SALINITY-INDUCED CHANGES IN ANATOMY, STOMATAL COUNTS AND PHOTOSYNTHETIC RATE OF ATRIPLEX SEMIBACCATA R BR

Anatomical changes in the roots and leaves of Atriplex semibaccata R. Br., induced by salinity stress, as well as photosynthetic and stomata l response to salinity, were investigated. As salinity increased, decr eases were observed in root diameter and leaf size, as well as in the number of chloroplasts in the chlorenchyma and bundle sheath cells. De velopment of these two cell types was also inhibited. Net leaf photosy nthetic rate and leaf stomatal conductance decreased with increasing s alinity, while the intercellular CO2 concentration increased. Both sto matal closure and inhibition of biochemical processes probably caused the reduced leaf photosynthetic rates. The stomatal indices suggest th at the trend towards an increase in number of stomata per unit leaf ar ea with an increase in salinity was not due to decreased epidermal cel l size.