Regulation of a GA 3/4pu 30 Compound (90 09)on Senescence of Hybrid Rice Leaf

1TANG Risheng, 2GU Qirong, 3ZHANG Futian, 1MEI Chuansheng, 4YANG Jiahe, and 5LOU Dengyi ( 1Institute of Agrobiological Genetics and Physiology, Jiangsu Academy of Agricultural Sciences,Nanjing

endogenous hormones; protein; nucleic acids; hemoglobin digesting proteinase; RNase; leaf senescence; hybrid rice

To study the effects of 90 09 on the senescence of hybrid rice leaf,the changes of contents of endogenous hormones (ABA,ZRs,GAs and IAA),and the changes of contents of protein and nucleic acids and their degradation enzyme activies were investigated during leaf senescence.Results showed that senescence of hybrid rice leaf treated with 90 09 was delayed obviously,and that increases of the content of endogenous ABA and the decreases of contents of endogenous ZRs,GAs and IAA were all slowed down than control,and the increases of specific activity of hemoglobin digesting proteinase and RNase and the decreases of contents of protein and RNA and DNA were significantly delayed.At the 28th day after first spray of 90 09,the content of ABA was 36 0% lower and the contents of ZRs,GAs and IAA were 108 9%,218 8% and 42 9% higher in 90 09 treatment than in control respectively,and the specific activity of hemoglobin digesting proteinase and RNase were 58 7% and 27 5% lower and the contents of protein,RNA and DNA were 34 5%,16 3% and 29 7% higher in 90 09 treatment than in control respectively. It was proposed that the regulation of 90 09 on the senescence of hybrid rice leaf is throughly regulating endogenous hormones(ABA,ZRs,GAs and IAA)levels,and inhibiting the increasing of specific activity of proteinase and RNase,and delaying the degradation of protein and nucleic acids during senescence of leaf.