| Popis: |
The allelopathic potential of Kochia scoparia (L.) Schrad., a common weed in cultivated fields, was demonstrated on grain sorghum and soybeans. Growth of sorghum seedlings was reduced when the nutrient medium contained an extract equivalent of 1 g fresh weight of Kochia in 60 mL of nutrient solution, or higher quantities. Soybean seedling growth was depressed by as little as 1 g of Kochia in 240 mL of nutrient solution. Treatments with Kochia extracts that reduced growth also caused seedlings to have either an increase in leaf diffusive resistance, a decrease in water potential, or both. The addition of dried Kochia to soil pots in which seedlings were germinated and grown showed that 0.5 g of debris per 80 g of soil resulted in a significant reduction in sorghum growth, and seedlings grown with 2.0-g additions also had an increase in leaf resistance and decrease in water potential. Effects on water metabolism are indicated as one mechanism of action of allelochemicals from Kochia. It is suggested that biochemical interference from Kochia weeds in sorghum and soybean fields can contribute to production losses. |
