Millions of IPs create science and technology talents to strengthen the country | Protecting the agricultural fire in the "Seed Noah's Ark"

The picture shows the germplasm resources preserved in test tube seedlings by the National Crop Germplasm Bank.

(Photo courtesy of the Chinese Academy of Agricultural Sciences)

Deep in the earth, seeds are quietly awakening from the soil. They once slept in the embrace of the soil, accumulating the power of life. In the National Crop Germplasm Bank, known as the "Noah's Ark of Seeds", with the help of technology, countless seeds that have transcended time and space have "settled down" here.

In September 2021, the National Crop Germplasm Bank was completed and put into trial operation. The purpose of building a germplasm resource bank is to preserve germplasm resources to support variety breeding, agricultural scientific research, etc.

The National Crop Germplasm Bank has several characteristics. The first is its large capacity - with a total capacity of 1.5 million copies, it is currently the world's largest national crop germplasm resource bank. The second is the systematization of preservation methods, which encompasses all current technical conditions for the preservation of plant germplasm resources, including low-temperature seed preservation, test tube seedling preservation, ultra-low temperature preservation and DNA preservation. The third is the realization of automated information management.

Seeds are the foundation of agriculture and the country. Crop germplasm resources are an important foundation for supporting a bumper grain harvest - just as the design concept of the National Crop Germplasm Bank is "to receive the sweet dew from heaven and nurture the reproduction of all things". Therefore, the mission of the germplasm resource bank is to preserve these germplasm resources for a long time and safely to provide support for agricultural development.

The main method of preserving germplasm resources is low-temperature seed preservation. The National Crop Germplasm Bank preserves seeds at a low temperature of minus 18 degrees Celsius and a relative humidity of less than 45%. About 90% of the world's germplasm resources are preserved in the form of seeds.

Another way to preserve germplasm resources is to use ultra-low temperatures. The tool needed for ultra-low temperature preservation is a liquid nitrogen tank. A liquid nitrogen tank in the National Crop Germplasm Bank can store about 10,000 germplasm resources.

For example, for seedless crops like bananas, the usual preservation method is to plant them one by one in the ground. We call this a germplasm resource garden, which is a very important way to preserve germplasm resources of asexual crops. However, it will face threats from natural disasters and pests and diseases in an open-air environment. In order to cope with this situation, we have combined ultra-low temperature preservation with germplasm resource garden preservation, taking out some key tissues of the plants, and after a series of treatments, putting them in liquid nitrogen at minus 196 degrees Celsius, so that they can be preserved permanently.

Tropical fruits such as mangoes also need to be stored in liquid nitrogen. Although mangoes have seeds, many mangoes have large cores that cannot withstand dehydration or low temperatures, so they are generally not stored in low-temperature seed banks. We will remove the embryo of the mango seed, that is, the growth point, and store it in liquid nitrogen after a series of treatments.

Germplasm resources can also be preserved in test tube seedlings. We take the stem tip and other growth points of the plant and put them in a bottle - there is a jelly-like culture medium under the bottle, which can provide nutrients for the stem tip to grow slowly on it. Ultra-low temperature and test tube seedlings are mainly used to preserve asexually propagated crops and some perennial crops. If the crop is easy to transform into a test tube seedling, it will be preserved in this way. If it is not easy to transform into a test tube seedling, the crop will be first ultra-low temperature preserved in a liquid nitrogen tank.

Germplasm resources preserved in test tube seedlings are in an active growth state. Test tube seedlings are real "flowers in a greenhouse", but if necessary, they can be quickly restored to production after being taken out of the bottle and "trained". The seeds are constantly growing in the bottle, so they are also constantly consumed. When the nutrients in the culture medium are used up, or the seedlings grow "old", it is necessary to take down its growth point and change the bottle, so that its life cycle can continue indefinitely.

Every seed carries the hope of life. From a tiny seed to a bountiful field, this is a tacit cooperation between science and nature. The National Crop Germplasm Bank is not only the guardian of seeds, but also the cornerstone of future agricultural development. These seemingly ordinary seeds are gathering together to become the foundation of the prosperity of the Chinese nation and support the dream of a strong agricultural country.

At present, my country has become one of the major countries in terms of crop germplasm resources, but has not yet become a resource power. In the journey of agricultural modernization, seeds play a cornerstone role and can be called the "chip" of agriculture. Small seeds are connected to the "major issues of the country" and are the key to ensuring China's food security. Protecting and preserving crop genetic resources is the key to the revitalization of the seed industry and our unswerving goal.

The author is Xin Xia, a researcher at the National Crop Germplasm Bank