Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (4): 755-763.DOI: 10.3773/j.issn.1005-264x.2009.04.014

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THE ROOT LONGEVITY OF ARTEMISIA HALODENDRON INHABITING TWO SANDY LAND HABITATS

HUANG Gang(), ZHAO Xue-Yong, HUANG Ying-Xin, LI Yu-Lin, SU Yan-Gui   

  1. Naiman Desertification Research Station, Cold and Arid Regions and Environmental & Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2008-12-01 Revised:2009-03-29 Online:2009-12-01 Published:2009-07-30
  • Contact: HUANG Gang

Abstract:

Aims Although the availability of soil resources is related to fine root longevity, contradictory conclusions regarding the relationship might be clarified by comparing fine root longevity of the same species living in different habitats with contrasting soil resource availabilities. Our objectives were to 1) compare fine root longevity of Artemisia halodendron in mobile and fixed sandy lands and analyze the effects of soil resource availability on fine root longevity, 2) determine the patterns of fine root longevity in different soil depths, and 3) analyze seasonality of fine root longevity.
Methods We established three plots in mobile and fixed sand lands and installed two tubes (clear plexiglass, 1 m long and 5 cm inner diameter) in each plot in April 2007. Images were taken at intervals of 20-30 d for each tube during July 13-September 10, 2007 and April 20-August 10, 2008. We recorded the length and width of new roots present on the minirhizotron screen and monitored them until they disappeared. Root survival time was defined as the period from appearance to disappearance. The proportion of roots surviving as a function of their age was described by the Kaplan-Meier survival function. Log-rank test was used to determine differences in fine root longevity between mobile and fixed sandy lands, two soil depths and appearance month.
Important findings Cumulative survival rate of fine roots in mobile sandy land was higher than fixed sandy land in each observation time, with median root longevity (MRL) of 47 d in mobile sandy land and 35 d in fixed sandy land. MRL had significant negative relationships with soil total nitrogen content and soil bulk density, and a positive relationship with soil volumetric water content. Multiple regression analysis indicated soil water content was the key factor influencing fine root longevity. MRL of deep soil layer (30-50 cm) was significantly longer than shallow soil layer (10-30 cm) in both habitats. The two habitats had similar seasonal patterns of fine root longevity. The lifespan of fine roots in spring (70 d) was longer than autumn (61 d), and it was shortest in summer (39 d) due to high temperature and drought. These results suggested variations of soil water content play an important role in fine root longevity.

Key words: Artermisia halodendron, depth, habitat, minirhizotron, root longevity