Differing Sensitivity of Corn and Soybean Photosynthesis and Transpiration to Lead Contamination
1974
Bazzaz, F. A. | Rolfe, G. L. | Windle, P.
Corn (Zea mays L.) and soybean (Glycine max L.) plants grown in media containing a range of Pb concentrations, supplied as PbCl₂, showed decreased net photosynthesis and transpiration with increasing Pb treatment levels. At lower Pb treatment levels, corn appearsto be more sensitive than soybeans. However, at high treatment levels (62.5–250 mg/plant) soybeans are more sensitive than corn. At 250 mg Pb/plant in the medium, photosynthesis is only 10% of maximum in soybeans but 47% in corn, even though corn Pb tissue content is much higher than that of soybeans. Transpiration exhibited similar trends to photosynthesis suggesting that, especially in corn, an appreciable part of the inhibition of the two processes is related to increased stomatal resistances with increased Pb concentrations. Lead accumulation trends were similar at treatment levels of 0 to 62.5 mg/plant but were slightly different at higher levels. The total amount of Pb accumulated was higher in corn than in soybeans. Maximum accumulation in both species occurred at 62.5 mg Pb/plant.
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