Effect of cadmium on germination, growth and photosynthetic pigments on cowpea seedlings
DOI:
https://doi.org/10.53550/jfl.v19i1.2281Keywords:
Cadmium, Cowpea, Germination, Seedling growth, Photosynthetic pigments, Vigna unguiculataAbstract
Seeds of cowpea (Vigna unguiculata) cv. 5269 were germinated in sand-filled pots treated with 0 (control), 0.5, 1.0, 2.5, 5.0 and 10.0 mM CdCl, solutions. Germination was significantly reduced in presence of cadmium (Cd). Presence of Cd also decreased length, fresh weight and dry matter in root and shoot of the resulting seedlings except for shoot dry matter at 1.0 mM and root fresh weight at 0.5 and 1.0 mM. The exceptional response seems to have occurred as a result of adaptation to Cd stress by synthesis of protectant metabolites in shoots and excessive water accumulation (hyperhydricity) in roots. Decrease in root length was very prominent and may be attributed to depressive effect of Cd on activity of hydrolytic enzymes. Chlorophyll contents and chl a to chl b ratio increased in presence of Cd up to 5.0 mM but decreased significantly at 10.0 mM. Carotenoid content increased with increasing Cd levels up to 10.0 mM. It could be concluded that germination and seedling growth were adversely affected in cowpea due to Cd toxicity.
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