1. Concerning the growth of womr crop plants in their own community, 【○!a】relation between the magnitude of whole plant in terms of dry weight per unit area or average hill (W) and that of parts -leaf blabe (F) and the rest (C), or root (R) and top (T)- or leaf area (f) were inquired, and 【○!b】some aspects deduced from these relations were discussed in conection with dry matter production and its distribution to parts in crop plants concerned. 2. Data used for the purpose were collected from the results of field experiments organized by Professor Togari in response to JIBP/PP and granted by the Ministry of Education, carried at seven locations for rice, five location for soybean, and each three locations for corn and sugar beet, in 1966-68. The author was one of the member incharge of rice plant at Konosu. At each place, one or two varieties adapted to each locality were cultivated under such condition as to get maximal dry matter production with reasonable economic yield. Total and partial dry weight or leaf area was measured four to six times with almost three weeks interval. 3. Throughout the growth of crop plants concerned in their own community, relations berween the magntiude of W and that of F, C, R, T, or f can be represented by formulae as follows (figs. 1, 3, 5) [table] Relations in this table seem somewhat different at early stage of growth, when the ratio of F/W in likely to stand constant. That is to say, the terms higher than the second order are negligibe in F-W equations (Fig. 2). 4. In cases of rice and soybean, the meximum of F or f appears at the time when W takes a value of μ/2ν or ε/2ζ, showing the value of μ
2/4ν or ε
2/4ζ, respectively. The time of appearance of F(max) is generally preceded by that of f(max). In a normal growth pattern of corn and sugar beet, F-W curves show maximum or minimum point before or behind the point of inflexion (namely, 3μλ<ν
2), but, in case of sugar beet grown in warmer region, the sitllation is different (Fig. 3). Excepting the latter case, a positive linear regression is seen between values of ν/3λ and μ/ν within the extent of 3μλ<ν
2<4μλ, and between values of μ nad ν (Fig. 4). 5. Relations between dry weight of parts, C/F, R/T, or their reciprocals can be expressed as functions of W, and, in the actual growth of a certain plant, those are indices of the magnitude of W (Fig. 7). 6. Differential forms such as dF/dW, dC/dW, dR/dW, dT/dW should represent the distribution ratio of dry matter increment to each part. As it is obvious that dF+dC = dR+dT = dW, dF/dC, dR/dT or their reciprocals are also dry matter distribution ratios between F-C and R-T, respectively. And those are coefticients therein, such as μ, ν, λ, in F-C or ρ, σ, τ in R-T. In respeet of dry matter reproduction, dF/dW or dF/dC should be of importance. All these distribution ratios are also expressed as functions of W. 7. If the formula of dry matter inerement by Monsi, ΔW=(p-r)F-r'·C where, p:rate of photosynthesis r and r':rate of respiration in F and C in which F and C are eliminated by substituting F-W and C-W equations, is integrated with respect to time (t), handling provisionally the rates of photosynthesis or respiration as constant, W-t equations can be obtained, representing a bfsic relation between growth and assimilation, dissimilation or dry matter distribution. These W-t equations are interpreted graphically as logistic (sigmoid) curve in cases of rice or soybean, and as W
shaped curve in cases of corn or sugar beet (if F/W ratio is constant at early stage of these crop plants, W-t relation is exponeptial). These curves may not fit to actual growth curves as they are, because of changes in rate of the physiological functions. [the rest omitted]
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