马铃薯块茎不同部位淀粉含量及淀粉合成关键酶活性差异比较

为探讨马铃薯块茎不同部位淀粉及相应酶活性差异,选用不同淀粉含量品种(高淀粉品种克新22号,低淀粉品种克新19号)为供试材料,分析块茎不同部位(顶部、右侧、脐部、左侧和髓部)干物质、淀粉含量(包括直、支链淀粉含量)和淀粉合成相关酶活性差异。结果表明,块茎淀粉品质(粗淀粉、直链淀粉和支链淀粉含量),由基因型可知,克新22号均高于克新19号;由块茎不同部位可知,两品种均表现块茎两侧脐部顶部髓部。淀粉形成关键酶活性,由基因型可知,克新22号SSS、GBSS和SBE活性均高于克新19号,而两品种AGPase活性差异不大;由块茎不同部位可知,总体表现块茎两侧脐部顶部髓部。其中,块茎不同部位SSS、GBSS和SBE活性差异显著,而AGPase活性差异不显著。研究结果为马铃薯块茎淀粉品质测定和淀粉合成酶活性合理取样提供科学依据。

Comparison of starch contents and starch synthase activities in different parts of potato tuber

The high-starch potato variety Kexin 22 and the low-starch variety Kexin 19 were selected as the test materials in order to investigate the difference of starch and the corresponding enzyme activities in different parts of potato tubers.The dry matter content,starch content (including amylose content and amylopectin content),as well as the activity of enzymes related to starch synthesis were measured and compared in the five parts of top,right,bottom,left and center tuber.For the tuber starch quality trait (crude starch content,amylose content and amylopectin content),Kenxin 22 was higher than Kexin 19,but Kexin 22 and Kexin 19 both showed the same tendency of sides＞ bottom＞ top＞ center.For the key enzyme activity of starch formation,the activities of soluble starch synthase (SSS),granule-bound starch synthase (GBSS) and starch branching enzyme (SBE) in Kexin 22 were higher than those in Kexin 19,however,there was no difference in ADP-glucosepyrophosphorylase (AGPase) between the two varieties.The overall trend was sides＞bottom＞ top＞center.The difference between GBSS,SSS and SBE in each sampling location was obvious,but the difference of AGPase was not.The results of this study would provide a scientific basis for adequately sampling potato tuber for determination of starch quantity and quality and starch synthase activity in potato tubers.