施氮对块茎形成期高温胁迫后马铃薯块茎产量、淀粉含量和相关酶代谢活性的影响

为了明确不同施氮量对高温胁迫后马铃薯块茎淀粉合成酶、淀粉含量及产量的影响,本研究于2019-2020年在宁南山区海原县进行田间试验.供试品种为青薯9号,通过搭建高温棚构建高温环境,设2个温度处理(T1:块茎形成初期高温胁迫,T2:自然温度),4个氮肥水平(不施氮N0:0 kg·hm-2,低氮水平N1:75 kg·hm-...

Effects of Nitrogen Application Rate on Potato Yield,Starch Content and Related Enzyme Metabolic During Tuber Formation After High Temperature Stress

An experiment was conducted in Haiyuan County in the Ningnan mountains of Ningxia,from 2019 to 2020,to determine the effects of different nitrogen application rate on starch synthase,starch content and yield of potato tubers after high temperature stress with the tested variety of Qingshu 9.In the field,a high-temperature environment was constructed by building a high-temperature shed.There were two temperature treatments(T1:high-temperature stress at the initial stage of tuber formation,T2:natural temperature),and four nitrogen levels(no nitrogen NO:0 kg·hm²,low nitrogen level N1:75 kg·hm²,conventional nitrogen level N2:150 kg·hm²,and high nitrogen level N3:225 kg·hm²).The contents of amylopectin,amylose and total starch in potato tubers were determined,and the activities and yields of ADPG pyrophosphorylase(AGPase),UDPG pyrophosphorylase(UGPase),starch branching enzyme(SBE),soluble starch synthase(SSS),bound starch synthase(GBSS)in potato tubers were measured to clarify the interaction between nitrogen fertilization and temperature.The results showed that the yield reduction rates under different nitrogen levels ranged from 3.03%to 10.35%,among which the yield under N2 treatment was the lowest,and the yields under normal temperature treatment and high temperature stress were 43.95 t·hm²and 41.54 t·hm²,respectively.Meanwhile,the decrease rates of amylose,amylopectin and total starch content were distributed in 8.84%~17.71%,13.44%~25.67%and 12.77%~23.90%,respectively,under different nitrogen levels,and the size relationship among treatments was N2>N3>N1>N0.This is also consistent with the activity of starch synthase.At the same time,this study also found that under high temperature stress,the starch synthase activity of N0 and N1 treatments decreased more than that of N2 and N3 treatments.Under the experimental conditions,the nitrogen application rate of 150 kg·hm²can maintain the high activity of starch synthase after high temperature stress,and significantly reduce the decline of starch content,so that potatoes can maintain high starch synthesis ability,thus reducing the loss of yield and ensuring economic benefits.The results of this study investigated the effect of moderate nitrogen application on the mitigation of high temperature stress in potatoes,clarified the mechanism of mitigation,and provided a theoretical basis for stress-resistant and high-yielding potato cultivation.