| Abstract: | This study examined the effects of exogenous nitric oxide (NO) on physiological characteristics of peanut (Arachis hypogaea L.) growing on calcareous soil. Sodium nitroprusside (SNP), a NO donor, was root application (directly; slow-release bag; slow-release capsule; slow-release particle) and foliar application. The results showed that SNP application alleviated iron (Fe) deficiency-induced chlorosis, increased the yield of peanut and increased the Fe concentration in peanut grain. SNP, especially supplied by slow-release particle improved the available Fe in soil by reducing pH of soil and increasing available Fe of soil. Furthermore, SNP application significantly increased the H+-ATPase and Fe3+ reductase activities and increased the total Fe concentration in the leaves. Meanwhile, SNP application, especially foliar application enhanced the availability of Fe in the plant by significantly increasing the active Fe content and chlorophyll content in the leaves. In addition, SNP also increased the antioxidant activities, but decreased the superoxide anion (O2??) generation rate and malondialdehyde content, which protected peanut against the Fe deficiency-induced oxidative stress. Therefore, these results support a physiological action of SNP on the availability, uptake and transport of Fe in the plant and foliar application SNP had the best effects in leaves and SNP supplied by slow-release particle had the best effects in roots. In addition, on the whole, the effects of SNP supplied by slow-release ways were better than directly supplied into the soil. |
