Study on the Appearance Characteristic of Tobacco Leaf at the Different Position in the Maturity Period

The experiment in change of the content of starch in fresh tobacco leaf indicated that the content of starch would decrease after it reached to the highest level and 0.28%,0.55% and 1.14% of the content of starch were dropped in the leaf at upper,middle and low position,respectively.The leaf at upper position could stand long time;the leaf at middle position was next and the leaf at low position could not keep long time during the period of maturity.Thus the standard of leaf-harvasting at different positions was put forward accord to the appearance characteristic.