The Influence Of Ca²⁺ On The Cold Resistance Of Sugarcane

The materials used in the study were ROC22and GT28. In the experiment, we used Fluo3-AM and DAPI fluorescence labeling method, and at0-4℃refrigerated two materials in the tissue culture systems which contain different concentrations of Ca2+for1-4hours such as0mg/L,220mg/L,440mg/L and660mg/L. Every other hour we sampled once and monitored the concentration changing trend of free Ca2+in the cells, meanwhile studied the concentration changing trend of free Ca2+in the growth cone cells after refrigerated at0-4℃for1-4hours, reveals the relationship between the concentration change of free Ca2+and resistance ability against cold, and study the leave about five indicators associated with plant resistance such as cell membrane permeability, free proline content, superoxide dismutase content (SOD), malondialdehyde content (MDA) and leaf protein content, in order to find out the relationship between Ca2+and sugar cane adaptation to low temperature. The test results are as follows:1. With the prolonging of cold stress time within4hours, the injured degree of callus cells were becoming increasing, free Ca2+of cells flew towards cell nucleus. Among four concentrations of Ca2+treatments,440mg/L of Ca2+made the injured degree of cells lest obvious.The influences of four concentrations of Ca2+on cold resistance of cell are as follows:440mg/L>660mg/L>220mg/L>0mg/L. In point of breed, cold resistance of ROC22was less than GT28.2. As for Ca2+distribution in growth cone cells of the two testing breeds, after refrigerated for five days the injured degree of cells were highest, after refrigerated for seven days the injured degree of cells became less because these cells adapt themselves to the surroundings. after cold stress Ca2+dynamic changes in the growth cone cells were the same as in single cell of callus. The influences of Ca2+concentration in the external environment on cold resistance of plant and the intensity of cold resistance of the two sugarcane varieties were consistent with the single cell.3.We tested the five physiological indicators of plant resistance:cell membrane permeability, free proline content, MDA, SOD, soluble protein content of the leaves, the results showed that in sequence refrigerated for1,3,5,7days, with the prolonging of cold stress time chilling injured degree of plant was gradually depended and to a certain degree chilling injured degree was becoming less. The injured degree of plant refrigerated for five days was most. The influences of four concentrations of Ca2+on cold resistance of cell were consistent with the single cell and tissue cell. The dynamic changes of cold resistance of plant were consistent with changing trend of free Ca2+in the growth cone cells.4.Certified by cell membrane penetrability,proline content and MDA content,SOD activity and soluble protein content, cold resistance of4-5leaves sugarcane seedlings which treated by calcium channel blockers LaCl3(200ML500μmol/L)was determined.The results showed chilling injury aggravation first then restoration as the cold stress time(0d,ld,3d,5d,7d),when5days of cold stress,the injury was most serious.Cold resistance of sugarcane treated by LaCl3decreased,it declared Ca2+could enhance the cold tolerance of sugarcane.