硼和半胱氨酸对水稻中氰化物吸收同化调控的综合效应研究

Synergistic Effect of Boron and Cysteine on the Regulation of Cyanide Absorption and Assimilation in Rice

摘要:

氮(N)是植物生长发育的必须元素，硼(B)缺失会影响体内N代谢，继而迫使植物从其他的途径获取N源。无毒剂量的氰化物(CN^-)可通过β-氰丙氨酸合成酶(β-CAS)的降解途径为植物提供辅助N源；半胱氨酸(Cys)被认为是β-CAS途径中的限制因素。该研究以水稻(Oryza sativa)幼苗为对象，设定CN^--B-Cys、CN^-+B-Cys、CN^--B+Cys和CN^-+B+Cys等4种处理，评估B和Cys对水稻幼苗CN^-吸收同化作用的综合调控效应。结果表明，CN^--B+Cys处理的水稻幼苗对CN^-的吸收率最高(P<0.05)，其次是CN^-+B+Cys；CN^--B+Cys和CN^-+B+Cys处理的水稻幼苗体内CN^-残留浓度显著低于其他处理(P<0.05); CN^--B+Cys处理的水稻幼苗具有最高的CN^-同化率(P<0.05)，其次是CN^-+B+Cys、CN^--B-Cys和CN^-+B-Cys。同时, CN^--B+ Cys处理的水稻幼苗对NH₄⁺的吸收率与同化率最高(P<0.05)，其次是CN^-+B+Cys。因此，添加Cys和缺B处理可促进水稻幼苗对CN^-和NH₄⁺的吸收和同化率，同时降低CN^-对水稻幼苗的毒性损伤。

Abstract:

Nitrogen (N) is an essential element for plant growth and development, and lack of boron (B) will affect N metabolism in the body, forcing plants to obtain N sources from other ways. Non-toxic dose of cyanide (CN^-) can provide auxiliary N source for plants through β-cyanoalanine synthetase (β-CAS) degradation pathway. Cysteine (Cys) is considered to be a limiting factor in the β-CAS pathway. In this study, rice (Oryza sativa) seedlings were treated with CN^--B-Cys, CN^-+B-Cys, CN^--B+Cys and CN^-+B+Cys to evaluate the combined regulatory effects of B and Cys on the absorption and assimilation of CN^- in rice seedlings. The results showed that CN^- absorption rate of rice seedlings treated with CN^--B+Cys was the highest (P<0.05), followed by CN^-+B+Cys. The residual concentration of CN^- in rice seedlings treated with CN^--B+Cys and CN^-+B+Cys was significantly lower than that of other treatments (P<0.05). CN^--B+Cys processing of rice seedlings have the highest CN^- assimilation rate (P<0.05), followed by CN^-+B+Cys, CN^--B-Cys and CN^-+B-Cys. Meanwhile, the NH₄⁺ absorption rate and assimilation rate of rice seedlings treated with CN^--B+Cys were the highest (P<0.05), followed by CN^-+B+Cys. Therefore, the addition of Cys and B deficiency treatment could promote the absorption and assimilation rate of CN^- and NH₄⁺ in rice seedlings, and reduce the toxic damage of CN^- to rice seedlings.