亚高山区华中碎米荠种子的休眠/萌发生理及出苗模式

Dormancy/germination physiology and seedling emergence patterns of Cardamine urbaniana in a subalpine region

幼苗出土的季节性选择是增加幼苗建成成功率所必需的。基于种子休眠/萌发对温度和光照的响应,本文研究了华中碎米荠在渝东北亚高山区生境中的出苗模式。新成熟的华中碎米荠种子是非深度生理休眠的,经过1个月的低温（4°C）层积处理后,休眠解除。低温层积之后的非休眠种子只有在光照和适宜的温度下才能萌发。枯草覆盖与土壤掩埋能明显抑制种子萌发。种子的暗休眠特性有利于形成土壤种子库。当光照充分时,种子在生境中的出苗高峰发生于5~6月,而且其发生模式与水和温度的季节性变化趋势是同步的。

The seasonal choice for seedling emergence would be essential for increasing the probability of successful seedling establishment. On the basis of the dormancy/germination responses of seeds to temperature and light, the seedling emergence pattern of Cardamine urbaniana in the habitat in a subalpine region of northeast Chongqing was investigated in this article. The dormancy was broken by 1 month low-temperature stratification at 4°C, implying that newly matured seeds was non-deep physiological dormant. The seeds which became non-dormant after low-temperature stratification could germinate only under the combination of light and appropriate temperatures. Withered grass cover and soil burial significantly inhibited the germination of this species. The nature of dark dormancy greatly facilitates the incorporation of the seeds into the soil seed bank. In the wild where light condition was fully provided, the seasonal patterns of seedling emergence with a peak in between May and June coincide well with the seasonal change trend of both temperature and precipitation.