Studies On Embryo Culture And Cut-Flower Preservation Technologies Of Nelumbo Nucifera Gaertn.

Mature embryos of lotus were used as explants in order to establish micro-propagation system in this study. For initial culture, the effect of different browning inhibitors, cutting methods, plant growth regulators on embryo germination and growth state of seedlings were determined; and the effect of different plant growth regulators were studied in subculture multiplication; meanwhile, the conditions for callus induction from mature embryos and young leaves were also studied. Besides, cut-flower cultivars and fresh preservation technologies were also studied in this paper. The main results are as follows:1. For initial culture:Soaking the embryos of ’Qiu Shui Chang Tian’ in the citric acid solution of 800 mg/L for 30 munities, and then cultured them in the medium added with 100 mg/L citric acid under light after 5 days’ dark culture. This would get the best average germination rate of 88.6%. The average germination rate of ’Dong Gua Lian’ reached 90.0% when retaining one of their cotyledons and then cultured them in the medium containing 0.2mg/L NAA and 2.0mg/L 6-BA, meanwhile, the seedlings showed good growth state.2. For subculture multiplication:Plantlets of’Qiu Shui Chang Tian’ cultured on the medium of MS+sucrose 5%+ active carbon 0.05%+ ZT 0.5mg/L showed the best propagation coefficient, which was 5.1, and the concentration of ZT and KT had significant effect on multiplication; while for ’Dong Gua Lian’, the medium containing MS+ sucrose 5%+ active carbon 0.05%+ZT0.5 mg/L+6-BA0.5 mg/L+NAA0.1 mg/L produced the best propagation coefficient, which was 4.2, and the concentration of 6-BA, NAA as well as ZT had significant effect on multiplication. The best subculture time for ’Qiu Shui Chang Tian’ was between 40 to 45 days, and that for’Dong Gua Lian’ was 35 to 40 days.3. Callus induction:Callus induction rate could reach to 50.0% when leaves were cultured on the medium supplemented with 2.0 mg/L 2,4-D and 2.0 mg/L NAA; high induction rate and good callus status obtained when culturing the mature embryos on the medium containing 2,4-D 4.0 mg/L under light, however, the explants began browning after in vitro for 14 days.4. Postharvest opening progress, the vase life and the water balance of the cut flowers of 28 Lotus cultivars were detected, and the results showed that:’Guo Zhen Huang’ and ’Jin Tai Yang’ exhibited opening progress in the vase and could last 4 to 5 days of vase life;’Zhong Shan Hong Tai’and’Zi Rui’could last 3 to 4 days of vase life and both cultivars showed certain opening rate; Cut flowers of other cultivars could last 2 to 3 days of vase life. Through detection of the relationship between the morphological characteristics and the vase life, the results demonstrated that the flower-bud size, the petaline type and the flower color had significant co-relationship with the vase life. Double-petalled flower cultivars owned longer vase life than that of simple-petalled ones, and yellow flower cultivars owned longer vase life than red and other color flower cultivars.5. Effect of eight kinds of different preservatives on fresh preservation of ’Dong Gua Lian’ cut flowers were studied, the results showed that B9 300mg/L, PP333 100mg/L, and alum 300mg/L could prolong 2 days’ of vase life; while sodium benzoate 50mg/L could prolong 1.5 days of vase life. Among these preservatives, B9, PP333 and sodium benzoate can slow down the ascent of MDA and relative conductivity, and then maintain the stability of membrane of petals, thus prolong the vase life and improve the ornamental quality; while PP333 100mg/L and alum can improve the water balance of cut flower effectively, then increase their fresh weight and promote their opening, thus prolong their vase life and improve their ornamental quality.