Abstract
Content and quantity of some constituents of the middle of tobacco plants with different phosphate levels at succesive periods after topping were studied. The results were shown in Table 1 and 2. The middle leaves of tobacco plants with low phosphate level had higher content in pectin, crude cellulose, lignin, malic acid and total resin and lower in protein, nicotin, oxalic acid, wax and gum compared with those with high phosphate level. There was no clear difference in tannin and citric acid content independent of phosphate level. After topping, content in pectin and malic acid of tobacco leaves decreased and nicotin, tannin, wax and gum increased to each maximum with subsequent decrease, but pectin, crude cellulose, lignin, oxalic acid and total resin increased to the end. Considering the delayed changes in content of cell wall materials, nitrogenous compounds and tannin of the middle leaves of tobacco plants with high phosphate level, it seems to be reasonable to conclude that the time of maturity of tobacco leaves with high phosphate level is later than that with low phosphate level.
