title: Effects of simulated microgravity on characteristics of photosynthesis in plant seedling.
abstract: OBJECTIVE
  To study the effects of simulated microgravity on the characteristics of photosynthesis in some plant seedlings.
  
  
  METHODS
  Plant samples were treated on a 1 pi clinostat rotated at 2 gamma/min for 120 h. Then chlorophyll absorption and chlorophyll fast fluorescence induction kinetics were determined.
  
  
  RESULTS
  After treatment on the clinostat: 1) there were some increase in height and number of leaves per plant; 2) the strawberry seedlings contained 47.5% less chlorophyll and the carnation seedlings contained 4.3% more; 3) there was no change in position of the main absorption peaks of chlorophyll in both seedlings after the rotation, but their intensity was increased; 4) there were significant increase in the parameters of fluorescence induction kinetics in the leaves of both seedlings: there was an increase in Fv/Fo, Fv/Fm and T1/2, except CA/Fo; 5) there were some differences in excitation energy distribution between the two photosystems in the chloroplasts of control and treated samples.
  
  
  CONCLUSIONS
  Simulated microgravity does not have a significant effect on normal photosynthetic function in chloroplasts, so plant seedlings can grow up normally under microgravity.
authors.affiliation: Dept of Biology, Capital Normal University, Beijing. zhaoqi@mail.cnu.edu.cn
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Liu
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism / Q000502:physiology; D029749:Dianthus / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D005453:Fluorescence; D005638:Fruit / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D006112:Gravitation; D045342:Light-Harvesting Protein Complexes; D010788:Photosynthesis / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D018520:Plant Shoots / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D027824:Rosaceae / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D012399:Rotation; D018474:Weightlessness Simulation
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll