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Acta Prataculturae Sinica ›› 2020, Vol. 29 ›› Issue (12): 95-104.DOI: 10.11686/cyxb2020036

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Effects of arbuscular mycorrhizal fungi on ion absorption and distribution in Leymus chinensis under saline-alkaline stress

Ying-kui WANG1(), Yu-rong YANG2, De-li WANG1,2()   

  1. 1.Key Laboratory of Vegetation Ecology,Northeast Normal University,Changchun 130024,China
    2.School of Environment,Northeast Normal University,Changchun 130117,China
  • Received:2020-02-05 Revised:2020-03-11 Online:2020-12-28 Published:2020-12-28
  • Contact: De-li WANG

Abstract:

To explore the mechanism by which arbuscular mycorrhizal fungi (AMF) improve plants’ tolerance to saline-alkaline stress, we determined their effects on ion absorption and distribution in above- and below-ground plant parts in a pot experiment. The dominant species in Songnen grassland, Leymus chinensis, was used as the experimental material. Saline-alkaline stress increased the Na+ content and reduced the contents of K+, Ca2+, and Mg2+ in above-ground parts, enhanced Na+ transport from below-ground to above-ground parts, inhibited the transport of K+, Ca2+, and Mg2+, and altered above- and below-ground ion distribution in L. chinensis. Under saline-alkaline stress, AMF inhibited the absorption of Na+, promoted the absorption of K+, Ca2+, and Mg2+, and improved the ability of L. chinensis roots to retain Na+. The ion balance was maintained by the ion transport ratio and the cation transport selection ratio, and this improved the salt and alkali tolerance of L. chinensis.With increasing saline-alkaline stress, the hyphal colonization rate and hyphal density of AMF decreased significantly, but vesicle colonization increased. This helped the AMF store more saline-alkaline ions in the vesicles, thereby reducing the damage caused by saline-alkaline stress to L. chinensis roots. Therefore, under saline-alkaline stress, AMF enhanced the salt-alkali tolerance of L. chinensis by inhibiting absorption of Na+, by using the vesicle structure to help the root intercept Na+, and by promoting the absorption of K+, Ca2+, and Mg2+. The results suggest that the L. chinensis-AMF symbiosis has the potential to improve the health of grasslands affected by salinization-alkalization. In addition, these results provide insights into the mechanisms by which AMF enhance plants’ salt-alkali tolerance.

Key words: grassland salinization-alkalization, arbuscular mycorrhizal fungi, Leymus chinensis, ion absorption and distribution