This study investigated some morphological and biochemical responses of maize to drought and salinity in open field in Tunisia with the aim of gaining insights into tolerance mechanisms. After seedling emergence, five treatments were applied until maturity: optimal water supply (control, 100% of maximum evapotranspiration - ETM); irrigation at 70% ETM (moderate drought) and at 35% ETM (severe drought); optimal supply of water containing 3 g NaCl L⁻¹ (moderate salinity) and 6 g NaCl L⁻¹ (severe salinity). Here, we demonstrated that extreme drought and salinity severely decreased the leaf area (−74% and −55%, respectively) and the above-ground biomass (−35% and −31%, respectively) at silking stage, indicating that the photosynthetic leaf apparatus is highly sensitive and that drought has a greater effect than salinity. Grain yield losses were also exacerbated under extreme stress conditions, viz. severe drought (−85% versus controls) and severe salinity (−73%), while productivity under moderate salinity approximated that of moderate drought, possibly due to increases in leaf chlorophyll and carotenoid content and K/Na ratio. The leaf area and its relative water content were positively correlated with grain yield under both salinity and drought stresses, and may therefore be used as markers for effective screening of maize genotypes for better stress tolerance.

这项研究调查了突尼斯开放田地玉米对干旱和盐分的一些形态和生化反应，目的是了解耐受机制。出苗后，进行五种处理直至成熟：最佳供水（对照，最大蒸散量的100％-ETM）；ETM为70％（中度干旱）和ETM为35％（重度干旱）时进行灌溉；最佳供水量为3 g NaCl L ^-1（中度盐度）和6 g NaCl L ^-1（重度盐度）。在这里，我们证明了极端干旱和盐碱化严重影响了蚕丝期的叶片面积（分别为-74％和-55％）和地上生物量（分别为-35％和-31％），表明光合作用叶片设备高度敏感，干旱比盐分影响更大。在极端胁迫条件下，谷物的产量损失也加剧了。严重干旱（−85％，对照）和严重盐度（-73％），而中等盐度下的生产力接近中等干旱，这可能是由于叶片中叶绿素和类胡萝卜素含量以及K / Na比的增加所致。在盐分和干旱胁迫下，叶面积及其相对含水量与籽粒产量呈正相关，