Homology and functions of inner staminodes in Anaxagorea javanica (Annonaceae).
Homology and functions of inner staminodes in Anaxagorea javanica (Annonaceae).
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DOI：
10.1093/aobpla/plaa057
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发表时间：
2020-12
期刊：
影响因子：
2.9
通讯作者：
Xu F
中科院分区：
文献类型：
--
作者：
Li B;Xu F
内部退化雄蕊在木兰目中广泛存在，并存在于Anaxagorea和Xylopia中，但在番荔枝科的其他属中丢失，并且在衍生的被子植物中没有对应物。爪哇Anaxagorea javanica正常雄蕊、变异雄蕊和内部退化雄蕊的共存对于理解内部退化雄蕊的同源性和授粉功能至关重要。通过光学和扫描电子显微镜对 Anaxagorea javanica 进行解剖学研究，并通过氨基酸分析仪评估分泌物的化学成分。内部退化雄蕊有分泌顶端，但没有卵泡管。它们在不同的花期向花被片或心皮弯曲，并充当防止自花受精和促进异型杂交的物理屏障。在雌花期，内部退化雄蕊的分泌物具有高浓度的氨基酸，对授粉昆虫具有吸引力；而丰富的脯氨酸仅在柱头分泌物中检测到，并为花粉萌发提供营养。变性雄蕊有一个分泌顶端和一两个卵泡膜，与正常雄蕊等长或短。作为过渡结构，修饰的雄蕊意味着从正常雄蕊到内部退化雄蕊的可能退化过程：首先产生分泌顶端，然后缩短卵泡膜长度，然后丧失卵泡膜。修饰雄蕊的存在以及花维管系统和个体发育意味着内部退化雄蕊与雄蕊同源。内部退化雄蕊在木兰目中广泛存在，并存在于Anaxagorea和Xylopia中，但在番荔枝科的其他属中丢失，并且在衍生的被子植物中没有对应物。本文通过记录具有减少的卵泡膜和分泌结构的改良雄蕊的存在以及雄蕊和退化雄蕊的相似的维管系统和叶序连续性，证明了内部退化雄蕊与Anaxagorea的雄蕊同源。本文还提供了花物候学以及退化雄蕊和柱头的化学渗出物的原始数据，证实了退化雄蕊在授粉过程中防止自花受精的功能。
Inner staminodes are widespread in Magnoliales and present in Anaxagorea and Xylopia, but were lost in the other genera of Annonaceae and have no counterparts in derived angiosperms. The coexistence of normal stamens, modified stamens and inner staminodes in Anaxagorea javanica is essential to understand the homology and pollination function of the inner staminodes. Anaxagorea javanica was subjected to an anatomical study by light and scanning electron microscopy, and the chemistry of secretions was evaluated by an amino acid analyser. Inner staminodes have a secretory apex, but do not have thecae. They bend towards either tepals or carpels at different floral stages, and function as a physical barrier preventing autogamy and promoting outcrossing. At the pistillate phase, the exudates from the inner staminodes have high concentration of amino acid, and provide attraction to pollinating insects; while abundant proline was only detected in stigmas exudates, and supply for pollen germination. Modified stamens have a secretory apex and one or two thecae, which are as long as or shorter than that of the normal stamens. As transitional structures, modified stamens imply a possible degeneration progress from normal stamens to inner staminodes: generating a secretory apex first, shortening of the thecae length next and then followed by the loss of thecae. The presence of modified stamens together with the floral vasculature and ontogeny imply that the inner staminodes are homologous with stamens. Inner staminodes are widespread in Magnoliales and present in Anaxagorea and Xylopia, but were lost in the other genera of Annonaceae and have no counterparts in derived angiosperms. This paper demonstrates that the inner staminodes are homologous with stamens in Anaxagorea by documenting the existence of modified stamens with reduced thecae and secretory structures, and similar vasculature and phyllotactic continuity of stamens and staminodes as well. This paper also provides original data on floral phenology and chemical exudates of the staminodes and stigmas, which confirm the function of the staminodes during pollination in preventing autogamy.
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影响因子：
1.9
作者：
GOTTSBERGER, G;SCHRAUWEN, J;LINSKENS, HF
通讯作者：
LINSKENS, HF
影响因子：
2.3
作者：
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Lorence, DH
影响因子：
2.4
作者：
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通讯作者：
BAKER, HG
影响因子：
1.9
作者：
ENDRESS, PK
通讯作者：
ENDRESS, PK
影响因子：
4.2
作者：
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通讯作者：
De Craene, Louis P. Ronse