A STUDY ON VA MYCORRHIZAE FORMED ON THE TISSUE-CULTURED PLANTLETS OF PAULOWNIA K+ Accumulation in Poplar Roots Induced by Osmotic Stress The ecological effects of Pb and Cd on the root activities of wheat Relation of Stomatal Movement and Ion Content Change of Guard Cells in Populus berolinensis under Water Stress Effect of NaCl Stress on Ion Distribution in Root and Growth of Cyclocarya paliurus Seedlings Ultracytochemical Localization of Calcium in the Stigma, Style and Micropyle of Sunflower