The interaction of salinity and gibberellin on leaf abscission, dry matter, antioxidant enzymes activity and ion content in guava (Psidium guajava L)

Guava is a rich source of vitamin C, with double-fruiting thorough a year and high yield, has considerable income to have delivered for the producer. But since the major tropical regions faced with the saline water, cultivating of this plant in such areas can affect the yield and the quality of the product. Therefore, in this research leaf abscission, dry matter, antioxidant enzymes activity and elemental content in Guava seedlings, under sodium chloride concentrations (1.7, 3 and 6 dSm-1) and gibberellic acid application (0, 250 and 500 ppm) was studied. According to results salt rising from 3 to 6 dSm-1, increased the chlorine, Ca/(Na+K), Na/K, Ca/Mg and Na/Ca in leaves and roots and reduced leave number and dry matter. salinity reduced the peroxidase and polyphenol oxidase activity, wherease it increased the catalase activity. The most sodium and the least potassium was observed under 6 dSm-1 salinity. Foliar gibberellic acid (500 ppm) application under salt condition, decreased leaf abscission and increased K, and K/Na as well as Ca content, which can be introduced as an effective approach to reduce the damages which caused by salinity stress on guava seedlings.