Changes in the contents of some carbohydrates in vegetables cumulating lead

Six vegetable crop species were investigated: lettuce, spinach, radish, carrot, red beet and onion. Each species was represented by two cultivars. The vegetables were cultivated in pots on substrates containing 0, 250 or 500 mg center dot kg(-1)d. m. of lead. Increasing lead doses caused a decrease in sucrose content in edible plant parts accompanied by an increase in starch content in comparison with vegetables cultivated on comparative substrate. No constant tendency of changes in glucose and fructose levels in the studied plant tissues were registered under the influence of cumulated lead. In the case of root vegetables and onion, in which sucrose is the dominating soluble sugar (approximately 80% of total soluble sugars), a weakening of sweet taste may be expected if the plants are cultivated in conditions of lead pollution.