Effects of water stress and osmoprotectant applications on the physiological and morphological properties of the chestnut nursery trees

This study was carried out in order to reveal the physiological and morphological changes of the chestnut nursery trees under water stress and to determine the effects of osmoprotectant application. N-3-4 genotype chestnut nursery trees were planted with the distance as 4x2 m in 2015. Five different irrigation levels were applied to the trees as; K1=rainfed, K2= Field capacity, provided by giving deficient water amounts every five days, K3= %75 of the K2 level, K4= %50 of the K2 level, K5= %25 of the K2 level. In addition to water stress, glycine betaine (GB) was applied between june-september as osmoprotectant to chestnut nursery trees four times at 0.5% dose. In order to determine the physiological effect of different water levels and GB applications on chestnut nursery trees, the values of leaf relative water content (RWC, %), electrolyte leakage (EC, %), chlorophyll density (CD) and leaf surface temperature (oC) were defined in 8 periods, before and after the GB applications. In order to determine the morphological changes, leaf number and leaf area (cm2) were measured . According to the results of the study, irrigation water amount applied throughout the vegetation period varied between 147,5 – 590,1 mm in GB applied treatments -except for rainfed treatment-. In parcels without GB application; irrigation water amount ranged between 90,9 -363,9 mm. It was revealed with morphological changes that chestnut nursery trees with 75% water deficit level and GB application had the best growth performance. The physiological effects of water stress and osmoprotectant applications were differed according to periods, and in this sense, it was determined that water level and GB applications had significant effects statistically on RWC, EC and CD after the third GB application.