不同株型玉米籽粒淀粉积累及相关酶活性的研究

【目的】研究不同株型玉米籽粒和穗位叶代谢底物、淀粉积累及相关酶活性的变化动态，同时探讨各种酶活性与淀粉含量的关系。【方法】以“先玉335”(紧凑型玉米品种)和“农大518”(平展型玉米品种)为试验材料，于授粉后10 d每隔5 d取植株的穗位叶及相应果穗中部籽粒，分别测定穗位叶蔗糖含量、磷酸蔗糖合成酶(SPS)和蔗糖合成酶(SS)活性，以及籽粒2种焦磷酸化酶(ADPGPPase、UDPGPPase)、可溶性淀粉合成酶(SSS)和束缚态淀粉合成酶(GBSS)活性及直链和支链淀粉含量。【结果】2个玉米品种的穗位叶SS活性在整个灌浆期呈现单峰曲线变化趋势，授粉后35～40 d，“先玉335”的SS活性显著高于“农大518”；“先玉335”的SPS活性则在授粉后25~35 d显著高于“农大518”。在整个灌浆期，2个玉米品种籽粒ADPGPPase、UDPGPPase、SSS和GBSS活性的变化均呈单峰曲线，其中“先玉335”籽粒ADPGPPase和UDPGPPase活性峰值出现的时间均比“农大518”晚5 d左右；在整个灌浆期，2个玉米品种籽粒SSS活性和直链淀粉含量无显著差异；在授粉后35～40 d，“先玉335”籽粒ADPGPPase、UDPGPPase、GBSS活性和支链淀粉含量显著高于“农大518”。相关分析表明，玉米穗位叶SS活性与籽粒ADPGPPase、UDPGPPase活性呈显著正相关；穗位叶SPS活性与籽粒SSS活性、直链淀粉含量呈显著正相关；籽粒GBSS活性与SSS和UDPGPPase活性、直链淀粉含量及穗位叶SS、SPS活性均呈显著正相关。【结论】“先玉335”源的光合产物比“农大518”能够更有效地向库端运输和分配；籽粒淀粉含量是各种酶综合作用的结果。

Analysis of starch accumulation and key enzymes activities for starch synthesis in different genotype maizes

【Objective】The objectives of this study were to elucidate the relationship between starch accumulation and grain starch,and to characterize the variance between the compact and loose-leaf cultivars in starch accumulation.【Method】"Xianyu 335"(the compact maize variety) and "Nongda 518"(the common maize variety) were chosen as the experiment material.Central kernels and ear leaf were collected after the pollination stage,and sugar content,SPS,SS,adenosine diphosphorate glucose pyrophrylase(ADPGPPase),uridine diphosphate glucose(UDPGPPase),soluble starch synthase(SSS) and granule-bound starch synthase(GBSS) and starch content were determined,and the relationship was analyzed.【Result】SS activities assumed the unimodal curve change during the whole filling,of which "Xianyu 335" in the leaf located near the ear were significantly higher than that of "Nongda 518" after the pollination 35-40 days.SPS activities of "Xianyu 335" were significantly higher than that of "Nongda 518" after the pollination 25-35 days.There was no significant difference in SSS activity and amylose content between "Xianyu 335" and "Nongda 518".And the activity of ADPGPPase,UDPGPPase,GBSS and amylopectin content were higher significantly than that of "Nongda 518" after the pollination 35-40 days.Correlation analysis indicated that SS activity was highly correlated with ADPGPPase and UDPGPPase,SPS activity was significantly correlated with SSS and amylose content.And there was close correlation between GBSS and SSS,UDPGPPase,amylose content,SS,SPS.【Conclusion】The transportation and distribution of "Xianyu 335" was overmatched compared with "Nongda 518".And the starch content of kernels was the results of the actions of all enzymes.