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在大田条件下,采用人工遮荫的方法探讨光照不足导致紫心甘薯块根品质下降的酶学机制。研究结果表明:在遮荫条件下,2个甘薯品种济薯18和Ayamurasaki叶片RUBPCase活性显著降低;叶片和块根中ATPase活性下降;块根ADPGPPase和UDPGPPase活性均显著降低,降低幅度随胁迫强度而增加;遮荫对块根可溶性淀粉合成酶(soluble starch synthase,SSS)和淀粉粒结合态淀粉合成酶(granulebound starch synthase,GBSS)活性的影响存在品种间差异,济薯18块根SSS活性显著降低,GBSS活性则不同程度高于对照,而Ayamurasaki的SSS活性却高于对照,GBSS活性则随遮光胁迫强度而降低;遮荫对花青素合成的关键酶苯丙氨酸解氨酶(Phenglalanine Ammonia Lyase,PAL)活性影响则很小。因此,遮荫胁迫从源库流各环节影响了紫心甘薯品质合成相关酶,其中RUBPCase、ATPase、ADPGPPase和UDPGPPase活性显著降低是导致紫心甘薯块根品质下降的主要原因。
Under field conditions, artificial shade method was used to explore the enzymatic mechanism of purple light sweet potato root quality caused by insufficient light. The results showed that under shading conditions, the RUBPCase activities of two sweet potato cultivars, Jishu 18 and Ayamurasaki, were significantly decreased; the activities of ATPase in leaves and roots were decreased; the activities of ADPGPPase and UDPGPPase in roots were significantly decreased, while the decreases were increased with the increasing of stress intensity; The effects of shading on the activities of soluble starch synthase (SSS) and granule binding starch synthase (GBSS) in root tuber differed among different cultivars. The activities of SSS in the roots of Jishu 18 were significantly decreased, while those of GBSS While the degree of SSS activity of Ayamurasaki was higher than that of the control, while the activity of GBSS was decreased with the intensity of shading. Phenglalanine Ammonia Lyase (PAL), a key enzyme in anthocyanin synthesis, The impact of activity is small. Therefore, shade-induced stress affected the quality-related enzymes of purple-purple sweet potato from the aspects of source and sink streams. The decrease of RUBPCase, ATPase, ADPGPPase and UDPGPPase activities was the main reason for the decrease of purple sweet potato tuber quality.