UV-B辐射增强对水稻多胺代谢及内源激素含量的影响

Effect of enhanced UV B radiation on polyamine metabolism and endogenous hormone contents in rice ( Oryza sativa L.).

研究表明 ,在处理前期 (7～ 14d) ,增强的UV B辐射能使供试水稻汕优 6 3(Sy6 3)的精氨酸脱羧酶(ADC)、鸟氨酸脱羧酶 (ODC)和s 腺苷蛋氨酸脱羧酶 (SAMDC)活性分别平均增加 16 5 .74 %、10 4 .6 0 %和89.6 0 % ,南川 (NC)的这 3种酶活性分别增加 5 9.91%、4 1.30 %和 2 3 .6 8% ,IR6560 0 85只表现出ADC和ODC活性分别平均提高 115 .93 %、14 .4 5 % ,SAMDC活性却下降 33.0 1% .在处理后期 (2 1～ 2 8d) ,Sy6 3的ADC和ODC活性分别比对照平均增加 89.72 %、3.71% ,NC则分别增加 73.95 %、2 7.38% ,IR6560 0 85表现为ADC活性增加 94 .4 1% ,ODC活性却下降 13 .5 7% .就SAMDC而言 ,处理后期 (2 1～ 2 8d) ,三者分别下降 4 0 .0 6 %、19.2 0 %和 38.2 1% .多胺氧化酶 (PAO)活性变化趋势恰好相反 ,从而引起多胺 (PA)含量特别是腐胺 (Put)含量明显上升 .此外 ,UV B辐射增强能使IAA和GA1/ 3 含量在整个处理期间 (7～ 2 8d)供试水稻品种 (组合 )Sy6 3分别平均下降 5 8.92 %和 4 5 .4 8% ,NC分别减少 4 3.31%和 5 6 .2 0 % ,IR6560 0 85则分别降低 38.6 9%和 4 7.33 % .所有供试水稻品种 (组合 )的ZRs含量表现为处理前期 (7～ 14d)有所降低 ,处理后期 (2 1～ 2 8d)则明显提高 .就ABA含量而言 ,整个处理期间

The results showed that the activities of Agrinine decarboxylase(ADC), Ornithine decarboxylase(ODC) and s Adenosylmethionine decarboxylase(SAMDC) were increased by 165.74%, 104.60% and 89.60% in the leaves of Shan You63(Sy63) and by 59.91%, 41.30% and 23.68% in the leaves of Nancheum(NC). Only ADC and ODC activities were increase by 115.93%, 14.45%, but SAMDC activity was decreased by 33.01% in the leaves of IR 65600 85 respectively in the exposure to enhanced UV B radiation for 7～14 days. In late treatment time course(21～28d), the activities of ADC and ODC were increased by 89.72% and 3.71% in the leaves of Sy63 exposed to UV B radiation for 21～28 days and by 73.95% and 27.38% in the leaves of NC. The activity of ADC was also increased by 94.41%, but ODC activity was decreased by 13.57% in the leaves of IR 65600 85 compared with the controls. As far as SAMDC was concerned, the enzymic activities in the leaves of Sy63, NC and IR 65600 85 were reduced by 40.06%, 19.20% and 38.21% respectively in the exposure to enhanced UV B radiation for 21～28 days. The reverse was true in the case of Polyamine Oxidase (PAO), this in turn resulted in increased contents of Polyamine(PA) especially putrescine(Put).In addition, the result also indicated that the contents of IAA and GA 1/3 were significantly reduced in all rice cultivars used for this experiments with enhanced UV B radiation treatments for 7～28 days, in which the contents of IAA and GA 1/3 were decreased by 58.92% and 45.48% in the leaves of Sy63, by 43.31% and 56.20% in the leaves of NC, and by 38.60% and 47.33% in the leaves of IR 65600 85 . The contents of ZRs in the leaves of the three cultivars concerned were lower in earlier treatment time courses (7～14d),but much higher in late courses(21～28d) compared with the their counterparts. With regard to the endogenous hormone of ABA, the content was significantly increased by 14 4%, 99.6 % and 56.7% respectively in the three rice cultivars concerned exposed to enhanced UV B radiation for 7～28 days, thereby led to decreased values of IAA/ABA, GA 1/3 /ABA and ZRs/ABA,consequently suppressed growth and development of rice.