| Xinjiang wild apple are important wild resources and excellent stress resistance germplasm resources in China. In This study of xinjiang wild apple as materials to measured the photosynthesis, chlorophyll fluorescence dynamic change in a day and different season to discuss the seasonal change of photosynthesis and the influence factors and reveals characteristics and rules of physiological ecology and analysis of the appropriate growth of ecological condition.Analysis and statistics the leaf shape phenotypic traits, combination of SSR molecular markers, to explore the genetic diversity of xinjiang wild apple and the relevance between the phenotypic traits, preliminary explore the relationship between the phenotypic traits and SSR molecular markers. In the study of the physiological characteristics, phenotypic traits of Xinjiang wild apple clones and SSR and ITS sequence analysis of the different types of apple, basically have the following conclusion.(1) Photosynthetic rate was not significant difference between different months. There was a significant difference between clones, the annual average photosynthetic rate of No.1 was significantly higher than other clones. The dominant factors affecting the photosynthetic were different, the dominant factor was Gs in June while in July and August the dominant factor was both Ci. In September Tr and Gs were turned into the dominant factor. There was no obvious difference on the influence of photosynthesis from Tr, Gs and Ci in October. The dynamic change of Chlorophyll Fluorescence showed that, Fo, Fm,Tfm, DIO/CSO, RC/CSO, PIcs and Area were all reached significant correlation level with Pn and photochemical reaction had great influence to Pn.(2) The average diurnal changes of photosynthesis rate of 8 Xinjiang wild apple clones showed two-peak curves, and the curves occurred in 11:00 and 15:00. The diurnal changes of transpiration rate and stomatal conductance were two-peak curves,and the curves both occurred in 9:00 and 15:00. The chlorophyll fluorescence analysis showed that the diurnal changes of Fo, Fm, Fv, ψo, DIo/CSo were two-peak curves while Tfm,φPo,φEo,PIABS,PICS were one-peak curves and occurred in 11:00. Fv, Tfm, ABS/CSm, TRo/CSo, ETo/CSo, RC/CSo were highly significant correlation with Pn and the highest correlation was RC/CSO, correlation coefficient is 0.946. It showed that electron transfer of photo chemical reaction have greater impact. There are only Tfm, ABS/CSO, ABS/CSm, ABS/CSm, RC/CSO, ETO/ CSO, TRO/CSO achieve significant correlation with the transpiration, which show the relation of transpiration rate and Phenomenological energy lfuxe is close. Gs get significant correlation with φPo, φDo, ABS/CSO, ETO/CSO, while get highly Significant correlation with Tfm, ABS/CSm, TRO/CSO, RC/CSO. It show that the connection of Gs and absorb, harvest optical energy and densityofreaction center are close. Analysis showed that xinjiang wild apple "noon break" phenomenon appears because the Tr rise, stomatal closure, Gs reduce; Fo increases at the same time, Fm reduced, cause the Fv(Fv = Fm-Fo) reduced, quantum yield decreased, increased rates of quantum for heat dissipation,The ability to capture, absorb light energy of pigment decreased, the density of the reaction center, at the same time due to the stomatal closure, used in the photolysis of water and photosynthetic phosphorylation is reduced, the ATP accumulation, in turn, inhibit the light reaction, photosynthetic rate decreased, appear "noon break" phenomenon.(3) There were rich genetic diversity in leaf traits between Xinjiang wild apple clones. All the 15 leaf traits were extremely significant differences between the clones. The maximum average coefficient of variation is shape of leaf tip(α), with the value of 25.39% while the shape index of leaf L1/L3 was the minimum with the variation value of 10.31%. Repeatability of the leaf length having the maximum value of 0.967 while the shape index of leaf L1/L3 was the minimum with the repeatability value of 0.495.With 15 blade shape traits clustering, all clones cluster into three groups and each clone can be completely separate with genetic distance variation changing between 1.293 to 7.235. The components analysis showed, contribution of γ, α, L1 were bigger, indicated that several parameters in xinjiang wild apple phenotype classification play an important role.The correlation coefficient of the clustering analysis of leaf traits and SSR was only 0.105. Correlation analysis of single leaf shape traits and the filtered portion of SSR markers clustering results showed that most of the assembly achieve significant correlation and most of the loci were closely related, and it also suggests that plant leaves traits joint decision is influenced by many gene interactions. Stepwise regression was the first time to applied in correlation analysis and results showed that the same leaf trait was closely related to several sites; likewise, the same site was closely related to several leaf traits. The sites correlation with each single trait varied between 11 and 20, in which 11 sites yielded a leaf index of L1/A1, 11 sites exhibited a leaf index of L1/A4, and 20 sites correlation with the width of 3/4 of the leaf(A4); therefore, phenotypic traits of the leaf were closely correlated with several SSR sites.(4) The genomic polymorphism of 18 sieversii superior clones, 23 varieties of eadible apples and 7 rootstocks apple were analyzed using 30 pairs of SSR primers. Totally, 254 loci were amplified, of which 99.61% were polymorphic. Specifically, each pair of primers could detect 8.47 polymorphic loci in average. Xinjiang wild apples had the the highest percentage of polymorphic loci(54.72%), followed by rootstocks apple and edible apple. The levels of of Nei’s gene diversity(h), Shannon’s information index(I) and effective alleles(Ne) were: rootstocks apple > Xinjiang wild apples > edible apple cultivars. Cluster results showed that 48 samples were divided into three groups, they are edible apple、Xinjiang wild apple and rootstockand apple. There is no intersect among the three groups. The genetically close cultivars were clustered together within the same group.(5) This paper classified the primers into three types. The relevant analysis of the comprehensive cluster results of all primers indicated that the second primer group had the best correlation, with coefficient of 0.957, whereas the first primer group had the lowest correlation, with coefficient of 0.871. The second primer group had better distinguishing ability for edible apple and rootstock apple; the third primer group had poor distinguishing ability for rootstock apple; and the first primer group can be applied to distinguish Xinjiang wild apple. The cluster results of the combination of 6 highly-effective primers on 48 apple samples had correlation coefficient of 0.940 with the comprehensive cluster results of 30 pairs of primers.(6) The ITS sequence analysis, three kinds of apple resources ITS sequence difference is smaller. The difference of average proportion of G + C % were smaller. Size relationships in the order: Xinjiang wild apples > edible apple >rootstocks apple cultivars. Phylogenetic tree research shows that eating apple originated from xinjiang wild apple. The ITS sequence discrimination result of the same kinds of varieties were worse than SSR markers. |
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