THE EFFECT OF DETOPPING THE FIELD BEAN-PLANTS (VICIA-FABA L MINOR) AND LACK OF THE POD SETTING ON THE SYMBIOSIS WITH ROOT-NODULE BACTERIA

The plants of field bean var. Nadwislanski were detopped after about 1 month since the beginning of flowering and after that all flower buds were removed from some plants. The effect of a change in the trophic balance on the setting and subsequent growth of root nodules was studi ed. The removal of pods had the greater effect on the increase in the weight of the remaining organs than the detopping of plants. Detopping retarded the ageing of the plants and delayed the phase of the greate st reduction of the number of pods. The detopping of plants revealed t heir considerable compensative possibilities in terms of production of the pod weight and the potential of leaves for biomass production. Th e data obtained indicate that plant detopping may disturb the root-bac teria exchange of signals, necessary to initiate the nodule developmen t, while the further growth of nodules depends, above all, on the amou nt of available photosynthates. A very high correlation between the dr y weight of the whole plant to the dry weight of leaves ratio and the weight of nodules was observed. It proves the importance of the trophi c balance of the plant for the root nodule weight production.