Comparative Studies On Activity Of ATPase, Ion Compartmentation And Salt Resistance In Populus Euphratica And Salt-sensitive Genotypes

In this study we investigated the effects of NaCl on activity of various types of ATPase and the relevance to ion compartmentation and salt resistance in Populus euphratica, and compared with P. 'popularis 35-44' (P. popularis) and P. x euramericana cv. I-214(P. cv. Italica).The main results are summarized as follows:1. Cytochemical localization of ATPase activity showed that, P. euphratica was treated with NaCl for 30 days, the activities of H⁺-ATPase and Ca²⁺-ATPase in plasmolemma and tonoplast were both increased evidently, compared with P. cv. Italica. The above results indicate that NaCl has enhanced the activities of ATPase in plasmolemma and tonoplast of P. euphratica leaf.2. The results of X-ray microanalysis of root and leaf of the poplars revealed that vacuolar Na⁺ and Cl^- of P. euphratica increased coincident with increasing salinity, suggesting that P. euphratica was capable of accumulating salt ions into vacuoles at high salinity compared with P. cv. Italica, especially Cl". According to the Na⁺ and Cl^-concentrations in cell wall and cytosol were lower than that of P. cv. Italica, P. euphratica exhibited a greated capacity to restrict the influxes of salt ions in cell.3. The salt-shock added the activities of chloroplast ATPase in P. euphratica. But the salt-adaptation made the enzyme activities approximative to those of control.4. Inhibitor caused a significant increase in the H⁺-ATPase activities in P. euphratica and the Ca²⁺-ATPase activities in P. 'popularis 35-44' among the treatments of control and salinity.