Impacts of arbuscular mycorrhizal fungi on nutrient uptake, N2 fixation, N transfer, and growth in a wheat/faba bean intercropping system

Abstract

Arbuscular mycorrhizal fungi (AMF) can play a key role in natural and agricultural ecosystems affecting plant nutrition, soil biological activity and modifying the availability of nutrients by plants. This research aimed at expanding the knowledge of the role played by AMF in the uptake of macro- and micronutrients and N transfer (using a 15N stem-labelling method) in a faba bean/wheat intercropping system. It also investigates the role of AMF in biological N fixation (using the natural isotopic abundance method) in faba bean grown in pure stand and in mixture. Finally, it examines the role of AMF in driving competition and facilitation between faba bean and wheat. Durum wheat and faba bean were grown in pots (five pots per treatment) as sole crops or in mixture in the presence or absence of AMF. Root colonisation by AMF was greater in faba bean than in wheat and increased when species were mixed compared to pure stand (particularly for faba bean). Mycorrhizal symbiosis positively influenced root biomass, specific root length, and root density and increased the uptake of P, Fe, and Zn in wheat (both in pure stand and in mixture) but not in faba bean. Furthermore, AMF symbiosis increased the percentage of N derived from the atmosphere in the total N biomass of faba bean grown in mixture (+20%) but not in pure stand. Nitrogen transfer from faba bean to wheat was low (2.5–3.0 mg pot-1); inoculation with AMF increased N transfer by 20%. Overall, in terms of above- and belowground growth and uptake of nutrients, mycorrhization favoured the stronger competitor in the mixture (wheat) without negatively affecting the companion species (faba bean). Results of this study confirm the role of AMF in driving biological interactions among neighbouring plants.

Effect of Inoculation with Biofertilizers and Molybdenum on the Growth and Productivity of Faba Bean (vicia faba l.) Grown in Sandy Soil under Drip Irrigation

“…Mean values of available K in soils were the highest in soils of the upper layer (Fig 3). The results obtained for available N, P, and K presented in Table 2 and Figs 1, 2, and 3 agree with the findings of Ingraffia et al, (2019) who found that AMF symbiosis improved the percentage of N derived from the atmosphere in the total N biomass of Faba bean grown in mixture (+20%) but not in pure sand. Nitrogen transfered from Faba bean soil to wheat soil was low (2.5-3.0 mg pot -1 ) and inoculation with AMF increased N transfer by 20% in terms of above-and below ground growth and uptake of nutrients.…”

Possible Roles of Rhizospheric and Endophytic Microbes to Provide a Safe and Affordable Means of Crop Biofortification

“…Besides, mycorrhizae also excrete H + and low-molecular weight organic chelating compounds, such as citric acid, oxalic acid, and siderophores, to solubilize Fe in soil [151]. Recently, mycorrhizal inoculation in wheat roots was reported to have increased the uptake of P, Fe, and Zn by the plant, along with greater root length and density [44]. In maize, the symbiosis of mycorrhiza alters the expression patterns of three key iron homeostasis genes in sulfur-deprived plants, which indicates sulfur works as a signaling molecule for Fe homeostasis [152,153].…”

Advances in the mechanism of cereal/legume intercropping promotion of symbiotic nitrogen fixation

“…大田试验中, 米豆和玉米间作系统中米豆的固氮比例 增加最高可达121% [9] . 在盆栽试验中, 蚕豆/小麦间作 使蚕豆的固氮比例增加最高可达108% [10] . 也有30%左 右的研究表明, 间作对豆科作物固氮比例没有显著的…”

“…在豌豆/燕麦间作系统中, 间作豌豆固氮比例 降低13% [14] . 不同豆科作物在不同禾/豆间作体系中固 氮能力的巨大差异主要受到豆科作物本身的种类、根 系分泌物和丛枝菌根真菌等生物因素的影响 [10,15,16] , 其 次还会受到一些环境因子即土壤水分、土壤矿质营养 和土壤pH等非生物因素的限制 [17~19] . 为了挖掘间作系 统中豆科作物固氮潜力并应用于农业生产, 需要更好 地了解禾本科/豆科间作提高豆科作物共生固氮的 机理.…”

“…AMF共生体系的碳成本变得越来越高, 因此丛枝菌根 真菌通常不会改善寄主植物的磷营养来增加生物固 氮 [46] . 在禾本科/豆科间作系统中, 豆科作物共生固氮 的增加会使作物生长受到磷的限制, 并且豆科作物在 养分和其他资源的竞争方面均弱于禾本科作物, 因此 间作豆科作物会增加对丛枝菌根共生体的依赖以克服 自身养分需求的局限性 [10,16] . 如在绿豆和水稻间作系 统中, 根系交互作用增加绿豆根部丛枝菌根真菌的侵 染, 使总磷和氮吸收量分别增加了65%和64%, 进而使 绿豆结瘤率增加了54% [29] .…”