红松苗木根土界面性质与调控及其与水曲柳混交增产的根际营养机制
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出 版 社:博士后出站报告 |
发表时间:null |
台 站:
长白山森林生态系统定位研究站
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作 者:陈永亮 |
点 击 率:46753 |
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关 键 字:红松,根土(生态)界面,根际,电子探针,N源,根分泌物,P活化,混交林 |
摘 要:本文通过电子探针技术、根垫法、剥落分离法等实验技术对红松苗木根土界面性质及调控进行了研究,同时通过剥落分离取样法对红松与水曲柳混交林增产的根际营养机制进行了探讨。结果表明:(1)应用电子探针技术可以对不同生长时期的苗木根组织与土壤同时进行元素的同位测定,在本实验条件下共检测出N、P、K、Ca、Mg、S、F、Mn、Cu、Zn、Si、Al、Ti等13种元素,这些元素在根际土壤、非根际土壤、粘液层和根组织内的含量分布有一定的规律性,从而为通过根表两测的元素浓度梯度确定根土生态界面的厚度成为可能。(2)不同N源的施加对苗木根土界面的性质产生不同的影响。与对照相比,NH4-N处理使根土界面 pH降低,NH3-N处理使根土界面PH升高,下降或升高的程度受所加N源浓度的影响。(3)在缺磷的条件下,红松苗木生长缓慢。(4)红松与水曲柳形成混交林后,通过两树种的相互作用使两树种根际土壤的养分状况较其各自纯林均发生了不同的变化。(5)红松根际对土壤中P具有很强的活化能力。两树种混交后,由于红松根际对土壤磷具有非常强的活化能力,借助其庞大的根系,使混交林土壤磷的有效性明显提高,这是混交林增产的重要原因之一。
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关 键 字(英文):Pinus koraiensis; root-soil eco-boundary; rhizosphere; electron microprobe analysis; N sources; root exudates; soil P mobilization; mixed plantation
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摘 要(英文):The characteristics and regulation of the root-soil interface of Pinus koraiensis seedling were studied by electron microprobe analysis, root mat method and peeling the adhering the soil of the root. In the meantime, the rhizosphere nutrient mechanism, by which the growth improvement of the mixed stand of Pinus koraiensis and Fraxinus mandshurica was obtained, was also discussed. The results are as follows: (1) the element contents in the root tissue and soil can be determined in the same time by electron microprobe analysis. Thirteen elements including N、P、K、Ca、Mg、S、Fe、Mn、Cu、Zn、Si、Al、Ti were determined. There existed a distribution regulation of these elements in the rhizospher and non-rhizosphere,mucilage layer and root tissue,which make the determination of the thickness of the root-soil eco-boundary feasible by concentration gradient changes.(2)The addition of different N sources had different influence on the characteristics of the root-soil interface. In contrast with the control treatment, the addition of ,NH4-N decreased the pH near the root plane, whereas the addition of NH3-N increased the pH near the root plane .(3) The seedlings grew slower under the condition of P lack. (4) The nutrient status in the rhizosphere sol of the Pinus koraiensis and Fraxinus mandshurica changed after they mixed in comparison to their pure plantations. (5) The roots of Pinus koraiensis had much higher P mobilization ability than those of Fraxinus mandshurica did. The high P activation ability of the Pinus koraiensis roots and their massive extension obviously increased the P availability of the soil under the mixed plantation, which was one of the most important reasons why the growth improvement of the mixed plantation was obtained.
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