Thompson N P, Jacobs W P
Biology Department, Princeton University, Princeton, New Jersey.
Plant Physiol. 1966 Apr;41(4):673-82. doi: 10.1104/pp.41.4.673.
A technique is described for the processing of regenerated xylem and sieve tubes from the same wound area for microscopic and quantitative comparison.Regeneration was examined in internodes of 2 developmental stages in Coleus: internode 2, elongating, characteristic of primary growth; and internode 5, non-elongating, characteristic of secondary growth.Transport of indoleacetic acid (IAA) in excised number 5 internodes of Coleus is strictly polar, in a basipetal direction, judging by a regeneration bioassay involving both sieve tube strands and xylem cells. Similar results were obtained with tomato.If isolated number 5 Coleus internodes are not treated with hormone, they regenerate no xylem cells and a small number of sieve tube strands. With increasing concentrations of IAA added apically, the number of regenerated sieve tube strands (and, with higher concentrations, of xylem cells) increases progressively up to 1% IAA, the highest concentration applied.Internode 2 of Coleus regenerates fewer xylem cells or sieve tube strands than internode 5, whether on the otherwise intact plant or with a given concentration of IAA added apically. The amount of regenerated xylem increases with added apical IAA, except that the highest concentration gives no further increase. The number of xylem cells regenerated in intact plants occurs at the same interpolated IAA concentration as in number 5 internodes. No concentration of IAA tried provided replacement of intact number of sieve tube strands in internode 2.IAA can exert a regenerative stimulus on both xylem and sieve tubes in the area immediately adjacent to the site of its application.
本文描述了一种从同一伤口区域处理再生木质部和筛管以进行微观和定量比较的技术。在彩叶草的两个发育阶段的节间中研究了再生情况：节间2，正在伸长，是初生生长的特征；节间5，不再伸长，是次生生长的特征。通过涉及筛管束和木质部细胞的再生生物测定法判断，吲哚乙酸（IAA）在彩叶草切除的第5节间中的运输是严格极性的，呈向基方向。番茄也得到了类似的结果。如果分离的彩叶草第5节间不进行激素处理，它们不会再生木质部细胞，只会再生少量筛管束。随着顶端添加的IAA浓度增加，再生筛管束的数量（以及更高浓度时的木质部细胞数量）逐渐增加，直至达到所应用的最高浓度1%IAA。无论在完整植株上还是顶端添加给定浓度的IAA，彩叶草的节间2再生的木质部细胞或筛管束都比节间5少。除了最高浓度不再增加外，再生木质部的数量随着顶端添加IAA而增加。完整植株中再生的木质部细胞数量出现在与第5节间相同的内插IAA浓度下。所尝试的任何IAA浓度都不能替代节间2中完整数量的筛管束。IAA可以对其应用部位紧邻区域的木质部和筛管施加再生刺激。
