葛根淀粉合成关键酶活性动态及其与块根产量和淀粉积累的相关性研究

Dynamics of key enzyme activity in starch synthesis and its correlation with yield and starch accumulation of root tubers in Kudzu

关键词:  葛根, 关键酶, 酶活性, 淀粉积累, 相关性

Key words:  Kudzu root, key enzyme, enzyme activity, starch accumulation, correlation

摘要:

为探讨葛根发育过程中淀粉合成关键酶活性与块根产量和淀粉积累的关系,以初步揭示其内在的生理机制。该研究以‘桂葛1号'粉葛和‘桂葛8号'野葛为材料,采取生理测定法对农艺性状、直链和支链淀粉的含量、淀粉合成关键酶活性等进行测定,并对葛根发育过程中淀粉合成关键酶活性、农艺性状和淀粉含量动态变化的关系进行相关性分析。结果表明:(1)块根发育过程中,两品种葛根腺苷二磷酸葡萄糖焦磷酸化酶(AGPase)、可溶性淀粉合成酶(SSS)、束缚性结合淀粉合成酶(GBSS)和淀粉分支酶(SBE)的活性呈现先增大后降低的单峰曲线变化,与直链淀粉、支链淀粉和总淀粉含量由缓慢增长到快速增长后趋于稳定的变化趋势基本一致,即在块根形成期至膨大期逐渐增长,至膨大后期达到最大,之后迅速下降,至成熟期缓慢下降,并维持在较高水平。(2)‘桂葛8号'的淀粉含量和产量显著高于‘桂葛1号',其酶活性也均显著高于‘桂葛1号'。(3)葛块根的根长、根粗、单株重、干物质含量、产量表现为“缓慢-快速-稳定”的变化趋势,淀粉含量表现出类似变化。(4)相关性分析结果显示,4个淀粉合成关键酶活性与块根直链淀粉、支链淀粉及总淀粉含量、根长均呈显著或极显著正相关,与单株重、产量、干物质含量及根粗呈正相关,但差异不显著。综上认为,淀粉含量增加是葛根生长膨大增粗的结果,提高AGPase、SSS、GBSS和SBE的酶活性和竞争底物的能力,可提高葛根淀粉及其组分的积累,从而提高产量和品质。

Abstract:

The purpose of this study was to explore the key enzyme activity of starch synthesis and its relation with yield and starch accumulation during the development of Kudzu root, and to reveal the intrinsic physiological mechanism. With ‘Guige 1'(Pueraria montana var. thomsonii)and ‘Guige 8'(P. montana var. lobata)as materials, we determined the agronomic traits, the content of amylose and amylopectin, and the key enzyme activity of starch synthesis, and analyzed their relationship of dynamic changes. The results were as follows:(1)During the development of root tubers, the activity changes of ADP-glucose pyrophosphorylase(AGPase), soluble starch synthase(SSS), granule-bound starch synthase(GBSS)and starch branching enzyme(SBE)in two varieties of P. lobata showed a single peak curve that first increased and then decreased, it was basically consistent with the trend that the contents of amylose, amylopectin and total starch increased from slow to rapid and then stabilizing, that was, from formation period to expansion period, they increased gradually; they reached the maximum in the later expansion stage and declined rapidly in a later; to the maturity stage, they declined gradually and maintained at a higher level.(2)The yield and starch content of ‘Guige 8' were significantly higher than those of ‘Guige 1', the enzyme activity of ‘Guige 8' was also significantly higher than that of ‘Guige 1'.(3)The average length and width of root tubers, fresh weight per plant, dry matter content and yield showed a trend of “slow-fast-stable”, and starch content showed similar changes.(4)Correlation analysis showed that four key enzyme activities of starch synthesis were significant or highly significant positively correlated with the contents of amylose, amylopectin and total starch and the average length of root tubers; they were positively correlated with the fresh weight per plant, yield, dry matter content and the width of root tubers, but the difference was not significant. On the whole, the increase of starch content is the result of swelling and thickening of Kudzu root. Improving the enzyme activities of AGPase, SSS, GBSS and SBE and the ability to compete for substrates can improve the accumulation of Kudzu root starch and its components, thereby improving the yield.