Abstract: To investigate effect of mulching on ridge-furrow for harvesting rainwater on the activity and gene expression of starch synthesis key enzyme and starch accumulation of rain-fed potato tuber during tuber formation, using Qingshu 9 as experimental material, the cultivated patterns included whole plastic mulching on double ridges and single ridge mulching with plastic film, the bare land flat sowing was set as control. The activity and gene expression of key enzymes in starch synthesis and starch accumulation indexes were determined by Ultraviolet-Visible Spectrophotometer and Fluorescence Quantitative PCR. The results showed that, compared with the control, under the whole plastic mulching on double ridges and single ridge mulching with plastic film, the soluble starch synthase (SSS) activity was increased significantly by 77.70% and 22.63%, respectively, and SSIII gene expression was increased significantly by 32.26% and 119.35%, respectively. Meantime, the activity of ADP-glucose pyrophosphorylase (AGPP), granule-bound starch synthase (GBSS) and ADP-glucose pyrophosphorylase AGPase, soluble starch synthase SSII, granule-bound starch synthase GBSSI, starch branching enzyme SBEI, and starch branching enzyme SBEII gene expression levels showed significant decrease, but the activity of starch branching enzyme (SBE) was not affected during the whole process of potato tuber formation. Compared with the control, the total starch content, amylase content and ratio of amylose to amylopectin were increased significantly by 5.04%, 17.57% and 27.81% under the whole plastic mulching on double ridges, respectively, while the starch accumulation index was decreased significantly by single ridge mulching with plastic film. SSS enzyme activity showed a significant negative correlation with GBSSI gene expression, and a significant positive correlation with amylase content and amylose to amylopectin ratio. The other key enzyme activity showed no significant correlation with the key enzyme gene expression and the starch accumulation index. The results are of great significance for selecting production measures of potato with high quality starch in the eastern arid area of Qinghai province.

Key words: mulching on ridge-furrow for harvesting rainwater, rain-fed potato, starch synthesis key enzyme activity, starch synthesis key enzyme gene expression, starch accumulation

摘要： 为探讨垄沟集雨覆盖栽培对旱作马铃薯块茎形成过程中淀粉合成关键酶活性、基因表达及淀粉累积的影响,以马铃薯栽培品种青薯9号为材料,设置全膜双垄和地膜垄作覆盖栽培模式,以露地平播为对照,测定马铃薯块茎形成过程中淀粉合成关键酶活性、基因表达及淀粉累积指标。结果表明,从块茎发育全过程来看,全膜双垄和地膜垄作覆盖栽培马铃薯可溶性淀粉合成酶(SSS)活性分别较露地平播显著提高77.70%、22.63%,可溶性淀粉合成酶SSIII基因表达量分别较露地平播显著提高32.26%、119.35%,同时,ADP-葡萄糖焦磷酸化酶(AGPP)、颗粒结合型淀粉合成酶(GBSS)活性和ADP-葡萄糖焦磷酸化酶AGPase、可溶性淀粉合成酶SSII、颗粒结合型淀粉合成酶GBSSI、淀粉分支酶SBEI、淀粉分支酶SBEII基因表达量均明显降低,而淀粉分支酶(SBE)活性无显著变化;全膜双垄覆盖栽培马铃薯总淀粉含量、直链淀粉含量及直/支链淀粉比较露地平播分别提高5.04%、17.57%和27.81%,达到显著水平,而地膜垄作明显降低了马铃薯总淀粉含量、直链淀粉含量及直/支链淀粉比;SSS活性与GBSSI基因表达量呈显著负相关,与直链淀粉含量及直/支链淀粉比呈显著正相关,其他淀粉合成关键酶活性均与基因表达量、淀粉累积指标无明显相关性。本研究结果对筛选青海东部旱区马铃薯适宜的淀粉优质生产措施具有重要意义。

关键词: 垄沟集雨覆盖, 旱作马铃薯, 淀粉合成关键酶活性, 淀粉合成关键酶基因表达, 淀粉累积