Abstract

Drought and salinity are the two major abiotic stresses limiting barley growth and productivity. In order to understand the physiological and biochemical traits associated with deficit irrigation using saline water in barley at heading stage, this study was performed under field conditions to treat two barley landraces, “Karkeni” (origin: irrigated) and “Bengardeni” (origin: rainfed in arid area), with three irrigation treatments as a function of cultural evapotranspiration ETc (T0: 100% ETc, T1: 75% ETc and T2: 50% ETc). In both barley landraces, deficit irrigation with saline water (T1 and T2 treatments) significantly decreased net photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), K⁺ content, K⁺/Na⁺ ratio and grain yield (GY); by contrast, DPPH and ABTS scavenging capacities as well as Na⁺ content were increased, concomitant with a landrace-dependent variation in phenolic compounds composition. Interestingly, under T1 and T2 treatments, “Karkeni” had the lowest A, E, gs and K⁺/Na⁺ ratio, and the highest Na⁺ content and GY. Overall, at heading stage, salt accumulation in deficit irrigated soils with saline water significantly reduces GY of barley by influencing gas exchange, phytochemical profiles and antioxidant activities, in a landrace-dependent manner.

摘要

干旱和盐度是限制大麦生长和生产力的两个主要非生物胁迫。为了了解抽穗期大麦使用盐水灌溉不足的生理和生化特性，本研究在田间条件下进行，以处理两种大麦地方品种，“ Karkeni”（原产地：灌溉）和“ Bengardeni”（原产地：在干旱地区进行雨养），根据文化蒸散量ETc进行三种灌溉处理（T0：100％ETc，T1：75％ETc和T2：50％ETc）。在这两个大麦长种中，用盐水（T1和T2处理）的亏水灌溉显着降低了净光合速率（A），蒸腾速率（E），气孔导度（gs），K ⁺含量，K ⁺ / Na ⁺比例和谷物产量（GY）；相比之下，DPPH和ABTS的清除能力以及Na ⁺含量增加了，伴随着酚类化合物组成中依赖于地方品种的变化。有趣的是，在T1和T2处理下，“ Karkeni”的A，E，gs和K ⁺ / Na ⁺比率最低，Na ⁺含量和GY最高。总体而言，在抽穗期，缺盐灌溉土壤中的盐分累积以大地依赖的方式通过影响气体交换，植物化学特征和抗氧化活性而显着降低了大麦的GY。