Studies On Fast Propagation Of Zizyphus Mauritiana Cv. Taiwanqingzao By Tissue Culture

Zizyphus mauritiana cv. Taiwanqingzao is a tropic fruit tree and propagation by grafting costs a lot of time. In order to search a fast way of propagation, the microprogation techniques of Zizyphus mauritiana cv. Taiwanqingzao were studied in this present. The process includes explants collection, sterilization, establishment of asepsis culture system, multiplication and rooting. Shoot tip and stem segment from one year-old lusty branches in the spring and in the autumn were used as the explants. After being sterilized in 70% alcohol for 30s and then in 0.1% HgCl2 for 3.5 min for shoot tip or in 70% alcohol for 30s and then in 0.1% HgCl2 for 4.5 min for stem segment, the pollution and the browning rate of the explants reached a rather low level. There was no remarkable difference in the initial culture of the four ber varieties (Wuqianzhong, Huangguan, Gaolangyihao, Mizao). The MS basic medium supplemented with 1.0 mg/L 6-BA, 0.1 mg/L IBA was the best initiation medium, in which the germination rate can reach 84.6%. Remarkable difference existed in the multiplication media of the four ber varieties. The new basic medium was composed of the macro-elements, organic substances, iron salts (all the three from MS basic medium) and the micro-elements (from meliorated MS), supplemented with 1.5 mg/L 6-BA and 0.3 mg/L IBA, which was the relatively suitable multiplication medium for Wuqianzhong. 0.5% agar and 3%sucrose were supplemented to all the media above with a pH of 6.0. As etiolation was serious and rooting was diffcult for Z mauritiana cv. Taiwanqingzao, the best multiplication and rooting media of the ber varieties should be further studied.Based on the previous work, the rooting and transplanting techniques of Zizyphus mauritiana Lam. were studied in this present. The rooting medium for Z. mauritiana Lam. was 1/2MS basic medium supplemented with 0.1 mg/L IBA , 0.4 mg/L NAA, 0.5% agar, 2% sucrose, and the pH of the medium was 6.0, in which the rooting rate reached 83.33% with the average root length of 1.38 cm and average root quantities of 4.86. The temperature in the tissue culture room was adjusted to 26+2C, with 12-hour illumination, light intensity of 2000 lx and relative humidity of 70%. Before being transplanted to a mixture of the vermiculite and the nutritious soil of 2:1(V/V), the seedlings were exposed to the greenhouse for 14 days with seals and 2 days without seals. Then the seedlings were saturated with water and covered with plastic film for one week and exposed to the air for ten minutes twice a day. After one month, the seedlings could be transplanted into the plastic cups or the cropland. The survivalrate of the seedlings was 90.2% in the spring.The rooting of Z mauritiana Lam. was easier than that of Z mauritiana cv. Taiwanqingzao, in order to resolve the rooting problem of Z mauritiana cv. Taiwanqingzao, the micrografting between Z mauritiana cv. Taiwanqingzao and Z mauritiana Lam. was studied in this present.The results were showed that the low dosage of sucrose and plant hormone was propitious to the survival of cions. In addition, the survival rate of cions was 15% in MS basic medium supplemented with 0.5 mg/L 6-BA , 0.05 mg/L IBA, 1.0% sucrose and 3% active carbon.