Seven maize inbred lines, Yi 0-4-1, Yizi24, Yi141, Yt183, Yt185, 311 and 8112, were used as experimental materials. Dried seeds of maize were carried by recoverable satellite under space conditions of 175 km to 253 km from sea level. Various changes of maize leaves were observed, including young plants, plasmolysis, expansion of vacuoles and cell walls, proliferation of plasmodesmata, variations of grana disc and stroma thylakoids, breadth of nuclear membranes, increase in number and enlargement of endoplasm reticulums and variations of othe endomembranes.(see Plates I-II).
Plate I. 1, Electron micrograph of corn leaf cells from ground control (X10000). 2~7, Electron micrographs of corn leaf cells after space flight. 2, Plasmolysis, cell walls out of shape and big central vacuoles (X9900). 3, Thickened cell walls and 3 uncertain objects in a cell (X26000). 4, Rich plasmodesmata between cells, some mitochondria around the plasmodesmata and plasmodesmata swollen in one end (arrow) (X30000). 5, Plasmodesmata branched in one end (X30000). 6, Changes of nucleus shape and concentric membrane bodies (X30000). 7, Breach of nuclear membrane and nucleolus vacuoles (X12450).
II. 1, Mitochondria from ground control cells (X49500). 2~6, Electron
micrographs of corn leaf cells after space flight. 2, Swollen endoplasmic
reticulums and dividing mitochondria (X30000). 3, Curly endomembrane and
concentric membrane body (X12450). 4, Swollen and circular endoplasmic
reticulums. Note some vesicles nearby (X1500). 5, Concentric membrane body
(X39000). 6, Paramutal body (39000).
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