Study On Low-temperature Tolerant Mechanism Of Kernel Apricot ’Weixuan1hao’ At Flowering Stage

In order to explore the low-temperature tolerant physiologicalmechanism and molecular mechanisms that kernel apricot‘weixuan1hao’flower organ resist the late spring frost, the artificial intelligent freezerchamber were employed on which to simulate the process of nature hoarfrostfalls，studied the changes of membrane permeablity and membrane lipidperoxidation，the changes of osmoregulation substance content，the changesof protective enzymes activity and antioxidant content，the changes of theendogenous hormones content in flower organ，and different proteins in pistilsof the frost resistant cultivar ‘weixuan1hao’(8-years-old) compared with thefrost sensitive cultivar ‘longwangmao’(8-years-old) under low temperaturestresses. The results showed that:1. The relative electrolytic leaking、MDA content、O-2generation arte andH2O2content in ‘weixuan1hao’flower organ increased with the decreasingtemperature. At-7℃, the relative electrolytic leaking、MDA content、 O-2generation arte and H2O2content in ‘weixuan1hao’petals were respectively3.7times,2.8times,2times,4.5times more than those at controlled temperature,were3.91times、3.1times、2.3times、4.8times more than those at controlledtemperature in ‘weixuan1hao’ stamens, and were4.41times、3.6times、2.9times、5.5times more than those at controlled temperature in ‘weixuan1hao’pistils. At-7℃, the relative electrolytic leakin、MDA content、O-2generationarte and H2O2content in ‘longwangmao’petals were respectively4.33times,3.9times,2.9times,4.8times more than those at controlledtemperature, were4.38times、5.3times、3.5times、5.9times more than those atcontrolled temperature in ‘weixuan1hao’ stamens, and were5.13times、6.3times、4.3times、7.2times more than those at controlled temperature in‘weixuan1hao’ pistils.2.The content of soluble protein and soluble sugar increased first and thendecreased in ‘weixuan1hao’flower organ with the decreasing temperature, andproline content increased with decreasing temperature. At-7℃, the content ofsoluble protein, soluble sugar and proline were respectively1.28times,2.1times,4.97times more than those at controlled temperature in‘weixuan1hao’petals, were1.24times、2.0times、4.92times more than thoseat controlled temperature in ‘weixuan1hao’ stamens, and were1.03times、1.5 times、3.95times more than those at controlled temperature in‘weixuan1hao’ pistils. At-7℃, the content of soluble protein, soluble sugarand proline were respectively1.03times,1.4times,4.03times more than thoseat controlled temperature in ‘longwangmao’petals, were97%、1.2times、4.0times more than those at controlled temperature in ‘longwangmao’ stamens,and were63%、1.9times、3.7times more than those at controlled temperaturein ‘longwangmao’ pistils.3.The activity of SOD、POD、CAT、APX、MDHA、GPX and GRincreased first and then decreased in ‘weixuan1hao’flower organ with thedecreasing temperature. At-7℃, the changes of enzyme activities were notthe same, APX activity in ‘weixuan1hao’ petals was the highest, was2.49times more than those at controlled temperature, SOD activity in‘weixuan1hao’pistils was lowest, reduced to47%.The content of AsA、DHA、GSH and GSSG were increased first and then decreased in‘weixuan1hao’flower organ with the decreasing temperature except GSSGcontent in ‘weixuan1hao’ pistils, GSSG content in ‘weixuan1hao’ pistildecreased with the decreasing temperature. GSH content in ‘weixuan1hao’petals was the highest, was1.37times more than those at controlledtemperature, GSSG content in ‘weixuan1hao’ pistils was lowest47%,The same antioxidant substances in ‘weixuan1hao’ flower organ was higher thanthat in ‘longwangmao’ flower organ under the same conditions.4.The GA3content increased first and then decreased,ZT contentincreased first and then decreased and then increased and decreased again,IAA content decreased, ABA content increased in ‘weixuan1hao’flowerorgan with the decreasing temperature.At-7℃, the content of GA3、ZT、IAAand ABA in ‘weixuan1hao’ petals were respectively61%、71%、33%、7.21times more than those at controlled temperature, were56%、85%、24%、6.36times more than those at controlled temperature in ‘weixuan1hao’stamens, and were54%、96%、18%、6.24times more than those at controlledtemperature in ‘weixuan1hao’ pistils..At-7℃, the content of GA3、ZT、IAAand ABA in ‘longwangmao’ petals were respectively56%、90%、30%、5.98times more than those at controlled temperature, were54%、84%、21%、5.73times more than those at controlled temperature in ‘longwangmao’stamens, and were52%、80%、14%、4.74times more than those at controlledtemperature in ‘longwangmao’ pistils.5.There were darker vertical stripes and low resolution in2-DE gels byTCA/acetone precipitation method and Tris-HCl extraction method, mostspots clustered in the upper of the gels,the protein spots in2-DE gel by henol -methanol were clear and round, moreover, the spots could be betterspread out and easily identified. we got937protein spots by TCA/acetoneprecipitation method,951protein spots by Tris-HCl extraction method,1160protein spots by phenol-methanol/ammonium acetate precipitation method.6.There are56differential proteins identified in ‘weixuan1hao’ pistilsand ‘longwangmao’ pistils under room temperature (18℃). The expression of10proteins in in ‘weixuan1hao’ pistils were more than thosein‘longwangmao’,4proteins involed in signal transduction,4proteins involedin other metabolic process,2proteins were unknown protein. The expressionof46proteins in ‘weixuan1hao’ pistils were lower than those in‘longwangmao’,18proteins involved in protein synthesis, transport anddecomposition metabolism,11proteins involved in ribosome constitution,6proteins involved in carbohydrate metabolism,4proteins involed in signaltransduction,6proteins involved three tricarboxylic acid cycle,5proteinsinvoled in other metabolic process,7.There are37differential proteins identified in ‘weixuan1hao’ pistilsand ‘longwangmao’ pistils under under mild low temperature stress(beforesuper-cooling point). The expression of27proteins in ‘weixuan1hao’ pistils were more than those in‘longwangmao’,10proteins involved in proteinsynthesis, transport and decomposition metabolism,6proteins involved incarbohydrate metabolism,2proteins involved in lipid metabolism,2proteinsinvolved in signal transduction,2proteins involved in hydrogendecomposition,7proteins involed in other metabolic process. The expressionof10proteins in ‘weixuan1hao’ pistils were lower than those in‘longwangmao’,5proteins involed in signal transduction,2proteins involvedin amino acid synthesis,5proteins involed in other metabolic process.8.There are23differential proteins identified in ‘weixuan1hao’ pistilsand ‘longwangmao’ pistils under under severe low temperature stress(aftersuper-cooling point).The expression of20proteins in ‘weixuan1hao’ pistilswere more than those in‘longwangmao’,11proteins involved in proteinsynthesis, transport and decomposition metabolism,4proteins involved insignal transduction,5proteins involed in other metabolic process.Theexpression of3proteins in ‘weixuan1hao’ pistils were lower than those in‘longwangmao’,1protein involed in nuclear mRNA splicing,1proteinsinvolved in Fatty acid metabolism,1protein involed in ATP hydrolysiscoupled proton transport.