植物生态学报 ›› 2011, Vol. 35 ›› Issue (2): 187-194.DOI: 10.3724/SP.J.1258.2011.00187

• 研究论文 • 上一篇    下一篇

鄂东南低丘地区枫香林下枫香幼苗更新限制因子

王传华1,2, 李俊清1,*(), 陈芳清2, 杨莹1   

  1. 1北京林业大学森林培育教育部重点实验室, 北京 100083
    2三峡大学化学与生命科学学院, 湖北宜昌, 443000
  • 收稿日期:2010-03-18 接受日期:2010-07-02 出版日期:2011-03-18 发布日期:2011-01-21
  • 通讯作者: 李俊清
  • 作者简介:*E-mail: lijq@bjfu.edu.cn

Factors affecting seedling regeneration of Liquidambar formosana in the L. formosana forests in hilly regions of Southeast Hubei, China

WANG Chuan-Hua1,2, LI Jun-Qing1,*(), CHEN Fang-Qing2, YANG Ying1   

  1. 1Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China
    2College of Chemistry and Life Science, China Three Gorges University, Yichang, Hubei 443000, China
  • Received:2010-03-18 Accepted:2010-07-02 Online:2011-03-18 Published:2011-01-21
  • Contact: LI Jun-Qing

摘要:

深入理解幼苗更新的生态过程及其限制因子是植物种群保育和森林管理的基础。在鄂东南的低丘地区, 采用控制试验研究了限制枫香(Liquidambar formosana)幼苗在其自身林下更新的生态因子。由于枫香幼苗在马尾松(Pinus massoniana)林下偶尔更新良好, 在枫香林下几乎没有更新, 以马尾松林为对照, 设计了4个试验来检验: (1)低温和土壤湿度对枫香种子储藏过程中寿命的影响, (2)两种林型的土壤、凋落物对枫香种子越冬及存活的影响, (3)凋落物对枫香种子萌发是否具有化感作用, (4)林下的光强变化是否影响幼苗的存活。结果表明, 枫香种子在很低的温度下仍可以立即萌发, 这表明枫香种子没有休眠特性是影响枫香幼苗更新的重要因子; 土壤、凋落物和凋落物滤液对种子越冬后的存活没有影响, 不能解释“枫香林下没有枫香苗”的问题; 两种林型的主要凋落物滤液对枫香种子萌发没有抑制作用或促进作用; 一年生枫香幼苗遮阴试验的结果表明, 3%透光率下幼苗的死亡率接近90%。因此枫香林下弱的光环境和种子的低温萌发特性是影响枫香幼苗更新的重要因子。

关键词: 枫香, 凋落物化感作用, 非休眠种子, 耐阴性

Abstract:

Aims Liquidambar formosana is an important canopy tree species widely distributed in the plains and mountains from the north-subtropical zone to the tropical zone in China. Full understanding of the natural regeneration processes of tree seedling and limiting factors is important for plant population conservation and forest management. Our objective is to investigate the factors that limit seedling regeneration of L. formosana under canopies of Formosan sweetgum forests in hilly regions of Southeast Hubei, China.
Methods Seedling regeneration of L. formosana occurs sporadically under canopies of mixed pine forests but poorly under Formosan sweetgum canopy. In 2008, we carried out a series of experiments to study factors limiting seedling regeneration of L. formosana under mixed pine forests and Formosan sweetgum forests and tested: (1) effects of lower temperature and soil moisture on seed longevity, (2) effects of forest type, soil type and litter cover on seed survival, (3) litter allelopathy effects on seed longevity and germination, and (4) effects of light intensity under canopies on seedling survival.
Important findings Dispersed seeds of L. formosana could germinate immediately at lower temperatures (4-8 °C), although such temperatures were fatal to seedling establishment. Contrary to our prediction, soil type, litter leachate and litter cover had no effects on L. formosana seed viability and could not be used to explain poor seedling regeneration under canopies of Formosan sweetgum forest. We also did not find any litter leachate inhibition or promotion effects on seed germination, although a short germination lag effect was found with leachate of pine needles and sweetgum leaves. Shading first-year seedlings of L. formosana indicated that about 90% would die under the canopy of the Formosan sweetgum forest (with its 3% transmittance of open-sky light). In general, our experiments suggested that non-dormant seed and shade-intolerant seedlings of L. formosana were key factors limiting seedling regeneration under canopies of Formosan sweetgum forest.

Key words: Liquidambar formosana, litter allelopathy, non-dormant seed, shade intolerance