Research For The Antifreeze Activity Of Apoplastic Protein In Elytrigia Repens L.

Low temperature is the adversity factor which effects the growth of plants, and is also important factor on limit the distributing.To adapt oneself to circumstance, plants could have a series of physiological change to accommodate the cold stress and produce the resistance to low temperature.More and more research on resistance on low temperature,people found the antifreeze protein,belonded to the cold-induced proteins,play the role in the cold stress.T The discovery and research of AFPs provide a new research way to study the cold stress of plant,this also provide the theory gist for production.This study took Elytrigia repens L. as material,which has strong resistance in Heilongjiang province to compare and analyse protein variety, basic character and the difference of freezing-resistence active under different seasons.To understand the root of the greast resistance of Elytrigia repens L,we search and identify the protein which plays the decisive role in freeze resistance in Elytrigia repens L,this will provide the basic data for empoldering the resource of antifreeze breeding in Graminea plants.The main results as follows:1,There are big differenes rhizome and root collar apoplastic proteins of Elytrigia repens L between winter and summer. The apoplastic proteins of winter are richer and more one band than summer,the band of molecular weight is 39 Kda; Differences between leaves apoplastic proteins in winter and summer,the bands of molecular weight 25,20,15 KDa disappeared.2,The bands of rhizome apoplastic proteins of Elytrigia repens L are similar to that of root collar in winter,but there are large differenes between rhizome and leaves apoplastic proteins in winter.Apoplastic proteins of Elytrigia repens L are rich,and the distributing of each lane is almost uniform which present in molecular masses of 20-60Kda.3,There are some higher antifreeze activity proteins in apoplastic proteins of Elytrigia repens L in winter, and the higher concentration,the higher antifreeze ability. There are few antifreeze activity proteins in apoplastic proteins of Elytrigia repens L in summer,if the concentration is higher,there will be some higher antifreeze activity protein in summer which might have association with drought resistance and disease resistance..4,Molecular weight 66,43,37,33,25,20,15 KDa of soluble protein in the summer apoplastic proteins of Elytrigia repens L separated by SDS-PAGE, near these protein existed some protein that can modify ice crystal growth. Near molecular weight 68,46,34,28,23KDa of protein in the winter apoplastic proteins of Elytrigia repens L, there existed antifreeze protein that can modify ice crystal morphology, and molecular weight 68,46,28,23Kda had high antifreeze activity, protein molecular weight 34Kda had weak antifreeze activity, protein molecular weight 39 had no antifreeze activity.5,The proteins can limited the ice crystal growing speed as high as the antifreeze activity. rotundity ice crystal growed faster than columnar ice crystal; Hexagon ice crystal>columnar ice crystal> spindle shape ice crystal> acicular ice crystal; In the case that had enough growth space, ice crystal morphology can grow in their original shape in the low temperature, if exceeded the low temperature ice crystal diffuse as branch. If there were other ice crystals effected each other, ice crystal growed slower or stop.