| Jujube（Ziziphus jujuba Mill.）,a member of the Rhamnaceae family,has a long cultivation history in China.Due to climate and geographical advantages,Xinjiang has become the main production area of jujube in China.However,jujube industry in Xinjiang start later,the cultivated varieties single,which are mainly huizao and junzao,and the fresh food varieties are rare,and the variety structure is extremely unreasonable.Nowadays,fresh jujube gradually enters the market,the development of fresh jujube varieties in Xinjiang is slow and unable to meet the needs of consumers.Therefore,it is urgent to introduce and breed excellent new varieties of fresh jujube.‘Saimisu 1’and its bud mutation jujube have been bred recently,with strong early high yield performance,grafting that year can be a small amount of fruit,which were fresh jujube varieties with crispy and sweet taste.In this study,‘Saimisu 1’jujube and its bud mutation jujube were selected as the test materials.The biological characteristics,cell structure,fruit quality,endogenous hormone content and sucrose metabolism-related enzyme activities in different growth and development stages were observed in order to lay a foundation for the utilization of bud variation and its excellent characters,variety breeding.The main research results are as follows:（1）Flow cytometry was used to estimate the ploidy and genome size of‘Saimisu 1’and its bud mutation jujube,both of which were diploid dates.DNA content of‘Saimisu 1’and its bud mutation jujube were 0.455 pg and 0.437 pg,respectively,and genome sizes were 444.71 Mb and 426.89 Mb.In addition,the number of living cells in the G2-phase was more than that of other controls,suggesting that diploid and tetraploid chimerism might exist.（2）During the jujube growth and development,there were significant differences in floral structure,leaf size,chlorophyll content and photosynthetic characteristics between‘Saimisu 1’and its bud mutation jujube.The flower of‘Saimisu 1’was small,the leaves were oval,the single hanging flower quantity was less than that of the bud mutation jujube,but its fruit setting rate was higher than that of‘Saimisu 1’,while the leaves of the bud mutation jujube were ovoid,the chlorophyll content was higher than that of‘Saimisu1’.The net photosynthetic rate and transpiration rate of both showed“bimodal”curves,showing obvious photosynthetic nap phenomenon,but the net photosynthesis rate and transpiration rate is higher than that of‘Saimisu 1’.the photosynthetic efficiency was higher.（3）‘Saimisu 1’jujube were oval,while the bud mutation jujube were oblate.As the fruits gradually ripened,the acid content decreased,the sugar content increased,and the nutritional value increased.Compared with‘Saimisu 1’,the bud fruits were crisper and sweeter,and the edible rate were higher.（4）By comparing the peel structure of the two cultivars,The thickness of the wax layer of jujube 1and its buds has been thickening,while the thickness of the cuticle and the epidermal layer is the trend to increase first and then decrease,and the thickest thickness period is the expansion period,Compared with‘Saimisu 1’jujube,the pericarp of bud mutation jujube became thinner and the taste was more crispy.（5）Indole acetic acid,Gibberellin A3and Zeatin contents increased in the fruit expansion stage,and these hormones contents were significantly higher in the bud mutation jujube than those in‘Saimisu 1’jujube.As the fruits gradually ripened,Indole acetic acid,Gibberellin A3and Zeatin contents decreased,while the Abscisic acid content kept increasing.（6）During fruit development,the activity of sucrose phosphate synthase in bud jujube was lower than that in‘saimisu 1’jujube,and the activity of acid invertase in bud mutation jujube was lower than that in‘saimisu 1’jujube at maturity.The fruit of‘saimisu 1’jujube and its bud mutation jujube mainly accumulated sucrose at maturity,and the bud jujube accumulated more sucrose. |
