| Armeniaca sibirica is an ecological and economic tree species unique to Asia,with great potential for development and broad application prospects.However,A.sibirica has serious pistil abortion phenomenon,resulting in low fruit set rate and low yield,which seriously limits its economic benefits and restricts the development of benevolent apricot industry.In this study,80 A.sibirica clones in the National Forest Germplasm Resources Preservation for A.sibirica at Kazuo were used to study.The pistil abortion rate and pistil development of aborted flowers were observed,the nutrients and endogenous hormones of aborted and fertile flower buds were measured,the types and stages of pistil abortion of A.sibirica were clarified,the effects of different nutrients and endogenous hormones on pistil development were investigated,and the control technology of pistil abortion was provided by exogenous spraying experiment.The aim is to provide a theoretical basis and technical support for analyzing the mechanism and regulation of pistil abortion in Siberian apricot,and to lay a foundation for improving the yield and economic benefits for it.The main findings of the study are as follows:(1)The average pistil abortion rate of A.sibirica was 27.44%.The pistil fertility of 85.00%clones was strong.The pistil abortion rate of each fruiting branch was in the order of long branches(22.80%)> medium branches(19.33%)> short branches(14.39%)> bouquet-shaped branches(10.63%).A.sibirica flower bud differentiation process can be divided into six stages:undifferentiated stage,flowering primordial differentiation,sepal differentiation stage,petal differentiation stage,stamen differentiation and pistil differentiation.The duration of flower bud differentiation of abortive flowers was 19 days longer than that of fertile flowers,and the flowering periods of both flowers lasted 11 days.The pistil abortion rate of A.sibirica No.595 clone is 95.09%.Its pistil abortion type is abnormal style structure.Its pistil abortion occurs in the white stage,which is characterized by pistil degeneration and dissolution,and the pistil completely disintegrates and disappears at the full flowering stage.(2)The soluble protein and soluble sugar of A.sibirica flower buds showed a "risingdeclining-rising" trend,starch showed a continuous declining trend,and total sugar showed a declining and then rising trend from the dormancy release to the full flowering stage.At the stage of pistil abortion(dew white stage),the contents of soluble protein(0.83 mg/g),soluble sugars(17.05 mg/g)and total sugars(22.32 mg/g)in aborted flowers were extremely significantly lower than those in fertile flowers(1.04 mg/g,23.65 mg/g and 28.34 mg/g).The results showed that the pistil abortion of A.sibirica were mainly related to the insufficient supply of soluble protein,soluble sugar and total sugar in flower buds.(3)The largest number of CTK species(36)affected pistil development in A.sibirica,followed by Auxin(26)and GA(10).At pistil abortion stage,Auxin(17.32 ng/g),GA(4.36ng/g),(Auxin + GA)/ ZR ratio(3.61)of abortive flowers were all extremely significantly lower than those of fertile flowers(30.82 ng/g,83.92 ng/g,28.39 ng/g),and the contents of ZT(0.45ng/g)and ZR(6.02 ng/g)were all extremely significantly higher than those of fertile flowers(0.24 ng/g,4.05 ng/g).The main causes of pistil abortion in A.sibirica at the hormone level were: insufficient supply of Auxin and GA,which promote pistil development,large accumulation of ZT and ZR,which inhibit pistil development,and imbalance of their own hormone balance.Exogenous application of glucose,gibberellin and auxin had an obvious effect on reducing the pistil abortion rate of A.sibirica.Among them,100 mg/L gibberellin,2% glucose and 150mg/L gibberellin could extremely significantly reduce the abortion rate of pistil,which were21.22%,16.59% and 16.43% lower than the control respectively.Exogenous application test verified that sugars,Auxin and GA had positive effects on pistil development in A.sibirica. |
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