Population Genetic Variation Of Pinus Yunnanensis Needle And Pinus Tabuliformis Cone And Seed Traits

Pinus yunnanensis and Pinus tabuliformis are typical conifers and important forestry resource w ith widely distributed in our country. Cone, seed and needle are important reproductive and vegetative organs for conifer. Their’ variations have important influences on plant reproductive and physiological adaptability. It is difficult to analyze population genetics, evolution and ecological effects by collecting samples from different geographical populations. Therefore, based on large-scale group sampling to analyse variations of conifer’s needle and cone traits in in situ and experimental field and the relationship with geographical environment, will help to explore conifer’s adaptive characteristics to the environment, and to accumulate data for pine reproductive ecology.To analyse quantitatively the relationship between conifer’s needle, cone and seed indices and geographical factors,7 Pinus yunnanensis populations and 8 common Pinus tabulaeformis populations from in situ and experimental field were selected, carrying out comparative anatomy analysis and observation morphology analysis to get 22 needle indices and 11 cone and seed traits. The results showed that:(1) Analysis of variance showed that variations among and within populations were significant for 22 needle traits and the variance components within population were generally higher than among populations in the most tested needle traits. The variation coefficient among populations ranged from 4.237% to 29.506%. Variation among and within populations on in situ and experimental field were extremely significant for 11 cone and seed traits. Variance components among populations on these traits in natural forest occupied more proportion than in experimental field. Correspondingly, variance components among individuals in experimental field almost occupied higher proportion. The variation coefficient among populations ranged from 7.83% to 37.59%.(2) Comparative analysis showed that three-needle fascicle accounted for a higher proportion in six Pinus yunnanensis populations. The majority of resin canal numbers on a needle were 3-4.(3) Correlation analysis and principal components analysis of Pinus yunnanensis showed that four principal components accounted for 81.596% of the variation with eigenvalues greater than 1. Except for the traits related to stomata, the correlations on other indices were significant. The differences among populations were mainly depended on needle width, stomatal density, section areas of vascular bundle, total resin canals and area ratio.(4) Most of cone and seed traits in Pinus tabulaeformis had correlation with each other. Correlation between cone length and all other traits were higher, while correlation between seed traits and cone traits were not significant. The differences among populations were mainly depended on cone length, fertile scale density, total scale density, seed width, length of seed wing and weight of one hundred seeds.(5) The correlations between needle traits and environmental factors showed that all needle traits were more correlated with longitude than other factors, and the correlation between monthly mean temperature were higher than monthly mean precipitation. The traits related with needle size were positive with longitude and negative with annual mean temperature and precipitation, except for stomatal traits. Most cone traits had closer relationship with ecological geographic factors than seed traits in Pinus tabulaeformis. This phenomenon was more obvious in in situ. Cone traits, reflected the ability of cone producing ovule, were significantly positive correlated with annual mean precipitation and negative correlation with latitude and altitude in in situ, while these traits were not significant correlation with precipitation in experimental field. Most cone traits were low correlation with annual mean temperature. The seed traits were increased with the latitude decreases in in situ.(6) 7 Pinus yunnanensis populations were divided into 3 categories by Euclidean distance, eastern, western and central populations were obvious differentiation. The cluster analysis showed 8 Pinus tabulaeformis populations had certain differences in in situ and experimental field. Eight populations were divided into 4 categories in in situ, while divided into 2 categories in experimental field.