The unique rhizosphere of aerial roots

Nazari, Meisam

doi:10.1016/j.rhisph.2024.100867

Cited by 1 publication

(2 citation statements)

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“…The notably high water-holding capacity of mucilage suggests its resemblance to superabsorbent polymers, as they both retain similar quantities of water (Ai et al 2021). This high water-holding capacity of mucilage can facilitate biological N fixation by reducing gas diffusion, thereby creating an anaerobic microenvironment conducive to oxygen-sensitive nitrogenase activity (Nazari 2024). However, it is worth noting that a lower water-holding capacity may prove advantageous in humid soils and under anoxic conditions to prevent restrictions in gaseous transport.…”

Section: Maize Varieties From Dry Regions Exhibit Higher Mucilage Wat...mentioning

confidence: 99%

“…The unique characteristics and functions of root mucilage may facilitate the provision of N to soil microorganisms during drought. This is due to its composition of N-rich compounds (Mary et al 1993;Nazari 2024), ability to retain soil moisture (Carminati et al 2010), and susceptibility to rapid decomposition (Ahmed et al 2018). However, there is limited information available regarding mucilage N, its source, and the mechanisms by which microorganisms can utilize it for their growth and activity under drought.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Root mucilage nitrogen for rhizosphere microorganisms under drought

Nazari,

Bickel,

Kuzyakov

et al. 2024

Biol Fertil Soils

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Nitrogen (N) is a crucial nutrient for the growth and activity of rhizosphere microorganisms, particularly during drought conditions. Plant root-secreted mucilage contains N that could potentially nourish rhizosphere microbial communities. However, there remains a significant gap in understanding mucilage N content, its source, and its utilization by microorganisms under drought stress. In this study, we investigated the impact of four maize varieties (DH02 and DH04 from Kenya, and Kentos and Keops from Germany) on the secretion rates of mucilage from aerial roots and explored the origin of mucilage N supporting microbial life in the rhizosphere. We found that DH02 exhibited a 96% higher mucilage secretion rate compared to Kentos, while Keops showed 114% and 89% higher secretion rates compared to Kentos and DH04, respectively. On average, the four maize varieties released 4 μg N per root tip per day, representing 2% of total mucilage secretion. Notably, the natural abundance of 15N isotopes increased (higher δ15N signature) with mucilage N release. This indicates a potential dilution of the isotopic signal from biological fixation of atmospheric N by mucilage-inhabiting bacteria as mucilage secretion rates increase. We proposed a model linking mucilage secretion to a mixture of isotopic signatures and estimated that biological N fixation may contribute to 45 - 75% of mucilage N per root tip. The N content of mucilage from a single maize root tip can support a bacterial population ranging from 107 to 1010 cells per day. In conclusion, mucilage serves as a significant N-rich resource for microbial communities in the rhizosphere during drought conditions.

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Section: Maize Varieties From Dry Regions Exhibit Higher Mucilage Wat...mentioning

confidence: 99%