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植物研究 ›› 2017, Vol. 37 ›› Issue (3): 377-386.doi: 10.7525/j.issn.1673-5102.2017.03.008

• 研究报告 • 上一篇    下一篇

香果树(Emmenopterys henryi)种群种子雨、种子库及 实生苗数量的海拔梯度变化

郭连金1, 曹昊玮1, 徐卫红1, 田玉清1,2, 肖志鹏1   

  1. 1. 上饶师范学院, 上饶 334000;
    2. 中国科学院昆明植物研究所, 昆明 650204
  • 收稿日期:2016-11-15 出版日期:2017-05-15 发布日期:2017-06-03
  • 作者简介:郭连金(1976-),男,副教授,主要从事植物生态学和生物多样性研究。
  • 基金资助:
    国家自然基金(31360145)资助

Seed Rain,Soil Seed Bank and Quantitative Dynamics of Seedlings of Emmenopterys henryi Populations in Different Altitude Regions

GUO Lian-Jin1, CAO Hao-Wei1, XU Wei-Hong1, TIAN Yu-Qing1,2, XIAO Zhi-Peng1   

  1. 1. Shangrao Normal University, Shanrao 334000;
    2. Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204
  • Received:2016-11-15 Online:2017-05-15 Published:2017-06-03
  • Supported by:
    The National Natural Science Foundation of China(31360145)

摘要: 香果树为我国Ⅱ级野生保护植物,由于原生境中香果树种群的数量迅速减少,目前已濒临灭绝,种群亟待恢复。研究了武夷山不同海拔的香果树种群种子雨、种子库及其幼苗存活现状,目的是阐明不同海拔地区的香果树种群自然更新的动态过程,寻找其更新脆弱的环节及其影响因素,为香果树自然种群的恢复提供理论依据。以分布于不同海拔高度(819、980、1 140及1 301 m)的香果树母树为中心,在其周围(东、南、西、北四个方位)布设种子雨收集框和土壤种子库样方,连续观测种子雨和种子库的动态,并对不同地表覆盖物中种子萌发及幼苗数量进行观测和记录。结果表明,武夷山香果树种群种子雨持续时间近2个月,尤其是11月底至12月中旬为种子雨高峰期;随着海拔的上升,香果树种子总密度以及虫蛀种子密度均显著降低,但千粒重以及饱满种子密度则有所增加;香果树土壤种子库为瞬时种子库,其水平分布以母树南侧和西侧种子密度较大,母树北侧种子密度最小。香果树种子的垂直分布主要集中于枯落物和苔藓层;3月时香果树土壤种子库中存留的饱满种子仅占种子散布后1.80%,而1年实生苗存活率为6.18%,土壤种子库的损耗是其种群自然更新困难的主要原因;不同地表覆盖物对香果树幼苗的存活产生显著影响,枯落物及苔藓层的幼苗死亡率显著高于土壤表面。建议清理林内枯落物及苔藓,增加林内裸露土壤的面积,减小地上草本的盖度,以减少种子霉烂、虫蛀的几率,增加香果树实生苗胚根与土壤接触的几率以及改善光照条件,促进香果树自然更新。

关键词: 种子雨, 土壤种子库, 种子特征, 种子萌发, 幼苗更新

Abstract: Emmenopterys henryi Oliv., the only species of the genus Emmenopterys belonging to the family Rubiaceae, is one of the most rare trees endemic to China. The size of the wild population of E.henryi has been noted to be very small and to be endangered now. In Wuyishan Natural Reserve, the seed rain, seed banks and the dynamics of seedlings of E.henryi were observed continuously. We demonstrated the dynamic processes of natural regeneration of E.henryi populations to find out the most weak stages as well as their impacting factors, and ultimately to provide scientific basis for the recovery of E.henryi populations. Five E.henryi trees were selected and labeled as the research objects in each plot with different altitudes. In the directions of east, west, south and north of every E.henryi tree labeled, five sampling points was arranged, and on each point one 0.5 m×0.5 m×0.2 m collection box was set to estimate the seed rain, nine 0.5 m×0.5 m mini-plots were set to study the dynamic of the soil seed bank, and the seed germination and growth dynamic of seedlings were observed in each plot. The seed rain lasted for about two months, and the maximum intensity of seed rain emerged from the late November to mid of December, which was the peak of seed rain. With the altitude increasing, both of the total seed density and predated seed density were decreased significantly, by contrast, the thousand seed weight and intact seed density were both increased. The seed bank of E.henryi populations was transient soil seed bank. The seed densities on the southern and eastern sides of the mother tree were more than those of other directions, and most of the seeds were distributed in litter and moss layers. In March, the proportion of intact seeds in soil seed bank was only 1.80% of all dispersed seeds and the survival rate of one-year E.henryi seedlings was 6.18%. The loss of seeds in soil seed bank is the main reason resulting in the difficulty of the natural regeneration of E.henryi population. Different ground surface types had a significant effect on the survival of the seedlings, since the mortality rate of seedlings growing in litter and moss layers was 88%, which was significantly higher than that in soil(64%). The litter and moss layers in the forest should be cleared up to release more space for soil and also reduce the coverage of the herbaceous, thus the probability of the seeds to go bad or be destroyed decreased and therefore the radicle of the seedlings could be better reach the soil. The light condition should also be improved, and therefore the natural regeneration of E.henryi population could be improved.

Key words: seed rain, soil seed bank, seed characteristics, seed germination, seedling regeneration

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