Comparative Studies on Dry Matter Production, Plant Type and Productivity in Soybean, Azuki Bean and Kidney Bean : II. Relationships between vertical destribution of leaf area and some morphological characteristics

Abstract

In order to clarify the differences of plant types and their relationships with some morphological characteristics of stem, petiole and leaf, length of petiole, angle of petiole inclination and leaf area of a compound leaf on each node were measured for two varieties in soybean, three varieties in azuki bean and four varieties in kidney bean, grown under the low population density (60cm × 45cm, singling). The results obtained are summarized as follows : 1. Each variety could be grouped into three different plant types according to their mode of the vertical distribution of leaf area. Tokachinagaha (determinate) and Harosoy (indeterminate) in soybean, Maruha No. 1 (late var.) in azuki bean, and Taishoshirokintoki (dwarf), Tokachishirokintoki (determinate, bush) in kidney bean had a greater leaf area distribution towards the top (table type). Takarashozu (early var.) in azuki bean and Kairyo-otebo (indeterminat, viny) in kidney bean had a leaf area distribution which was most abundant in the middle layer and became smaller towards the base and the top (oval type or barrel type). Ofuku (pole type) had a greater leaf area distribution towards the base (triangular type). 2. Angles of petiole inclination changed throughout the growing season in all varieties (examples in soybean are indicated in Fig.2). At the topmost-leaf-expanding stage, there are the specific trends in the vertical distribution of angles (angle of elevation) of petiole inclination; in soybean varieties, number of petioles which showed an upward wider angle increased gradually from the base to the top. In contrast to this, almost all azuki bean and kidney bean varieties except Takarashozu showed the opposite trends with soybean, that is, petioles which had an upward wider angle distributed more in the base than in the top. Takarashozu showed the same mode of distribution at each height. The viny types, Tsurushozu, Tokachishirokintoki and Kairyo-otebo, had more petioles which inclined downward than the non-viny types. 3. There was a highly positive correlation between petiole length and leaf area of a compound leaf on each node. In almost varieties, petiole length and leaf area of a compound leaf are greater on the middle nodes than on the base and the top, but those in Tokachinagaha, determinate type in soybean, became greater towards the top. Thus, the movement of petiole inclination was considered to play the significant role in the vertical distribution of leaf area.