PJB-2018-1068
Improved water status is involved in melatonin-induced mitigated salt stress in maize seedlings
Jiakun Yan
Abstract
As an important biological hormone, Melatonin has been reported to involve in many abiotic stress responses and plant developmental processes. Although exogenous melatonin application is known to enhance plant stress tolerance, the underlying mechanisms of this effect remain unclear. Here, the influence of melatonin (1 μM) on maize (Zea mays L.) seedling growth under short-term salt stress was investigated. According to the result, after seven days salt treatment the growth of seedlings was not significantly affected by melatonin (MT) application under normal conditions(CK), while MT application increased the biomass accumulation under salt treatment, and MT content analysis showed exogenous MT had increased the endogenous MT content in maize root, too. Under salt stress, the photosynthetic rate, stomatal conductance, transpiration rate, whole plant hydraulic conductance and root hydraulic conductance (Lp) were significantly inhibited, but this inhibition was alleviated by exogenous melatonin application. In addition, melatonin increased specific aquaporin gene (ZmPIP1;6, ZmPIP2;3 and ZmPIP2;7) expression and improved aquaporin activity, as HgCl2 application eliminated the advantage melatonin-treated seedlings had under salt stress. Taking all these results into consideration, this study indicates that exogenous melatonin pretreatment enhances maize resistance to short-term salt stress by regulating Lp through improving aquaporin activity. These results suggest that melatonin holds potential application value in improving crop production in saline land.
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