Chemical Investigation of "Trashy" Leaf Phenomenon in Australian-Grown Flue-Cured Tobacco

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Abstract
Carbohydrate and N distr. in flue-cured tobacco leaves described as "trashy" were detd. Sugars in "trashy" leaf were as low as 3 % and in "good" leaf as high as 28 %. "Trashy" leaf, relatively to normal leaf, had large total N, protein N, and ammonia N contents and low amide N values, while its wt. per unit area was about 30-50% less than that of "good" leaf. Uncured "affected" leaf also had low sugar and high N values and low wt. per unit area. It is believed that trashiness is due to processes associated with carbohydrate impoverishment in leaves on the plant and that its development is conditioned by constraints such as soil nitrogen (N), temp. (T), and sunlight (L). It is suggested that effects of the N-L-T constraints on compounds available to the plant for degradation as "foods" can be expressed in simplified form as [SIGMA]R[image]NT, where [SIGMA]R is the total energy "spent" irreversibly (i.e. become non-available for various living processes) by the plant in unit time. If [SIGMA]E is the total available energy from all sources during the same time, then for certain values of [SIGMA] E -[SIGMA]R "sugars" will decrease with corresponding approach to the state of exhaustion of other compounds and onset of trashiness. In agricultural practice it is suggested that, when considering measures for control of trashiness, attention should be given to plant spacing, N supply, number of hrs. of sunshine, and night temps.