水稻wx 基因对籽粒糖类积累和萌发种子淀粉酶活力的影响

 利用糯和非糯籼稻近等基因系原丰早和原丰早糯、珍竹19和珍竹19糯研究了糯质基因wx对籽粒糖类积累和萌发种子淀粉酶活力的影 响。wx使原丰早糯的还原糖和非还原糖分别较原丰早高0.07～2.94和1.04～4.55个百分点，珍竹19糯较珍竹19高 1.01～5.08及1.60～6.59个百分点。相反糯性籽粒发育过程中的淀粉含量分别较非糯籽粒低0.34～5.01及0.72～6.64个百分点。wx自籽粒发育始期就控制合成稳定高比例的支链淀粉。萌发的糯性种子β-淀粉酶和R酶活力较高，而非糯种子α-淀粉酶活力较高。同工酶电泳结果表明wx基因对种子α-淀粉酶带影响较大。外源GA3诱导后，带胚的非糯籽粒α-淀粉酶活力也较强。

Effect of Rice wx Gene on Carbohydrate Accumulation and Amylase Activity of Germinating Grain

Effects of rice wx gene on accumulation of carbohydrates during grain development and activitiesof amylases in germinating grains were studied using two pairs of waxy and nonwaxy near-isogenic lines Yuanfengzao and waxy-Yuanfengzao, Zhenzhu 19 and waxy-Zhenzhu 19(Oryza sativa L. subsp. indica). The wx led to 0.07-2.94 and 1.04-4.55 percentage point respectively more reducing and nonreducing sugars in waxy-Yuanfengzao than Yuanfengzao and 1.01-5.08 and 1.60-6.94 Percentage point respectively more in waxy-Zhenzhu 19 than Zhenzhu 19. Starch content was 0.34-5.01 and 0.72-6.59 percentage point lower in the waxy grains than in the nonwaxy grains respectively. It is suggested that the wx gene control the synthesis of amylopetin with stable high ratio since the early stage of grain development. Activities of β-amylasc and R-enzyme were higher, while α-amylase was lower activity in the germinating waxy grains than in the germinating nonwaxy grains. Electrophoresis of amylase isozymes indicated that the α-amylase band was more greatly affected by the ax gene. Higher α-amylase activity induced by GA₃ was also observed in the nonwaxy grains than waxy grains.