Peroxidation of membrane lipid and Ca2+ homeostasis in grape mesophyll cells during the process of cross-adaptation to temperature stresses

The changes of thiobarbituric acid-reactive-substances (TBARS), ascorbic acid (AsA), and glutathione (GSH) contents, and the Ca(2+) homeostasis in heat acclimated grape (Vitis vinifera L. cv. Jingxiu) leaves under cold stress, or in cold-acclimated grape leaves under heat stress, were investigated. Under cold (heat) stress, TBARS content in heat (cold) acclimated leaves was less than that in the control, showing that the heat (cold) acclimation could alleviate the damage of cell membrane caused by cold (heat) stress. The contents of GSH and AsA in heat (cold) acclimated leaves under cold (heat) stress were higher than those in the control. The deposits of calcium antimonite, an indicator for Ca(2+) localization, were observed within the vacuoles, intercellular spaces in the control leaves of young grape plants grown under normal temperature. After heat or cold acclimation, the amount of cytosolic Ca(2+) was more, but Ca(2+) in vacuoles and intercellular spaces in mesophyll cells less than that in the control. The cytosolic Ca(2+) were pumped back to vacuoles and intercellular spaces in heat acclimated-cells under cold stress, or in cold acclimated-cells under heat stress, both of which did not cause the chloroplast structure to be destroyed. In contrast, a large amount of cytosolic Ca(2+) in the control mesophyll cells of grape, which was directly laid under heat or cold stress, appeared in intracellular spaces, and the chloroplast structure was destroyed. These results suggest that Ca(2+) homeostasis is very important in grape mesophyll cells during the process of cross-adaptation of plants to temperature stresses. (C) 2004 Elsevier Ireland Ltd. All rights reserved.