Investigation to salinity tolerance of different rootstocks used in pear growing with morphological, physiological and biochemical parameters

In the world, approximately 50% of irrigated agricultural lands have salinity problems. The gradual increase in saline areas, especially in arid and semi-arid regions, threatens the sustainability of agricultural production. In this study, it was aimed to determine the responses of some pear (OHXF 97, OHXF 333 and Fox 11) and quince (BA 29) rootstocks under different levels of NaCl stress by morphological, physiological and biochemical parameters. For this purpose, one-year-old ungrafted plants in 18 lt pots in a temparature controlled greenhouse; Irrigation water containing control [3 mM], 20 mM, 40 mM, and 80 mM sodium chloride (NaCl) was applied for two months. The study was repeated for two years (2017 and 2018). In the study, stomatal conductivity decreased linearly as salt stress increased, while SOD, CAT, GPX, GR activities increased linearly. While Na+ content increased in 80 mM NaCl application, P4+ and B+ content decreased. Fox 11 and BA 29 rootstocks were more adversely affected in terms of plant height, root fresh weight, leaf area, degree of damage, chlorophyll density, lipid peroxidation and sodium contents in the leaves. The amount of glycine betaine in the leaves was higher in OHxF rootstocks, and the proline content was higher in Fox 11 rootstock. Chlorogenic acid and arbutine amounts showed a relative or significant decrease with salt stress in Fox 11 rootstock. SOD, CAT, APX, GR and DHAR enzyme activities in the leaves were significantly changed in OHxF rootstocks, especially in OHxF 97 rootstocks, with salt stress. Fox 11 and BA 29 rootstocks showed lower GPX activity. As a result, OHxF 97 rootstock was found to be more tolerant and Fox 11 rootstock more sensitive to NaCl stress.