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【目的】阐明叶喷水杨酸(SA)对山药地下块茎蔗糖—淀粉转化的影响,为了解山药蔗糖转化机制、提高其淀粉形成提供参考。【方法】设置SA 0.0(对照)、0.5、1.0和5.0 mmol/L 4个处理,在山药(Dioscorea alata L.)“白扁”地下块茎形成的早期和后期分别进行叶面喷施,定期采样测定地下块茎主要碳水化合物含量和蔗糖裂解与淀粉形成的相关酶活性。【结果】除5.0 mmol/L SA处理的后期地下块茎总可溶性糖(TSS)含量急剧增加外,地下块茎的TSS、蔗糖、葡萄糖、果糖、淀粉、直链淀粉(AM)、支链淀粉(AP)和纤维素的含量在其他处理间的变化趋势相同。与对照相比,0.5mmol/L与5.0 mmol/L SA处理对山药地下块茎的影响作用相反,前者不仅显著提高了蔗糖合成酶(SuSase)、酸性转化酶(SAInv)、细胞壁结合酸性转化酶(CWBAInv)、中性转化酶(NInv)等酶的活性,而且显著增加腺苷二磷酸焦磷酸化酶(AGPase)、可溶性淀粉合成酶(SSS)、颗粒结合淀粉合成酶(GBSS)、淀粉分支酶(SBE)等酶的活性,1.0 mmol/L仅在块茎发育中期对上述酶有微小的促进作用。所有SA处理中,虽然蔗糖含量与SuSase及淀粉合成相关酶的活性呈不显著正相关,但蔗糖与总可溶性糖含量的比率与这些酶活性及淀粉含量成显著正相关。葡萄糖、果糖含量及它们所占总可溶性糖的比率与上述酶的活性分别呈显著负相关,葡萄糖与果糖的比率与上述酶的活性无显著相关性,蔗糖与葡萄糖、果糖的比率均与AGPase、SSS、GBSS的活性呈显著正相关。【结论】叶面喷施SA在山药地下块茎发育过程中通过作用于蔗糖裂解和淀粉合成相关酶的活性来影响蔗糖的运输和流向,小于1.0 mmol/L的SA通过提高酶活性来促进蔗糖转运入山药地下块茎并转化成淀粉,而其他浓度SA具有相反的作用。
【Objective】 The objective of this study is to elucidate the effects of foliar spray on the sucrose-starch conversion of yam undergrowth, in order to provide a reference for understanding the mechanism of sucrose conversion and the starch formation. 【Method】 Four treatments of SA 0.0 (control), 0.5, 1.0 and 5.0 mmol / L were set up, and foliar spraying was carried out in the early and late stages of tuber formation of Dioscorea alata L. Periodic sampling was used to determine the major carbohydrate content of underground tubers and the activity of enzymes involved in sucrose cracking and starch formation. 【Result】 The results showed that TSS, sucrose, glucose, fructose, starch, amylose (AM), amylopectin (AP) of underground tubers were significantly increased except for the content of total soluble sugar (TSS) ) And cellulose content in the other trends in the same trend. Compared with the control, 0.5 mmol / L and 5.0 mmol / L SA had the opposite effect on the underground tuber of yam, the former not only significantly increased the content of sucrose synthase (SuSase), acid invertase (SAInv), cell wall combined with acidic invertase CWBAInv and NInv, but also significantly increased the activities of AGPase, SSS, GBSS, Starch Branching Enzyme (SBE) and other enzymes activity, 1.0 mmol / L only in the tuberous mid-term on the enzyme has a slight role in promoting. In all SA treatments, although the sucrose content had no significant positive correlation with the activities of SuSase and starch synthesis related enzymes, the ratio of sucrose to total soluble sugar content had a significantly positive correlation with these enzyme activities and starch content. Glucose and fructose content and the proportion of their total soluble sugars were negatively correlated with the activity of the above enzymes respectively. The ratio of glucose and fructose had no significant correlation with the activity of the above enzymes. The ratios of sucrose to glucose and fructose were both significantly correlated with AGPase, SSS, GBSS activity was significantly positive correlation. 【Conclusion】 Foliar application of SA can affect the transport and flow of sucrose through the action of enzymes related to sucrose lysis and starch synthesis during the tuber development of yams. SA less than 1.0 mmol / L promoted sucrose transport by increasing the enzyme activity Into the yam underground tubers and transformed into starch, while other concentrations of SA have the opposite effect.