Indole Acetic Acid (IAA) Mediated Amelioration of Lead (Pb) Stress-Physiological Indices of Mung Bean [Vigna radiata (L.) Wilczek]

Heavy metals have their adverse effects on growth and physiology of plant. Plant growth regulators help in improving the growth and physiological phenomenon in plants. A pot culture experiment was devised to explore the ameliorative potential of Indole Acetic Acid (IAA) for toxicity of rhizospheric lead (Pb) on two varieties of Mung bean [Vigna radiate (L.) Wickzek].

Seeds of two varieties i.e., M- 8 and MN-92 were grown in earthen pots filled with sandy loam soil and were arranged under complete randomization. Fifteen days after germination, the lead (Pb) was added @ 10mg/kg and 20mg/kg soil as solution Pb NO₃. Indole Acetic Acid @100.0mM was foliarly sprayed twice at 15 and 30 days of plants emergence. Physiological parameters i.e., Photosynthetic Rate, Transpiration Rate, Stomatal conductance, Sub Stomatal CO₂ Concentration and biomass production in the form of stem, root and leaf dry weights were determined at the age of physiological maturity for three replicates.

By application of IAA, photostnthetic rate reduction was declined from 24.61% to 17.78% under 10mg Pb stress and from 55.54% to 27.35% under 20mg Pb stress. Stomatal conductance reduction was declined from 0.56% to 0.28% under 10mg Pb stress and from 3.37% to 1.68% under 20mg Pb stress. Alleviation of Pb stress by IAA for transpiration rate was non significant. Similarly, the role of IAA for alleviation of Pb stress in term of dry weights of stem,root and leaves were non significant statistically.