Influence of elevated CO2 on the sensitivity of two soybean cultivars to sulphur dioxide
2001
Deepak, S.S. | Agrawal, M.
Two cultivars of soybean (Glycine max cv. Bragg and PK 472) were subjected to elevated concentrations of CO2 (600 microliter l(-1)) and/or SO2 (0.06 microliter l(-1)), for 8 h from germination to grain maturity in open top chambers under field conditions to assess the modification in response to SO2 exposure resulting form CO2 enrichment. Exposure to SO2 alone resulted in reductions in plant growth, biomass and yield, as well as declines in foliar starch and protein content in both the cultivars of soybean. Elevated CO2 stimulated plant growth, yield and enhanced foliar starch content, photosynthesis and WUE in both the cultivars. In plants exposed to the combination of elevated CO2 + SO2, the adverse influence of SO2 was mitigated by CO2 enrichment. This effect was considered to result from the provision of extra carbon sources required for repair and detoxification processes and a reduction in SO2 uptake through reduction in stomatal conductance. PK 472 exhibited greater sensitivity to SO2 than Bragg. PK 472 also showed greater stimulation of yield under CO2 + SO2 treatment than Bragg.
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