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Studies on the nitrogen nutrition of tulips.

1963; Japanese Society for Horticultural Science; Volume: 32; Issue: 1 Linguagem: Inglês

10.2503/jjshs.32.65

1880-358X

Kanae Nishii, Kiyoshi Tsutsui,

Plant Physiology and Cultivation Studies

Effect of nitrogen supply and omission at the various stages of growth on the absorption of nutrients and on growth and yields of tulip were studied with 11.0g bulbs of‘William Pitt’in sand culture. Growth period was divided into the following five stages:I. Stage of root system development (Nov. 1-Mar. 14), II. Stage of earlier vegetative growth (Mar. 15-Apr. 19), III. Stage of later vegetative growth (Apr. 20-May 4), IV. Stage of bulb weight increase (May 5-May 31), and V. Stage of maturity (June 1-June 24).1. Growth of tops was remarkably reduced by the omission of nitrogen: leaves and flowers were considerably smaller and flowering was a little hastened than those of complete nutrition. Among the stages, stage II showed the greatest effects.2. Withering up of tops was accelerated by the omission of nitrogen at stage IV and delayed by the supply of nitrogen at this stage. The other stages had little effect on it.3. The effect of nitrogen on yields was the greatest at stage II and III, and much less at the earlier or later stages. Reduction of bulb weight due to nitrogen shortage was greater in lateral bulbs than in main bulbs.4. The omission of nitrogen at later stages indicated more marked reducing effects on the nitrogen content in bulbs than at earlier stages. And nitrogen supply at stage IV kept the content at its highest level, irrespective of the nitrogen supply before and after that stage.5. The nitrogen content of tops showed the same trend as that of bulbs; the only difference between them was that plants suffered from nitrogen dificiency for the period of vegetative growth failed to recover their nitrogen content in the tops by the nitrogen supply at stage IV.6. There were observed positive correlations between the contents of nitrogen and phosphorus in tops, bulbs and flowers. But when plants were grown under the condition of extreme deficiency of nitrogen, phosphorus concentration in each part of plants did not reduce so much as that of nitrogen.7. Potassium content in each part of plants showed no distinct differences among the treatments.8. The differentiation of flower bud in the harvested bulbs during the storage period was extremely delayed by the severe deficiency of nitrogen. The delay in other cases, however, could not be attributed either to bulb weight or final content of nitrogen, but to the nitrogen omission of stage I and/or II.9. There happened to be noted an unknown disease which caused brown necrotic spots on the surface of the outermost living scales. This disease prevailed when plants suffered from nitrogen deficiency during the period of their vegetative growth and received sufficient nitrogen supply at the stage of bulb weight increase. This fact suggested that the trouble might be of physiological nature.10. Among the studied five stages, the absorption of nitrogen was more active at stage II, III and IV. On the other hand, the efficiency of producing bulbs by the absorbed nitrogen was higher at stage I, II and III. It is considered, therefore, that stage II and III should be the most important period for nitrogen supply.