Progress in the effects of microgravity on plant growth and development

Microgravity is the unique and most important character in the space.Research of the effects of microgravity on different kinds of plants or different plant parts is important for space biology,which is significant for us to establish the bio-regenerative life supporting system.Bio-regenerative life supporting system was raised and established as one of the core technologies for future long-term manned space missions,it has the advantage that can continue the regeneration of oxygen,water and food for higher animals necessities in a closed system.Plant component is an important part of bio-regenerative life supporting system.Understanding and knowledge of the effects of space microgravity condition on plant growth and development will contribute to build the effective operation system to ensure their normal growth and reproduction,which is the primary key to successfully establish bio-regenerative life supporting system.The paper summarized the status and function of plants in space exploring,the simulated microgravity apparatus on ground and the research related to the real and simulated microgravity on different plant species and different plant parts at home and abroad.Existing research results were as follows:future long-term space missions required loading plant photosynthesis to provide some animal nutrition and clean water and removed some solid waste and carbon dioxide in the bio-regenerative life supporting system;three-dimension random positioning machine was the most effective tool to simulated microgravity on the ground,especially for long-term plant experiments;research reports about the effects of microgravity on plant in physiological and biochemical level at home and abroad mainly concentrated on plant growth and development and physiological response,such as phenotypic changes or redistribution hormone or calcium ions associated with gravity.Studies on cellular or subcellular level mainly focus on cell wall,mitochondria,chloroplasts,and the cytoskeleton.Arabidopsis is almost the only study object in the gene and protein expression level.Due to the divergence between the experimental methods and materials,the effects of microgravity on different plants or different parts are not consistent in each level.More research work is required in the future.