부산대학교 도서관

Aluminum (Al) is a major environmental stress that limits crop growth and production. 24-Epibrassinolide (EBR) can control stress responses, but how it regulates Al homeostasis in Al-stressed maize seedlings is poorly understood. Therefore, seedlings of two lines of maize (Zea mays L.) under Al stress (60 μM AlCl3) were treated with 1.0 × 10−6 M EBR. In roots exposed to Al, EBR helped protect membranes and reduced reactive oxygen species by activating antioxidant enzymes, the ascorbate-glutathione cycle, phytohormone signal, and proline accumulation. In leaves under Al stress, EBR increased photosynthetic performance by protecting chloroplast ultrastructure, increasing ribulose 1,5-biphosphate carboxylase activity, and improving gas exchange. With EBR, inhibiting photoinhibition and promoting photosystem II efficiency maximized chlorophyll fluorescence. Changes in expression levels of ten candidate genes associated with antioxidant enzymes, phytohormone signals, mitogen-activated protein kinase (MAPK) pathway, photosynthesis, and chlorophyll fluorescence were consistent with changes in physiological assays in maize seedlings in the different treatments. Therefore, EBR can help alleviate Al toxicity in maize by improving activity in multiple metabolic pathways. [ABSTRACT FROM AUTHOR]