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Response of senescing cotyledons of clusterbean to water stress in moderate and low light: Possible photoprotective role of β ‐carotene
Author(s) -
Deo Prativa M.,
Biswal Basanti
Publication year - 2001
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2001.1120107.x
Subject(s) - lipid peroxidation , senescence , xanthophyll , chemistry , antioxidant , biochemistry , botany , biology , carotenoid , microbiology and biotechnology
Senescence of clusterbean ( Cyamopsis tetragonoloba L.) cotyledons in moderate light (12 W m −2 ) brings about a loss in the pigments, enhanced lipid peroxidation and a decline in PS II photochemical activity without any loss either in Dl protein or in the level of β ‐carotene. The senescence syndrome is aggravated in the cotyledons of water‐stressed seedlings with an increase in thylakoid lipid peroxidation, a decline in the level of β ‐carotene and a quantitative loss in the Dl protein. Loss of the protein, however, is arrested in the seedlings experiencing water stress at low light (3 W m −2 ) intensity that correlates with the stability in the level of β ‐ carotene and a slow rate of lipid peroxidation. Loss of the protein in moderate light is attributed to water‐stress sensitized photoinhibitory damage. The data on changes in the components of xanthophyll cycle suggest the low activity of the cycle both during senescence and water stress. It is, therefore, concluded that β ‐carotene may contribute to the assembly and stability of the Dl protein during senescence and water stress in clusterbean cotyledons.