Abstract: For exploring the effect mechanism of different nitrogen application amounts impact on potato tuber starch formation and yield in Ningxia arid areas, field trials were carried out in the mountainous areas of southern Ningxia in 2017(normal year) and 2019(wet year) respectively. The potato cultivar Qingshu No. 9 was used as the material and a single factor random Block experiment was designed, with no nitrogen fertilizer (N0) as the control, to study the effects of pure nitrogen application rate of 75 (N1), 150 (N2), 225 kg·hm^-2 (N3) on potato starch content, key starch forming enzymes and yield. The results showed that with the increase of nitrogen application amount, the total starch and amylopectin content increased first and then decreased, with N2 being the highest, significantly increasing by 21.23, 26.42 percentage point (2017) and 19.74、24.93 percentage point(2019); while the amylose content increased with the increase of nitrogen application amount, reaching the highest at N3, which was 1.59 percentage point (2017) and 1.78 percentage point (2019) higher than N0. Both adenosine diphosphate glucose pyrophosphorylase (AGPP) and starch branching enzyme (SBE) had the highest N2, which increased by 57.38%, 36.83% (2017) and 67.19%, 29.01% (2019) compared with N0, respectively; while soluble starch synthase (SSS) and bound starch synthase (GBSS) were the highest with N3, which increased by 33.90%, 49.51% (2017) and 46.02%, 51.00% (2019) respectively compared with N0. Correlation and general analysis show that starch content and key enzymes in starch synthesis have a positive correlation, and AGPP, SSS, and GBSS have a greater direct contribution to the process of starch synthesis; Compared with N0, the potato output of N1~N3 increased by 10.72%~21.02% and 8.40%~16.30% in 2017 and 2019, respectively. The yield of N2 is the best; the best nitrogen application rate to achieve the highest yield is 150-184 (2017), 150-196 kg·hm^-2 (2019). Therefore, it is suggested that the nitrogen application amount of 150-200 kg·hm^-2 for potato in arid areas of Ningxia can effectively increase the activity of key enzymes in starch formation, accelerate starch formation and accumulation, and promote the increase of potato production, thereby increasing the economic benefits of local people.

Key words: potato, nitrogen, starch, starch forming key enzyme, yield

摘要： 为探索不同施氮量对宁夏旱区马铃薯块茎淀粉形成和产量的影响机理,分别于2017年(平水年)和2019年(丰水年)在宁夏南部山区开展大田试验,以马铃薯栽培品种青薯9号为材料,采用单因素随机区组试验设计,以不施氮肥(N0)为对照,研究施纯氮量75(N1)、150(N2)、225 kg·hm^-2(N3)对马铃薯淀粉含量、淀粉形成关键酶及产量的影响。结果表明,随着施氮量的增加,总淀粉和支链淀粉含量呈先上升后下降的趋势,以N2最高,分别较N0显著提高21.23、26.42个百分点(2017年)和19.74、24.93个百分点(2019年);而直链淀粉含量随着施氮量的增加而增加,在N3达到最高,比N0增加1.59个百分点(2017年)、1.78个百分点(2019年)。腺苷二磷酸葡萄糖焦磷酸化酶(AGPP)和淀粉分支酶(SBE)均以N2最高,分别较N0增加了57.38%、36.83%(2017年)和67.19%、29.01%(2019年);而可溶性淀粉合酶(SSS)和束缚态淀粉合酶(GBSS)活性则以N3最高,分别较N0增加33.90%、49.51%(2017年)和46.02%、51.00%(2019年)。相关、通径分析结果表明,淀粉含量与淀粉合成关键酶均呈正相关,AGPP、SSS、GBSS在淀粉合成过程中的直接贡献较大;与N0相比,N1~N3在2017年和2019年的产量分别增加了10.72%~21.02%和8.40%~16.30%,以N2的产量最优;综合产量回归曲线分析可知,达到最高产量的最佳施氮量为150~184(2017年)、150~196 kg·hm^-2(2019年)。因此,建议宁夏旱区马铃薯施氮量为150~200 kg·hm^-2,该条件能有效提高淀粉形成关键酶活性,加快淀粉形成和积累,促进马铃薯产量增加,从而提高当地农民的经济收益。

关键词: 马铃薯, 氮素, 淀粉, 淀粉形成关键酶, 产量