Ziwei tissue culture bottle seedling expansion and rooting technology
Li Rongquan et al
Lagerstroemia indica L. is a deciduous shrub or small tree of the genus Hydra in the family Plesiaceae, also known as purple flowers, tickle flowers, Western water arbutus, barkless trees, etc. Ziwei has the characteristics of smooth bark and beautiful tree shape, beautiful tree shape, summer and autumn flowering, beautiful flower shape, bright flower color, etc., and is often used as a single tree or bush tree in garden applications, and can also be potted. In addition, Ziwei has high medicinal value, and all parts of the whole plant can be medicated, which has the effect of clearing heat and detoxification. The traditional propagation methods of Ziwei are sowing and propagation, cuttings propagation, branch propagation, etc., but due to the limitations of seasons and technology, the above methods are not suitable for large-scale breeding. With the development of tissue culture technology, Ziwei tissue culture technology has entered the production application, but in the production process, the expansion and rooting coefficient of tissue culture bottle seedlings are low. Therefore, this experiment adjusts the medium formula to improve the propagation and rooting coefficient of Ziwei tissue culture bottle seedlings, in order to provide a theoretical basis for the rapid propagation of Ziwei tissue culture and accelerate the factory seedling process of Ziwei.
1 Materials and methods
1.1 Test materials
The ziwei bottle seedlings for experimental use are provided by the Liaoning Academy of Forestry Sciences. The trial was conducted from October 2020 to May 2021 in the tissue culture laboratory of the College of Forestry, Shenyang Agricultural University.
1.2 Test methods
1.2.1 Screening of medium formulations in the propagation phase will be tissue culture flasks
The seedlings were cut into 1-2 cm segments and transferred to seven different propagation medium formulations, namely A1:MS+6-BA 0.5 mg/L, A2:MS+6-BA 0.5 mg/L+IBA 0.2 mg/L, A3:MS+6-BA 0.5 mg/L+IBA 0.4 mg/L, A4:MS+6-BA0.5 mg/L+IBA 0.6 mg/L, and A5:MS+6-BA 1.0 mg/L+IAA 0.2 mg/L A6: MS+6-BA 1.0 mg/L + IAA0.4 mg/L; A7: MS+6-BA 1.0 mg/L+ IAA 0.6 mg/L, plus 6 g/L agar, 30 g/L sucrose, pH 5.8. On the 28th day after the bottle transfer, the expansion and proliferation of seedlings in each bottle are counted. The temperature of the propagation stage is controlled at 25~28°C, the illuminance is 2000~3000 lx, and the illumination time is 8~12 h/d.
1.2.2 Screening of the medium formulation at the rooting stage The bottle seedlings have passed
After 3 generations of propagation reached a certain amount, the seedlings were cut into 1-2 cm segments and transferred to 4 different rooting mediums for culture, and the rooting conditions were observed. The ratios of the four media formulations in the rooting stage were B1: 1/2 MS+IAA 0.3 mg/L, B2:1/2 MS+IAA0.5 mg/L, B3:1/2 MS+NAA 0.3 mg/L, and B4:1/2MS+NAA 0.5 mg/L. 6 g/L agar and 30 g/L sucrose were added to the above formulations, and the pH of each formulation was adjusted to 5.8. The temperature in the early stage of rooting is controlled at 25 °C, and the temperature in the later stage is controlled at 25 ~28 °C, and the light intensity gradually increases, the range is controlled at 1500~4000 lx, and the light time is 14 h/d.
2 Results and analysis
2.1 Effects of different propagation medium on proliferation of Ziwei seedlings
As can be seen from Table 1, different formulations have different effects on the proliferation of Ziwei seedlings. The proliferation factor of A5, A6, A7 medium was significantly higher than that of A1, A2, A3, A4 (P< 0.05), indicating that the addition of 1.0 mg/L of 6-BA could increase the proliferation factor of Ziwei seedlings. The average seedling height of A5 was 4.2 cm, which was significantly higher than that of other treatments (P< 0.05), indicating that the low concentration of IAA was high instead of the high seedling value, indicating that there was an interaction between 6-BA and IAA. A combination of proliferative factor and average seedling height analysis shows that A5 treatment is the most suitable. However, by observing the vitrification phenomenon, it is found that the vitrification phenomenon of A5, A6 and A7 is very high, especially the vitrification ratio of A6 and A7 is significantly higher than that of other treatments (P< 0.05), indicating that the addition of 1.0 mg/L 6-BA is easy to lead to the occurrence of vitrification.
After reviewing the data, the addition of 1.0 mg/L GA3 to the medium can reduce the incidence of vitrification. Therefore, in the 2nd and 3rd succession cultures, the A5+1.0 mg/LGA3 formulation was used. There is very little vitrification in the 2nd succession; in the 3rd succession, there is no glassification. In a comprehensive review, MS+6-BA 1.0 mg/L + IAA 0.2 mg/L + GA 3 1.0 mg/L is most suitable as a propagation medium.
Table 1 Proliferation of ziwei seedlings in different propagation mediums
Note: Different lowercase letters on shoulder tags in the same column indicate significant differences (P < 0.05).
2.2 Effects of different rooting media on the rooting of Ziwei seedlings
The effects of different media components on the rooting rate and average number of roots of Ziwei seedlings are shown in Table 2. In the rooting culture experiment, the rooting rates of B1 and B2 were significantly higher than those in B3 and B4 (P< 0.05), and there was no significant difference between B1 and B2 (P > 0.05), indicating that the addition of IAA was more beneficial to rooting than NAA. Although the rooting rate of both B1 and B2 formulations was 100%, the average number of roots in B2 group was significantly higher than that in B1 group (P< 0.05), and the average number of roots was more conducive to vial survival. In addition, the morphology of the roots of the B2 group and the B1 group is not very different, and the roots formed by both are thicker and upright, and there is no callus at the root. The combined rooting rate and average number of roots show that the B2 formula, that is, 1/2MS+IAA 0.5 mg/L, is most suitable as a rooting medium formulation.
Table 2 Rooting of Ziwei seedlings in different rooting media
3 Conclusion
This experiment was prone to vitrification during the proliferation phase, and after 2 successions, it was verified that adding 1.0 mg/L of GA3 to the medium can reduce vitrification. In the propagation stage of Ziwei tissue culture bottle seedlings, 7 media formulations were selected for comparison in this experiment, combined with the prevention of vitrification, and finally it was concluded that MS+6-BA1.0 mg/L+IAA 0.2 mg/L+ GA 3 1.0 mg/L was the most suitable as the proliferation medium formulation of Ziwei tissue culture bottle seedlings. During the rooting phase, four rooting medium formulations were compared to determine that 1/2 MS+IAA 0.5 mg/L formulation was most suitable as the rooting medium formulation for Ziwei tissue culture bottle seedlings. However, this test needs further optimization, especially the later bottle delivery management needs to be further tested.