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EFFECTS OF CAPSICUM LEACHATES ON GERMINATION, SEEDLING GROWTH AND CHLOROPHYLL ACCUMULATION IN VIGNA RADIATA (L.) WILCZEK SEEDLINGS

ZAMIN SHAHEED SIDDIQUI* AND ARIF-UZ-ZAMAN

Abstract: The effects of three concentrations of Capsicum leachates on germination, seedling growth, chlorophyll and chlorophyll supply-orientation (precursors for chlorophyll biosynthesis) in Vigna radiata var. NM98 were investigated. Capsicum leachates inhibited the germination of V. radiata seeds and also negatively affected root and shoot growths at 50 or 75%. Two-week old etiolated seedlings of V. radiata were cultured in growth chamber in one-tenth Hoagland culture solution with or without 25, 50 or 75% leachates. Leaves were harvested at 0, 6, 12, 24 and 48h time interval after treatment. The concentrations of chlorophyll and its three biosynthetic porphyrin precursors i.e. proto porphyrin IX (Proto), Mg-proto porphyrin IX (Mg-Proto), and proto-chlorophyllide (Pchlide) were determined and the mole percent of total porphyrins was calculated. Accumulation of chlorophyll and porphyrin contents was inhibited as the leachate concentrations increased. The mole percent of Mg-Proto affected by the leachate exhibited the same pattern as that of Pchlide and Proto. The data strongly suggests that enzymes responsible for the conversion of Proto to Mg-Proto or Mg-Proto to Pchlide may be the major targets of the leachates causing the significant decrease in chlorophyll contents.
 

Stress Physiology & Environmental Pollution Lab., Department of Botany, University of Karachi, Karachi, 75270. Pakistan.
Corresponding Author : zaminsiddiqui@yahoo.co.in