外源硅对连作基质浸提液抑制黄瓜种子萌发的缓解效应

Mitigation Effect of Exogenous Silicon on Inhibiting Cucumber Seed Germination by Continuous Cropping Matrix Extract

该试验以‘新春4号’黄瓜为试材,研究在连作基质浸提液(基质∶水=1∶6)处理下,外源添加4 mmol·L^-1 Na2SiO3·9H 2O对黄瓜种子萌发、膜脂过氧化、抗氧化酶活性及淀粉转化的影响,以揭示外源硅对连作基质浸提液抑制黄瓜种子萌发的缓解效应及其生理生化机制,为生产中解决黄瓜基质栽培连作障碍问题提供理论依据。结果显示:(1)连作基质浸提液处理显著抑制了黄瓜种子的萌发,使得丙二醛(MDA)和脯氨酸(Pro)含量升高,抗氧化酶活性和淀粉水解酶活性降低,淀粉含量升高而可溶性糖含量降低,同时AMY和BMY基因的表达水平显著下调。(2)添加外源硅处理后,可有效缓解连作基质浸提液对黄瓜种子萌发生长的抑制,降低MDA和Pro含量,提高抗氧化酶和淀粉水解酶活性,且提高了可溶性糖含量,AMY和BMY基因表达水平上调。研究表明,1∶6浓度的连作基质浸提液可显著抑制黄瓜种子萌发,使淀粉转化受阻,基因表达水平下调;外源添加4 mmol·L^-1 Na2SiO3·9H2O可提高受胁迫黄瓜种子芽苗中淀粉的转化速率,维护黄瓜种子萌发的正常生理功能,进而缓解连作基质浸提液对黄瓜种子萌发造成的伤害。

The‘Xinchun No.4’cucumber was used as the test material in this experiment.Meanwhile,the effects of exogenous 4 mmol·L^-1 Na 2SiO3·9H2O 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 down-regulated.(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 up-regulating 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 down-regulation;However,exogenous addition of 4 mmol·L^-1 Na 2SiO3·9H2O 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.