Improving growth and structure of root system after transplanting in plug-grown seedlings

穴盘中的穴盘苗由于根区受到严格限制，很容易过度生长。通过对甘蓝幼苗根系呼吸速率和伤流液速率的测定，发现过长的甘蓝幼苗根系活力受到抑制。为了分析刚移植后插塞生长的幼苗中的根生长，将卷心菜幼苗移植到填充有沙子的盆中，并在人工气候室玻璃室中在受控环境下生长两周。随后的新的根伸出的根丛的生长进行了检查的图像分析的根系从沙子挖出来。延迟移植抑郁的伸长和发展的蓬勃锚定根移植后，虽然体积的新根补充了快速增加的细根分支频繁。因此，在穴盘中过度生长的幼苗在移栽后不能成为深根植株，并且它们可能不耐受根部环境的剧烈变化。用铜化合物涂覆托盘以防止根丛的形成，在一定程度上改善了过度生长的幼苗随后的根生长。这种新的方法可能有助于使穴盘技术适用于世界上广泛地区的农业植物生产。

Plug-grown seedlings in a plug tray can be easily overgrown, because of the tightly-restricted root zone. Depression of root activity was found in overgrown cabbage seedlings by evaluation of respiration and bleeding sap rate of the root system. For analysis of root growth in plug-grown seedlings just after transplanting, cabbage seedlings were transplanted in pots filled with sand and grown for two weeks under controlled environment in a phytotron glass room. Subsequent growth of new roots sticked out of a root clump was examined by image analysis of the root system dug out from sand. The delay of transplanting depressed elongation and development of vigorous anchoring roots after transplanting, although volume of new roots was supplemented with a rapid increase in fine roots by branching frequently. Thus, the seedlings overgrown in a plug tray could not become deeply-rooted plants after transplanting, and they might be intolerant of drastic changes in root environment. Coating the tray with a copper compound for preventing formation of a root clump improved subsequent root growth of overgrown seedlings to some extent. Such a new methodology may help to make a plug technique applicable to wide regions in the world for agricultural plant production.