| Popis: |
This study was conducted to examine the physiological effect of agriculturally relevant levels of cadmium on field and greenhouse grown soybean (Glycine max). Cadmium levels of 0, 2.5, 5, and 10 ìg Cd/g dry wgt soil were selected. Measurements of instantaneous gas exchange, carbon assimilation response to leaf internal CO2 concentration, sap flow, chlorophyll fluorescence, growth parameters and cadmium levels in leaf and soil were conducted throughout the soybeans life span. There was a significant increase in total sap flow between the control and 10 ìg Cd/g soil plants. Peak sap flow was found to significantly increase in the 10 ìg Cd/g treatment. Time of initial sap flow was also significantly delayed in Cd treated plants. Additionally, instantaneous transpiration was significantly increased during one sampling period in the 10 ìg Cd/g treatment. The changes in sap flow rates following low-level Cd treatment may be attributed to damaged and non-responsive stomata. |
