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Pak. J. Bot., 48(2): 793-798, 2016.

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MYCORRHIZAL GLOMUS SPP. VARY IN THEIR EFFECTS ON THE DYNAMICS AND TURNOVER OF FINE ALFALFA (MEDICAGO SATIVA L.) ROOTS

AITIAN REN^1,2, NARKES WALY¹, WEIHUA LU^1*, CHUNHUI MA¹, QIANBING ZHANG¹, HONGLING LIU³ AND JIEJING YANG¹

Abstract:The distribution of fine roots in the soil profile has important implications related to water and nutrient uptake. The objective of this study was to compare the effects of different arbuscular mycorrhizal fungi (AMF) on the fine root dynamics of Medicago sativa L. cv. Sanditi. We used minirhizotrons to observe changes in fine root length density (FRLD, mm/cm²) and fine root surface area density (FRSAD, mm²/cm²) during the growing season. Fine root P concentrations and turnover rate were also measured. The colonization rate of fine roots varied depending on the AMF species. Colonization rates were highest when roots were inoculated with Glomus mosseae and lowest when roots were inoculated G. intraradices. Inoculation with AMF significantly increased both FRLD and FRSAD. G. versiforme increased FRLD and FRSAD most, whereas G. mosseae had the least effect. Inoculation with AMF also decreased fine root turnover rates. Inoculation with a mixture of AMF species increased fine root turnover and P concentrations more than inoculation with a single AMF species. Fine root length density increased to a maximum on Aug. 6 and then decreased. In comparison, FRSAD exhibited two peaks during the growing season. Overall, the results indicated that inoculation with AMF can significantly promote fine root growth and P uptake by alfalfa growing on soil with low P availability. The AMF may preserve fine root function late in the growing season.

Key words: Arbuscular mycorrhizal fungi, Fine root, Root length density, Root surface area density, Phosphorus content.

¹College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832000, China

²State Key Laboratory of Grassland Agroecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China

³College of Teacher-training, Shihezi University, Shihezi, Xinjiang 832000, China

^*Corresponding author’s email: winnerlwh@sina.com