Effects of Exogenous Brassinolide Application at the Silking Stage on Nutrient Accumulation, Translocation and Remobilization of Waxy Maize under Post–Silking Heat Stress

Abstract

Exogenous brassinolide (BR) application is a feasible measure to alleviate abiotic stresses on crop productivity. The effects of BR application at the silking–stage on the accumulation, trans-location, and remobilization of dry matter (DM) and nutrients (nitrogen, phosphorus, and potas-sium) of waxy maize exposed to post–silking high temperature (HT) were studied using Jingken-uo2000 (JKN2000, heat–tolerant) and Yunuo7 (YN7, heat–sensitive) as materials. BR application mitigated the penalty of HT on grain yield. HT reduced the post–silking accumulation and increased the translocation of pre–silking DM and nutrients in YN7. In JKN2000, accumulation and remobilization of DM were unaffected by HT. The contribution rate of DM and nutrients translo-cation to grain yield were unaffected by HT in JKN2000 and increased in YN7. Under HT, the ac-cumulation, translocation, and remobilization of DM were unaffected by BR application, whereas the nitrogen, phosphorus, and potassium response were dependent on hybrids. The harvest index of DM and nutrients in response to HT and BR were different between the two hybrids. In conclu-sion, BR application relieved the negative effects of HT mainly caused by the increased post– silking accumulation and remobilization of DM and nitrogen, and the alleviation was more obvi-ous in the heat–tolerant hybrid.