Some Leaf Characters of Flue-Cured Tobacco Leaves Sprayed with Transpiration Suppressant

[摘要] Experiments were conducted to reveal the influence of OED-treatment on the dimension of intercellular spaces and the colour of flue-cured leaves. 1, 2, 8 and 25 days before priming, upper and lower surfaces of half side of the fresh leaves were sprayed with a 1/20 solution of 'OED Green', a transpiration suppressant, and those of the other halves were kept without treatment. In the OED-sprayed halves, dimensions of intercellular spaces estimated by alcohol lesion method were obviously smaller than those in the non-sprayed ones. This effect appeared on the next day of the spraying and this decreased state persisted for 25 days at least. To find the cause of the decrease of intercellular spaces, several cut blades, each of which contained a side vein, were put into the glass bottles which had been filled with CO2, O2 and air respectively and kept them in the room temperature around 30°C for 14 hours. The dimension of intercellular spaces of the blades which had been subjected to CO2, decreased obviously in comparison with those which had been kept in the air. In case of the O2 treatment, however, the result was vice versa. On these basis, it is provable that the development of intercellular spaces is widely controlled by O2 pressure in the leaf system. Samples of flue-cured leaves of various grades (1st-5th grades) were rearranged into 3 groups according to the colour ratio between upper and lower sides of the leaves. Intercellular spaces in the leaves having least or inermediate colour differences were larger than in those with intermediately or most different ones. Average grading values of the leaves of the above cited 3 groups were 1.0, 2.5 and 3.8 respectively. In the OED-sprayed leaves, dominant wave length and excitation purity were obviously larger than those in the non-sprayed leaves approaching to the character observed on the leaves from U. S. A. The differeaces of spectral reflectance between non-sprayed and OED-sprayed leaves were measured on both sides of the surface. The result revealed that in both surfaces, non-sprayed leaves showed larger differences than the sprayed ones especially at the wave length ranging from 533 to 612 mμ. This means that the spraying with OED reduces the green shade of the cured leaves. From these facts, we may draw a conclusion that spraying with a dilute solution of OED will work toward reducing both the green shade of the leaves and the colour differences between upper and lower sides and, moreover, producing orange type of leaves with high excitation purity.

[学科分类] 农业科学（综合）