Plants exude a large proportion of their photosynthetically
assimilated carbon from their roots to soil. These root-released organic carbon
compounds can significantly influence the chemical, physical and biological
processes in the rhizosphere. Rhizodeposition is defined as all material lost
from plant roots, including water-soluble exudates, secretions of insoluble
materials, lysates, dead fine roots, and gases, such as CO2 and ethylene. The
high molecular weight rhizodeposits (e.g. mucilage, cellulose) which are not
easily used by microorganisms make up the majority of carbon released from the
root. However, the low molecular compounds (e.g. root exudates) are more
diverse and have lot of potential functions. Root exudate compounds can be
categorized into organic acids, amino acids, proteins, sugar, phenolics and
other secondary metabolites which are more easily used by microorganisms. Root
secretes mucilage, a viscous insoluble polysaccharide-rich substance, which
aids in lubricating and protecting the root. Root volatile organic carbons have
role in below ground plant interactions. The border cells released from root
cap act as root extracellular traps for root pathogens. Plants have passive and
active transports mechanisms to secrete these rhizodeposits into the
rhizosphere. Root exudation pattern can be affected quantitatively and
qualitatively by different physical, chemical, and biological factors. The
amount of root exudates varies with plant species, the cultivar, and age of
plants, soil properties, and stress factors. Rhizodeposits play an important
role in soil and plant health by triggering various rhizosphere processes like
nutrient solubilization, signaling for symbionts and pathogens, metal
detoxification, promotion of soil aggregation, building of microbial
communities and soil organic matter turn over etc., Hence, next-generation
field management requires the promotion of microbial biomass formation through
plant rhizodeposition to maintain healthy soils, ecosystem and climate.
Author(s) Details:
K. Prasanthi,
Kerala Agricultural University, Vellanikkara, Thrissur, Kerala,
India.
S. Anitha,
Kerala
Agricultural University, Vellanikkara, Thrissur, Kerala, India.
Please see the link here: https://stm.bookpi.org/RACAS-V4/article/view/13484
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