Studies On Cultivation And Blooming Regulation Of Holland Narcissus

Holland Narcissus (Narcissus pseudonarcissus) is a famous bulb flower and widely used for pot cultivation and landscape. Currently, in our country the bulbs of Holland Narcissus are mainly replied on import from abroad, wasting a lot of foreign exchange. Besides, the domestic studies on Holland Narcissus cultivation, physical and biochemical characteristics are at the beginning stage.Eight varieties of Holland Narcissus were used in this experiment, according the climate characters in Shanghai, the ecology and biology speciality of Holland Narcissus, several following aspects were researched:1. Phenological recording of 8 varieties of Holland Narcissus in Shanghai area. The most suitable planting time in Shanghai is late November, through 2 months'(December and January) low temperature treatment, all of the 8 varieties can sprout in the next January and February, bloom in next March. Significant differences between different varieties in terms of florescence: early blooming-seasoned varieties sprouted in late January, bloomed in early or middle March and full-bloomed in middle or late March; late blooming-seasoned varieties sprouted in early or middle February, bloomed in late March and full-bloomed in early April.2. Study on Holland Narcissus propagation. None of the 8 varieties can normally set seed. At first a lot of ovules can normally grow in the ovary, however, these ovules gradually aborted. In Shanghai area, the bulb reproduction coefficients were usually between 2.00~2.30, but significant differences were showed between different varieties, the bulb reproduction coefficient of Spellbinder even performed negative increase of bulb number and weight.3. Plant physical and photosynthetic characteristics of Holland Narcissus. After flower remove, changes of total soluble sugar contents and sucrose content in leaves of Holland Narcissus were measured, result showed that both total soluble sugar contents and sucrose content were declined since the photosynthetic product were gradually transformed to the growth of bulb underground. The photosynthesis characteristics of the 2 varieties Dutch Master and Sovereign were determined. The diurnal changes of net photosynthetic rates of the 2 varieties both had 2 peaks a day and stoma is not the main factor of"midday depression of photosynthesis"phenomenon.4. Studies on flower bud differentiation of Holland Narcissus. Observed the dynamic process of flower bud differentiation of Holland Narcissus, result showed that in Shanghai area, Holland narcissus began to flower differentiate in middle May and finished in middle July. The whole process lasted about 2 months. 5. Blooming time regulation of Holland Narcissus. Bulbs of Dutch Master and Prof. Einstein were stored under 4~6℃for different time. Physical and biochemical indexes were also measured. Result showed that the longer cooling time, the earlier blooming. Every 1-week increase cooling time can result in 2~3 days florescence advancement. Stem height of 9 weeks'cooling performed the highest and had significant differences compared with 6~8 weeks'cooling. There are no effects of cooling time on the number of leaves. As the increase of cooling time, the soluble proteins content both in flower bud and scale gradually raised. The soluble proteins content was much higher in flower bud than in the scale. Analyzed the soluble proteins in flower bud by SDS-PAGE electrophoresis, it showed that during the process of cooling, some proteins disappeared while some new proteins generated. POD activity was proportional to the cooling time while POD activity in scale was inversely proportional to the cooling time. POD activity in flower bud was much higher than it in scale. In the 9 weeks'treatment, some new POD isozymes were generated.