EFFECT OF SALINITY ON THE STRUCTURE OF ASSIMILATING ORGANS AND C-14 LABELING PATTERNS IN C3 AND C4 PLANTS OF ARARAT PLAIN

Structural and physiological characteristics of C3 and C4 plants (20 s pecies) grown along a soil salinity gradient were studied. The majorit y of plants occupying salt-marshes were succulent chenopods, mainly C4 annuals. The NAD-malic enzyme (NAD-ME) group was dominant among C4 su cculents. The photosynthetic metabolism of C4 plants correlated with u ltrastructural changes of assimilating organs. In plants with a low in dex of granal chloroplasts in bundle sheath cells the malate pool was a larger than the aspartate pool, and in plants with high index of gra nal chloroplasts in bundle sheath cells the aspartate pool was larger. Among low mass compounds, photosynthetically accumulating under salt stress, alanine (that may promote maintenance of ionic balance) was im portant.