Detailed Explanation of Key Techniques for Introducing and Cultivating Rhodiola

Biological Characteristics

The morphological characteristics of the original plants of Rhodiola sachalinensis and Rhodiola rosea are very similar. The former is mainly distributed in the Changbai Mountain area of Jilin Province, while the latter is mainly distributed in **, Shanxi, Hebei and other provinces. Although their distribution ranges and altitudes differ slightly, after artificial cultivation, through actual observation, their biological characteristics are basically the same. When Rhodiola rosea is cultivated in mountainous areas at lower altitudes, its adaptability to the adverse environment of high temperature and rainy summers is much stronger than that of Rhodiola sachalinensis, and the content of active ingredients is also relatively higher.

I. Biological Characteristics of Seeds

1. Morphological characteristics: The seeds of both Rhodiola species are very small, with no obvious differences in shape, color or size. If the seeds of the two species are mixed together, it is very difficult to distinguish them. The seeds are oblong or broadly lanceolate, slightly flattened and round, about 2 mm long and less than 0.5 mm wide. The surface of freshly harvested seeds is yellow-brown or light brown, and the color darkens after drying to brownish-brown or brown. The thousand-grain weight of the seeds is 0.12-0.14 g, and there are about 800,000 seeds per 100 g. The top of the seed has a membranous seed ridge, the seed pore is located at the base, the embryo is straight and parallel to the long axis of the seed, and several uniform longitudinal striations can be seen on the seed coat surface under a magnifying glass, as shown in Figure 3-1.

2. Biological characteristics: Wild Rhodiola seeds are often unable to fully mature due to adverse climate effects such as low autumn temperatures, excessive rain or early frost, and plump, mature seeds account for only about 30%-40% of the total. The suitable germination temperature for seeds is 15-20°C, and the suitable humidity is 60%-70%. When directly sown in the field, if the temperature and soil moisture are suitable, full emergence can occur in 5-7 days. If the temperature is below 15°C, the emergence time requires more than 10 days. When sown in autumn, emergence begins in the following early spring when the surface temperature is 8—10°C.

Wild Rhodiola seeds have incomplete dormancy characteristics. Newly harvested seeds, without treatment, when sown and observed under suitable temperature and humidity conditions, show only 10%-20% emergence. After artificial cultivation, seed dormancy weakens, and the germination rate of untreated seeds is over 50%. This dormancy characteristic of Rhodiola seeds was formed through long-term growth in harsh natural environments. This characteristic is undoubtedly a self-protection of its own vitality, enabling it to grow and germinate under suitable conditions and reproduce offspring. The mechanism of dormancy has not yet been studied in depth, but experiments have found that the seed coat contains a germination-inhibiting substance, and this substance can dissolve in water. Therefore, soaking the seeds in water before sowing significantly increases the germination rate.