Effects of irrigation water salinity and deficit irrigation on morpho physiological and biochemical properties of lettuce

Drought and salinity issues are of vital global importance for the future of agricultural production. Determining tolerance levels to these stress factors in each plant's growing region is an effective strategy for food security and proper planning. This study investigated the effects of different irrigation water salinity and water deficit levels on the morpho-physiological and biochemical characteristics of cauliflower plants grown in greenhouses under Konya conditions. A total of 15 experimental plots, including 5 different NaCl concentrations and 3 different irrigation levels, were designed in a factorial design with 3 replications. Consequently, the highest per-plant water consumption (ET, evapotranspiration) of 4915 ml/plant was calculated in T1S1. Generally, both water stress and increasing NaCl doses decreased ET. Salinity stress decreased stomatal conductance, leaf relative water content, chlorophyll and carotenoid contents, while increasing membrane damage and protein values. Drought stress, on the other hand, increased leaf temperature, chlorophyll, carotenoids, protein, and proline levels, while significantly decreasing stomatal conductance, as expected. When the data obtained from the study are evaluated together, the use of water with an EC value above 4.0 dS/m for irrigation, although varying depending on different parameters, has significant negative effects on cauliflower plants. In regions with limited water resources, implementing a 25% water restriction for cauliflower to conserve irrigation water has been proposed as an important strategy for both conserving water resources and ensuring sustainable irrigation management.