Rapid In Vitro Multiplication Of Ziziphus Mauritiana Lam.

Taiwanqingzao is a very precious and rare variety of date in which Chinese cultivars recently were selected from Ziziphus mauritiana. This variety has good fruit sense properties and high yielding, so it is chosen by people. But under-developed propagation technique and climate conditions made it impossible to develop rapidly, thus a restricted it availability to farmers occured. Stem explants of elite strains were selected for multiplication through tissue culture. The optimum media were screened out through studies conducted on the condition of initiation, proliferation and rooting culture. Main achievements were shown as follows:In March, it is a perfect time for cutting explants from healthy growing plant. Because in this period it can reduce the rate of contamination, while improve the rate of germination for stem explants culture.In general, hormone play a key role in explants initiation. In this experiment stems were cultured in the MS media containing cytokinin and auxin of different kinds and concentration for initiating explants germination. The result showed that the suitable medium for Ziziphus mauritiana was MS medium supplemented with BAG.8 mg.L"1 and IBA0.4 mg.L"1. For.Taiwanqingzao the best medium is MS medium supplemented with ZT Omg.L"1 and IBA0.4 mg.L"1.It has been proposed that multiplication of shoots remained a major bottleneck in the establishment of a complete protocol for micropropogation. Besides the nature of explants, the generation number of propagation and composition of medium are reported to affect the proliferation rate. To determine their effects, we used different generation young shoots as material and cultured them on MS basal medium supplemented with different kinds and different levels of hormone. The result showed that six to eight generation were suitable for shoot multiplication and the medium favourable for shoot multiplication was MS medium supplemented withBA1.2mg.L'and IBA0.5 mg.L"1 for Ziziphus mauritiana. While for Taiwanqingzao, six or seven generation and MS medium containing ZTO.4mg.L~1 and IBA0.4 mg.L"1 are optimum.IB A is essential for the rooting of in vitro cultured shoot. Because there are many various species and varieties diverse concentrations of IBA are needed. In this experiment, in vitro propagated shoots that grow healthy and strong were chosen to root. The result demonstrated that about 84.3 % of the multiplied shoots rooted within four weeks when treated with IBA (3.0mg.L~l) on 1/2 strength MS basal medium. More and longer roots without callus were observed on the optimal medium.