Low Temperatures, Cold-sensitive Plant Spring Wheat And Cold Plant Winter Wheat Cells Of Ca (2 +) Steady-state Balance, The Comparative Study

1 .Use cerium trichloride precipitation method with electromicroscopic- cytochemical assay, we compared the difference of the Ca2-ATPase activities in plasmolemma between cold-resistance winter wheat seedlings and cold-sensitive spring wheat seedlings. The conclusions are: 1)Grown under 20, the Ca2- ATPase activities of the winter wheat seedlings mainly localized in plasmolemma. Treated at 2 for a period of time (1h 3h 12h), the Ca2-ATPase activities increased step by step. 2 treated for 24h, the enzyme reactions decreased slightly. Treated at 2 for 3d, the enzyme activities remained active and higher than control. 2)Spring wheat seedlings grown under 20, the level of Ca2- ATPase activities in plasmolemma are similar with the winter wheat seedlings under the same treatment conditions 2 treated for lh and 3h, the enzyme activities in plasmolemma increased considerably. 2 treated for 12h, a sharp decrease of the enzyme activities happened and the products of the enzyme activities are less than winter wheat seedlings. A further impediment of the enzyme activities were observed when the cold-stress was prolonged to 24h at 2 . Subject to 2 for 3d, the products of the enzyme activities are less than control and almost all of the enzymes are inactivated. Subcellular calcium localization was analyzed through EM-cytochemical procedures. The observations revealed that antimonate Ca2 deposits were localized in the vacuole of cold-resistance winter wheat seedlings when they were grown at 20. After 1 or 3h 2 chilling, deposits increased in the cytosol and the nucleus. After 12, 24, or lid chilling, the increased cytosolic and nuclear antimonate Ca2 deposits were restored to a low resting level. The results were suited to the changes of the plasmolenima Ca2-ATPase activities of the cold-resistance winter wheat seedlings grown at 2 . Conclusions show: under 2 low temperature, the activity and stability of the Ca2-ATPase are the key elements in developing the cold resistance abilities of plants. 2.Using Fluo-3/AM as the indicator to study the spatial-temporal changes of [Ca2] in the protoplasts of cold-resistant and cold-sensitive wheat under resting and temperature dropping conditions. Experimental results show that Fluo-3/AM being used as a fluorescent indicator, its dye effects in protoplasm are reliable and effective. The following three different solution systems(pH5.6) are used in experiments: standard solution with 5mM CaC12.2H20, standard solution, standard solution with 1mM EGTA. The results show that when the wheat seedlings were treated under the above mentioned three solution systems, the resulting intensity of fluorescence in cytoplasm decreased in this order, which also implies a decrease of [Ca2] in a similar order. Anyway, [Ca2] could keep a stable level during the time been treated by different solution systems. Meantime, different [Ca2] levels appeared in the two different kinds of wheat, which further demonstrate that the resting value of [Ca2] is the key factor in deciding the cells?response abilities and response levels under stimulation. When temperature drop from 15 to 2, the [Ca2] show different dynamic changes: the [Ca2] level of cold-resistance winter wheat restored to the resting level at 2 after increased, and then increased even higher than the former; however, the [Ca2] level of cold- sensitive spring wheat continues to increase to a maximal level from 1 5 to 2 without decrease. Indicating that the different dynamic chan...