Ecology of seed germination of eight non-pioneer tree species from a tropical seasonal rain forest in southwest China

Yang Yu, Jerry M. Baskin, Carol C. Baskin, Yong Tang, Min Cao

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49 Scopus citations

Abstract

We compared various aspects of the seed biology of eight non-pioneer tree species from a tropical seasonal rain forest in Xishuangbanna, SW China, that differ in time of dispersal, size and fresh seed moisture content (MC). Seeds were tested for germination under laboratory conditions after dehydration to different moisture levels and under 3.5, 10 and 30% solar irradiances in neutral-shade houses. For six species, germination was also compared in forest understory (3.5% light) and center of a forest gap (32.5% light). Under continuous dehydration over activated silica gel, 100% of seeds of four species had lost the ability to germinate after 48 h, and those of all species except Castanopsis hystrix (decreased from >90 to 30% germination) had lost the ability to germinate after 120 h. Four species did not differ in final germination percentages at the three irradiances (i.e. uniform germination). However, final germination percentages of Horsfieldia pandurifolia and Litsea pierrei var. szemaois were significantly lower in 30% than in 10 or 3.5% light, and seeds of Antiaris toxicaria and C. hystrix germinated to higher percentages in 30 and 10% than in 3.5% light. Mean time to germination (MTG) of the eight species (forest and shade house data combined) ranged from 5-5 days for Pometia tomentosa to 72-207days for L. pierrei; MTG for four species was ≤21 days. There was no obvious relationship between relative desiccation resistance and either time of dispersal, MTG or uniformity of germination at the three light levels, or between seed size and MC or MTG. However, the relationship between seed MC at maturity (25-60% fresh mass basis) and MC at 50% loss of seed viability (12.4-42.5%) was significant. Seven of the species fit Garwood's (Ecol Monogr 53:159-181, 1983) rapid-rainy germination syndrome and one, L. pierrei, either her delayed-rainy or intermediate-dry germination syndrome. However, fresh, non-dehydrated seeds of all eight species germinated in ≤30 days at constant 30°C in light.

Original languageEnglish
Pages (from-to)1-16
Number of pages16
JournalPlant Ecology
Volume197
Issue number1
DOIs
StatePublished - Jul 2008

Bibliographical note

Funding Information:
Acknowledgments We thank the staff of the Xishuangbanna Station for Tropical Rain Forest Ecosystem Studies (XSTRE) and the Herbarium of Xishuangbanna Tropical Botanical Garden (HITBC) for providing meteorological data and for field and laboratory assistance; and Gehan Jayasuriya, University of Kentucky, for performing the regression analysis of initial seed moisture content vs.WC50. This study was supported by The Yunnan Provincial Natural Science Foundation (2005C0058M) and The National Key Project for Basic Research on Ecosystem Changes in Longitudinal Range-Gorge Region and Transboundary Eco-security of Southwest China (2003CB415100).

Keywords

  • Desiccation-sensitive seeds
  • Forest gap
  • Forest understory
  • Fresh seed moisture content
  • Seed dispersal
  • Seed germination
  • Seed light response
  • Seed size

ASJC Scopus subject areas

  • Ecology
  • Plant Science

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