抄録
In pot culture, not only morphological characters but also wilting degree by drought varied quantitatively in the individuals, especially obviously between leafy and non-leafy types, but not so distinctly between 4x and 8x (Figs. 1 and 2). The close relations were obtained among degree of wilting, soil water content and number of leaves (Fig. 2, 3 and 4), but loose relation existed between wilting degree and transpiratiom amount per leaf, which was not governed by stomata number and size but leaf size (Figs. 5 and 6). Therefore, under limited volume of soil, wilting degree of a plant due to drought, in general, is considered to be determined mainly by number of its leaves, but not by its mean leaf area (c. f. Table 1). On the contrary, the leaty type, A, was superior in drought tolerance to the non-leafy, B, when grown in deep soil (Figs. 7. 8 and Table 2), probably because the former developed its roots so well that abundant water lost from its larger area of transpiration could be sufficiently supplied. From these results, the possbility to breed some new strains tolerating drought is suggested.
