Growth parameters and elemental status of cucumber (Cucumus sativus) seedlings in response to Cadmium accumulation
2008
Abu-Muriefah, S.S. (Girls Coll. of Education, Riyadh (Saudi Arabia). Botany Dept.)
The influence of cadmium (Cd2+) on growth index and mineral composition of cucumber (Cucumus sativus L.) was investigated. Seedlings were grown in hydroponics media containing a nutrient solution amended with Cd2+ at various concentrations (0.00, 100, 150, 200 & 250 mg L-1 Cd2+). Phytotoxicity of metal, quantified as growth inhibition, was observed well before there was any other change in the elemental status. After 10 days of treatment, tissue-dependent decrease of fresh mass, dry mass, lengths of both shoot and root and area of the leaf segments were correlated with concentration especially 200 and 250 mg L-1 Cd2+ in the growth medium. Cucumber was tolerant to 100 mg L-1 Cd2+, with a tolerance index (TI of 95%) but not to 250 mg L-1 (TI = 46%). Tissue concentrations of Mg, P, K Mn Cu and Zn decreased significantly in both shoots and roots at higher concentrations of Cd2+. The specific areas and densities of macro and micronutrients in the chloroplast membrane of leaf segments were significantly decreased with 250 mg L-1 Cd2+ treatment. A close relation between the plant organs and the elemental status in shoots and roots of cucumber plants was evident. Results indicated that cucumber plants could increase their hyper accumulating potential and could be used to supplement human diet.
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