Vol. 10, Issue 2 (2021)

Author(s):
Aisina Yomso and Bhagawan Baharli

Abstract:
Manganese, being an essential micronutrient plays crucial roles in physiological and biochemical processes in plants. The essentiality of available oxidised Manganese (Mn²⁺) in most acid soils (toxic) at low pH (<5.5) is recognised in plant processes. In contrast, Mn²⁺ is insufficient at higher soil pH (up to 8.0) in alkaline soils. The present review includes manganese dynamics in soil, absorption by rhizosphere, physical transport mechanisms, Mn²⁺ transporters in plants, Mn²⁺ functioning at the level of organelles, and its uptake by leaf cells. Besides, metabolic roles of manganese as cofactors of several enzymes that involve in carbon assimilation, nitrogen assimilation, mediation of growth regulation through hormones, are discussed. The physiological and biochemical indices manifested plausibly by Mn²⁺ deficiency and toxicity in plants are presented for practical importance. The mechanisms of tolerance and susceptibility of plants to Mn²⁺ at cellular level in terms of synthesis of certain organic molecules, anti-oxidant systems, sequestration of manganese internally, ionic interaction etc, have been discussed. Evidences on plant growth, morphology and yield & yield components of crop plants modulated by Mn distribution in plants are portrayed. Physical environmental factors related to manganese availability to plants occupy a fair discussion in the chapter. Finally, influences of manganese on pest and diseases infestation in plants are exemplified in the paper.