Difference in foliar tissue structure of flue-cured tobacco fertilized with nitrogen of various forms and its effects on cigarette tar delivery

Five forms of nitrogen were designed in field study where tissue structure of flue-cured tobacco leaves was observed and tar delivery of unblended cigarette was determined to study growth characteristics of tissue structure in flue-cured tobacco leaves. Results showed that: 1) tar delivery of unblended cigarette reduced with the increase of nitric nitrogen;2) leaf blade, palisade cell and spongy tissue treated with nitric nitrogen were thicker than those with ammonium nitrogen. 3) tar delivery was significantly negatively correlated with leaf blade and spongy tissue thickness, yet non-significant with palisade tissue thickness. In conclusion, palisade tissue thickness had direct effect on tar delivery and therefore was affected by different forms of nitrogen.