水分胁迫下一氧化氮对小麦幼苗根系生长和吸收的影响

以25%聚乙二醇(PEG-6000)模拟干旱, 利用一氧化氮(nitric oxide, NO)供体硝普钠(sodium nitroprusside, SNP) 处理小麦幼苗, 探讨外源NO对水分胁迫下小麦幼苗根系生长和吸收的影响。结果表明, 50 mol L^-1 SNP可增加小麦主根长度及侧根数目, 分别比对照增加11.94%和83.78%。同时, SNP可使水分胁迫下小麦的根系活力提高55.88%, 根系K⁺ 的含量提高42.52%。膜片钳全细胞电流显示, SNP处理可增强小麦根细胞质膜内向K⁺ 电流, 而NO的专一清除剂c-PTIO可以逆转SNP的上述效应。因此认为, 外源NO可通过提高小麦根系活力, 增强根细胞质膜内向K⁺ 通道的活性, 从而促进根细胞对K⁺ 的吸收以适应水分胁迫。

Effects of Nitric Oxide on Root Growth and Absorption in Wheat Seedlings in Response to Water Stress

To investigate the effects of exogenous NO donor sodium nitroprusside (SNP) on root growth and absorption in wheat seedlings (Triticum aestivum L.) under water stress, we cultured Yumai 49 seeds in Hoagland solution for 8 days, and then treated them for 2 days in Hoagland solution (CK) and Hoagland adding 50 μmol L^-1 SNP, 25% PEG-6000 ( Ó0.8 MPa), and 50 μmol L^-1 SNP+25% PEG-6000, respectively. The results showed that 50 mmol L^-1 SNP increased the length of primary roots and the number of lateral roots by 11.94% and 83.78% respectively, and enhanced the root activity by 55.88%. Meanwhile, the K⁺ content in wheat roots increased by 42.52%. In the patch-clamp experiment, SNP increased the inward-rectifying K⁺ current of wheat root cells under water stress and the NO specific scavenger c-PTIO reversed the effect above. The results above indicated that exogenous NO enhanced wheat drought resistance possible by improving wheat roots growth, increasing root activity to enhance K⁺ influx by activating root inward-rectifying K⁺ channels.