不同品质类型玉米籽粒充实期的胚乳细胞增殖与生理活性比较

Comparison of Multiplication of Endosperm Cell and Physiological Activity in Developing Kernels among Normal Corn, Glutinous Corn, and Pop Corn

以普通玉米、糯玉米和爆裂玉米为试材,比较研究了籽粒胚乳细胞数目、物质积累特点、激素含量变化和淀粉合成相关酶活性等方面的类型间差异。结果表明,3种类型玉米籽粒胚乳细胞增殖进程早于干物质的增加进程,普、糯、爆籽粒胚乳细胞数目分别在授粉后24、18和13d达到最大值,粒重分别在授粉后45、40和30d达最大值;在籽粒淀粉积累全程,糯玉米总淀粉含量高于同时期普通玉米和爆裂玉米,尤其是在授粉后30d内差异最明显,普通玉米与爆裂玉米间差异不大;籽粒淀粉积累速率的类型间差异主要表现在积累速率极值大小及其出现时间的早晚两个方面,糯玉米淀粉积累速率最大值分别是普通玉米和爆裂玉米的1.61倍和1.34倍,糯玉米淀粉积累速率最大值出现在授粉后10d,普通玉米和爆裂玉米则在授粉后20d。普通玉米的胚乳细胞数目与籽粒灌浆速率极显著正相关,糯玉米显著正相关,爆裂玉米相关不显著。在整个籽粒充实期,普通玉米籽粒的玉米素(ZR)含量都高于同时期的糯玉米和爆裂玉米,而糯玉米又高于爆裂玉米;籽粒生长素(IAA)、脱落酸(ABA)和赤霉素(GA3)含量在3个类型间的差异规律则与ZR刚好相反。3个品质类型的籽粒蔗糖合成酶(SS)活性类型间差异不显著,但在籽粒充实后期普通玉米SS活性下降最慢,而爆裂玉米下降最快;糯玉米的可溶性淀粉合成酶(SSS)和ADPG焦磷酸化酶(ADPGPPase)的籽粒充实期平均活性明显高于普通玉米和爆裂玉米;爆裂玉米的束缚态淀粉合成酶(GBSS)的籽粒充实期平均活性高于普通玉米和糯玉米。

The multiplication of endosperm cell and the physiological characteristics in developing kernels were investigated among normal corn, glutinouscorn and pop corn in this study. The number of endosperm cell, the traits of carbohydrate accumulation, the change of hormone content and the activities of enzymes related to starch corn, the process of kernel endosperm cell proliferation was earlier than that of the dry matter increase; the number of kernel endosperm cells reached the maximum at 24, 18, 13 days after pollination, while kernel weight at 45, 40, 30 d respectively. In the process of starch accumulation, the total content of starch of glutinous corn was higher than that of normal corn and pop corn at the same period, especially at 30 d after pollination and the difference was obvious, and that between normal corn and pop corn was not distinct; the difference of the speed of kernel starch accumulation among different types was mainly manifested in two aspects faster or slower and earlier or later for accumulation. The maximum of glutinous corn starch accumulation rate was 1.61, 1.34 times higher than that of normal corn and pop corn. The maximum rate of starch accumulation of glutinous corn appeared at 10 d after pollination, while that of normal corn and pop corn at 20 d after pollination. The number of endosperm cell was significantly correlated with the filling rate of kernel in normal corn at the 0.01 probability level, and in glutinous corn at 0.05 level, while not significantly correlated in pop corn. In kernel-filling period, the content of ZR was higher in normal corn than in glutinous corn and pop corn at the same period, moreover, in the glutinous corn than in pop corn. The differences among the three typesin the content of IAA, ABA, and GA3 were exactly opposite to those of ZR. The difference of SS activity among the three quality types was not significant, but in later kernel-filling stage, the SS activity declined slowly in normal corn and fast in pop corn fast. The average activity of SSS and synthesis were compared in different types of corn. The results showed that for normal, glutinous and popADPG-PPase of glutinous corn was significantly higher than that of normal corn and pop corn in the kernel-filling period. The average activity of GBSS of pop corn was higher than that of normal corn and glutinous corn. The activity of GBSS for pop corn kernel was the highest one in the three corn types.