reduction of major photosynthetic pigments under salinity stress in some native rice cultivars of north kerala, india

Research Article
Abhilash Joseph, E, Radhakrishnan, VV, Chandramohanan, KT and Mohanan, KV
Abiotic stress; carotenoids; leaf chlorophyll; Oryza sativa; salt tolerance.

Salt stress as a major adverse factor can lower leaf water potential, interrupting the metabolic processes of plants, leading to reduced turgor and some other responses, and ultimately lower crop productivity. Leaf chlorophyll content, a good indicator of photosynthetic activity is of special significance to precision agriculture. Chlorophyll is an essential element of photosynthesis and its content in plant leaves indicates their photosynthetic capacity as well as the presence of stress or diseases. The purpose of this work was to estimate chlorophyll and total carotenoid contents in different rice cultivars collected from the rice tracts of North Kerala, India. Results showed that Chlorophyll a, Chlorophyll b, total chlorophyll and total carotenoid contents got significantly reduced among the rice cultivars under different salinity conditions (0, 10, 30, 50, 70, 100 and 200mM NaCl). Five rice cultivars viz; Orthadian, Chovvarian, Kuttusan, Kuthiru and Orkazhama collected from a saline rice tract and two cultivars Kunhutty and Veliyan collected from a traditional non saline rice tract were used for the experiment. Both the groups exhibited significant reduction in chlorophyll content and carotenoid content under salt stress and the reduction was in proportion with the increase in salt content in the growth medium. Chlorophyll b showed higher percentage of reduction when compared to chlorophyll a content and total chlorophyll content.