In Vitro Plant Regeneration And Storage System Of Populus Alba Var.pyramidalis

Populus alba var. pyramidal is Bge is a valuable poplar which has strong resistance to saltity, drought and cold. This paper explored the germplasm resourse preservation in vitro of Populus alba var pyramidal is. The study included the establishing a reliable regeneration system and the factors that affected the quality of the preservation in vitro of this species. And the best concentration and ratio of additive was also been explored. The main results were as fellows:1) Proliferation of axillary buds and plant regeneration were obtained on Populus alba L. var pyramidalis Bge. It was found that there were a low contamination ratio with about 4. 5% in all the axillary buds were sterilized in 0.1% HgCl2 solution for 10min, in this way the phenomenon of browning could be well avoided. 1/2MS can effectively avoided vitrofacation. Then cultured on 1/2 MS medium supplemented with 0. 5mg/L TDZ and 0. 05mg/L NAA. Elongation of buds was obtained. MS medium supplemented with 1. Omg/L BA and 0. 5mg/L NAA was used for shoots proliferation.2)Adventitious shoots were also obtained via callus dedifferentiation- differentiation from leaf explants of Populus alba L. var pyramidalis Bge. In primary culture, MS medium supplemented with 0. 05mg/L IBA and 0. lmg/L TDZ was used. Throngh 28 days of culture, many adventitious shoots regenerated from callus on leaf explants. Proliferation of shoots was obtained on 1/2 MS medium supplemented with 1.0mg/L BA and 0.5mg/L NAA in subculture.3) Rooting of shoots was obtained on 1/2 MS medium supplemented with IBA (0. 01-0. lmg/L) or NAACO. 01-0. 1 mg/L). Medium supplemented with 0. 05mg/LIBA or 0. 05mg/L NAA induced maximum roots.4) When plantlets of Populus alba L. var pyramidal is Bge were estabished, storage system was also studied. Adventitious shoots obtained from leaf explants were used as storage material, then the influence of chemical elements, temperature, illumination strength and different caps on storage effect were investigated. Data from observation of morphologic changing, such as yellowish leaves, red stems and proliferation in the course of storage were statistically analyzed. Sugar played an important role in the growth of shoots. Both the concentration of mannitol and the concentration of sucrose significantly affect the growth of shoots {p<0. 0$). Additionally, strong interaction occurred between mannitol effect and sucrose effect {p<0. OS). Best treatment was 20g/L mannitol+20g/L sugrose. Lower strength of illumination (5001x) and lower temperature (4C) were effective for shoot growth and the maintaining of vitality. The adding of a layer of preservative film on the cap, was effective for the maintaining of humidity, which was favorable for the reduction of subculture and the maintaining of shootvitality.The results indicated that regeneration of Populus alba L var pyramidalis Bge can be obtained from axillary explants and leaf explants. Though osmotic treatments (adding of mannitol or/and sucrose) and adjustments of temperature and illumination strength in the culture environment, shoots can be stored in the medium for over 5 months and regain growth potential (100% of survival and proliferation) when transfered to normal condition. To establish a reliable regeneration system of this species and utilize in commercial propogation, the in vitro culture and in vitro storage system were studieded.