Growth Rate Analysis of Soybean Nodules and Particle Size Distribution

Abstract

Surveying the number and/or weight of nodules is a simple, but important method for rough assessment of N_2-fixation activity of field-grown soybean plants. Konno et al. observed that the distribution pattern of soybean nodule diameter was in accordance with the Erlan's distribution equation. And they proposed that Erlan's distribution equation is applicable to survey the modulation of soybean. The report is intended to determine the reason why the distribution pattern of soybean nodule size follows the Erlan's distribution. The results are summarized as follows. (1) Development pattern of nodule dry weight can be simulated by the modified logistic equation. In addition, development pattern nodule size can be estimated from the development pattern of nodule dry weight calculated with the modified logistic equation. (2) Increase pattern of nodules number is in accordance with logistic equation. (3) It was confirmed that the distribution of nodule diameter followed Erlan's distribution. It might be due to the relationship of growth rate of nodule size and increase rate of nodule number. (4) It was established that the distribution of nodules weight showed Erlan's distribution in the same way as nodule number.