HETEROPHYLLY AND NEOFORMATION OF LEAVES IN SUGAR MAPLE (ACER SACCHARUM)
HETEROPHYLLY AND NEOFORMATION OF LEAVES IN SUGAR MAPLE (ACER SACCHARUM)
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糖槭（Acer Saccharum）叶子的异叶和新生
DOI：
10.1002/j.1537-2197.1982.tb13373.x
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发表时间：
1982
影响因子：
3
通讯作者：
D. Steingraeber
中科院分区：
文献类型：
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作者：
D. Steingraeber
研究了开放生长的树苗和较大的糖枫林树（Acer saccharum Marsh.）的旺盛的先导枝条的叶形和叶萌生时间的变化。主枝的冬芽通常含有 6 或 8 个叶原基和胚叶，而每年通常沿着枝条扩展 12 至 18 个叶子。预成形（早期）叶子的形状与新成形（晚期）叶子不同。与其他一些宏碁物种一样，最初形成的晚叶具有大角度的次生叶发散角和深凹的窦。这种异源性模式有助于开放生长的树苗和糖枫森林树的先导枝的多层性质。糖枫（Acer saccharum Marsh.）经常被描述为芽已完全形成的物种（Critchfield，1971；Marks，1975；Bormann 和 Likens，1979；Kramer 和 Kozlowski，1979）。即一年内沿枝条生出的叶子均是前一年萌生并在芽中作为胚叶和叶原基越冬的。相反的情况，即叶子新生，发生在一些原基在启动后立即成熟时，没有任何中间的休息期（Halle、Oldeman 和 Tomlinson，1978）。除非生长是连续的，否则表现出新形成的芽也会通过预形成产生一些叶子。在这样的芽中，预形成的叶子在生长高峰期开始时迅速成熟，而新形成的叶子在生长高峰期后期成熟。因此，这两种类型的叶子被称为“早”叶和“晚”叶（Critchfield，1960；Clausen 和 Kozlowski，1965；Kozlowski，1971）。如果早叶和晚叶的形状明显不同，则具有两种叶类型的芽被称为季节性异叶。初步观察表明，先前描述的露天种植的糖枫树苗的主枝（Steingraeber、Kascht 和 Franck，1979 年）含有更多 1 于 1981 年 6 月 16 日出版；修订于 1981 年 1 月 21 日接受。我感谢 Don Waller、Dan Franck、Larry Kascht、Gary Breckon、George Diggs 和 Robert Kowal 在本研究中提供的帮助。我还要感谢杰克·费舍尔审阅了手稿。这项工作的部分内容包含在提交给威斯康星大学研究生院的论文中。在 F.T.G. 工作得到 NSF Grant DEB79-14635 的支持。 2 目前地址：Department of Botany and Plant Pathology, Colorado State University, Fort Collins, Colorado 80523。叶子比其他糖槭树芽要好。主枝通常有 12 至 24 片叶子（在某些情况下，多达 52 片），而大多数其他枝条最多有 8 片叶子。根据这些观察，我假设旺盛的树苗的先导枝会产生预成型（早期）叶子和新成型（晚期）叶子。本研究的目的是确定糖槭旺盛的先导枝是否表现出叶子和异形的新生。材料和方法 - 叶子萌生的时间 - 1976 年秋天，大约 65 棵露天生长的树苗（来自 Steingraeber、Kascht 和 Franck，1979 年之前描述的种群）上的可比较的主枝芽被标记用于进一步研究。 1976 年 11 月，随机收集了 40 个这样的芽。对于每个芽，计算 1976 个叶子的叶痕数量，然后解剖顶芽以确定胚叶和叶原基的数量（以及 1977 年预形成的叶子数量）。 1977 年 11 月，对剩余的标记枝条进行取样，以确定 1977 年期间每个枝条的叶子数量。然后使用 t 检验成对比较冬芽中的平均叶子数量以及 1976 年和 1977 年产生的叶子的平均数量，并使用 Tukey's (1977) 修改确定显着性水平。 1979 年秋天，从同一树苗群体中又采集了 21 个主枝。记录 1979 年每个枝条上的叶子数量，然后解剖每个枝条的顶芽，以确定 1980 年用于扩展的叶子数量。配对数据的 t 检验
Variation in leaf form and timing of leaf initiation were investigated in vigorous leader shoots of open-grown saplings and larger forest trees of sugar maple (Acer saccharum Marsh.). Winter buds of leader shoots usually contained 6 or 8 leaf primordia and embryonic leaves, whereas 12 to 18 leaves typically expanded along the shoots each year. Preformed (early) leaves differ in form from neoformed (late) leaves. As in some other Acer species, the first-formed late leaves have large angles of secondary lobe divergence and deeply indented sinuses. This pattern of heterophylly contributes to the multilayered nature of open-grown saplings and leader shoots of forest trees of sugar maple. SUGAR MAPLE (Acer saccharum Marsh.) has frequently been characterized as a species in which shoots are fully preformed (Critchfield, 1971; Marks, 1975; Bormann and Likens, 1979; Kramer and Kozlowski, 1979). That is, the leaves which are borne along the shoot one year are all initiated the previous year and overwinter in the bud as embryonic leaves and leaf primordia. The contrasting condition, leaf neoformation, occurs when some primordia mature immediately after they are initiated, without any intervening period of rest (Halle, Oldeman and Tomlinson, 1978). Unless growth is continuous, shoots which exhibit neoformation also produce some leaves by preformation. In such a shoot, the preformed leaves mature rapidly at the beginning of a growth flush, while the neoformed leaves mature later in the flush. Hence, the two types of leaves are referred to as "early" and "late" leaves (Critchfield, 1960; Clausen and Kozlowski, 1965; Kozlowski, 1971). If early and late leaves differ markedly in their form, shoots with both leaf types are referred to as seasonally heterophyllous. Preliminary observations indicated that the leader shoots of open-grown sugar maple saplings described previously (Steingraeber, Kascht and Franck, 1979) contained more 1 Received for publication 16 June 1981; revision accepted 21 January 1981. I am grateful to Don Waller, Dan Franck, Larry Kascht, Gary Breckon, George Diggs, and Robert Kowal for their assistance in this study. I also thank Jack Fisher for reviewing the manuscript. Portions of this work are contained in a dissertation submitted to the Graduate School of the University of Wisconsin. Work at F.T.G. was supported by NSF Grant DEB79-14635. 2 Present address: Department of Botany and Plant Pathology, Colorado State University, Fort Collins, Colorado 80523. leaves than other sugar maple shoots. Leader shoots often had 12 to 24 leaves (and, in some cases, as many as 52), while most other shoots had, at most, eight leaves. Based upon these observations, I hypothesized that leader shoots of vigorous saplings produce both preformed (early) and neoformed (late) leaves. The purpose of this study is to determine whether vigorous leader shoots of sugar maple exhibit neoformation of leaves and heterophylly. MATERIALS AND METHODs-Timing of leaf initiation-During the autumn of 1976, comparable leader shoots on approximately 65 open-grown saplings (from populations previously described by Steingraeber, Kascht and Franck, 1979) were tagged for further study. In November of 1976, 40 of these shoots were randomly collected. For each shoot, the number of leaf scars from 1976 leaves was counted and the terminal bud was then dissected to determine the number of embryonic leaves and leaf primordia (and, hence, the number of leaves preformed for expansion in 1977). In November of 1977, the remaining tagged shoots were sampled to determine the number of leaves per shoot during 1977. The mean number of leaves in the winter bud, and the mean numbers of leaves produced in 1976 and 1977 were then compared using t-tests pairwise, with the level of significance determined using Tukey's (1977) modification. During the autumn of 1979, 21 additional leader shoots were collected from the same populations of saplings. The number of leaves on each shoot in 1979 was recorded, and the terminal bud of each shoot was then dissected to determine the number of leaves preformed for expansion in 1980. A t-test with paired data