Agronomic and physiological characteristics of a rice leaf early senescence mutant during its whole growth period

Abstract

AbstractDiverse rice (Oryza sativa L.) leaf early senescence mutants have been identified and used for studies on senescence mechanisms. However, the reports are few about the agronomic and physiological characteristics of rice leaf early senescence mutants during the whole growth period. This study used a rice leaf early senescence mutant (osled) and its wild type (WT) to compare their main phenotypic and agronomic traits at different growth stages, as well as some physiological characteristics. The results showed the osled plants exhibited leaf early senescence initiating from the middle seedling stage to maturation, accompanied with dwarf phenotype, prolonged vegetative growth period, decreased green leaf area, reduced aboveground biomass, decreased crop growth rate and net assimilation rate, smaller panicle, an awn of 1.56‐ to 1.58‐cm length, and more panicles. Compared with WT, the osled plants had significantly reduced chlorophyll content, photosynthetic capacity, N content, and activities of nitrate reductase and glutamine synthase in leaves and enhanced activity of glutamate synthase and lowered pre‐anthesis nonstructural carbohydrate accumulation and remobilization in stems. The study revealed some physiological mechanisms underlying leaf senescence of the osled and provided new perspectives for understanding the growth characteristics of rice leaf early senescence mutants.