The Comprehensive Responses of Young Sweet Cherry Trees Under Moderate Saline Conditions Depending on the Different Rootstocks

Sweet cherry is a temperate zone fruit tree grown under a wide range of climate conditions worldwide. Thus, understanding its responses to salt stress is important since cherry growing is influenced by salinity stress. In our study, many morphological, physiological and molecular responses were evaluated to investigate the influences of moderate salinity stress on sweet cherry. The study was conducted for 2 consecutive years. '0900 Ziraat' sweet cherry plants (1 year old) grafted onto Mazzard (Prunus avium L.), MaxMa 14 (Mahaleb x Mazzard) and CAB-6P (Prunus cerasus L.) were planted in 13 L plastic containers filled with soil, peat and perlite (1:3:1). After about 1 month of acclimation, salinity application was started by irrigation with 35 mM NaCl solution except control plants. The saplings were treated by salinity for 4 months. At the end of the experiment, remarkable decreases in plant growth were noted under salinity conditions. 0900/Mazzard possessed remarkable decline in shoot diameter. 0900/Mazzard possessed higher declines in SPAD and stomatal conductivity values by 23.9 and 18.7%, respectively. The lowest increase in membrane permeability was found in 0900/CAB-6P. Total score analysis based on the morphological and physiological parameters revealed that 0900/CAB-6P with the lowest score was considered the most tolerant, whereas 0900/MaxMa 14 with the highest score was regarded as the most sensitive one. The expression of WRKY25, WRKY33 and WRKY38 genes in all plants was significantly increased by salinity. We consider that the increment in gene expression triggered a defense mechanism to salinity.