Abstract:The ‘Xinchun No.4’ cucumber was used as the test material in this experiment. Meanwhile, the effects of exogenous 4 mmol·L-1Na2SiO3·9H2O on the cucumber seed germination and growth, membrane lipid peroxidation level, antioxidant enzyme activities and starch transformation were studied under continuous substrate leach solution (subtract∶water = 1∶6) for revealing the alleviating effect of exogenous silicon on cucumber seed germination inhibited by continuous cropping matrix extract and its physiological and biochemical mechanisms, moreover, providing theoretical basis for solving the problem of continuous cropping obstacles in cucumber substrate cultivation in production. The results showed that: (1) continuous substrate leach solution significantly inhibited the germination of cucumber seeds by increasing malondialdehyde (MDA) and proline (Pro) contents, decreasing the activities of antioxidant enzymes and starch hydrolase activities, and enhancing starch content during seed germination. Also, the leach solution decreased soluble sugar content, and the gene expression levels of AMY and BMY were significantly downregulated. (2) Application of exogenous silicon could effectively alleviate the inhibition of cucumber seed germination by reducing MDA and Pro contents, enhancing activities of antioxidant enzymes and starch hydrolase, elevating soluble sugar content, and upregulating the expression of AMY and BMY genes. The research showed that 1∶6 concentration of continuous substrate leach solution can inhibit the germination of cucumber seeds, led to block starch transformation, and gene expression downregulation;However, exogenous addition of 4 mmol·L-1 Na2SiO3·9H2O could accelerate the rate ofstarch conversion and maintain the normal physiological function during germination of cucumber seeds and to alleviate the negative effects caused by the continuous substrate leach solution on cucumber seed germination.