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Scientia Silvae Sinicae ›› 2015, Vol. 51 ›› Issue (2): 154-162.doi: 10.11707/j.1001-7488.20150219

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Phenotypic Variations in Natural Populations of Vatica mangachapoi in Hainan, China

Shang Shuaibin, Guo Junjie, Wang Chunsheng, Zhao Zhigang, Zeng Jie   

  1. Research Institute of Tropical Forestry, CAF Guangzhou 510520
  • Received:2014-09-26 Revised:2014-11-26 Online:2015-02-25 Published:2015-03-11

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Abstract:

【Objective】Vatica mangachapoi is an endangered tree species distributed naturally in Hainan Island, China. Its population decreased rapidly along with heavy loss of natural forest resources and habitat fragmentation due to over-harvesting and devastating forests for arable land. Efficient strategies are urgently needed for conserving natural forest resources of this species. Moreover, the taxonomy of this species is in controversy, taxonomic status of some varieties still need to be proved. Properties of fruits and leaves were measured for trees sampled from different populations to reveal phenotypic variations within and among natural populations. The study would provide scientific evidences for conservation and management of natural forests, and collection, conservation and utilization of genetic resources of the species, and provide basic data for revision of the taxonomy of species and its varieties. 【Method】 Based on surveys of whole range of natural distribution of V. mangachapoi in Hainan Island, 17 traits of fruit and leaf morphology were investigated for 133 individuals in 9 natural populations, and level of phenotypic diversity in its natural populations was assessed, and relationship between the diversity level and geographic and environmental factors was estimated using nest design, multiple comparison test, correlation analysis and cluster analysis.【Result】The variance analysis showed significant differences in the 17 morphological traits of fruit and leaf both within and among populations, indicating abundant variation among and within populations. The within-population variation (50.57%) was far greater than the among-population variation (11.38%); and the average phenotypic population differentiation coefficient was 18.31% with a range from 4.52% for the number of lateral leaf veins to 40.31% for the length/width ratio of the short sepal. Correlation analysis revealed that there were significant positive correlations between leaf length and petiole length, leaf length/width ratio and distance from the widest position to leaf base, while the length of long fruit sepals were in significantly negative correlation with the number of lateral leaf veins and petiole length. No significant correlation was found between fruit and leaf traits and mean annual air temperature and precipitation. While there were significantly negative correlation between number of lateral vein, leaf length and mean air temperature in January, and the number of lateral veins and petiole length increased remarkably with the increment of elevation. The 9 natural populations were divided into 3 groups by UPGMA cluster analysis based on Euclidean distance calculated from phenotypic traits.【Conclusion】It is important to conserve the remaining natural forests and habitats of V. mangachapoi, and in particular, more attention need to be paid to conservation of populations with abundant variations such as Kafaling (Population 4) and populations with special soil conditions such as Shimeiwan (Population 7). Within-population variation was the main source of variation, more individual trees and fewer populations should be used for genetic improvement and conservation of genetic resources. Furthermore, the findings of the present study do not support the new species and varieties in the Hainan Island which were published previously since morphological variation of fruit and leaf varied greatly and continuously, and the variation range were of considerable overlap among individuals within population and among all populations.

Key words: Vatica mangachapoi, natural population, phenotypic diversity, Hainan Island

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