GROWTH AND PHYSIOLOGICAL ATTRIBUTES OF WHEAT IN ZN-CONTAMINATED SOILSSANGHPRIYA GAUTAM AND S.N. PANDEYAbstract Zn-contaminated soils were rated for various levels of available (DTPA extractable) Zn viz. 0.42, 2.8, 4.5, 9.6 and 26.3 ppm and used to grow wheat (Tritium aestivumLinn.) plants. Effect of these soils on growth (length and dry matter production), visible symptoms of toxicity and biochemical constituents (protein, pigments and sugar contents and catalase activity) of wheat were evaluated. Plants grown at high Zn-contaminated soil (26.3 ppm) had visible symptoms of toxicity such as decreased growth, chlorosis and tip burning of young leaves and reduced leaf lamina. Length and dry matter yield of wheat were increased maximum at 4.5 ppm available Zn in soil. Pigment, sugar and protein contents were also stimulated upto 4.5 ppm of available Zn, whereas these values decreased with increase in Zn levels in soil. Antioxidative defense systems with respect to carotenoids and protein contents and catalase activity favoured the dry weight production in wheat which were grown at 4.5 ppm of available Zn in soil. Study revealed the tolerance of wheat found maximum at 4.5 ppm of available Zn in soil, where as tissue concentrations of root and shoot were 30.6 and 35.6 μg Zn g -1 of dry weight, respectively. High Zn concentrations (9.6 and 26.3 ppm) were not stimulatory to the wheat growth reduced biochemical constituents in cells and produced visible symptoms of toxicity in wheat.
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