A Physiological Study of the Differential Response of Navy Beans (Phaseolus Vulgaria L.) to Zinc

摘要

In 1965 two varieties of navy beans were reported to respond differentially to low and high levels of zinc(Zn). Saginaw was tolerant and Sanilac sensitive. The parameters measured in this study were: (1) a comparison of the dry weight accumulation between the two varieties at several levels of Zn supply; (2) comparative nutrient accumulation in various anatomical parts; and (3) an electron probe analysis of specific tissues. The results of dry weight determinations provided quantitative confirmation of what was previously observed; namely that Saginaw was tolerant and Sanilac was sensitive to both deficient and excess Zn concentrations. Elemental analysis in the various plant parts indicated that the severity of Zn deficiency symptoms is not reflected by the Zn concentration in the tissue, but is likely due to increased phosphorous (P) accumulation, translocation, and to the abnormal P/Zn ratio. Electron microprobe analysis showed a fluctuation in the calcium (Ca) /P and potassium (K)/P ratios with respect to various tissues. Another occurrence disclosed by microprobe analysis was a differential accumulation of elements at the point of juncture between a lateral and main root. Saginaw accumulated K, P, Ca, and Zn in this area while Sanilac indicated no accumulation. (Author)