[Effects of nitrogen fertilization on fine root lifespan of Fraxinus mandshurica and Larix gmelinii].
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. gmelinii 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.
Yu
Shui-Qiang
SQ
Department of Ecology and Environmental Science, Nanjing Forestry University, Nanjing 210037, China. ysqiang77@yahoo.com.cn
Wang
Zheng-Quan
ZQ
Shi
Jian-Wei
JW
Yu
Li-Zhong
LZ
Quan
Xian-Kui
XK
D005308:Fertilizers; D031661:Fraxinus / Q000254:growth & development*; D028221:Larix / Q000254:growth & development*; D009584:Nitrogen / Q000494:pharmacology*; D018517:Plant Roots / Q000254:growth & development*; D013997:Time Factors
D005308:Fertilizers; D009584:Nitrogen