National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Calcium is an essential macro-nutrient in plants, with concentrations in the shoot ranging from 0.1 to 5% of dry wt.Ca2+ is taken up by the root and transported to the shoot in a mainly apoplastic way to avoid interference with its function as second messenger. To circumvent the casparian strip, it has to enter the cytosol of the endodermal cells via channel proteins and subsequently be exported into the apoplast via Ca2+-ATPases or Ca2+/H+anti porters. H+/Ca2+anti porters and Ca2+-ATPases, which actively deliver Ca2+ into the apoplast or intracellular stores. These channels maintain a low (Ca2+) cyt in the resting (un-stimulated) cell appropriate for Cytoplasmic metabolism,restore (Ca2+) cyt to resting levels following a (Ca2+) cyt perturbation (stimulated). Ca2+ contributes to the structure of cell wall, stability of cell membrane, photosynthetic reaction, photo-protection (D1 protein, PsbS regulated by Ca2+), stomatal movement and pollen tube growth and elongation. Calcium sensors, including calmodulin (CaM), calmodulin-like (CML) proteins, calcineurin B-like proteins (CBL), and calcium-dependent protein kinases (CDPK) helps in Ca2+ signaling pathway during stress and non-stress condition. Deficiency symptoms occur more often in developing tissue such as young leaves and fruits, due to low remobilization from old to young tissue via the phloem. This leads to a strong dependency of Ca2+ supply via the xylem. Resulting physiological disorder are tip burn in lettuce or blossom end rot in tomato. Plants deficient in calcium have been shown to be more susceptible to pathogens and exogenous calcium supply in turn has been shown to improve the plant’s resistance. Conserved microbial patterns for example PAMP initiating a signaling cascade leading to induction of downstream responses of defense gene expression. Future research will shed more light on the different functions of this important nutrient and how they are interconnected.
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