The experiment was conducted to investigate the relationships amongst the leaf red edge characteristics and physiological and biochemical matters in tobacco leaf

especially pigment contents

in different mature stages.The tobaccos were grown under three levels of nitrogen supply during the period of May 2005 to September 2005.The regression analysis showed there was a significant correlation between the red edge position and chlorophyll a+b contents in tobacco.The results indicated that the red edge position within the range of 693—695nm was able to be used as a good reflection of ripe leaves

and the red edge position of 688nm was confirmed as the character of best overripe.Leaf maturity could be identified through chlorophyll a+b contents estimated by the corresponding red edge positions.Accordingly

this study suggests that the spectral data serve as promising measures to predict the maturity level of tobacco leaf

and also provides a strong support for decision making of tobacco production.