Rooting culture is based on the principle of plant tissue culture technology. When the material proliferates to a certain amount, part of the culture should be diverted to the rooting culture stage. If the culture cannot be transferred to the rooting medium in time, the seedlings that have not been transferred for a long time will turn yellow and age, or the number of invalid seedlings will increase due to overcrowding, resulting in waste. Rooting culture is the process of rooting rootless seedlings. The purpose of this process is to make adventitious roots strong. Rooting culture can adopt 1/2 or 1/4MS medium, completely remove cytokinins and add appropriate auxins (NAA, IBA, etc.). ).

Induction rooting method

(1) Soak the base of the new tip in 50 or 100× 10-6I IBA solution for 4-8 hours; (2) culturing in a culture medium containing auxin for 4-6 days; ③ Direct transfer to rooting medium containing auxin. All the above three methods can induce new shoots to take root, but the first two methods are more conducive to the growth and development of new roots. The third can inhibit the growth of young roots. The reason is that higher concentrations of auxin continue to exist after the formation of root primordium, which is not conducive to the growth and development of young roots. But this method is more feasible.

In addition, the following methods can also be used for rooting: ① prolonging the culture time in the proliferation medium; (2) deliberately reducing some proliferation rates and the dosage of cytokinin (that is, combining proliferation and rooting into one step); (3) Cutting stout shoots and rooting directly in a nutrient pot, but this method has no rooting stage. The production of disposable culture medium can be omitted, and the cut cuttings can be soaked in auxin solution, but this method is only suitable for some crops that are easy to take root.

When a few other plants are difficult to take root, we should put a filter paper bridge in the culture medium to make it slightly higher than the liquid level, and rely on the filter paper to absorb water to supplement water and nutrition, thus inducing rooting. Seedlings developed from embryoids usually have differentiated roots, which can grow without inducing rooting. However, because the number of seedlings developed through embryoid pathway is very large and the individuals are very small, in order to make them take root, they often need to be cultured in a medium with low concentration or without plant hormones. In the stage of rooting and strengthening seedlings in vitro, in order to successfully transplant seedlings into the environment outside the test tube, the test tube seedlings can adapt to the external environmental conditions. Generally, the suitable acclimation temperature of different plants is different. Such as chrysanthemum, 18 ~ 20℃ is appropriate. Practice has proved that too high plant growth temperature will not only involve the enhancement of transpiration. It also involves the problem that fungi are easy to breed. Too low temperature makes seedlings grow slowly, or it is not easy to survive. When the temperature is low in spring, the seedbed can be equipped with an electric hotline to make the temperature of the tomb slightly higher than 2 ~ 3℃, which is not only conducive to rooting, promoting root development, but also conducive to early survival.

The light intensity of plant seedlings transplanted outside the test tube should be higher than that before transplanting, and they can adapt to high-intensity diffuse light (about 4000h) to maintain the light intensity needed for photosynthesis. But too strong light stimulates transpiration, which will make the contradiction of water balance more acute.