Studies on the Assimilation and Translocation of ¹⁴CO₂ in Ladino Clover : VI. Effect of the removal of growing point, lateral buds, and defoliation on the translocation

Abstract

In order to clarify the effect of removal of the growing point of the main stem, lateral buds, and the defoliation of the leaves expect the ¹⁴C-fed leaf on the translocation of ¹⁴C-assimilates, the following two experiments were conducted, Experiment 1 : plants were given the treatment of 1) control, 2) removal of the growing point of main stem, 3) defoliation expect ¹⁴C-fed leaf, 4) combination of removal of the growing point and defoliation of leaves, 5) removal of growing point, lateral buds and defoliation. Two days after these treatments, ¹⁴CO₂ was fed to the 5th leaf from the growing point for 1 hr. Three days after ¹⁴CO₂ assimilation, plants were harvested and cunting of ¹⁴C and radioautographs were made. Experiment 2 : ¹⁴CO₂ was fed to the leaves of different ages i. e. leaf No. 1, 3 and 6 from growing point, and the effect of defoliation of the leaves except the ¹⁴C-fed leaf on the translocation of assimilates was studied. Results of these experiments were as follows: 1) When the growing point of main stem was removed, appical dominance in the distribution of assimilates disappeared and ¹⁴C was distributed to the stolon and lateral buds near ¹⁴C-fed leaf. 2) Defoliation of the leaves except the ¹⁴C-fed lead influenced the translocation and distribution of the assimilates. When all the leaves except ¹⁴C-fed leaf was defoliated, ¹⁴C was translocated and accumulated intensely, without regard to age of ¹⁴C-fed leaf into the growing point of the main stolon, emphatically showing the appical dominance of distribution. 3) When all the leaves were defoliated except one of the younger leaf, ¹⁴C-assimilates by the young leaf was distributed more widely to the older part of the plant compared with those of control plants.