Study On Biological Characteristics Of Flowering And Pollination And Fruit Development In ’Dongxing’

In order to understand the features of flowering pollination biology and fruit development dyn-amic of the very late mature apricot varieties ‘Dongxing’.The flower biological characteristics, poll-ination biology, leaf photosynthetic characteristics, fruit development dynamic, and the changes dy-namic of inclusions’ content, endogenous hormone’ content and polyamine’ content were all investi-gated and studied, the main results were as follows:(1) The flower bud differentiation of ‘Dongxing’ was started in late June, and the differentiate-on of main tissue were completed in late September. In late March the buds begin to bloomed.Inearly April begin to flower, flowering sustained for5days. The number of anther of per flowerwas39.2grains. The pollen amount of per anther was821.0grains. The optimum medium was1%agar+15%sucrose+0.01%boric acid, the pollen viability was53.0%. The maximum conjoi-ned pollen viability was appeared on the first day after flowering, after the third day the pollenviability was fell to50%. Storage pollen viability was fell to half of the initial value after three days. The strongest of stigma receptivity was achieved extremely strong after flowering for2hoursto4hours. After flowering for1hour to8hours was the appropriate pollination period for ‘Don-gxing’.(2) The selfing fruit set percentage of ‘Dongxing’ was1.5%, showed self-incompatibility. Thepollen of ‘Muzijianali’ and ‘Saimaiti’ were highly valued on the ‘Dongxing’, they were suitableas the pollinate trees of ‘Dongxing’. The pollen most were began to germinate2hours after pollination, and reached to style base96hours after pollination. The apricot varieties such as ‘Jiagedamayisang’,‘Muzijianali’,‘Saimaiti’, et al, were all have a high cross compatibility with ‘Dongxing’.(3) The characteristic values of photosynthetic diurnal variation of ‘Dongxing’ were showedbimodal type in addition to the Ci was appeared corresponding opposite rule. Gs and Ci were themain factors to influence the Pn when the sunlight condition was sufficient. The two peak of Pnwere respectively appeared at11:00and18:00, and the photosynthetic midday depression was app-eared at15:00. The light compensation point (LCP) was68.33μmol CO2/(m2.s), light saturationpoint (LSP) was947.29μmolCO2/(m2.s). CO2compensation point (CCP),135.72μmolCO2/(m2.s),and CO2saturation point (CSP),1149.38μmol CO2/(m2.s). And the higher AQY, LSP, CE, CSPand lower LCP, CCP can promote the net photosynthetic rate increase and the accumulation ofphotosynthetic products. The factors for fruit maturation extension of ‘Dongxing’ not only the AQY,LCP, LSP, CE, CCP and CSP of photosynthesis, but also the Rd was a key factor.(4) The fruit developing period of ‘Dongxing’ was about196days, and fruit growth was pers-ent to double ‘S’ type curve for ‘slow-fast-slow–fast’, but the nuclear and embryo growthwere persent to ‘S’ type curve for ‘slow-fast–slow’. The largest daily average growth was in thefruit rapid growth phase for the first time. The second slow fruit growth period of ‘Dongxing’was84days, it was delay to60~70days that compared with the other different maturity periodvarieties. The second rapid growth phase was49days, it was delay to35days that compared wit-h the other different maturity varieties. And these two stages were the main periods for the dryweight of fruit, nuclear and embryo to increase. The nuclear was began to sclerosis in the secondfruit slow growth period, and the nuclear and embryo were maturation about7days after the sec-ond rapid growth began. The main fruit development periods for ‘Dongxing’ were the second slo-w growth period and the second fast growth period.(5) The fruit soluble sugar growth curve of ‘Dongxing’ was close to ‘S’ type, titratable acidgrowth curve was close to ‘M’ type, vitamin C growth curve was close to ‘W’ type, starch conte-nt change curve was an inverted ‘V’ type, protein was step growth curve. The soluble sugar, titrat-able acid and protein growth of embryo were all step growth curve, and the vitamin C growth cu-rve was close to ‘V’ type. The second slow growth period of the fruit was the main period toaccumulate inclusions of embryo. The rate of accumulate inclusions in the embryo determines howlong the stage of the second fruit slow growth stage. During the fruit development period of ‘Do -ngxing’, the soluble sugar, vitamin C and protein content of fruit and embryo were all under theother earlier mature varieties, but the titratable acid content of fruit and embryo were higher thanother varieties. SOD and CAT were maintain a highly active in two fruit rapid growth period.(6) During the fruit and embryo rapid growing period of ‘Dongxing’, the content of IAA,ABA, GA3, Spd and Put were rapid increased, but the Spm was diminishing. The changes of6kinds endogenous substance of embryo were mainly occurred in the second fruit slow growth period,in this time endogenous substance content were higher than other fruits but ABA. The Spd conte-nt in fruit and embryo were higher than Put and higher than Spm, GA3were higher than IAAand higher than ABA. The changing trends of6kinds endogenous substance of different maturityvarieties apricot fruit and embryo were basic similar. And the earlier matured the earlier peakappeared. In addition to the ABA and Spd of fruit and embryo of ‘Dongxing’, other endogenoussubstances were higher than other different maturity varieties.