| Rehmannia glutinosa Libosch is perennial herbaceous medicine plant of scrophulariaceae family and known as one of four famous Huai Chinese traditional medicine. Its fresh tuberous root named fresh R. glutinosa and finished products named crude R. glutinosa or prepared R. glutinosa were used as medicine. R. glutinosa is easy to suffered by many diseases especially viruses that usually infect plants by 100% and lead to serious variety degeneration and decrease economic benefit of the farmers. Shoot-tip culture in vitro is the most efficient approach to produce virus-free plants. However, low propagation rate, long procedure, low survival ratio and difficulties in plantlets handling prevent this strategy from its popularization. In recent years, the microtubers ofPinellia ternate and potato, corm of dasheen have been induced in vitro aiming at to substitute virus-free plantlets. Especially virus-free potato micro tubers has proved a possible alternative in seed potato production. Up to now, there is no reports on tuberous root of R. glutinosa in vitro. In addition, it is unsuitable to conserve R. glutininosa with true seeds because it belongs to cross-pollilated plants. Vegetable propagation by tuberous roots is, therefore, commonly used for the germplasm conservation and commercial production. However, conservation through tuberous roots can be easily influenced by climate, cultivation conditions, insect pests and diseases, which leads to degenerationand even loss of the germplasm. Cryopreservation by vitrification is a hopeful method for conservation of plant gemplasm developed in recent years, but little attention has been payed on R. glutininosa. In the present research, the induction and formation of the tuberous root of R. glutinosa in vitro and cryopreservation of shoot tips were conducted with variety "85-5". The main results gained as following:1. Formation of tuberous root of R. glutinosa in vitro included two main phases: adventitious root initiation and tuberous root swelling. The formation of tuberous root occuredafter the adventitious root initiated that favoured by addition of low concentration of 6-BA and NAA and the best medium combination was MS + 2mg/L6-BA + 0.lmg/L NAA. With this medium, it was found that sucrose has functions of enhancing swelling of the adventitious roots to form root tubers. Comparing with 3% sucrose, When grew on the medium added with5% and 8% sucrose, the leaves of plantlets showed deep green and flat, shoot growth was partially suppressed, and short and white adventitious roots formed that became tuberous roots later. The results revealed that high concentration of sucrose played important role in adventitious roots initiation and tuberous root formation, and 5% sucrose was the best in the present research. The results also showed that 12 h daylength,2000-3000 Ix light intensity and 25 癈 were favourable for tuberous root induction while GA3 and active carbon were not necessary substances of the medium.2. The endogenous growth regulators related to morphogenesis of tuberous roots in vitro. Hereafter endogenous growth regulators were isolated and purified from roots of different growth periods, the results indicated that the contents of GA3, IAA, ABA and JA fluctuated during tuberous root development of R. glutinosa. The levels of IAA decreased in first 20 days followed by a slow increase. GA3 was stable in early growth stage but rose quickly from 25 to 30 days, then declined gradually but still maintain a relative high level. The level of ABA increased slightly in the first 10 to 20 days and then went up rapidly in the bulking phase of tuberous roots between 20 to 30 days and henceforth trend to stability. This demonstrated that high level of ABA was helpful to tuberous root swelling of R, glutinosa. The results also showed that JA might play a very important role in tuberous root formation since its level was low in the initial stages but increased to the highest level during tuberous root bulking.3. Taking the leaves of R. glutininosa plantlets as explants, en...
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