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 Plant Nutrients in Plant Growth and Physiology

Abstract: A mineral element is considered as essential based on the criteria of essentiality given by Arnon (Criteria of essentiality of inorganic micronutrients for plants. In: Wallace T Trace elements and plant physiology. Chronica Botanica, Waltham, pp 31–39, 1954), according to which 16 elements known as mineral nutrients are required for completion of a productive life cycle in plants. These mineral nutrients are carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, manganese, zinc, copper, boron, molybdenum and chlorine. Of these C and at times S are taken up from air as CO2 and SO2, and oxygen and hydrogen are provided as water. The soil is the source for uptake of the other elements by plants. Based on their requirement, these nutrients have been classified as macronutrients (N, P, K, Ca, Mg and S) because they are required at concentrations higher than 1–150 g per kg of plant dry matter and micronutrients (Fe, Zn, Mn, Cu, B, Mo and Cl) which are required at concentration of 0.1–100 mg per kg of plant dry matter. However their requirement per se does not alter their significance for the plant growth and metabolism. The mineral nutrient elements play essential roles such as constituent of cell structures and cell metabolites, in cell osmotic relations and turgor-related processes, energy transfer reactions, enzyme-catalysed reactions and plant reproduction. Plant productivity depends on the efficient discharge of these functions. In this chapter we focus on the main functions of the mineral nutrients that have a bearing on the quantitative and qualitative aspects of crop productivity.

Expression of a plant cell wall invertase in roots of Arabidopsis leads to early flowering and an increase in whole plant biomass.

Abstract: In order to enhance sink strength, we expressed a heterologous plant cell wall invertase (CrCIN1) under the control of a root-specific promoter (ppyk10) in Arabidopsis thaliana. Slightly elevated apoplastic invertase activity resulted in apparent phenotypic changes. Transgenic plants developed more secondary roots and subsequently, possibly because of a higher capacity to acquire nutrients, a higher shoot and whole plant biomass. Furthermore, an early flowering phenotype was detected. The data presented here demonstrate that it is possible to modulate carbohydrate metabolism by ectopic expression of cell wall invertases and thereby influence sink organ size and whole plant development.

Hormonal regulation during plant fruit development

Abstract: The modern concept of the hormonal regulation of fruit set, growth, maturation, and ripening is considered. Pollination and fertilization induce ovule activation by surmounting the blocking action of ethylene and ABA to be manifested in auxin accumulation. Active fruit growth by pericarp cell division and elongation is due to the syntheses ofauxin in the developing seed and ofgibberellins in the pericarp. In climacteric fleshy fruits, the maturation is controlled by ethylene via so-called System 1 combining the possibilities of autoinhibition and autocatalysis by ethylene of its own biosynthesis. Transition of tomato fruits from maturation to ripening is characterized by highly active synthesis of ethylene and its receptors due to the functioning of regulatory System 2 resulting in the up-regulation of much greater number of ethylene-inducible genes. In peach fruits, the hormonal regulation of ripening includes also an active auxin involvement in the ethylene biosynthesis, which is combined with the ethylene-induced expression of genes encoding both auxin biosynthesis and the response to auxin. Ethylene induces the expression of genes responsible for the fruit softening, its taste, color, and flavor. Nonclimacteric fleshy fruits produce very small amounts ofethylene; its evolution increases only by the very end of ripening and can be described by a reduced System 1. The ripening of nonclimacteric fruits only weakly depends on ethylene but is stimulated by abscisic acid.

Alleviation of Field Low-Temperature Stress in Winter Wheat by Exogenous Application of Salicylic Acid

Abstract: Low temperature in later spring severely limits plant growth and causes considerable yield loss in wheat. In this study, the impacts of exogenous salicylic acid (SA) on plant growth, grain yield and key physiological parameters of wheat plants were investigated under field low-temperature conditions using a field air temperature control system (FATC). The results showed that low-temperature stress significantly decreased leaf net photosynthetic rate, plant height and biomass production of wheat plants at the jointing stage, resulting in a reduction in grain yield. Moreover, the growth period of wheat plants was prolonged by low-temperature stress. However, SA-treated plants significantly improved the photochemical efficiency of photosystem II, accumulation of osmo-protectants, activities of enzymatic antioxidants, and pool of non-enzymatic low molecular substances compared with non-SA-treated plants under low-temperature stress. Pretreatment with SA effectively alleviated low-temperature-induced reduction in leaf net photosynthetic rate, plant height, biomass production and grain yield as well as prolonging of growth period of wheat plants. However, SA-treated plants had no significant effects on the expression levels of cold-responsive genes compared with non-SA-treated plants under low-temperature stress. Our results demonstrated that exogenous application of SA is an appropriate strategy for wheat to resist late spring low-temperature stress under field conditions.