喜树花序内性别表达及性别分配

doi:10.3724/SP.J.1258.2011.01290

摘要/Abstract

摘要：

花序内性别表达和性别分配的差异在被子植物中非常普遍。常见的变化模式是: 在顺次开放的花序内, 从早开的花到晚开的花, 生殖结构大小和数量依次减少, 晚开的花偏向雄性。通常认为资源竞争和位置效应是形成这种差异的主要原因。在喜树(Camptotheca acuminata)的聚伞花序内, 早开的头状花序在花序直径、小花直径、短雄蕊长度、坐果率、果序重量等方面与晚开的头状花序差异显著。通过去除喜树聚伞花序一级或一级和二级头状花序来控制花序内的资源分配, 从而分析影响喜树花序内花性状、性别分配及生殖能力的主要因子。结果显示, 去除部分头状花序后, 剩余头状花序的花序直径、小花直径明显增加, 短雄蕊长度明显缩短, 位置间差异消失; 而坐果率、果序重量的位置间差异依然显著。表明资源限制对花序直径、小花直径和短雄蕊长度等影响显著, 而坐果率和果序重量受位置效应影响明显。喜树雄全同株的性别分配可能是对特定生殖状况和资源状况适应的结果。

关键词: 位置效应, 喜树, 花序内差异, 资源竞争, 性别分配

Abstract:

Aims Variation in intra-inﬂorescence sex expression and allocation is a common phenomenon in Angiosperms. The typical pattern is that the size and number of reproductive structures decrease from early to late blooming flowers within the same inflorescence, and the late ones tend to male. Resource competition and architectural effects are regarded as the main causes of these variations. Within the cyme of Camptotheca acuminata, the early capitula demonstrate more significant differences in the diameters of capitulum and corolla, length of short stamen, fruit set rate, and infructescence mass than the late capitula. Our main objective is to determine the causes behind the intra-inﬂorescence sex expression and allocation variations in C. acuminata.
Methods The distribution of resources within inﬂorescences of C. acuminata was manipulated by removing the primary or primary and secondary capitula to determine the factors influencing flower sex allocation and reproductive capacity in an inﬂorescence.
Important findings After removing part of the capitula, the diameters of capitulum and corolla in the remaining capitula increased significantly, the length of short stamen decreased significantly, and the differences between positions disappeared. The differences, however, in fruit set and infructescence mass remained unchanged. This suggests that resource constraints rather than architectural effects have stronger influence on the diameters of capitulum and corolla as well as the length of short stamen, while architectural effects play a dominant role on fruit set and infructescence mass. The andromonoecy in C. acuminatamay be the result of adaptation to specific reproduction and resources competition.

Key words: architectural effects, Camptotheca acuminata, intra-in?orescence variation, resource competition, sex allocation

徐申林, 刘文哲. 喜树花序内性别表达及性别分配. 植物生态学报, 2011, 35(12): 1290-1299. DOI: 10.3724/SP.J.1258.2011.01290

XU Shen-Lin, LIU Wen-Zhe. Intra-inﬂorescence sex expression and allocation in Camptotheca acuminata. Chinese Journal of Plant Ecology, 2011, 35(12): 1290-1299. DOI: 10.3724/SP.J.1258.2011.01290

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链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2011.01290

https://www.plant-ecology.com/CN/Y2011/V35/I12/1290

图/表 8

图1 喜树花序结构示意图。数字表示头状花序位置: 1, 一级; 2, 二级; 3, 三级。

Fig. 1 Structure diagram of Camptotheca acuminata inflorescence. Number refer to inflorescence position: 1, primary; 2, secondary; 3, tertiary。

图2 实验处理示意图。A, 去除一级头状花序。B, 去除一级和二级头状花序。C, 对照。

Fig. 2 Diagram of experimental treatment. A, Removing primary capitulum. B, Removing primary and secondary capitulum. C, Control.

表1 实验处理及分组

Table 1 Experimental treatment and groups

分组 Group (150个聚伞花序 150 cyme)	亚组 Subgroup (50个聚伞花序 50 cyme)	处理对象 Object	处理 Treatment
A组 Group A	A1	最初可见的花芽 First visible buds	去除一级头状花序 Removing primary capitulum
	A2	发育10天后的花芽 Flower buds after 10 days
	A3	发育20天后的花芽 Flower buds after 20 days
B组 Group B	B1	最初可见的花芽 First visible buds	去除一级和二级头状花序 Removing primary and secondary capitulum
	B2	发育10天后的花芽 Flower buds after 10 days
	B3	发育20天后的花芽 Flower buds after 20 days
C组 Group C	不做任何处理 No treatment

图3 喜树C组(对照组)花序内不同位置花性状的平均值(±标准误差)。不同字母表示在p < 0.05水平差异显著。花序位置同图1。

Fig. 3 Means (± SE) of ?oral traits at different intra-in?orescence positions for Group C (control) of Camptotheca acuminate. Different letters denote significant differences (p < 0.05) level. Inflorescence position see .

图4 喜树花序内同一位置不同处理组花性状的平均值(±标准误差)。不同字母表示在 p < 0.05水平差异显著。A组, 去除一级头状花序; B组, 去除一级和二级头状花序; C组, 对照组。花序位置同图1。

Fig. 4 Means (± SE) of ?oral traits at equal intra-in?orescence position of different treatments of Camptotheca acuminate. Different letters denote significant differences (p < 0.05) level. Group A, remove primary capitulum; Group B, remove primary and secondary capitulum; Group C, control. Inflorescence position see .

表2 处理和处理时间的双因素方差分析(p值)

Table 2 Two-way ANOVA of treatment and treat time (p value)

来源 Source	df	花特征 Floral trait
来源 Source	df	花序直径 Capitulum diameter	花数目 Flower number	花直径 Corolla diameter	花瓣长度 Petal length	单花花粉粒 Pollen grains per flower	长雄蕊长度 Long stamen length	短雄蕊长度 Short stamen length
处理 Treatment	1	0.352	0.886	0.001	0.330	0.813	0.549	0.020
处理时间 Treat time	2	0.980	0.863	0.070	0.786	0.124	0.399	0.180
处理×处理时间 Treatment × treat time	2	0.875	0.491	0.870	0.228	0.042	0.217	0.195

图5 喜树不同处理组花序内不同位置花性状的平均值(±标准误差)。不同字母表示在p < 0.05水平差异显著。A组, 去除一级头状花序; B组, 去除一级和二级头状花序; C组, 对照组。花序位置同图1。

Fig. 5 Means (± SE) of ?oral traits at different intra-in?orescence positions of different treatment groups of Camptotheca acuminate. Different letters denote significant differences (p < 0.05) level. Group A, remove primary capitulum; Group B, remove primary and secondary capitulum; Group C, control. Inflorescence position see .

图6 喜树花序轴的横切面。A, 一级花序的花序轴及其维管组织。B, 二级花序的花序轴及其维管组织。C, 三级花序的花序轴及其维管组织。

Fig. 6 Cross section of inflorescence axle for Camptotheca acuminate. A, Inflorescence axle of primary position and the vascular tissue in it. B, Inflorescence axle of secondary position and the vascular tissue in it. C, Inflorescence axle of tertiary position and the vascular tissue in it.

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