Studies Of Cold Resistance In Apricot

Apricot (Armeniaca sp".) is the important fruit tree. Apricot tree bloom early, so it is always harmed by late frost endangement. making yield on the prowl. From the study of cold resistance to 25 species and varieties, The main results are as follows:Using principal component analysis and linkage cluster analysis the cold resistance of 25 apricot cultivars was evaluated with 9 physiology and porphology indexs. the resistance of 25 apricot species and varieties was sorted, the equation measuring cold resistance was also found.Y=-10. 5600+0. 2152Xi-0. 0369X3+0. 1076X4+0. 2519X7-0. 0634X8+0. 0229X9XI , X3, X4, X7, X8, X9 represent separately: SOD activity ^ MDA contend protein content^ anthocyanine content^ half-lethal temperature, ratio of xylem ?Under the domestication of fall and winter low temperature, the cold resistant ability reach the highest at January, and the cold hardness capacity represent the real level.The order of shoot tissue from weak to strong is : pith MDA content, and higher SOD > POD enzyme activity. Low temperature can induce ABA composition, the ABA content of increase 2 fold from -1癈 to -5"C. The content of soluble protein enhance from 0 to -4t^ , at -5*C, its content decrease.Supercooling point of floral organs of 4 varieties are being discovered. Petal > pistil supercooling point of Youyi is the lowest, reaching -5.9癈 and -4.71C separately. According to supercooling point, we can get the sequence: Youyi >Baiyubian>Yiwofeng >Longwangmao.The cold resistance trait of apricot is related to not only the physiology and biochemistry, but structure (such as the structure of leaf > branch). The results show that: the higher the xylem ratio and the larger the CTR of blade, the higher the cold resistant capacity.Experiment test that: cold resistance vary with different cultivars ^ differentorgans^ different low temperature. The sequence in organs is one-year-old dormancy branch>flower bud>full opened flower>young fruit, petal>stament>pistil, pulp>embryo. There are relationship between branch-, flower bud^ full opened flower young fruit, with the relation between flower bud and the others highest, so the determination of LTso of flower bud can define cold hardness strong or weak.