Studies on the Wilting Treatment of Corn Plants : V. The influence of tryptophan spray treatment on the growth and fodder yield of plants

Abstract

We reported in previous papers that the growth and fordder yield of the corn plants passed through temporary or successive wilting at early definite of growth were increased certainly, and then this increaring was considered to be due to the raising of tryptophan content in the corn plants. But it is very difficult in practice to do wilt the corn plants cultivated in field as our pleases. Then we tried to spray tryptophan 1000 ppm solution on the nine leaves age of corn plants cultivated in field instead of wilting treatment. At the same the spray treatments with indoleacetic acid (IAA) or naphthalene acetic acid (NAA) solutions were tried as compared with tryptophan spray treatment. 1. Both IAA as the nature auxin and NAA as the synthetic auxin had the same effects on the growth and root behavior of corn plants. 2. The effects of tryptophan treatment upon the primordium of roots in the neighbouring of each node were a few. On the plants with the spray of IAA or NAA 100 ppm solutions, not only increasing the number of roots in neighbouring of lower nodes but also the decrease of those in upper were significant. The effects of IAA or NAA 10 ppm spray on the corn plants were between the effects of tryptophan spray and those of IAA or NAA 100 ppm spray. 3. The rate of that the primordiums grew ub to absorptive roots was about a hundred per cent in the neighbouring of lower nodes. But in upper nodes, tryptohan spray had the greatest effect upon the increase of absorptive roots, next was IAA or NAA 100ppm spray, and then there was the least significance between IAA or NAA 10ppm spray and control. 4. The effects of tryptophan spray upon the root behavior of corn plants were just same as the effects reported in previous papers, and the assumption that tryptophan absorbed into corn plants will gradually turn into IAA and will actuate upon the growth of corn plants was reaffirmed. 5. Absorbed tryptophan must gradually have turned into IAA and had good effects on the growth of corn plants, and those effects seemed to have continued to the final stage of growth. But IAA or NAA absorbed must have had some effects upon corn plants immediately aeter the spray, and then those effects must have decreased in consequence of the lapse of time in order to be oxidized during a short term. 6. The dry matters at the harvest time were increased by spraying tryptophan. Those with IAA or NAA spray were more weighty than those of control, but were more light than with tryptophan spray. Such significant increases on the yield of corn plants appeared a few on leaves or internodes, and much on ears.