中文摘要：

【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，0.5 mmol/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。

英文摘要：

[Objective]Effects of leaf-sprayed salicylic acid （ SA ） on the conversion of sucrose to starch in yam underground tuber was elucidated in order to provide references on knowing the mechanism of sucrose transformation and enhancing starch formation of yam. [Method]Four treatments of SA with 0.0（i.e. the control）, 0.5, 1.0, and 5.0 mmol/L were respectively sprayed thoroughly on leaves of Dioscorea alata L. cv. Baibian both at early and later of tuber forma-tion stages. Underground tuber was periodically sampled to determine the contents of predominant carbohydrates and the activities of enzymes related to sucrose cleavage and starch biosynthesis . [Result]With the exception of the sharp in-creases of total soluble sugar （TSS） content at later stage for 5.0 mmol/L SA treatment, the contents of TSS, sucrose, glucose, fructose, starch, amylose （AM）, amylopectin（AP）, and cellulose among the other treatments had the same pro-files of general change during the sampled period. Compared with the control , 0.5 and 5.0 mmol/L SA presented op-posed effects on underground tuber development , the former not only significantly increased activities of sucrose synthase （SuSase）, soluble acid invertase （SAInv）, cell wall-bound acid invertase （CWBAInv）, and neutral invertase（NInv）, but also significantly enhanced activities of adenosine diphosphate pyrophosphorylase （AGPase）, soluble starch synthase （SSS）, grain-bound starch synthase （GBSS）, and starch branching enzyme（SBE）. But 1.0 mmol/L SA treatment had slight-ly positive effects on these measured enzymes only at middle stage. In all treatments , although sucrose content showed insignificantly positive correlations with activities of both SuSase and related starch-synthesized enzymes, the ratio of su-crose to total soluble sugar was significantly and positively correlated with activities of SuSase, SAInv, CWBAInv, NInv, AGPase, SSS, GBSS, SBE and starch content. The contents of glucose, fructose and their ratios in total solubl