Vascular System Construction And Variation Rule Of Cell Morphology In Tissue Culture Of Populus×Euramericana 'Nanlin 895'

The paper studied on vascular system construction and variation rule of cell morphology in tissue culture of Populus×euramericana'Nanlin 895'.The results were as follows:1.Selected Populus×euramericana'Nanlin 895'stems as explants to induct callus, selected vigorous growth callus as explants for further adventitious buds, adventitious buds will reproduce to induct adventitious roots , and finally completed callus to tissue culture system construction.2.The length of cells in the vascular system was gradually increasing from top to base in different inter-node of vascular tissue. In corresponding inter-node, the length of bast fibers was longer than wood fibedrs, while the width of bast fibers was less than wood fibedrs. The length frequency of fibers in vascular tissue was about 720μm, belongs to medium categories,the wide belongs to the second grade and the length of wall belongs to the fourth grade.The length of wood fiber was about 2 times than the vessel tubes, was about 7 times than the length of vessel tube wall, The width of wood fiber was about one-third of the vessel tubes. The length of sieve tubes was about half of the vessel tubes3.When the length of leaf in adventitious bud of vascular tissue reach to 4mm,There was a single one-grade leaf vein appears, The one-grade leaf vein gradually come more into focus and keep moving straight to the apex of leaf.When the length of leaf in adventitious bud of vascular tissue reach to 7mm,There were many two-grade leaf veins appears from two halves of the one-grade leaf vein,The number was about 14,later,Some two-grade leaf veins start to extend , making them into many hoops each other, When the length of leaf in adventitious bud of vascular tissue reach to 13mm, Many two-grade leaf veins become to spread about or scatter,and form three-grade leaf vein,without rules. When the length of leaf in adventitious bud of vascular tissue reach to 15mm, Three-grade leaf vein extend, fourth-grade leaf vein, extended.then,formed a fully mature leaf.4.The length of bast fibers in adventitious root was about 381μm to 610μm,while the width was about 15.1μm to 19.2μm.From one-grade to third-grade adventitious root,There was a commom rule which the length of bast fibers was longer than wood fibers and the width of bast fibers was shorter than wood fibers. The length of vessel tubes and sieve tubes in adventitious root was respectivly about 240μm to 407μm,137μm to 253μm,while the width was respectivly about 18.8μm to 38μm,8.9μm to11.7μm.Also the length of vessel tubes was about 1.5 times than the sieve tube and the width of vessel tubes was about 3 times than the sieve tube.All of cells in vascular system had a rule that the one-grade greater than the two-grade and the two-grade was greater than the three-grade.