Department of Botany and Plant Pathology, Iowa State University, Ames, Iowa 50010.
Plant Physiol. 1969 Jan;44(1):21-6. doi: 10.1104/pp.44.1.21.
Pectin esterase (PE) activities in abscission zones, other portions of leaves, and adjacent stem tissues were compared in attached leaves and abscissing petioles (previously debladed) of Coleus blumei Benth. and Phaseolus vulgaris L., cv. Canadian Wonder. Earlier findings of Osborne in bean were confirmed and changes in PE activity in coleus were shown to resemble those in bean in some respects. In both plants PE was lower in the distal portion of abscission zones of abscissing petioles than in that portion of attached leaves but this difference was not as large or as consistently clear-cut in coleus as in bean. The general level of PE activity was an order of magnitude lower and changes associated with abscission were smaller in coleus than in bean. Auxin treatment of debladed petioles of coleus prevented abscission and resulted in small increases in PE activity in abscission zones and most of the other regions sampled. The largest increase was observed in the stem tissue adjacent to the attached leaf opposite the debladed, auxin treated one.The activity of coleus PE was highest in the pH range from 7.3 to 7.6. The pH of distal tissue from abscission zones of abscissing petioles was 5.8. This was 0.7 pH units lower than that of proximal tissue from the same zones.PE from both coleus and bean appears to be denatured by freezing and/or thawing.
在贴叶和已去叶（先前去叶）的黄耆属植物和菜豆的叶柄离区、叶片其他部分和相邻茎组织中比较果胶酯酶（PE）的活性。在菜豆中Osborne 的早期发现得到了证实，并且在黄耆属植物中 PE 活性的变化在某些方面与菜豆相似。在这两种植物中，去叶叶柄离区的远侧部分的 PE 活性低于贴叶的相应部分，但在黄耆属植物中，这种差异不如在菜豆中那么大或那么明显。PE 活性的总体水平低一个数量级，与离区相关的变化在黄耆属植物中比在菜豆中小。用生长素处理黄耆属植物的去叶叶柄可阻止离区形成，并导致离区和大部分其他取样部位的 PE 活性略有增加。在与去叶的、用生长素处理的叶柄相对的贴叶对面的相邻茎组织中观察到最大的增加。黄耆属植物的 PE 活性在 pH 值为 7.3 到 7.6 的范围内最高。去叶叶柄离区远侧组织的 pH 值为 5.8。这比同一区域的近侧组织低 0.7 pH 单位。来自黄耆属植物和菜豆的 PE 似乎通过冷冻和/或解冻而变性。
