Analysis of the varying trends and correlation of the density of glandular trichome and leaf surface exudate of flue-cured tobacco

The research results showed that the density of glandular trichome on the leaf surface went down gradually during the growth period of flue-cured tobacco leaf. The density of glandular trichome decreased quickly in early growth stages of the leaf and decreased slowly at the middle growth period and came down obviously when the leaf got mature. The appropriate time for studying the density of glandular trichome was when the lower cutter and upper leaf of tobacco plant grew to 40-50 50-60 and 60-70 days respectively. When the leaf was growing the weight of the leaf surface exudate per unit area showed a double-peak curve varying trend. Before the leaf grew to 30 days,it increased then it declined until the lower leaf of tobacco plant grew to 40 days and the cutter and upper leaf grew to 50 days. After that it began to increase and was the most when the lower cutter and upper leaf grew to 50 60 and 70 days respectively and then it began to come down again. As the weight of the leaf surface exudate per unit area reached the maximum its variation was the most significant among different tobacco genotypes so it was the appropriate time for studying it. Furthermore there existed significant variation for the density of glandular trichome and the weight of the leaf surface exudate per unit area among different tobacco genotypes. The density of glandular trichome was highly positively significantly correlated with the weight of the leaf surface exudate per unit area and highly significantly negatively correlation with the tobacco plant's stalk circumference the biggest leaf length and the biggest leaf width respectively.