• Journal of Plant Biology
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• 제38권3호
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• pp.281-288
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• 1995

The progressive differentiation of interfascicular cambium from residual meristem in the first internode of Ginkgo biloba seedlings was elucidated by light and electron microscopy. The cells of residual meristem were small and homogeneous and heterogeneous in their arrangement but those of the adjacent cortex and pith were large and homogeneous. Some interprocambial residual meristem progressively became elongated and vacuolated during the process of the differentiation. In tangential section, residual meristem composed of long and short cells. The eventual interfascicular cambium had long fusiform initials and short ray initials. Storage materials in the cells progressively disappeared from the interprocambial residual meristem and were absent in early interfascicular cambium. Both the radial and tangential walls of cells of the interprocambial residual meristem were almost the same, but the radial wall became progressively thicker than the tangential wall during differentiation of interfascicular cambium. From these results, it is clear that interfascicular cambium is gradually differentiated from residual meristem.

• Journal of Plant Biology
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• 제35권3호
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• pp.273-281
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• 1992

잔존분열조직으로부터 유관속간형성층의 기원은 접선 및 횡단면 관찰로 밝힐 수 있다. 전형성층간 및 유관속간 잔존분열조직과 인접 유조직 사이의 구조적인 특징이 분명하게 나타난다. 따라서 잔존분열조직은 유조직으로 전환되지 않고 유관속간형성층의 발생으로 이어진다. 접선면 관찰에서 초기의 유관속간 잔존분열조직의 균일구조는 후기에 점진적으로 비균일구조로 변하는데, 이 경우에 방추형시원세포의 기원이 될 긴세포와 방사조직시원세포의 기원이 될 짧은 세포를 갖추게 된다. 그러나 유관속간잔존분열조직에 인접한 유조직의 균일구조는 비균일구조로 변화되지 않고 발생과정의 전시기에 걸쳐서 균일구조를 유지하게 된다. 그러므로 유관속간형성층은 잔존분열조직과 직접적인 연속성을 갖게 되며, 분화된 유조직으로부터 2차적인 기원을 갖는 것이 아니다. 더욱이 유관속간형성층의 분화유형은 유관속내형성층의 분화유형과 거의 같다.

• Journal of Plant Biology
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• 제33권1호
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• pp.31-40
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• 1990

Procambium developed in the histogenetical zone below the marginal meristem. The development of procambium is correlated with the developmental stage of the leaf. As long as the marginal cells are crescent-shaped, the first-order procambium develops. When the marginal cell becomes wedge-shaped, the higher order procambium appears. The reticulated venation is developed through forking and anastomosis. The meshes of the first order enlarge in the process of leaf growth and the meshes of the second and third order develop in the meshes of the first-order through the differentiation of the residual meristem. Therefore, the venation is hierachically arranged and is as recognizable from the thickening of the veins. The outermost vein is produced parallel to the leaf margin, in which the differences between the costal and intercostal parts of the marginal meristem are removed. The endodermis and pericycle differentiate from the same mother cell. The procambium and sclerenchyma originate from a common source during the first developmental stage. A small cellular cluster lies within the parenchyma at the upper and lower sides of the procambial trace and differentiates into sclerenchyma.