Structure of Shoot Apical Meristem and Leaf Development in Seedlings of Thuja orientalis L
نویسنده
چکیده
The structure and leaf development of the shoot apical meristem in embryos and seedlings of Thuja orientalis L.were observed by using SEM,and the area of the shoot apical meristem was studied by an image analyzer.The shoot apex of embryos was of a round tip cone shape with flat sides;it was transformed into an inverted boat shape.In seedlings,the shoot apical meristem was of a convex-rectangular shape during the early stages of development of two decussatelst leaf primordia;but in the later stage of the development,it turned into a flat square shape.The shoot apical meristem was of a convex diamond shape during the early development of whorled four 2nd leaf primordia;but it turned into a flat diamond shape in the later stage of this process.In the early development of the3rd leaf primordia,it was transformed into a convex square shape.Both the minimal and maximal areas of the shoot apical meristem gradually decreased as the plant developed from an embryo into a seedling.In seedlings,the1st leaves showed a decussate phyllotaxis,while the2nd leaves and later leaves all showed a four-leaf whorl phyllotaxis.All the leaves developed into needles.
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