abscisic acid

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Abscisic acid is one of the phytohormones present in plants and was firstly discovered in 1963 by Frederick Addicott and his colleagues (Fursule, Kulkarni, & Agarkar, 2006). It plays an important role in regulating the physiological process especially in extreme conditions, besides plant growth and plant development. Under non-stressful conditions, abscisic acid presents in low levels in plants cells. This is because plant cells require just a low level of abscisic acid for normal growth. In stress conditions like extreme environments, abscisic acid content increases when plants exposed to extreme environments such as water shortage, salt stress, and cold. When there is water deficiency in plants, the concentration of abscisic acid in plants’ cells increases triggering the closure of stomata. Karp (2009) stated that “abscisic acid binds to a GPCR in plasma membrane of guard cells” (p.638). The receptors then activate several pathways in response to this condition. This attachment causes the opening of Ca2+ channels which transfer Ca2+ from vacuole into cytosol. At ...

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