Variation of seed mass and its effects on germination in Polylepis australis: implications for seed collection
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- 作者：Peggy Seltmann ; Ilona Leyer ; Daniel Renison and Isabell Hensen
- 关键词：Argentina ; Logistic regression ; Mountain woodlands ; Polylepis australis ; Reforestation ; Seed germination ; Seed mass
- 刊名：New Forests
- 出版年：2007
- 出版时间：March, 2007
- 年：2007
- 卷：33
- 期：2
- 页码：171-181
- 全文大小：188 KB
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Life Sciences
Forestry - 出版者：Springer Netherlands
- ISSN：1573-5095
文摘
South American Polylepis mountain forests are recognised as being one of the most endangered forest ecosystems in the world. Reforestation measures have been strongly recommended but may be hampered due to the very low seed germination reported for several Polylepis species. In order to facilitate reforestation we analysed the influence of seed mass on germination probability for Polylepis australis seeds in the Córdoba mountains (central Argentina). We collected seeds from 43 trees distributed throughout five woodland fragments located within two regions differing in size, topographical position, and altitude (1,900 m a.s.l. and 2,200 m a.s.l.). Seeds of Polylepis australis exhibited a great variation in terms of mass and percent seed germination among individual trees and among geographical regions. The results of logistic regression showed that germination probability was highly correlated with seed mass. However, the explained deviance significantly increased by including the region, the woodland fragment and especially the individual tree in addition to seed mass in the regression models. We conclude that selecting seeds on the basis of mass is an appropriate way to enhance germination prospects for reforestation projects. However, no absolute mass values are applicable in this context as the highest germination probabilities were reached at varying seed mass values depending on geographical region, woodland fragment or individual tree. We suggest collecting the relatively heaviest available seeds, even though the absolute seed mass may be low.