Differential Cultivar Tolerance in Soybean to Phytotoxic Levels of Soil Zn. I. Range of Cultivar Response1
- M. C. White,
- A. M. Decker and
- R. L. Chaney2
Heavy metals in waste materials added to agricultural soils can severely inhibit subsequent crop growth. This study was conducted to evaluate the variation in tolerance among cultivars of an agriculturally important plant species to phytotoxic levels of added soil Zn. Twenty soybean (Glycine max L. Merr.) cultivars were screened, through greenhouse pot studies, for their growth response to Zn at pH 5.5 and 6.5 on a Sassafras sandy loam (Fragiudult) amended with 1.31 (control), 131, and 262 ppm Zn. Significant differential responses were found, and the cultivars were grouped into several tolerance and uptake classes, based on the results of the H 6.5, 262-ppm Zn treatment: tolerant (9 to 18% leaf dry weight yield reduction [YR], 5 cultivars), normal (20 to 32% YR, 12 cultivars), sensitive (33 to 48% YR, 3 cultivars); accumulator (696 to 730 pprn trifoliolate leaf Zn, 5 cultivars), normal (549 to 675 ppm Zn, 11 cultivars), and excluder (389 to 540 ppm Zn, 4 cultivars). Soil Zn additions significantly increased root and foliar Mn contents to reported phytotoxic levels at both pH 5.5 and 6.5, but did not influence DTPA-TEA extractable soil Mn. Significant cultivar differences in root and leaf Mn contents were observed. The results of this work illustrate the importance of cultivar selection, not only for field planting of Zn-enriched soils, hut also for its influence on experimental results.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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