晩抽型ホウレン草の開花促進に関する研究(第2報)

低温処理温度及び期間並びに処理後種子の乾燥が開花・結実に及ぼす影響

抄録

1. In order to establish the seed vernalization technique for the seed production in slow bolting spinach, the author studied the effects of the tem-perature of chilling treatment and of drying of chilled seeds on the floral initiation of spinach. Spinach seeds (var. King of Denmark) were soaked in 1/5M KH₂PO₄ solution and exposed to tempera-tures of 2°, 5°, or 8°C. for one, two, three or four weeks. On the other hand, some chilled seeds for 2 weeks at 2° and 5°C. were transfered into desic-cator, in which they were maintained for 7, 10, and 14 days. Those seeds were sown in soil in greenhouse flats in spring (March 5) and fall (Oct. 5).
2. The promotive effects of the floral initiation were evidenced by all chilling temperatures, and the longer the treatment period, the greater the acceleration of flowering.
3. In the first experiment (sown in March 5), the plants grown from vernalized seeds passed normally over the courses of bolting, flowering and fruiting, and obtained seeds amounting mostly to 20.3cc in average per plant ip the plots of exposure for 14 days at 2° and 5°C, their size and uniformity were both in good condition, but the obtained quantity decreased in the cases both of longer period and shorter one of treatment than the above mentioned.
4. In the second experiments (sown in Oct. 5), the time of the initiation of floral primordia in vernalized plants was markedly accelerated, but the development of flower stalks was retarded under the short-days in fall; but with the coming of long-day of spring, the plants grown from vernalized and unvernalized seeds were acceler-ated to elongate their seedstalks, those plants, however, showed abnormal flowering and produced small amount of seeds.
5. The promotive effects of low temperature treatments was not nullified by drying chilled seeds for 1_??_2 weeks, but germination of those seeds was checked remarkably.