水曲柳落叶松根系之间的相互作用研究

 通过水曲柳(Fraxinus mandshurica)和落叶松(Larix gmelinii)两个树种苗木纯栽和混栽试验，在温室条件下研究两树种根系之间的相互作用。结果表明，水曲柳与落叶松混栽使水曲柳细根和粗根生物量比纯栽分别增加47％和46％，叶和茎生物量分别增加30％和48％，同时改变了水曲柳地下部分与地上部分比率，促进了水曲柳细根和叶协调生长。而混栽的落叶松细根和粗根生物量比纯栽分别减少19％和35％左右，叶和茎生物量减少22％和34％，但是落叶松地下部分和地上部分各生物量组分变化不存在显著差异。混栽改变了水曲柳根系的空间分布和根系的形态，导致根系密度和根长度分别增加47％和34％，有利于水曲柳吸收较多的养分和水分，提高其竞争效率。落叶松起到改变土壤环境作用。

STUDY ON THE ROOT INTERACTIONS BETWEEN FRAXINUS MANDSHURICA AND LARIX GMELINII

Root root interactions were studied in green house potted Manchurian ash (Fraxinus mandshurica) and Dahurian larch ( Larix gmelinii ) seedlings. Above and below ground growth of ash mixed was influenced significantly by the interaction with larch in mixture. The root system of ash was more sensitive to soil conditions than that of the larch, and its competitive effectiveness was enhanced by impoved nutrition. Relative to their mass in unmixed pots the fine and coarse root mass was increased by 47% and 46% respectively, and leaf and stem mass was increased about 30% and 48% respectively in mixed pots. Root root interactions affected the root/shoot ratio, especially the fine root mass/leaf mass ratio, in ash. In contrast, biomass components and root/shoot ratio of larch showed no significant response in mixture. Through morphological adaptations ash altered its root distribution and morphology in mixture: fine root density and specific root length increased by 47% and 34% over pure planted pots. With relatively larger root mass and thinner root diameter, ash is a superior competitor for soil nutrients and moisture. Larch, on the other hand, is capable of improving soil conditions through its growth.