Structural changes in phi thickenings during primary and secondary growth in roots. 1. Apple (Pyrus malus) Rosaceae
Structural changes in phi thickenings during primary and secondary growth in roots. 1. Apple (Pyrus malus) Rosaceae
复制标题
根的初生和次生生长过程中 phi 增厚的结构变化。
作者：
C. Weerdenburg;C. Peterson
苹果根的整个根部和徒手横截面经过清理并用白屈菜根部提取物染色，揭示了单列 phi 增厚层的存在。该层外部邻近内皮层，由细胞组成，在其横向和径向壁的增厚中部部分有大量木质素沉积。增厚部分在距根尖 3-5mm 的范围内完全发育。侧根原基通过皮层中的开口穿过皮层出现，这是由于从皮层细胞去除整个皮层增厚而产生的。与内皮层的凯氏带不同，该层从主根到侧根并不连续。在二次生长过程中，phi层细胞的中间片层分裂，破坏了该层的正常外观。最终，当中柱鞘中出现的周皮发育形成成熟根的最外部组织时，表皮和皮层脱落。然而，残留的...
Whole roots and freehand cross sections of apple roots, cleared and stained with a root extract of Chelidonium majus L., revealed the presence of a uniseriate layer of phi thickenings. The layer, externally adjacent to the endodermis, consisted of cells with a heavy deposition of lignin in the thickened midportions of their transverse and radial walls. The thickenings were completely developed within 3–5 mm from the root tip. Lateral root primordia emerged through the phi layer by means of openings in the layer resulting from the removal of entire phi thickenings from the cortical cells. The layer was not continuous from the main to the lateral roots unlike the Casparian band of the endodermis. During secondary growth, the middle lamellae of the cells of the phi layer split, disrupting the regular appearance of the layer. Ultimately, the epidermis and cortex were sloughed off as the periderm, arising in the pericycle, developed to form the most external tissue of the mature root. However, remnants of the ...