Jojoba Shoot Tip In Vitro Propagation

Jojoba (Simmandsia chinensis (Link) Schndider) is a new desert oil crop with highly economic potential and extensively application fields in industry. The seeds of jojoba contain 50-60% liquid wax by dry weight. There are many characters in seeds of Jojoba, such as high oxidation resistance, high viscosity coefficient, high flash point, high ignition point and stability, insulativity and so on. Therefore, it is one and only oil that can substitute for the oil of spermaceti wax. It is used for anti-friction material, adhesives, food, medicine and fire retardant etc. There are many good characters, including high drought and salt resistance, thus it is a good plant for water and soil conservation. However, it is difficult to be introduced into our country because of its low flood and low temperature resistance.Presently, most of studies on Jojoba focus on the field of ecology and molecular biology, but seldom on tissue culture. There are still many unresolved problems , such as the unstable induction of callus, low induction rate and rate of survival of transplant. Besides, there is no valid method to realize the stable shoot differentiation of the callus. This thesis is aimed at solving these problems and we hope it can get a good condition to cultivate new species and realize the heredity transformation.Taking of successive transfer culture and exophyte, the induction and differentiation of its callus, rooting and transplanting were studied, and some conclusions were shown as follows:1. The best culture medium for callus induction of Jojoba's successive transfer culture seedlings was MS+0.5mg/L6-BA+2.5 μ g/LIAA(6-BA/IAA=200:l), and the rate of induction was 100%.2. The culture medium of MS+1.0mg/L6-BA+1.0mg/LIAA was suited to the callus' successive transfer culture relatively.3. One-step rooting method, through using improved culture medium of 1/2MS+roA1.5mg/L+3.0mg/LNAA+0.5mg/LIAA, and four leaves of Jojoba successive transfer culture seedlings shoot-tips (about 3 cm), is good for rooting and the rate of rooting is 82.5%.4. Increasing the length of the shoots, by one-step rooting method with improved medium 1/2MS+1.5mg/LIBA+3.0mg/LNAA+0.5mg/LIAA to cultivate Jojoba successive transfer culture seedlings, can improve the rooting efficency and volume.5. The process of rooting of Jojoba successive transfer culture seedlings was that callus was induced from the bottom of the shoot at first, and then, differentiated roots quickly.6. The concentration of IAA of medium was increased aptly, and the time of rooting of Jojoba's successive transfer culture seedlings could be shortened.7. Transplanting preliminary results showed that substrate, the components and the amount of irrigation fluid were the important factors affecting the survival rate of Jojoba transplanting.With the MS culture medium that 6-BA/IAA was 200:1, the callus inducing rate was 100%. Based on the previous study of Jojoba, we improved culture medium thus the rate of rooting reached 82.5%. Although the anticipated results hadn't been achieved, it provided experience for Jojoba physiological research and the reference meaning for the building of the rapid-propagation system of other xylophyta.