.)

Abstract: The present study investigated the role of sugar beet extract (SBE) as a bio-stimulant to ameliorate the adverse effects of drought on seed germination and growth of wheat (Triticum aestivum L.). Different concentrations of SBE (0, 10, 20, 30, 40 and 50%) were used for priming the wheat seeds. The experiment was conducted in laboratory (PEG-8000 was used to create water stress) as well as under natural environmental conditions (using soil with 100 and 60% field capacity). Significant ameliorating effects of seed priming with SBE were recorded on different germination attributes, i.e., time to 50% emergence (E50), germination index (GI), mean emergence time (MET), germination percentage (G%), coefficient of uniformity of emergence (CUE) and germination energy (GE) under water stress. Without priming, the plants exhibited symptoms of water stress like decreased biomass, reduction in photosynthetic pigments, e.g., chlorophyll, carotenoids. Seed pre-conditioning with SBE improved the plant growth, photosynthetic pigments, antioxidants’ activities and nutrient homeostasis of plants facing water deficit and grown under well-watered conditions. The maximum increase in biomass, content of chlorophyll, carotenoids and activities of superoxide dismutase (SOD) and peroxidase (POD) was 13.4, 8.5, 11.9, 7.6, 13.6, 42.0, 19.8%, respectively, with SBE seed priming under water stress. In conclusion, SBE seed priming effectively reduced the negativities of water stress on seed germination which resulted in better plant growth in terms of enhanced biomass, photosynthetic pigments, antioxidant defense mechanism and better nutrient homeostasis. Overall, the findings suggest that seed pre-conditioning with SBE as a bio-stimulant will be helpful for better crop stand establishment under low field capacity, especially in semi-arid and arid agricultural fields.

Handbook of Plant Growth pH as the Master Variable

Abstract: H+-ATPases in the plasma membrane - physiology and molecular biology H+-ATPase and H+-PPase in the vacuolar membrane - physiology and molecular biology the cytoplasmic pH stat confocal pH topography in plant cells - shifts of proton distribution involved in plant signalling pH as a signal and regulator of membrane transport the role of the apoplastic pH on cell wall extension and cell enlargement mechanisms and physiological roles of proton movements in plant thylakoid membranes dynamics of H+ fluxes in mitochondrial membrane H+ fluxes in nitrogen assimilation by plants.