Studies On The Physiological And Molecular Mechanism Of Submergence Tolerance In Rice (Oryza Sativa L.)

Submergence stress does severe harm to rice production. Evaluation of rice submergence tolerance at tillering stage was set up in the paper, submergence tolerance of 19 varieties at tillering stage was evaluated. At one time, physiologic and biochemical changes between hybrid and inbred rice after different submergence stress was compared in the paper. Then , Differential Display Reverse Transcript Polymerase Chain Reaction (DDRT—PCR)was applied to study the differences of gene expression profile between the most submergence tolerant rice and the most submergence sensitive rice under submergence stress at tillering stage, separation and cloning of differentially expressed gene were also done. Finally, the F₁ and F₂ propagates derived from the most submergence tolerant and the most submergence sensitive parents were studied for genetic analysis and SSR analysis. The results showed that:(1) This thesis studied the capacity for submergence tolerance and the effects of different submergence stress on some agronomic characters in rice at tillering stage. The results showed that: The relative survival of leaf and degree of stem injury can be used in evaluation of submergence tolerance. The 19 varieties can be divided into three types: submergence tolerant, submergence moderate and submergence sensitive. FR13A and IR39595-503-2-1-2 were established as the most submergence tolerant and the most submergence sensitive varieties. As submergence stress increased , the plant height changed generally from short to high and then to short, and delayed days of heading date increased and showed submergence tolerant>submergence moderate> submergence sensitive in three types, and the effects of submergence stress on yield indicated that submergence sensitive>submergence moderate>submergence tolerant.(2) The agronomic traits and biochemical characters of 16 varieties of hybrid rice and inbred rice, which widely planted in Hunan province, were investigated under different submergence stress at tillering stage in this thesis. The results were showed as follows: The submergence tolerance of hybrid rice, scaled by the relative survival of leaf,...