On May 24th, the Shenzhou-23 manned spacecraft was successfully launched, and experimental materials such as rice seeds were flown to the Chinese space station on board. Subsequently, the Chinese space station will conduct experiments on the molecular mechanisms of genetic stability and environmental adaptability regulation in multiple generations of space rice. This experiment will achieve two generations of rice cultivation in orbit for the first time, and is expected to complete the complete growth cycle from seed to seed, and then to the new generation of seeds in space, analyzing the impact of long-term microgravity environment on the genetic stability of rice. This means that in the future journey of deep space exploration, it may be possible to achieve in-situ production of food. Is this the first time sending rice seeds into space? What is the difference between growing rice in space and on Earth? What is the main focus of this experiment? Why choose to send rice seeds into space instead of other food crops? With the above questions in mind, the reporter interviewed relevant experts. First question: Is this the first time rice seeds have been launched into space? This time sending rice seeds to the space station is not the first time China has conducted rice experiments in orbit. ”Zheng Huiqiong, a researcher at the Center for Excellence and Innovation in Molecular Plant Science of the Chinese Academy of Sciences, said that as early as 2022, rice seeds had been taken into space, completing the complete life cycle from seed germination, growth and development to harvesting new seeds, and the obtained seeds returned to the ground with the Shenzhou XIV crew. The seeds sent to space this time consist of two types of materials: one is the offspring produced by planting two consecutive crops of seeds harvested from the space station last time after returning to the ground, whose "ancestors" have experienced the space environment; The other type is ordinary seeds that have never ascended to heaven. This experiment consists of 4 units, each of which is seeded with 6 seeds that serve as backups for each other. The four units are divided into two groups, corresponding to the two reproductive modes of rice. One group will carry out sexual reproduction, harvest rice ears after the seeds mature, and then transfer the rice ears to a new culture box for second-generation planting, to investigate the "transgenerational memory" that has undergone sexual processes, that is, whether the seeds that have been raised to heaven by ancestors are better adapted to the spatial environment than those that have never been raised to heaven. The other group adopts the regenerative rice mode, cutting off the aboveground part from the roots after maturity, allowing the root stubble to germinate new rice, which is equivalent to prolonging the growth time of the same plant, and comparing the adaptability differences between vegetative reproduction and sexual reproduction in spatial environment. Unlike the previous experiment where only one generation of rice was propagated in orbit, the key to this experiment is to allow rice to reproduce continuously for two generations under microgravity conditions, in order to observe the impact of changes in the gravity environment on transgenerational inheritance. ”Zheng Huiqiong said. Question 2: What is the difference between growing rice in space and on Earth? All living organisms on Earth have evolved under a constant gravitational environment, and their morphological structure, metabolic levels, and genetic mechanisms are all adapted to this constant gravity. For example, plants always have stems that grow upwards and roots that root downwards. The microgravity environment of the space station changes gravity from a "constant" to a "variable", causing significant changes in biological metabolism and life activities, and genetic mechanisms may also change accordingly, but these changes require long-term observation. Zheng Huiqiong explained that after the seeds developed on the ground bear new seeds in the space station, if the new seeds do not return to the ground to receive gravity stimulation and reproduce another generation directly in a microgravity environment, the role of gravity changes in the reproduction process of rice generations can be clearly revealed. This not only enhances our understanding of the mechanisms by which gravity affects life, but also relates to whether humans can achieve in situ food production outside of Earth in the future. Once leaving low Earth orbit and heading towards farther planets, it is difficult to sustain food supply from Earth, and crops must be produced in situ. However, if the seeds planted in space degrade from generation to generation, it cannot guarantee a stable supply of excellent varieties. Therefore, in truly moving towards unprecedented depth, it is necessary to use space stations to figure out whether rice is gradually adapting to the space environment or experiencing intergenerational decline, and explore measures to maintain stable and reliable varieties, "said Zheng Huiqiong. Question 3: Why choose to send rice into space? The reason for choosing rice instead of other food crops as the research object, Zheng Huiqiong said, is mainly based on four principles: strong adaptability, short growth cycle, high yield, and relatively short plant type that does not affect yield. This time, we are carrying our own japonica rice variety, which belongs to the model rice. Its genetic and molecular mechanism research foundation is very solid. Conducting experiments in the sky is already full of unknowns, and choosing a variety that has not been thoroughly studied on the ground is equivalent to a double unknown, making it difficult to analyze the results. Choosing materials with clear ground research backgrounds can quickly identify changes in space and help obtain clear experimental conclusions. ”Zheng Huiqiong said that the biggest difficulty in growing rice on the space station is still microgravity. Plants, like humans, can "faint", and the universal laws reflected in rice can also provide reference for other plants to a certain extent. In this experiment, astronauts not only need to collect rice ears and seeds, but also need to freeze samples such as stems and leaves in a -80 ℃ environment and bring them back. Through comprehensive analysis of phenotype and molecular level, we aim to study the deep-seated changes caused by microgravity and explore whether biotechnology can intervene in the effects of microgravity, providing a basis for variety cultivation in extraterrestrial environments. At the same time, such spatial research can also benefit ground-based agriculture. The extreme environment in space is equivalent to a completely new stress condition, which may prompt rice to exhibit traits that are difficult to observe on the ground, discover new genetic resources, and use them for breeding, cultivating excellent varieties such as drought resistant and salt tolerant. (Looking into the New Era)