EFFECT OF NACL SALINITY ON GROWTH, PIGMENT AND MINERAL ELEMENT CONTENTS, AND GAS-EXCHANGE OF BROAD BEAN AND PEA-PLANTS

Increasing salinity of growth medium induced a reduction in growth and transpiration rate. The concentrations of chlorophylls and carotenoids were increased in most cases in broad bean leaves while in pea plants they remained more or less unchanged with the rise of salinization up to 80 mM NaCl. Thereabove a significant decrease in these contents was observed. A stimulation of the net photosynthetic rate of pea was observed at the lowest levels of NaCl but at the highest levels inhibitory effect was recorded. In broad bean all salinization levels inhibited photosynthetic activity, but dark respiration of both plant species was stimulated. The content of Na+ in the roots and shoots of both species increased at increasing salinity. In broad bean, Ca2+ concentration in shoots and K+ and Ca2+ contents of roots increased at increasing salinization, while in pea plants, the content of K+ and Ca2+ was almost unaffected by salinity. Salinity induced an increase in the content of these ions in pea roots. Mg2+ content in shoots and roots of both broad bean and pea decreased at increasing salinity except in roots of pea, where it was generally increased.