Analysis of Non-Structural Carbohydrate in Relation with Shoot Elongation of Rice under Complete Submergence

Abstract

Regulation of non-structural carbohydrates (NSCs) are important for plants in response to submergence. In this study, the difference in non-structural carbohydrates in relation with shoot elongation between Sub1A and non-Sub1A rice genotypes was investigated. Two rice genotypes, namely Inpari30 (Sub1A genotype) and IR72442 (non-Sub1A genotype), were submerged completely for 6 days and re-aerated by lowering water level up to stem base for 6 days of post submergence. In addition, non-submerged plants (control) was treated with water level up to stem base during the experiment. Photosynthesis rate decreased in both submerged Inpari30 and IR72442 genotypes 71% and 96% lower than their control, respectively. Submerged IR72442 declined Fv/Fm 15.6% lowest than its control and both control and submerged Inpari30. Investigation of the distribution of starch and soluble sugar content in plant organs suggested that shoot elongation of non-Sub1A genotype led to starch and sugar consumption that distributed faster to the new developed organ during submergence. In contrast, Sub1A genotype of Inpari30, which did not exhibit shoot elongation and showed slower NSCs distribution during submergence, performed better on post submergence by maintaining NSCs and distributing to the new developed organ faster than IR72442. These results suggest that Sub1A genotype managed elongation and NSCs during submergence more efficiently than non-Sub1A genotype.