The Variation And Genetic Characteristics Of The Density Of Glandular Trichome And The Weight Of The Exudates Per Unit Area On The Surface Of Tobacco Leaf

The exudates of the glandular trichome on the green leaf surface of Nicotiana tabacum L. is the important precursor of the aroma and flavour matter of cured tacco leaf. This paper studied the variation and genetic characteristics of the density of glandular trichome and the exudates per unit area on the surface of tobacco leaf through two years' field and laboratory experiments during the year 2002 and 2003, the primary results was the following:1,The density of glandular trichome of tobacco leaf became smaller and smaller with the growth of the leaf. It reduced quickly when the leaf was in infancy , only changed a little at the leaf's middle growing stages and reduced gradually when the leaf became hypermature. The appropriate time for the researcher to study the density of glandular trichome on the leaf surface was during the lower leaf grows to its 40-50 days, the lumber leaf grows to its 50-60 days and the topper leaf grows to its 60-70 days.During the leaf's growing period, the weight of the leaf surface exudates per unit area showed a change trend of a curve with double peaks. Before the leaf grew to 30 days, it increased; after this it declined until the leaf's length didn't increased. Then it began to increase and was at the most on the leaf's physical mature. On the following , as the leaf got hypermature, it began to reduce again. When the lower leaf, the lumber leaf and the topper leaf of tobacco plant grows to 50, 60 and its 70 days respectively, it's the appropriate time for mensurating the weight of the leaf surface per unit area, because at this time the weight of the exudates per unit area is at the most. and the difference among different tobacco varieties is the most significant.2,The density of glandular trichome and the weight of the leaf surface exudates per unit area is obvious different from the tobacco's different growing environment (such as different fertilizer),different genotypes, different leaf position of the plant. The weight of the leaf surface exudates per unit area is extremely significant and positive relative to the density of the total glandular trichome ,the long stem glandular trichome, the content of petroleum extract of the leaf respectively, and the relative coefficients is 0.6180, 0.5928 and 0.5275. The density of glandular trichome of the lumbar leaf of tobacco plant reached significant or extremely significant and positive relativity to the weight of the leaf surface exudates per unit area, and also had a extremely significant and negative relativity to the tobacco plant's stalk circumference, length of the lumber leaf, the area of the lumber leaf respectively.3,The heterosis of the density and the weight of the leaf exudates per unit area of tobacco leaf was not obvious among the hybrids got from the cross between the oriental tobacco variety and the flue-cured tobacco variety. The density of glandular trichome of the crossbreed F1 of the riciprocal cross of flue-cured and the dialel cross experiments is lower than the mean of their parent generally, but the weight of the leaf exudates per unit area generally was higher than the mean of their parent and has obvious heterosis.4,The phenotype of the density of glandular trichome and the weight of the leaf exudates per unit area is controlled by both the additive and non-additive effects, but the additive effects is dominant. The "Wr-Vr" of the weight of the leaf exudates per unit area is significant different among the parents, it shows that there is epistatic effects in the character, but there isn't dominent effects. However, the "Wr-Vr"and "Wr+Vr"of the density of total glandular trichome, the density of the long stem glandular trichome, the density of short stem glandular trichome is not significant different among the parents, so both of the epistatic and dominant effects is not existed. The higher phenotype of the weight of the leaf exudates per unit area is determined by the recessive gene and the lower was determined by the dominant gene. And responding to the density of the...