氮肥对水曲柳和落叶松细根寿命的影响  

Effects of nitrogen fertilization on fine root lifespan of Fraxinus mandshurica and Larix gmelinii

作　　者：于水强[1] 王政权[2] 史建伟[3] 于立忠[4] 全先奎[2] 

机构地区：[1]南京林业大学生态与环境科学系,南京210037 [2]东北林业大学林学院,哈尔滨150040 [3]山西大学黄土高原研究所,太原030006 [4]中国科学院沈阳应用生态研究所,沈阳110016

出　　处：《应用生态学报》2009年第10期2332-2338,共7页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金青年项目(30800137);国家自然科学基金重点项目(30130160)资助

摘　　要：采用微根管技术研究了氮肥对水曲柳和落叶松细根生长、衰老和死亡的影响,探讨两树种细根寿命与氮有效性之间的相关关系.结果表明:林地施氮肥后,两树种细根数量都呈减少趋势,细根总体直径增加,分枝程度降低;氮肥使水曲柳细根存活率提高,细根中位值寿命延长105d,而落叶松细根存活率对氮肥反应不敏感;施氮肥对细根寿命的延长效应主要体现在直径较小的一级根、表层(0～15cm)根系和春夏季新生的细根,表明氮肥对高生理活性的细根影响较强.Root observation tubes （minirhizotrons） were used to study the effects of nitrogen addition on the fine root growth of Fraxinus mandshurica and Larix gmelinii, with the correlations between the fine root lifespan and nitrogen availability analyzed. After the nitrogen addition, the fine root number of F. mandshurica and L. grnelinii had a decreasing trend, but the fine root diameter became larger and the branching ratio decreased. The survival rate of F. mandshurica fine roots increased, and the median root lifespan prolonged 105 days, compared with the control. No significant responses to the nitrogen addition were observed in the survival rate of L. gmelinii fine roots. The first-order fine roots with smaller diameter, the roots in surface soil （0-15 cm） , and the fine roots newly born in spring and summer were vulnerable to extend their lifespan by nitrogen addition, suggesting that the fine roots with higher physiological activity were easily to be affected by nitrogen fertilization.

关 键 词：氮肥 细根寿命 微根管 水曲柳 落叶松 

分 类 号：Q948.1[生物学—植物学] S718.5[农业科学—林学]