Effects of Sand Burial, Soil Water Content and Distribution Pattern of Seeds in Sand on Seed Germination and Seedling Survival of Eremosparton songoricum

Eremosparton songoricum (Fabaceae) is a rare and endangered Central Asian endemic species that occurs in severely wind-eroded mobile and semi-mobile sand dunes of the Gurbantunggut Desert, Xinjiang, China. In recent years, scientists have come to understand the biological and ecological characteristics of this sand dune species for its conservation. Sand burial, persistent seed bank and soil water content are three important factors that potentially can affect population regeneration of E. songoricum.

In order to evaluate the effects of these three factors on population regeneration of E. songoricum, Dr. LIU Huiliang and other researchers from Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, and Shihezi University, investigated seed germination, seedling emergence and seedling survival in greenhouse and controlled field experiments in different sand dunes microsites. By this study, they revealed that (1) the seeds have physical dormancy, and (2) the responses of seed germination, seedling emergence and seedling development to environmental factors such as sand burial depth and soil water content at different microhabitats are critically responsible for few seedlings that survived. Population regeneration under natural conditions rarely occurred via sexual reproduction, owing to the limited water resources available for seedling establishment. Responses of seed germination and seedling growth to sand burial depth and soil water content can partly explain why E. songoricum seldom reproduces via seeds, and this information helps explain why this species is endangered. Thus, rational field seeding practices, including manually scarified or dry stored seeds before sowing, sowing the seeds at right time and suitable place, are suggested for ecological restoration of endangered E. songoricum populations.

This work has received the support from the National Natural Science Foundation (30970461, 30872074 and 31070472) of China, the Key Knowledge Innovation Project of the Chinese Academy of Science (KSCX2-YW-Z-1020), and the National Basic Research Program of China (2009CB825104).

The findings have been published in Plant and Soil, 2011, 345: 69-87. The article can be linked as follows: http://www.springerlink.com/content/r367808726h9533w.