Floral ontogeny of Annonaceae: evidence for high variability in floral form.
Floral ontogeny of Annonaceae: evidence for high variability in floral form.
复制标题
番荔枝科的花个体发育：花形高度变异性的证据。
DOI：
10.1093/aob/mcq158
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发表时间：
2010-10
期刊：
影响因子：
4.2
通讯作者：
Fengxia Xu, Louis Ronse De Craene
中科院分区：
文献类型：
--
作者：
Fengxia Xu, Louis Ronse De Craene
背景和目标
番荔枝科是木兰科植物中最大的科之一。本研究对15个种的花发育进行了比较研究，以了解花被、雄蕊和心皮的进化变化的基础，并为系统发育研究提供额外的性状。
方法
用扫描电子显微镜观察和描述了12属15种植物的花个体发育。
关键结果
三个花被轮的起始是螺旋的或单向的。分生组织多数为三分体，偶尔为四分体，内花被轮的成员可能缺失或处于双重位置。雄蕊和雌蕊的器官数目是不同的(从高度聚合到固定数目，雄蕊中有6个，雌蕊中有1到2个)。雄蕊原基始于三对雄蕊原基，沿着六角形花端两侧。内退化雄蕊虽未观察到，但在木兰科和肉豆蔻科以外的木兰科和木兰科的其他属和科中均有报道。进一步器官的启动是向心性的。雄蕊数目较少的雄蕊，其叶序始终为轮生，而雄蕊数目较多的雄蕊，其叶序则变得不规则。雄蕊和心皮之间的界限是不稳定的，心皮以类似的变异性延续雄蕊的序列。
结论
人们发现，花的分生组织在某些物种中经常是不同的，在三分体和四分体之间波动。内花被部分的加倍是由原基的(不等)分裂引起的，与雄蕊群相反，与分生组织的变化无关。衍生的特征，如可变的分生组织，内部花被和内部退化雄蕊的缺失，固定数量的雄蕊和心皮，头状或拉长的花柱分布在不同的分支中，并独立进化。在基本被子植物的背景下讨论了雄蕊的进化：成对的外雄蕊是大的花被部分和小得多的雄蕊之间过渡的结果，而不是分裂的结果。雄蕊数目的增加与其发生时较小的尺寸有关，而雄蕊和心皮之间的界限尚不清楚，在某些属中，一种器官类型很容易转换为另一种器官类型，或者在单性花中雄蕊完全被雄蕊取代。
BACKGROUND AND AIMS
Annonaceae are one of the largest families of Magnoliales. This study investigates the comparative floral development of 15 species to understand the basis for evolutionary changes in the perianth, androecium and carpels and to provide additional characters for phylogenetic investigation.
METHODS
Floral ontogeny of 15 species from 12 genera is examined and described using scanning electron microscopy.
KEY RESULTS
Initiation of the three perianth whorls is either helical or unidirectional. Merism is mostly trimerous, occasionally tetramerous and the members of the inner perianth whorl may be missing or are in double position. The androecium and the gynoecium were found to be variable in organ numbers (from highly polymerous to a fixed number, six in the androecium and one or two in the gynoecium). Initiation of the androecium starts invariably with three pairs of stamen primordia along the sides of the hexagonal floral apex. Although inner staminodes were not observed, they were reported in other genera and other families of Magnoliales, except Magnoliaceae and Myristicaceae. Initiation of further organs is centripetal. Androecia with relatively low stamen numbers have a whorled phyllotaxis throughout, while phyllotaxis becomes irregular with higher stamen numbers. The limits between stamens and carpels are unstable and carpels continue the sequence of stamens with a similar variability.
CONCLUSIONS
It was found that merism of flowers is often variable in some species with fluctuations between trimery and tetramery. Doubling of inner perianth parts is caused by (unequal) splitting of primordia, contrary to the androecium, and is independent of changes of merism. Derived features, such as a variable merism, absence of the inner perianth and inner staminodes, fixed numbers of stamen and carpels, and capitate or elongate styles are distributed in different clades and evolved independently. The evolution of the androecium is discussed in the context of basal angiosperms: paired outer stamens are the consequence of the transition between the larger perianth parts and much smaller stamens, and not the result of splitting. An increase in stamen number is correlated with their smaller size at initiation, while limits between stamens and carpels are unclear with easy transitions of one organ type into another in some genera, or the complete replacement of carpels by stamens in unisexual flowers.
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DOI：
--
发表时间：
1982
期刊：
--
影响因子：
--
作者：
P. Leins;C. Erbar
通讯作者：
P. Leins;C. Erbar
影响因子：
--
作者：
L. R. Decraene;E. Smets
通讯作者：
L. R. Decraene;E. Smets
DOI：
--
发表时间：
1988
期刊：
--
影响因子：
--
作者：
M. Moncur
通讯作者：
M. Moncur
影响因子：
3
作者：
T. Scharaschkin;J. Doyle
通讯作者：
T. Scharaschkin;J. Doyle
影响因子：
1.9
作者：
M. Zanis;P. Soltis;Y. Qiu;E. Zimmer;D. Soltis
通讯作者：
M. Zanis;P. Soltis;Y. Qiu;E. Zimmer;D. Soltis