氮营养水平对秋马铃薯块茎发育中淀粉合成关键酶的影响

【目的】研究在秋季栽植条件下不同氮营养水平对马铃薯块茎发育过程中淀粉合成关键酶的影响。【方法】以高、低两类淀粉型品种为试验材料,4种氮营养水平处理,块茎形成后每隔7d取样测定块茎发育过程中的ADPG焦磷酸化酶(ADPGPPase)、可溶性淀粉合成酶(SSS)、淀粉分支酶(SBE)和结合性淀粉合成酶(GBSS),探讨他们之间的内在联系。【结果】结果表明:随着生育期的推进,各马铃薯块茎中不同施氮水平下的ADPGPPase、SSS、GBSS、SBE,呈现先逐渐增加,达到最大值后又开始下降的单峰曲线变化趋势,各施氮水平组的淀粉合成酶活性均在出苗后54～61d左右达到最大值。随着施氮量的增加,ADPGPPase、SSS也出现先升后降的单峰曲线变化趋势,而对于GBSS和SBE的影响,品种间表现差异。低淀粉品种CY-117的ADPGPPase、SSS的含量在各施氮水平下均高于高淀粉品种QS-2,具有较高的ADPGPPase、SSS活性。在氮营养影响条件下,SSS活性与淀粉总含量和支链淀粉的含量极显著正相关(r总淀粉=0.86**,r支链淀粉=0.83**),而与直链淀粉含量相关不大。【结论】氮营养主要是通过影响SSS的活性来实现对马铃薯块茎淀粉含量的影响。

Effects of Nourishment on the Key Enzymes of Starch Synthesis in the Process of Tuber Formation in Autumn Solanum tuberosumL.

【Objective】 In order to provide technical support for optimized planting techniques of autumn potatoes,we studied the effects of different levels of nitrogen fertilizer on the key enzymes of starch synthesis process during the development of the potato tuber under autumn planting condition.【Method】 High-and low-starch potatoes respectively were grown under four nitrogen levels(0,1.74,3.48,5.22 g/plant) in this experiment by single factor randomized block,and measured the related starch synthase activity and analyze their interrelation.【Results】 The results showed that: in the process of tuber development,all of the content of ADPGPPase,SSS,GBSS,SBE increased at first,then decreased after reaching the maximum,showing a single peak trend at every nitrogen level and reaching the maximal content at 54-61 days after emergence of seeding.With the increase in the amount of nitrogen,the ADPGPPase and SSS showed the same changes of single peak trend,but for the influence of GBSS and SBE,there were differences among varieties.The content and activity of ADPGPPase and SSS of low-starch potato CY-117 was higher than that of high-starch potato QS-2 at each nitrogen level.In nitrogen nutrition conditions,the SSS activity was significantly and positively correlated with the starch and amylopectin content(rstarch=0.86* *,ramylopectin=0.83* *),but was not significantly correlated with amylase content.【Conclusion】 The influence of nitrogen nutrition on tuber starch content is mainly by influencing the activity of SSS.