植物生态学报 ›› 2007, Vol. 31 ›› Issue (2): 291-299.DOI: 10.17521/cjpe.2007.0033

• 论文 • 上一篇    下一篇

高山松种实性状与生殖适应性

毛建丰1,2, 李悦3, 刘玉军3, 刘灏4, 王晓茹1,*()   

  1. 1 中国科学院植物研究所系统与进化植物学国家重点实验室,北京 100093
    2 中国科学院研究生院,北京 100049
    3 北京林业大学教育部林木花卉遗传育种重点实验室,北京 100083
    4 西藏大学农牧学院林学系,西藏林芝 860000
  • 收稿日期:2005-10-17 接受日期:2006-03-03 出版日期:2007-10-17 发布日期:2007-03-30
  • 通讯作者: 王晓茹
  • 作者简介:* E-mail: Xiao-Ru.Wang@niwl.se
  • 基金资助:
    国家杰出青年科学基金(30325006)

CONE AND SEED CHARACTERISTICS OF PINUS DENSATA AND THEIR ADAPTIVE FITNESS IMPLICATIONS

MAO Jian-Feng1,2, LI Yue3, LIU Yu-Jun3, LIU Hao4, WANG Xiao-Ru1,*()   

  1. 1State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
    3Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing 100083, China
    4College of Agriculture, Tibet University, Linzhi, Tibet 860000, China
  • Received:2005-10-17 Accepted:2006-03-03 Online:2007-10-17 Published:2007-03-30
  • Contact: WANG Xiao-Ru

摘要:

高山松(Pinus densata)是云南松(P. yunnanensis)与油松(P. tabulaeformis)自然杂交产生的二倍体杂种,是植物同倍体杂交物种形成的典型案例。高山松分布于青藏高原东南缘,占据了两个亲本种都不能正常生长的高海拔地带。良好生殖适应性的产生是物种形成的关键,但对高山松在高海拔生境下生殖适应性的变异与杂交起源遗传背景关系的研究尚未见报道。该研究通过对来自该种分布区内6个代表居群样本、13个反映高山松生殖适应性的种实性状的分析,探讨了其生殖性状在居群水平的变异模式,揭示了具有不同遗传组成和起源历史的高山松居群的生殖特性。研究结果表明:6个研究居群在种实性状上存在显著差异;可育种鳞数、总种鳞数、总种子数、可育种鳞率和可育种鳞密度等与纬度呈显著负相关关系;球果结种率与经度和生态梯度值呈显著的正相关关系;胚珠败育率则与经度和生态梯度值呈显著的负相关关系;球果长度也呈现了与经度的显著负相关。高山松球果结种率很高,平均为74%;球果的结种数、种子长和种翅长与云南松、油松及其它松属双维管亚属多数种接近;球果长度、球果总种鳞数接近油松的报道。这些结果表明,高山松在亲本种不能正常生长、繁衍的高原环境下具备正常的生殖能力;其种实特征在居群间分化显著并呈现一定的地理梯度变化。居群间的显著差异反映了其杂种起源特性,与高山松居群的遗传背景有关,也反映了处在异质生态环境中的高山松居群具有各自的生殖生态进化趋向。

关键词: 自然杂种, 居群分化, 生殖特性, 变异模式, 生态适应性

Abstract:

Aims Pinus densata is an important forest species in the high mountains of the southeastern Tibetan Plateau. Previous investigations demonstrated that this pine originated through natural hybridization between P. yunnanensis and P. tabulaeformis. The mechanisms underlying this hybrid speciation and especially its adaptive evolution are poorly understood. Reproductive fitness plays a critical role in hybrid speciation; however, the fitness of P. densata in the high plateau environment has not been investigated.

Methods We investigated 13 cone and seed characters, related to reproductive potential of the species, from six representative populations distributed throughout its natural range. The 13 characters are cone length, number of scales per cone, number of fertile scales, cone scale density, fertile scale density, ratio of fertile scales, number of seeds per cone, seed length, length of seed wing, total seed length per cone, total length of seed wing per cone, seed productivity per cone and ovule abortion rate. Patterns of variation of these characters were analyzed using one-way ANOVA and correlated to geo-ecological factors of each population.

Important fingdings Characters, such as cone length, total number of scales in a cone and number of seeds per cone in P. densata were similar to that in P. tabulaeformis, P. yunnanensis and several other species of Pinus. The maximum mean value of seed productivity per cone was 74%. One-way ANOVA showed significant (p<0.01) differentiation in all 13 characters among the six populations. Correlation analysis between cone and seed characters and geo-ecological factors indicated that total number of cone scales, number of fertile scales, number of seeds per cone and ratio of fertile scales were negatively correlated with latitude and seed productivity was positively correlated with longitude and ecological gradient axes. All results suggested thatP. densata as a hybrid species is not inferior in reproductive fitness in the plateau environment. The patterns of geographic variations in cone and seed characters seem to be related to the genetic background and divergent ecological environments of the populations.

Key words: hybrid, reproductive characters, population differentiation, geographic variation, ecological adaptation