木薯内源细胞分裂素含量对块根淀粉积累的影响

Effects of endogenous cytokinin content on starch accumulation in root tuber of cassava

【目的】探讨木薯内源细胞分裂素(CTK)含量与块根淀粉积累的关系,为高淀粉木薯品种选育及栽培提供理论依据。【方法】以低淀粉木薯品种华南124和高淀粉木薯品种辐选01为试材,测定不同生育时期木薯叶片、茎秆和块根中的CTK含量与淀粉积累量,并分析两者间的相关性。【结果】华南124叶片CTK含量呈先下降后缓慢上升的变化趋势,辐选01则与之相反,呈先上升后缓慢下降的变化趋势。两个品种茎秆、块根CTK含量及块根淀粉积累速率均呈先上升后下降的变化趋势,淀粉含量从苗期至成熟期逐渐上升。在淀粉积累的关键时期即块根膨大中期(9月15日),辐选01叶片、茎秆和块根的CTK含量及淀粉积累速率均大于华南124,且除茎秆CTK含量外其他指标均达差异显著水平(P<0.05),说明该时期是形成高、低淀粉木薯品种淀粉含量差异的主要时期。相关性分析结果表明,华南124和辐选01块根CTK含量与淀粉积累量呈极显著正相关(P<0.01,下同),相关系数分别为0.58和0.60;华南124茎秆CTK含量和辐选01叶片CTK含量与其块根淀粉积累量呈极显著负相关,相关系数分别为-0.66和-0.75。【结论】木薯块根CTK含量对淀粉的积累起促进作用,而茎秆CTK和叶片CTK含量分别对低淀粉和高淀粉木薯品种的淀粉积累呈极显著的负向调节作用。

[ Objective IT he relationship between cassava endogenous cytokinin （CTK） and starch accumulation in the root tuber of different varieties of cassava was studied, in order to provide theoretical basis for breeding and cultivation of high-starch cassava variety. [Method]Using low-starch variety SC124 and high-starch variety Fuxuan 01 as materials, CTK content and starch accumulation in leaf, stem and root tuber of cassava were determined at different growth stages, and their correlations were analyzed. [Result]The content of CTK in leaf of SC124 first decreased and then increased slowly, conversely, Fuxuan 01 first increased and then decreased slowly. The CTK content in stem and root tuber and starch accu- mulation rate in root tuber of SC124 and Fuxuan 01 first increased and then decreased. The starch content increased gradu- ally from seedling stage to mature stage. Furthermore, the CTK content in leaf, stem and root tuber and starch accumulation rate of Fuxuan O1 were more than those of SC124 at middle stage of root tuber expansion （September 15 ）, with significant difference （P〈0.05） expect CTK content in root tuber, so which was key and main period of causing difference in starch content between high-starch and low-starch cassava cultivars. The correlation analysis results showed that, CTK content in root tuber of SC124 and Fuxuan 01 was significant positively correlated with starch accumulation in root tuber（P〈0.01 ,the same below）, the corresponding correlation coefficients were 0.58 and 0.60, respectively. And the CTK content in stem of SC124 was significantly negatively correlated with starch accumulation in root tuber, the corresponding correlation coeffi- cient was -0.66, and the CTK content in leaf of Fuxuan 01 was also significantly negatively correlated with starch accumu- lation in root tuber, the corresponding correlation coefficient was -0.75. [Conclusion]The CTK content in root tuber of cas- sava plays an important role in the starch accumulation, while the CTK content in stem and leaf has extremely significantly negative regulating effect on starch accumulation of low-starch and high-starch cassava varieties,