Detailed Explanation of Tea Plant Cutting Propagation Methods and Steps

Tea plants can be propagated from seeds, or vegetatively (also called asexual propagation) using parts of vegetative organs such as stems, leaves and roots. There are many methods of vegetative propagation, including cuttings and layering. The main vegetative propagation method used is short-stem cutting. Most tea plant varieties have both sexual and vegetative reproductive capacity. Vegetative propagation can preserve the excellent traits of superior tea varieties, produce offspring with uniform characteristics, and give a high propagation coefficient. However, it is labor-intensive, costly, and places high demands on nursery cultivation and management.

I. Physiological basis of rooting in cuttings. The vegetative organs of tea plants have a natural physiological regeneration capacity. That is, when part of an organ is lost or incomplete, under suitable conditions it can grow back the lost or incomplete part and restore itself to its original complete state. Tea plant cutting propagation makes use of the natural regeneration and polarity phenomena of tea plant vegetative organs: a stem-and-leaf segment is cut from a semi-lignified tea branch, its lower end is inserted into a seedbed, and after cultivation it can take root and sprout shoots, forming an independent new tea seedling.

After the cutting is inserted into the seedbed, the cells near the upper and lower cut surfaces of the cutting quickly produce a film that seals the upper and lower cuts. Beneath the film, wound cork forms, covering the cuts. The wound cork has a protective effect, preventing water loss and the invasion of microorganisms. At this time, if the lower cut is kept under suitable temperature and humidity, after a certain period the cambium and phloem parenchyma cells divide to produce callus tissue. At the same time, new roots emerge from the inner sheath of the central cylinder, or from the intersections of the medullary rays and the cambium. This is the process of rooting in cuttings.

The carbohydrate content of the cutting, including starch and sugar, is closely related to root formation. It is generally believed that the ratio of carbohydrates to nitrogenous compounds (C/N) is an important factor in root formation. A high carbon-to-nitrogen ratio favors root and shoot growth. Experiments have shown that when the branches and leaves turn reddish-brown, reach semi-lignified status, and the leaves mature and take shape, the carbon-to-nitrogen ratio is high, the cutting survival rate is high, rooting is good, and the seedlings are robust.

The physiological process of rooting in cuttings is closely related to the humidity, temperature, air, light and soil physical and chemical conditions surrounding the cutting, and these factors influence and are connected with one another. During cutting propagation, the relationships among the various ecological factors should be properly coordinated so as to give full play to the physiological rooting characteristics of the cuttings.