鼠尾草属不同物种的雄蕊杠杆机制对传粉者空间变异的进化响应

doi:10.3724/SP.J.1258.2012.00681

摘要/Abstract

摘要：

被子植物虫媒传粉植物的物种分化通常被认为是花性状响应传粉环境(传粉者)的空间变异而发生适应性分化的结果。通过对鼠尾草属(Salvia) 3个物种(共4个居群)传粉互作系统的比较, 探索了花性状对不同传粉环境的进化响应。结果表明: 各居群的传粉者组成、主要传粉者类型及其大小各不相同, 杠杆状雄蕊及相关花部性状大小在不同居群间具有显著差异; 各居群均表现出腹部传粉和背部传粉2种传粉模式, 但背部传粉仍然是最有效的传粉方式; 居群间杠杆状雄蕊长度与传粉者体长表现出极显著的正相关, 然而花冠长与传粉者体长表现出负相关; 花冠口高度和柱头高度与传粉者胸厚也表现出一定的协同变异。鼠尾草属植物的杠杆状雄蕊及相关花部性状在传粉系统的进化过程中表现出高度的可塑性, 表明雄蕊杠杆传粉机制对传粉环境的变异非常敏感, 在该属植物的物种分化过程中具有关键作用。

关键词: 适应辐射, 协同进化, 地理趋异, 关键性状, 局域适应分化, 传粉

Abstract:

Aims Floral diversification in animal-pollinated species was widely believed to be driven by pollinator-mediated natural selection in response to the geographical mosaic of pollinators. Our objective was to explore the evolutionary response of staminal lever mechanism in Salvia to variation in pollinator assemblage in a spatial context.

Methods We employed three species (four populations) and conducted comparative studies on pollinator-flower interactions in different populations through investigating pollinator assemblage and measuring floral traits and body size of pollinators.

Important findings Floral traits investigated, including corolla length, staminal lever length and other structural traits, exhibited distinct differences among populations. These corresponded with variations in composition of pollinators and the main pollinator and its body size in each population. The two types of pollination modes in each population were ventral pollination and dorsal pollination, which was the effective one. The main pollinator’s body length was significantly positively correlated with staminal lever length and negatively correlated with corolla length in spatial context. Both corolla entrance height and stigma height were related to variation in body thickness of the main pollinator among populations. In conclusion, the vulnerability of lever-like stamens and other relevant floral traits to the geographical mosaic of pollinators implies the key role that the staminal lever plays in pollination, and its high evolutionary plasticity might have contributed to adaptive radiation of species in Salvia.

Key words: adaptive radiation, co-evolution, geographical divergence, key innovation, local adaptive diversification, pollination

张勃, 孙杉, 方强恩, 白小明. 鼠尾草属不同物种的雄蕊杠杆机制对传粉者空间变异的进化响应. 植物生态学报, 2012, 36(7): 681-689. DOI: 10.3724/SP.J.1258.2012.00681

ZHANG Bo, SUN Shan, FANG Qiang-En, BAI Xiao-Ming. Evolutionary response of staminal lever mechanism of different species in Salvia to spatial variation in pollinators. Chinese Journal of Plant Ecology, 2012, 36(7): 681-689. DOI: 10.3724/SP.J.1258.2012.00681

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链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2012.00681

https://www.plant-ecology.com/CN/Y2012/V36/I7/681

图/表 5

表1 鼠尾草不同物种居群的概况和花部性状比较(平均值±标准误差)

Table 1 Floral traits and information of different populations in Salvia (mean ± SE)

物种/居群 Species/Population		毛地黄鼠尾草I S. digitaloides I	毛地黄鼠尾草II S. digitaloides II	近掌脉鼠尾草 S. subpalmatinervis	圆苞鼠尾草 S. cyclostegia
居群描述 Population description
	地点 Location	丽江干河坝 Ganheba in Lijiang	丽江甘海子 Ganhaizi in Lijiang	中甸纳帕海 Napahai in Zhongdian	丽江文海 Wenhai in Lijiang
	经纬度 Longitude/Latitude	27°04.307′ N 100°14.683′ E	27°00.897′ N 100°14.671′ E	27°55.377′ N 99°38.060′ E	27°00.447′ N 100°09.334′ E
	海拔 Altitude (m)	3 200 ± 10	2 660 ± 10	3 350 ± 10	3 160 ± 25
	花期 Flowering period	7-9月 July-Sept.	4-5月 Apr.-May	7-8月 July-Aug.	5月 May
花部性状 Floral trait (mm)		n = 86	n = 33	n = 53	n = 36
	冠长 Corolla length	32.14 ± 0.23^a	30.81 ± 0.30^ab	31.58 ± 0.42^ab	30.19 ± 0.37^b
	雄蕊杠杆长 Stamen lever length	4.55 ± 0.05^c	5.25 ± 0.07^b	4.66 ± 0.08^c	5.83 ± 0.06^a
	冠口高 Corolla entrance height	5.30 ± 0.05^c	6.02 ± 0.10^b	5.37 ± 0.07^c	6.48 ± 0.10^a
	柱高 Stigma height	5.53 ± 0.12^b	6.70 ± 0.17^a	4.36 ± 0.13^c	6.99 ± 0.21^a
	柱头探出距离 Style exertion	3.95 ± 0.10^b	4.41 ± 0.17^ab	4.81 ± 0.13^a	4.47 ± 0.24^ab

图1 鼠尾草花部性状测量示意图。A, 花的侧面图。B, 雄蕊杠杆放大图。C, 花的正面图。ceh, 冠口高; cew, 冠口宽; cl, 花冠长; se, 柱头探出距离; sll, 雄蕊杠杆长度; sth, 柱头高度。

Fig. 1 Morphometrics of flower in Salvia. A, side view of a flower. B, enlarged view of stamen lever. C, front view of a flower. ceh, corolla entrance height; cew, corolla entrance width; cl, corolla length; se, style exsertion; sll, stamen lever length; sth, stigma height.

表2 鼠尾草各居群的传粉者组成、体型指标、访花模式和访花效率(平均值±标准误差)

Table 2 Pollinator assemblage and body morphometrics, modes and efficiency of pollination of different pollinator in each population of Salvia (mean ± SE)

居群Population	传粉者 Pollinator assemblage	传粉者大小 Pollinator’s body size (mm)			相对频次 Frequency	单花访花时间 Visit time per flower (s)	访花率指数 Visitation rate index	传粉方式 Pollination mode
居群Population	传粉者 Pollinator assemblage	体长 Body length	胸厚 Body thickness	喙长 Tongue length	相对频次 Frequency	单花访花时间 Visit time per flower (s)	访花率指数 Visitation rate index	传粉方式 Pollination mode
毛地黄鼠尾草I S. digitaloides Population I
	Bombus friseanus ?	15.97 ± 0.55	4.97 ± 0.08	4.33 ± 0.16	0.65	15.50 ± 1.92	2.36	D/V
	B. personatus	20.54 ± 0.91	5.27 ± 0.06	10.71 ± 1.21	0.09	2.55 ± 0.22	2.12	D
	B. infrequens	15.16 ± 0.76	4.40 ± 0.18	4.96 ± 0.82	0.26	17.1 ± 1.23	0.91	D
毛地黄鼠尾草II S. digitaloides Population II
	Psithyrus sp. ?	23.11 ± 1.41	7.43 ± 0.27	5.17 ± 0.07	0.57	8.68 ± 0.90	3.94	D
	B. lepidus	13.55 ± 0.46	4.46 ± 0.16	3.70 ± 0.37	0.20	15.57 ± 1.20	0.77	D/V
	B. infrequens	14.78	4.46	3.02	< 0.20	-	-	D
近掌脉鼠尾草 S. subpalmatinervis
	B. friseanus ?	16.60 ± 0.28	5.06 ± 0.12	4.49 ± 0.3	0.87	13.58 ± 0.91	3.84	D/V
	B. personatus	18.76 ± 1.32	5.28 ± 0.04	10.30 ± 1	0.10	4.21 ± 0.40	1.42	D
	B. atrocinctus	18.00 ± 0.15	5.96 ± 0.15	5.38 ± 0.09	< 0.03	-	-	D
圆苞鼠尾草 S. cyclostegia
	B. friseanus	14.14 ± 0.32	4.36 ± 0.16	4.44 ± 0.42	0.05	11.77 ± 0.75	0.24	V/D
	B. personatus ?	27.29 ± 0.96	7.22 ± 0.09	12.49 ± 1.01	0.90	3.53 ± 0.15	15.30	D
	B. remotus	17.61 ± 0.14	6.03 ± 0.08	6.29 ± 0.48	0.05	10.89 ± 1.54	0.28	D

图2 花部性状与主要传粉者体型大小在居群间的变异关系。A, 花冠长与传粉者体长的变异关系(r = -0.97, p = 0.024)。B, 雄蕊杠杆长与传粉者体长的变异关系(r = 0.99, p = 0.004)。C, 花冠口高与传粉者胸厚的变异关系(r = 0.92, p = 0.08)。D, 柱头高度与传粉者胸厚的变异关系(r = 0.89, p = 0.10)。

Fig. 2 Variation relationship of floral traits to body size of main pollinator’s among populations. A, relationship between corolla length and pollinator’s body length (r = -0.97, p = 0.024). B, relationship between staminal lever length and pollinator’s body length (r = 0.99, p = 0.004). C, relationship between corolla entrance height and pollinator’s body thickness (r = 0.92, p = 0.08). D, relationship between stigma height and pollinator’s body thickness (r = 0.89, p = 0.10).

图3 鼠尾草各居群不同传粉者的传粉模式。毛地黄鼠尾草(干河坝)居群I: 背部传粉(A、C)和腹部传粉(B); 毛地黄鼠尾草(甘海子)居群II: 背部传粉(D); 圆苞鼠尾草居群: 背部传粉(E)和腹部传粉(F); 近掌脉鼠尾草居群: 背部传粉(G、I)和腹部传粉(H)。

Fig. 3 Pollination modes of different pollinators in each population of Salvia. Population I of S. digitaloides in Ganheba: dorsal pollinations by bigger Bombus friseanus (A) and B. personatus (C), and ventral pollinations by smaller B. friseanus (B); population II of S. digitaloides in Dongbagu: dorsal pollination by Psithyrus sp. (D); population of S. cyclostegia: dorsal pollinations by B. personatus (E) and ventral pollinations by smaller B. friseanus (F); population of S. subpalmatinervis: dorsal pollinations by bigger B. friseanus (G) and B. personatus (I), and ventral pollinations by smaller B. friseanus (H).

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