Alleviation of Drought Stress in White Clover after Inoculation with Arbuscular Mycorrhizal Fungi

Xiao-Qing Tuo,Li He,Ying-Ning Zou

doi:10.15835/nbha45110709

Xiao-Qing Tuo, Li He + Show 1 more

Open Access

https://doi.org/10.15835/nbha45110709

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Abstract

White clover is extremely susceptive to drought stress (DS), while it is not clear whether arbuscular mycorrhizal fungi (AMF) enhance drought tolerance of the plant. This study was carried out to evaluate effects of two AMF species, Funneliformis mosseae and Paraglomus occultum, on flavonoid, soluble protein, proline, and nutrient uptake in roots of white clover under well-watered (WW) and DS conditions. Root colonization by F. mosseae and P. occultum was heavily decreased by 7-week DS treatment. Mycorrhizal plants showed considerably greater biomass production in shoot, root, and total (shoot+root) than non-mycorrhizal plants, irrespective of soil water status. AMF inoculation led to significantly higher root soluble protein and proline accumulation under WW and DS and root flavonoid level under DS, regardless of AMF species. Root N, P, K and Cu concentrations were dramatically increased by mycorrhization under WW and DS, and root Ca, Mg, Fe, and Mn levels were significantly higher in AMF plants than in non-AMF plants under WW. It concluded that AMF strongly enhanced plant growth and drought tolerance of white clover by greater nutrient absorption and protective substances (soluble protein, proline, and flavonoid) accumulation.

Highlights

Drought stress (DS), one of most predominant abiotic stresses, often results in an evident decrease in crop productivity and growth throughout the world (Zhang et al, 2016)
Mycorrhizal symbiosis can benefit from carbon provided by host plants and make larger contributions to plant growth nutrient and water uptake
Underlying mechanisms under mycorrhization attribute to increasing water uptake and transport by external hyphae at low soil moisture level, improving osmotic adjustment by means of accumulating osmoprotectants, increasing photosynthetic activities, promoting acquisition of mineral nutrients especially P, activating antioxidant protected systems to eliminate the accumulation of reactive oxygen species, and release of glomalin to improve soil structure (Smith et al, 2010; Li et al, 2012; Wu et al, 2014, 2016a, 2016b)

Summary

Introduction

Drought stress (DS), one of most predominant abiotic stresses, often results in an evident decrease in crop productivity and growth throughout the world (Zhang et al, 2016). DS has adverse effects on mineral nutrient uptake and osmotic adjustment as the result of dehydration in plants. Underlying mechanisms under mycorrhization attribute to increasing water uptake and transport by external hyphae at low soil moisture level, improving osmotic adjustment by means of accumulating osmoprotectants (sugar, protein, proline, etc.), increasing photosynthetic activities, promoting acquisition of mineral nutrients especially P, activating antioxidant protected systems to eliminate the accumulation of reactive oxygen species, and release of glomalin to improve soil structure (Smith et al, 2010; Li et al, 2012; Wu et al, 2014, 2016a, 2016b). Mycorrhizal effects on drought tolerance of plants depend on AMF species and host plant species, with greater compatibility

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