Botany Department, Lucknow Univetsity, Lucknow 226007
The influence of variable Cu on pea cv. Azad was studied by growing plants till maturity in refined sand at 0.00065 (acute deficiency) to 6.5 mg Cu/litre (excess). The visible symptoms of low Cu (0.00065 mg/litre) were observed as patchy discolouration on young trifoliates, inward curling of margins and reduction in leaf and tendril size whereas excess (6.5 mg/litre) Cu induced chlorosis on young trifoliates. Both lower (< 0.065) and high (> 0.065 mg/litre) levels of copper lowered seed yield more effectively than biomass of pea. In addition to this, the quality of seeds was deteriorated when the concentration of sugars, starch and protein were decreased by low as well as excess (> 0.65 mg/litre) copper. In pea leaves, the activity of polyphenol oxidase decreased significantly by Cu stress. The values of deficiency and threshold of deficiency in leaves were respectively 4 and 10 μg/g dry matter.
