Effect of salinity and drought stresses on tomato growth

Tomato is a vegetable that plays a part in nourishment and has a high economic value. Abiotic and biotic stress factors, however, affect negatively tomato development and cause yield losses. With this study, tolerance mechanisms of MSC50 and SC2121 tomato varieties grown in Ege Agricultural Research Center against different salt (50 mM, 100 mM and 150 mM NaCl) and drought (25 %, 50 %, 75 %) treatments have been studied. For this purpose, photosynthetic pigments, proline, total soluble protein, malondialdehyde (MDA), hydrogen peroxide (H2O2), glucose, fructose, sucrose and total soluble carbohydrates amount and also ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GuPX) and superoxide dismutase (SOD) activities have been measured on leaves collected from seedlings on which stress have been treated. According to the findings, chlorophyll a, chlorophyll b, total chlorophyll and carotenoid contents have been higher at both treatments in MCS50 tomato variety compared to the control. While pigment values decreased at salt treatments in SC2121 tomato variety, they rose at drought treatments. MDA content increased at drought treatments and lowered at salt treatments and H2O2content was high at 100 mM salt and 75 % drought treatments. MDA was the lowest in SC2121 at 100 mM salt and 25 % drought, while H2O2 was high at both salt and drought treatments. While proline amount was high in MSC50 variety at 150 and 50 mM NaCI treatments, total soluble protein rose at 50 mM salt and 50 % drought treatments. While proline content increased in SC2121 tomato variety at both stress treatments, protein content increased at salt treatments. For tomato varieties, glucose content was high at all treatments in MSC50 but it was lower in SC2121 at 150 mM salt and 50 % drought. While salt treatments and 75 % drought treatment caused an increase in fructose content in MSC50, it caused a decrease in SC2121 at 50 mM and 150 mM NaCI. Sucrose content was generally high in both varieties, however, total soluble carbohydrate content was usually higher in MSC50 and lower in SC2121. CAT activity was high in MSC50 at salt treatments, GuPX activity was high only at 50 % drought and SOD activity was high at 50 and 150 mM salt treatments. In SC2121 CAT activity was high at 25 % drought and GuPX activity was high at 50 mM salt and 25 % drought treatments and SOC activity was lower at 50 mM salt treatment. In conclusion, it is concluded that MSC50 is high tolerant to 50 % drought and SC2121 is medium-tolerant to all drought treatments. Besides, it is found that MSC50 is sensitive to 50 and 150 mM NaCI and SC2121 is sensitive to 150 mM NaCI. Given all the results, MSC50 variety is concluded to be more tolerant compared to SC2121. Key Words: Resistance, drought, salinity, MSC50, SC2121