Studies On The Relationship Between Endogenous Hormones And Metaxenia Of Dangshansu Pear

Dangshansu pear is the main variety of chinese pear, occupys about a quarter ofchinese planting area of pear. Pear is the kind of fruit trees that have obvious phenomenonof xenia, using different kinds of pear trees’ pollen to pollinate the Dangshansu pear canobviously effect the external and internal quality of Dangshansu pear. Therefore, the studyof xenia of Dangshansu pear is very important to increase the economic benefits of pear’sproduction. This study selected some kinds of pears that have different characters to be themale parents, pollinated the Dangshansu pear(female parent), and then assayed thepollination stigmas,pollination ovarys, pulp and seeds’ contents of IAA, CTK, GA, ABAwithin the fruits’ growth and development, observed the xenia phenomenon of some partsof Dangshansu pear’s characters; ascertained the relationship between the changes ofendogenous hormones and Xenia from pollination to maturity. Further clarified theprinciple of xenia, enriched the academic theory of xenia. Meanwhile, provided effectivemethods and theoretical basis for choosing appropriate pollenating trees, improving thequality of fruits and increasing economic benefits. The main results of the test research areas follows.1. Pollinated Dangshansu pear by different kinds of pear pollen could influence theinternal quality, external quality and seed of Dangshansu pear. Dangshansu pear’s fruitsshowed xenia phenomenon on size of fruit point, per fruit weight, numbers of seed and perseed weight, while, the xenia phenomenon was not obvious on density of fruit point,vertical and horizontal diameter of fruit, index of fruit shape; Dangshansu pear’s fruitsshowed xenia phenomenon on contents of soluble sugar, total acid, vitamine C, stone cell,while, the xenia phenomenon was not obvious on soluble solid states and hardness.2. Pollinated Dangshansu pear by different kinds of pear pollen, the IAA and ZRcontents of Dangshansu pear’s pollinated stigma increased, the GA and ABA contentsdecreased; Within72hours after different kinds of pollinators pollinated Dangshansu pear,the IAA content of ovary increased at first and decreased, and then increased again; theABA content of ovary decreased within0~48hours, then increased within48~72hours;the GA content of ovary increased; the ZR content of ovary decreased in24hours, thenincreased within24~72hours, after the pollen tube entered ovary (24~48h) theendogenous hormones contents of ovary increased.3. Pollinated Dangshansu pear by different kinds of pear pollen, the change tendencies of endogenous hormones in pulp of different treatments were concurrent, the contents ofgrowth promotion hormone like ZR, GA and IAA showed high values in15days afterpollination. The ZR content in pulp had a highest value at the beginning of the firstfast-developing period (cell division period), then had a tendency of decrease until thefruits were ripe. The change tendencies of IAA and GA were almost the same, the contentswere higher at the first fast-developing period (cell division period), then decreased as thefruits developing, in60days after pollination of Dangshansu pear, the fruits began to enterthe second fast-developing period (fruit expands period), at the same time the IAA and GAcontents in pulp increased fast, and had the highest values respectively in90days and120days after pollination, concurrent with the call volume and weight increased, mainlycoincident with the fruit growth dynamic. The ABA content had the highest valuesrespectively in15days,45days and120days, mainly concurrent with the fruit droppingperiod and fruit mature period of Dangshansu pear. There were close connections betweenthe fruit growth and development of Dangshansu pear and the contents of endogenoushormones.4. Pollinated Dangshansu pear by different kinds of pear pollen, obviously effectedthe ZR content in pulp at the cell exuberant division period (15days after pollination) andthe GA content in pulp at the fruit expands period (120days after pollination) ofDangshansu pear, made the per fruit weight of Dangshansu pear show obvious xeniaphenomenon.