Phenotypic Variation Of Ziziphus Jujuba Var. Spinosa Along Natural Drought Gradient

For some plants, phenotypic variation is a strategy coping withenvironmental changes, Ziziphus jujuba var. spinosa is widelydistributed from east coast to inland hinterland in north China, andthe variations in phenotypic traits may be considered as theadaptive mechanism of this species to natural drought gradient. Inorder to test the hypothesis, forty-one phenotypic traits of triennialfrom four natural populations along an aridity gradient (Yantai,Shijiazhuang, Yinchuan and Turpan) were examined. Variations inphenotypic traits of Z. jujuba var. spinosa were determined bynested analysis of variance, relevance analysis, principalcomponent analysis and the coefficient of variation, predicting Z.jujuba var. spinosa population respond to future climate change, toexplore the adaptive mechanism on natural drought gradient, thusenriching strategies theory of Z. jujuba var. spinosa adapt toenvironmental changes, at the same time predicting under theclimate change, Z. jujuba var. spinosa plant morphological evolutiontrend response to the extreme drought climate and the populationdynamics in the future. The main results are as follows:1. Variance analysis results showed that, among the41 phenotypic traits, there were33phenotypic traits showingsignificant or extremely significant differences, except for leaf drymass content, laminae water content, plant height, canopy, canopyheight, bud scale scar distance, the spur of jujube number ofsecondary branch, the distance between the spur of jujube.2. The mean phenotypic traits and the standard deviation chartindicated that, with the enhancement of drought gradient, leaflength, laminae length, laminae area, laminae perimeter, leafstalklength, base diameter of secondary branch, the bearing branchnumber of secondary branch and semen width showed andecreased trend from Yantai to Turpan, but specific laminae area,the ratio of laminae area to laminae perimeter, the ratio ofsecondary branch length to base diameter and stem dry mattercontent were increased. Laminae width, secondary branch length,stipular spine base width, stipular spine middle width, stem specificdensity, stem water content and semen weight showed andecreased trend from Yantai to Yinchuan, but stipular spine lengthand the ratio of laminae length to laminae width were increased.3. For four populations along the natural drought gradient, theaverage coefficients of variation of Z. jujuba var. spinosa were22.73%,19.60%,20.29%and19.60%, respectively.16traits ofbranch of average coefficients of variation (26.03%)>17traits ofleaf of average coefficients of variation (23.30%)>4traits of seedof average coefficients of variation (5.61%)>4traits of the fruit ofaverage coefficients of variation (4.41%). Average relative rangewere branch (65.03%)>leaf (63.68%)> seed (48.65%)> fruit(34.54%),the results were basically as the same as coefficient of variation, that the variation of branch and leaf traits bigger than seed and fruitcharacters.4. For four populations along the natural drought gradient,17traits of leaf of average plasticity index (0.697)>16traits of branchof average plasticity index (0.617)>4traits of seed of averageplasticity index (0.314)>4traits of the fruit of average plasticityindex (0.256).5. The variation of41phenotypic characters was analyzed byprincipal component analysis (PCA) and three principal componentswere formed. The first three principal components cumulativecontribution rate was100%, which summarized the most plantphenotypic characteristics information. The first principalcomponent contribution rate was60.182%, the contribution of LW(1.000) and decisive, LA (1.000), LAP (0.999) and DBS (0.995) and soon, they represented the information of the leaves and branches;the second principal component contribution rate was22.314%, thecontribution of LDMC (0.997), LWC (0.997) and SL (0.954) and so on,they represented the information of the leaves and seeds; the thirdprincipal component contribution rate was17.504%, thecontribution of LLL (0.927), BBL (0.889) and NLBB (0.735) and so on,they represented the information of the leaves and branches. Theprincipal component analysis (PCA) showed that, in the middle ofthe basic source of phenotypic variation the contribution of leafswas the largest, followed by the contribution of branches.6. There were extreme variations among the41differentcharacteristics. The LA、LL、LML、LW、LP、LSL、LAP、SSL、SSMW、SSBW of leaf, the SBL、BDSB、SBBD、SNSB、NBSB、SSD、SDMC、 SWC of branch, the FL、FWT、SWT、SW of fruit and seed were themost important phenotypic traits which were important to theefficiency for the measurement of Z. jujuba var. spinosa. and themeasured traits had strong integration.