Barium effects inPhaseolus aureus, Cephalandra indica,Canna indica, Beta vulgaris, Triticum aestivum andLactuca sativa

Barium chloride at 0.1 mM concentration inhibited elongation of mungbean ( Phaseolus aureus ) roots more strongly than elongation of hypocotyls. Root growth was completely inhibited at 80 mM and there was no germination at 100 mM. Respiration rates which were directly proportional to seedling vigour declined at varying degrees at the growth-inhibitory concentrations of BaCl 2 . Barium retarded senescence in isolated leaf discs of Cephalandra indica by maintaining the chlorophyll level in darkness. The carotenes were similarly protected from degradation by Ba in darkness whereas xanthophylls were retained both in darkness and light. Ba also protected anthocyanin pigments in the staminode discs of Canna indica flowers and reduced to a variable extent the leakage of betacyanin pigment from Beta vulgaris root discs caused by various membrane active chemicals. Applied either alone or in combination with IAA, Ba inhibited cell enlargement in wheat ( Triticum aestivum ) coleoptile sections. Barium-induced inhibition of lettuce ( Lactuca sativa ) hypocotyl elongation was largely overcome by GA 3 .