Ajay PalJhandai, Sonia2022-05-042022-05-042020https://krishikosh.egranth.ac.in/handle/1/5810184141Water dearth is the most critical issues in modern agriculture. Therefore, aerobic cultivation condition is sustainable concept to grow rice (Oryza sativaL.) which favors huge water impetus and labor. A better understanding of sucrose mobilization in shoots at vegetative and reproductive stages and developing grains at 7th–14th DAA may help in selection of rice genotypes to grow under aerobic condition. Herein, we have studied the effect of aerobic and conventional conditions on the activities of sucrose mobilization enzymes in four rice varieties viz. PAU201, HBC19 (lowland) and MAS26, MAS25 (aerobic) under pot condition. Aerobic condition significantly increased activities of sucrose synthesizing enzyme viz. sucrose phosphate synthase (SPS), sucrose phosphate phosphatase (SPP) and sucrose synthase (synthesis) (SSs). Activities of starch synthesizing enzymes viz.sucrose synthase (cleavage) (SSc), ADP-glucose pyrophosphorylase (AGPase) and soluble starch synthase (SSS) were reduced in concord with starch content under aerobic condition. Sucrose, soluble sugars, reducing and non-reducing sugars increased under aerobic condition in contrast with starch, UDP-glucose and ADP-glucose. UDP glucose pyrophosphorylase (UGPase) activity increased in shoot under aerobic condition to contribute sucrose synthesis while decreased in developing grains resulting in decreased starch content. Nitrogen, an essential component of all proteins, is one of the essential macronutrients required for better yield and therefore, nitrogen metabolism pathway was also studied under aerobic condition with respect to conventional condition and observed decreased activities under aerobic condition in both shoots and roots. Similar to enzymes, diminished metabolites viz. nitrite and alanine were observed under aerobic condition Crop sustainability under aerobic condition in all varieties could be attributed to osmoprotective role of sucrose and total soluble sugars. Our findings by semi-quantitative RT-PCR analysis also revealed up-regulation of SPS with down-regulation of AGPase and SUS transcript under aerobic condition is responsible for significant decrease in starch with increase in sucrose. Our results reveal decreased yield attributes under aerobic condition. Biochemical analysis, gene expression and yield attributes highlight the role of various enzymes prioritized for assimilate translocation under aerobic condition, and provide evidence of differentiation of metabolic pathway under two growing condition as well as aerobic and lowland rice varieties.EnglishThesis