SEPARATE AND COMBINED ACTION OF SALINITY AND HARDENING TEMPERATURES ON PLANTS

We investigated the response of cucumber (Cucumis sativus L.) and whea t (Triticum aestivum L.) plants to chloride salinity in relation to it s strength (concentration) and duration, and the combined action of sa linity and hardening (low and high) temperatures. Salinity doses havin g no effect on seedlings of the indicated species are clarified, as we ll as ones causing weak and lethal injuries to the plants. It is estab lished that both cold (10-degrees-C) and heat (38-degrees-C) pretreatm ent of cucumber seedlings can reduce the harmful action of salinity. S hort-term salinity (lasting 1-6 h) in tum promotes additional increase of temperature resistance during cold and beat hardening of cucumber seedlings, although longerlasting salinity causes decline of their res istance. It is demonstrated that the response of cucumber seedlings to both salinity and hardening temperatures is accompanied by sharp incr ease of the ABA level in leaves.