Spatiotemporal dynamics of the clone of white clover in a grazed sward

在放牧草地上研究了白色三叶草单克隆的时空动态。首先，建立了白色三叶草无性系生长的测定和描述技术。利用该技术，在多年生黑麦草-白三叶三叶草草地上对目标无性系的克隆生长进行了两年的监测。结果表明：（1）该无性系在夏季至秋末广布，在冬季至初夏缩小。这一萧条是由于解冻-结霜循环。(2)无性系破碎化发生在冬季至早春。具有根和分支的模块可能是分离的地点。(3)观察到挤压现象。(4)找出了分支策略。(5)牛的落叶的程度和模式进行了评估。没有被吃掉的健康叶子数量很少。它们分布在匍匐茎顶端附近。(6)在一个密集放牧草地，落叶胁迫白色三叶草无性系一致严重。(7)落叶胁迫给它们带来严重的伤害，并促进大小的变化，导致高死亡率的风险。

Spatiotemporal dynamics of a single clone of white clover was examined in a grazed sward. Firstly, new techniques were developrd to measure and describe the clonal growth of white clover. Using the techiques, clonal growth of the target clone was monitored for two years in a perennial ryegrass-white clover sward. Following results were obtained : (1) The clone spreaded widely in summer to late-autumn but decreased its size in winter to early-summer. This depression was due to the thawing-frosting cycle. (2) Fragmentation of the clone occurred in winter to early-spring. Modules with roots and branches were likely to be sites for the separation. (3) Crush phenomenon was observed. (4) Branching strategy was found out. (5) The extent and pattern of defoliation by cattle were assessed. Number of healthy leaves which were not eaten was small. They placed near around the apex of stolons. (6) In an intensively grazed sward, defoliation stress to white clover clones was uniformly severe.(7) Defoliation stress gives them heavy damage and promotes the changes in size, resulting in high mortality risk.