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

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

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^(2)、常规氮水平N2:150 kg·hm^(2)、高氮水平N3:225 kg·hm^(2)),测定马铃薯块茎支链淀粉、直链淀粉、总淀粉含量,腺苷二磷酸葡萄糖焦磷酸化酶(AGP)、尿苷二磷酸葡萄糖焦磷酸化酶(UGP)、淀粉分支酶(SBE)、可溶性淀粉合酶(SSS)、束缚态淀粉合酶(GBSS)活性和产量。结果表明,高温胁迫后各施氮水平下的减产率不同,介于3.03%~10.35%之间,其中N2的减产率最低,其常温处理与高温胁迫下的产量分别为43.95和41.54 t·hm^(2);各施氮水平下的直链淀粉、支链淀粉与总淀粉含量下降率分别介于8.84%~17.71%、13.44%~25.67%以及12.77%~23.90%之间,且处理间均表现为N2>N3>N1>N0,这也与各淀粉合成酶活性大小关系相吻合;本研究还发现,高温胁迫下N0、N1的淀粉合成酶活性下降幅度大于N2、N3。综上,本试验条件下,150 kg·hm^(2)的施氮量可以在高温胁迫后维持淀粉合成酶较高的活性,并明显减小了淀粉含量的下降幅度,使马铃薯保持较高的淀粉合成能力,从而减少产量的损失,保证经济效益。本研究探究了适量施氮对马铃薯高温胁迫的缓解效应,明确了其缓解机理,为马铃薯抗逆高产栽培提供了理论依据。

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·hm^(2),low nitrogen level N1:75 kg·hm^(2),conventional nitrogen level N2:150 kg·hm^(2),and high nitrogen level N3:225 kg·hm^(2)).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·hm^(2)and 41.54 t·hm^(2),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·hm^(2)can 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.