Soil seed bank : its dynamics and roles in maintaining populations and vegetations

设计了一种简单的实验装置，利用马里奥特虹吸式自动供水系统，在恒定的土壤水分条件下，使种子暴露在地表土壤温度的自然波动中。除夏季干旱期间外，装置内5 cm深度的表层土壤温度及其波动与受自然水分波动影响的表层土壤温度基本一致。该装置被证明在几种河岸和潮湿生境的土壤种子库研究中非常有用。为了预测物种间形成持久土壤种子库的潜力并研究其动态变化，研究了日本中部湖滨生境中7种珍珠藻种子在0~6wk湿冷后恒温和变温条件下的休眠/萌发特性。同时，对这些物种在室外条件下放置1-12个月不同时间的种子的萌发和休眠状态进行了分析。

A simple experimental device was designed, in which seeds can be exposed to natural fluctuation of surface soil temperature under a constant soil moisture condition maintained by an automatic water supply system based on Mariotte-siphon principle. Except for the period during summer drought, surface soil temperature at the depth of 5 cm and its fluctuation within the device were largely similar to the temperature of the surface soil subjected to natural fluctuation of moisture. The device was demonstrated to be very useful in the study of soil seed banks in several types of riparian and moist habitats. In order to predict species-specific potential to form persistent soil seed banks and to characterize their dynamics, the dormancy/germination traits of the seeds of seven Persicaria species sharing the lakeshore habitats of central Japan were examined at constant and alternating temperatures after 0 to 6-wk moist chilling. Simultaneously, germination and dormancy states of the seeds placed under a outdoor condition in the device for various length of the time from 1-12 months were analyzed for these species.