Preliminary studies on the carbohydrates in the roots of bindweed

Data have been presented to show that the percentage of reducing sugars in bindweed roots cultivated at 3-week intervals was markedly lower than that found in the roots of undisturbed plants. A slight additional decrease was observed in the roots from the first foot level of plants cultivated bi-weekly. The roots of plants cultivated at 3-week intervals contained 55 to 60% less sucrose than the roots of undisturbed plants, while those cultivated bi-weekly showed 92 and 99% depletion of sucrose in the first and second foot levels, respectively. The total sugar content followed very closely the trend of the sucrose and was governed chiefly by this fraction. The polysaccharide fraction extracted with 10% alcohol and designated "dextrin" showed slow but constant depletion as a result of cultivation. The roots of plants cultivated every 7 days throughout the experiment contained 58% of the quantity of dextrin found in the check plants. The data further show that the starch content of the roots of bindweed was decreased markedly when the plants were cultivated at 3 week intervals, while more frequent cultivation caused but very little additional depletion of this fraction. An important observation to be made as a result of this study is the marked depletion of the total carbohydrates in the roots of plants which had undergone systematic cultivation. Prolonged cultivation, either occasional or frequent, caused a significant decrease in the food materials stored in the roots. This was found to be true of the plants in this investigation which were under cultivation at intervals of 3 weeks or less. Slight additional decrease was observed with increased frequency of cultivation. It is suggested that total carbohydrate analyses may be used, or that improved methods based on the detection of specific carbohydrate fractions may be developed, which should simplify investigations where large numbers of samples are to be studied.