Tree strategies of sprouting new shoots : why do trees have different ability of sprouting?

以天然生长的皱皮栎（Quercus crispula）实生苗为试材，研究了不同立地条件下皱皮栎实生苗萌发新枝的能力。同时测定了作为发芽源的总非结构性碳水化合物（INC）。虽然该物种可以建立在广泛的光照条件下相当大的，发芽能力不同的微生境：Q.crispula容易发芽在开放的网站，符合大量的TNC在其根中。分别于5、6、7、8月对3年生锯缘青冈实生苗进行扦插试验，并结合根中TNC的动态研究其新梢恢复过程。对于完整的幼苗，地上生物量强烈相关的结构部分的根，而不是整个根生物量，表明TNC有一个功能，是不是直接相关的顺序生长。扦插后1个月内，几乎所有的苗木都萌发了新梢，其干重可以用扦插时根系的TNC来解释，表明高含量的TNC是为了干扰后的新梢恢复。虽然生物量的恢复速度取决于扦插时间和光照条件，但所有幼苗都趋向于在季末完成根冠比恢复至完整水平，且5月或6月扦插的幼苗也完成了TNC恢复。

To examine the site and age dependency in the ability of sprouting new shoots for tee seedlings, naturally growing Quercus crispula seedlings were experimentally cut and monitored. Total non-structural carbohydrates(INC), as the resource for sprouting, were also measured. Although this species can establish considerably under wide range of light condition, sprouting ability differed among microhabitats : Q.crispula easily sprouted at open sites, coinciding with large amount of TNC in its root.To investigate seasonal dynamics after a disturbance was investigated for Quercus serrata, the most common oak tree in temperate regions, Japan, that has high sprouting ability. Cutting experiments were carried out in May, June, Jury and August for three-year old Q.serrata seedlings and shoot recovery process was investigated with dynamics of TNC in roots. For intact seedlings, above ground biomass strongly correlated with structural part of roots rather than whole root biomass, suggesting TNC had a function that was not directly related to the ordinal growth. After the cutting, almost seedlings sprouted new shoots during the first month, and its dry mass could be explained with the root TNC at the time of cutting, indicating the high content of TNC is for shoot recovery after disturbance. Although recovery rate in biomass depended on the cutting time and light condition, all seedlings tended to complete recovering root shoot ratio to the intact level at the end of the season, and TNC restoration was also finished for the seedlings cut in May or June.