抄録
In order to investigate the effects of light intensity, inoculation and nitrogen application on a tropical legume Greenleaf desmodium, a sand culture experiment was conducted in a green house at Kyushu University. It included 4 treatments of IN, IO, ON and OO, i.e., with (I) or without (O) inoculation and with (N) or without (O) nitrogen application under light (L) or shade (S: relative light intensity was 30% of L) condition. Plants were sampled 7 times at 5 day intervals from the 7th day of treatment imposed. Results obtained are as follows, 1) The effect of N to increase dry matter weight was recognized under both light conditions of L and S. It however appeared greater and earlier under L than under S. I affected almost similar to N excluding delayed and small at the early stage. NAR and LAR behaved differently in accordance with the effects of N and I. 2) Number and weight of nodule were increased in IN more than in IO under L on the contraty to those obtained under S. 3) Nitrogen percentage in whole plants was higher in IO than in ON under both light conditions though the effect appeared earlier in ON. 4) Total non-structural carbohydrate contents in ON were decreased at the earlier growth periods followed by the lower value in IO and the lowest was observed in IN. 5) In view of the above described results, it might be concluded that the favor effects emerged from IN under L on dry matter and nitrogen contents were resulted from the facts that (1) at early experimental periods N application increased the number of nodule, which came from the increase of plant size and of translocated photosynthetic products into nodule, (1) consequently N application increased per nodule weight indicating active nitrogen fixation and (3) the inverse effect of nitrogen on the nodule activity was nullified by (1) and (2) at the later periods of the experiment.
