Studies on the Artificial Changes in Size and Weight of Seeds in the Pod of Peanut

[摘要] As shown in Table 1, in the research conducted in 1931 as to the development of fruit in the bunch type of peanut, the upper seed in the pod became much larger in size and weight than the lower, but in the similar experiment conducted in 1932 such phenomenon was not found, because the upper seed never exceeded the lower. In the present experiment the author has tried to discover the causes responsible for these changes in the size and weight of the seeds according to the position in the pod. The experiment was carried out in the open field in 1933 with the same variety, " Java small-seeded No. 3 ", as used in the experiments above described. Removing the ovaries from the soil 15 days after their initial soil-penetration, they were divided into two groups according to whether the upper position of the pod was made to face (1) downwards or (2) upwards. The pods were in both cases subsequently buried anew in the soil for 35 days, i.e. 50 days after their initial soil-penetration, after which they were once more taken out and the form and weight etc. of the pods and the seeds belonging to each group were compared with one another. Each group consisted of 15 pods and the average figures per fruit were shown in Table 2. According to the table, the upper seed is larger but not so wide as the lower seed whether in the case of the facing the pod upwards or downwards. This phenomenon will be stated in the future report upon the development of the fruit. As far as volume, fresh weight and dry weight are concerned, the upper seed is inferior to the lower in the case where the pod faces upwards, but the upper is superior to the lower in the case where the pod faces downwards; i.e. the lower seed grows larger in the former case, and the upper seed develops more in the latter. As mentioned above, the position of the pods under the ground has an effect upon the ratio of growth between the upper and the lower. It is clear therefore that the seeds located on the lower side are generally larger than those on the upper side, no matter whether they may happen to be upper or lower seed in the pod itself. This phenomenon seems to be connected with the translocation of the nutrient elements in the tissue. Though the difference above mentioned between the results of two experiments carried out in 1931 and 1932 may be produced by various factors, the fact deduced from the present experiment may be counted as constituting one of the important factors. It may be possible to infer from those results that physiological causes such as the soil conditions and oxygen content in the soil, and mechanical causes such as subterranean abstruction may bring about changes not only in the development of the ovary and seed themselves, but also the position of seed in the pods executes certain influences on their development.

[学科分类] 农业科学（综合）