Ion Compartmentation of Leaf Cells of Ginkgo biloba and Ailanthus altissima under Salt Stress

The ion compartmentation in G. biloba (Ginkgo biloba L.) and A. altissima (Ailanthus altissima S.) was investigated by X-ray microanalysis. The leaves were sampled after treated with 100 mmol·L^-1 and 200 mmol·L^-1 NaCl for one month. It was found that the content of Na⁺,Cl^- and Na/K in the cell wall,cytoplasm and vacuole increased after subjected to salt stress. This trend was found both in leaf epidermis,palisade and spongy tissue. But the K⁺ content show ed the reverse tendency. After treated with 100 mmol·L^-1 NaCl, both G. biloba and A. altissima compartmentalized Na⁺ in vacuole. Exposure to 200 mmol·L^-1 NaCl stress,only G. biloba compartmentalized Na⁺ in vacuole and A. altissima lost their Na⁺ compartmentation. G. biloba absorbed more Na⁺ than Cl^-, and A. altissima took up much more Cl^-than Na⁺ under salt stress. G. biloba compartmentalized Cl^-in vacuole under 100mmol·L^-1 NaCl stress,but this did not happen in the present of 200 mmol·L^-1 stress. A. altissima lost their Cl^-compartmentation under both 100 mmol·L^-1 and 200 mmol·L^-1 NaCl stress.