设为首页 加入收藏

Botanical Research
Vol.1 No.2(2012), Article ID:813,9 pages DOI:10.4236/BR.2012.12003

Leaflet Morphology of Pueraria (Leguminosae) from the Miocene Shanwang Formation of Shandong Province and Its Palaeoecological Implications*

Qi Wang1, Honghe Xu2, Si Shen1

1State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing

2State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing

Email: happyking@ibcas.ac.cn

Received: May 23rd, 2012; revised: May 28th, 2012; accepted: Jun. 14th, 2012

ABSTRACT:

Pueraria DC. is the largest papilionoid legume, trifoliolate genus of the subtribe Glycininae in the tribe Phaseoleae, the majority species of which are climbing lianas distributed in East Asia, South Asia, Southeast Asia, and Oceania. The known three fossil species of Pueraria described from the subtropical and temperate floras of the Balkan Peninsula, the Caucasus, and eastern Asia respectively are P. shanwangensis (fruit) from the Miocene Shanwang of China, P. miothunbergiana (leaf and leaflet) from the Miocene of Shanwang and numerous localities in the Mio-Pliocene of Japan, and P. maxima (leaflet) from the Miocene of Croatia and Georgian Abkhazia. On the basis of observations on the newly collected Pueraria leaflet impressions and comparisons with the leaflets of living P. montana, the morphology and developmental variation of Pueraria leaflet fossils are studied. The result shows that the leaflets of both living species P. montana and fossil species P. miothunbergiana and P. maxima bear poorly developed intersecondary veins, which were not observed in former reports on P. miothunbergiana. Also, two adjacent secondary veins or agrophic veins at different angles are sometimes diverged respectively from the primary vein (midvein) and the exmedial side of secondary veins in both extant and fossil Pueraria leaflets, which is a feature that has long been neglected. Overall, the venation of fossil Pueraria leaflets that are widely occurred across the Miocene of middle latitudes in Eurasia is highly similar, but the lobed leaflets similar to those of living P. montana are only discovered from the Miocene Shanwang flora of China and Takamine flora of Japan. Extant P. montana bears larger leaflets than fossil Pueraria and seems to have developed more lobed leaflets than fossil P. miothunbergiana does, which might have been related to the change of atmospheric CO2 concentrations since the Miocene onwards. Living individuals of P. montana growing in shady, closed habitats as well as climbing on supports (e.g., pergolas or other woody plants) develop more lobed leaflets than those inhabiting open habitats and trailing, which may efficiently enhance light interception and heat dissipation within leaves and canopies. It is inferred that populations of P. miothunbergiana lived in the Mio-Pliocene of China and Japan may have wider ecological tolerances than those of P. maxima occurred in the Miocene of Croatia and Abkhazia, so the eastern Asian populations may not only live in shady habitats more relied on forests, but also grow in open habitats less relied on forests or even sprawl.

Keywords: Developmental Variation; Evolution; Leaflet Fossils; Leguminosae; Miocene; Palaeoecology; Pueraria

山东中新世山旺组葛属(豆科)小叶的形态及其古生态学意义*

王  祺1,徐洪河2,申  思1

1中国科学院植物研究所,系统与进化植物学国家重点实验室,北京

2中国科学院南京地质古生物研究所,现代古生物学和地层学国家重点实验室,南京

Email: happyking@ibcas.ac.cn

摘 要:

葛属Pueraria是豆科蝶形花亚科、菜豆族大豆亚族中最大的、具有三小叶复叶的属,其大多数种为攀援性藤本植物,分布于东亚、南亚、东南亚和大洋洲。化石记录表明,葛属早在中新世就已出现在东亚、巴尔干半岛和高加索地区的亚热带和温带植物群中,目前已知有3个化石种,即中国山旺中新世的荚果化石山旺葛藤P. shanwangensis、山旺和日本数个中、上新世产地的叶、小叶化石鲁葛藤P. miothunbergiana以及克罗地亚和格鲁吉亚阿布哈兹中新世的小叶化石大葛藤P. maxima。本文基于对中新世山旺组最近采集的葛属小叶印痕化石的观察和对现生种葛P. montana小叶的形态比较,研究了该属化石种的小叶形态和发育变异。结果表明,现生种葛与化石种鲁葛藤和大葛藤的小叶都具有不甚发育的间二级脉,这个特征在先前报道的鲁葛藤小叶化石中未见保存。另外,它们的主脉和二级脉远轴侧有时都会分别发出两条挨得很近、角度不同的二级脉和二级脉梳脉,这个特征过去在葛属中则被忽视了。总体上,葛属小叶化石的叶脉特征在中新世广阔的欧亚中纬度地区显示了高度的相似性。目前,仅在中国中新世山旺植物群和日本中新世高峰山组植物群中发现了与现生的葛小叶相似的、具有裂瓣的鲁葛藤小叶化石,但现生葛比化石葛的小叶更大些、似乎发育了更多具有裂瓣的小叶,这可能与中新世以来大气二氧化碳浓度的变化有关。现生葛长在荫蔽生境以及攀援于支持物(如藤架或其他木本植物)上的植株比生于开阔生境以及蔓生的植株发育了更多的、具有裂瓣的小叶,这可能有效促进了整株植物的叶片和冠层中的光照截取和通风散热。据此推测,中国和日本中、上新世的鲁葛藤居群可能比克罗地亚和阿布哈兹中新世的大葛藤居群的生态耐受性更加宽泛,东亚的居群既生于荫蔽的、更多依赖森林的生境中,也长在开阔的、较少依赖森林生境中,甚至蔓生。

收稿日期:2012年5月23日;修回日期:2012年5月28日;录用日期:2012年6月14日

关键词:发育变异;演化;小叶化石;豆科;中新世;古生态学;葛属

1. 引言

葛属Pueraria DC.隶属于豆科蝶形花亚科,为菜豆族大豆亚族中最大的、具有三小叶复叶的属,约有15~20个现生种,分布于东亚、南亚、东南亚和大洋洲[1-13]。该属在亚洲(特别是中国和日本)民间有着悠久的使用历史[3,4,7,8,10,14],一些种被用做观赏植物和药用植物(如葛P. montana (Lour.) Merr.,其根含葛根素等成分,有解表退热和止泻等功效)、食用植物(如粉葛P. thomsonii Benth.,其块根富含淀粉)、饲用植物、覆盖和绿肥植物以及造纸和织布等工业用途(如葛富含纤维,古称“夏布”)。葛属植物在1876年费城园艺博览会上被引入美国,随后作为一种观赏植物、饲用植物和覆盖植物被广泛栽培,但是它们生长非常迅速,在美国东南部严重地影响了当地植物的生长,上世纪八十年代以后被美国农业部宣布为有害的外来入侵植物[14-16]。同样,葛属在南非也被视为外来入侵植物。然而,引入和栽培的葛属植物在欧洲和南美的一些国家却并未造成明显的入侵效应[3]。此外,葛属植物还对中国和日本的文学有着深远的影响。例如,《诗经—周南·葛覃》中的描述:“葛之覃兮,施于中谷,维叶萋萋。黄鸟于飞,集于灌木,其鸣喈喈。葛之覃兮,施于中谷,维叶莫莫。是刈是濩,为絺为绤,服之无斁”,它以葛藤来比喻女子的缠绵柔情,以葛叶来比喻女子的美貌容颜,使淳朴的先秦女子在葛藤间的劳作之歌空谷流传两千多年后,仿佛依然悦耳动听。总之,葛属植物从古至今已经引起了文学家、植物学家、园艺学家、生态学家和保护生物学家的广泛关注。

葛属的分类主要依据其生长习性、小叶和托叶形态、花和花序特征(即花序轴上每节含花的数目、花萼上方连合的程度和旗瓣是否有胼胝体)、荚果形态、种子数目和形态[1-4,7,8,12]。古植物学家通常只能研究一些散生的、离体保存的小叶和荚果化石。化石记录表明,葛属早在中新世就已经出现在东亚、巴尔干半岛和高加索地区的亚热带和温带植物群中,目前已经发现了3个葛属化石种,即山旺中新世的荚果化石山旺葛藤P. shanwangensis Wang, Manchester et Dilcher、中国山旺和日本数个中、上新世产地的叶、小叶化石鲁葛藤P. miothunbergiana Hu et Chaney以及克罗地亚和格鲁吉亚阿布哈兹中新世的小叶化石大葛藤P. maxima (Unger) Wang, Manchester et Dilcher[13,17]。尽管葛属的现代分布中心在印度—马来西亚地区[2,5,6,10,12],即属于热带亚洲分布型[18],但该属的化石记录在中新世业已出现在上述欧亚大陆的中纬度地区,因此其现代分布和多样性中心可能是在新近纪次生散布的结果。据此,我们亟需了解葛属小叶化石的形态在广阔的欧亚中纬度地区的演化途径以及可能的原因。本文基于对中新世山旺组最近采集的葛属小叶印痕化石的新观察,比较了所有已知化石种小叶的形态,补充描述了先前未被发现或被忽视的叶结构特征,讨论了这些小叶化石的发育变异和潜在的古生态学意义。

2. 材料和方法

本文描述的5块小叶均保存为印痕化石,采自山东省临朐县城东约22公里处的山旺盆地山旺组硅藻页岩地层(地理坐标为北纬36˚54',东经118˚20')[19-21]。山旺组富含十分精美的古生物化石,素有“古生物化石宝库”之称[20,22,23]。目前,山旺组生物群的地质时代被认为是中中新世[13,20,21,24-27]或早中新世晚期至中中新世早期[19,28-32]

我们对小叶印痕化石作了直接观察,详细描述了其叶结构特征。为了便于比较,绘制了过去发表的相关小叶化石叶结构的线条图。对栽培于北京植物研究所植物园内的葛属现生种葛P. montana的小叶形态和生态习性作了观察,并总结了前人相关的研究成果。描述叶结构的术语采纳了Ellis等[33]的用法。标本照相使用了数码相机(型号Panasonic DMC-FZ30)。植物化石材料(标本编号前缀PE、UCMP和LMJ)分别保存于中国科学院植物研究所国家标本馆、美国加利福尼亚大学古生物博物馆和奥地利格拉茨大学Provincial Museum Joanneum。

3. 结果

3.1. 小叶化石描述

豆科 Leguminosae Juss., 1789;

蝶形花亚科 Papilionoideae L. ex DC., 1825;

菜豆族 Phaseoleae (Bronn) DC., 1825;

大豆亚族 Glycininae (Burnett) Benth., 1837;

葛属 Pueraria DC., 1825;

鲁葛藤 Pueraria miothunbergiana Hu et Chaney, 1938(图1. 1~5,图2. 1~4);

1938 P. miothunbergiana Hu et Chaney[17], p. 52, pl. 28, fig. 1;

1974 P. tanaii Ozaki[36], p. 15, pl. 2, fig. 11, pl. 3, fig. 3;

1975 P. miothunbergiana Hu et Chaney in Hayashi[34], p. 25, pl. 17, fig. 4, pl. 18, fig. 5;

1978 P. miothunbergiana Hu et Chaney,中国科学院植物研究所、南京地质古生物研究所《中国新生代植物》编写组[78],p. 109, pl. 85, fig. 3, pl. 91, fig. 5, pl. 92;

1988 Pueraria sp., Uemura[35], p. 149, fig. 34, pl. 9, fig. 8;

1991 P. miothunbergiana Hu et Chaney in Ozaki[37], p. 133, fig. 29-2, pl. 5, fig. 11;

1992 P. miothunbergiana Hu et Chaney in Guo, Zhou[79], p. 209, tab. 1;

1999 P. miothunbergiana Hu et Chaney,陶君容等[54],p. 41, 70, pl. 28, fig. 2-3;

2010 P. miothunbergiana Hu et Chaney in Wang et al.[13], p. 1988, fig. 10-21, 23。

凭证标本 PE-081024,20110529,081023,09513和09514(图1. 1~5,按图号依次)。

描述 小叶印痕化石,包括3种主要类型:对称型(1份标本)、左偏斜型(3份标本)和右偏斜型(1份标本)。因此,它们可能脱落于3小叶组成的复叶。顶生小叶对称型,叶片宽卵形,有点斜方状,15厘米长、13厘米宽,边缘全缘,顶端渐尖,基部宽楔形,小叶柄膨大,形成一个短粗的叶枕,矩形,6毫米长、4毫米宽。侧生小叶强烈不对称,向左偏斜(即叶片左半边较大)或向右偏斜(即叶片右半边较大),叶片宽卵形,8~14.8厘米长、6~11.2厘米宽,边缘全缘、轻微的波状或具有极浅钝圆裂湾的掌状三裂瓣,顶端急尖、渐尖或(稀)钝圆,基部宽楔形、钝圆或平截形,小叶柄膨大,形成一个短粗的叶枕,矩形,3~9毫米长、1.5~3毫米宽。叶质地纸质。

叶片具羽状脉pinnate。主脉(即中脉)较粗,在顶

Figure 1. Leaflet impressions of Pueraria miothunbergiana Hu et Chaney from the Miocene Shanwang Formation. 1: A lateral leaflet, showing very shallow trilobation; 2: A terminal leaflet, indicating an intersecondary vein from the upper left of the mid-vein; 3: A lateral leaflet, showing two adjacent agrophic veins at different angles diverged from the exmedial side of the left basal secondary vein; 4: A lateral leaflet, showing two adjacent secondary veins or agrophic veins respectively diverged from the mid-vein or the exmedial side of the left basal secondary vein at different angles; 5: A lateral leaflet, indicating a poorly developed, intersecondary vein from the middle-lower of the mid-vein

图1. 山东中新世山旺组鲁葛藤小叶印痕化石。1:侧生小叶,显示了极浅的三裂瓣;2:顶生小叶,显示中脉上部左侧有一条间二级脉;3:侧生小叶,显示了左侧基脉远轴侧发出2条挨得很近的、角度不同的外侧脉;4:侧生小叶,显示了中脉左侧和左侧基脉远轴侧分别发出2条挨得很近的、角度不同的二级脉和外侧脉;5:侧生小叶,显示了中脉中下部左侧有一条不甚发育的间二级脉

生小叶中很直,而在侧生小叶中则略弯。二级脉属于真曲脉eucamptodromous,4~7对,包括1对强的基脉,从中脉以30˚~60˚伸出,间距通常较宽(但有时在侧生小叶片的较大那半发出两条挨得很近、角度不同的二级脉),对生或互生,脉形向上弧曲,临近叶缘急剧上弯,与相邻的二级脉和二级脉外侧脉联成环形,在边缘没有形成较高级的脉环。二级脉梳脉agrophic veins复合型,1~7条,从二级脉远轴侧以30˚~90˚分出,间距通常较宽,但有时在侧生小叶片的较大那半发出两条挨得很近、角度不同的二级脉梳脉。间二级脉单一型,与中脉上相邻二级脉近平行,但仅发至半边叶片的中部。三级脉及顶型percurrent为主,稀随机网状,互生或以对生为主,或多或少平行,脉形直、波状弯曲或中部向远轴方向微微拱起,脉间距2~10毫米,与中脉的角度呈90˚~150˚,但以120˚的倾斜为主,与二级脉和二级脉梳脉呈70˚~90˚。四级脉形成规则的多边形网状。五级脉二歧式分支。脉间区areolation发育得很好。叶缘末级脉结成环形,在叶片基部有时呈流苏状。

产地层位 山东省临朐县城东约22 km处的山旺盆地,中新统山旺组硅藻页岩。

讨论 当前描述的小叶印痕化石具有短粗的叶枕和真曲型的二级脉,因此可以归入豆科。这种具有相似叶结构特征,大型对称的、顶生小叶和强烈不对称的、侧生小叶主要局限于蝶形花亚科菜豆族及其近缘类群中具有三小叶复叶的属[13]。根据这些化石具有一致的真曲型二级脉(包括一对较强的基脉)、复合型二级脉梳脉、对生及顶型为主的三级脉和规则的多边形网状四级脉等叶结构特征,它们被归入葛属Pueraria,进而归入先前描述的化石种鲁葛藤P. miothunbergiana Hu et Chaney[17]。当前描述的小叶化石标本中还保存了不太发育的间二级脉,它们先前曾发现于现生种葛P. montana和化石种大葛藤P. maxima[13]的小叶中(图2. 5)。现生种葛与化石种鲁葛藤和大葛藤的小叶的主脉和二级脉远轴侧有时都会发出两条挨得很近、角度不同的二级脉梳脉(图2. 2, 6~7;图3),这个叶结构特征先前一直被忽视了。

除了山旺,鲁葛藤还发现于日本中新世至上新世的多个产地[13,34-37]。我们这里排除了Ina[38]的图版24图9中描述于中新世可儿Kani盆地的葛属小叶化石,这块标本呈非常宽的卵形,极不对称,较小,约4.5厘米长、4.8厘米宽,它可能属于椴树科Tiliaceae Juss.中的化石种Plafkeria basiobliqua (Oishi et Huzioka) Tanai[39]。值得一提的是,在日本壹歧Iki岛中中新世长者原Chōjabaru组发现了一件比较完整的、显示鲁葛藤顶生小叶和侧生小叶有机连接的三小叶复叶标本[13,34]。另外,在山旺组和日本晚中新世高峰山组Takamine都发现了具有掌状3裂瓣的鲁葛藤小叶(图2. 3~4),但标本数量很少(仅有3块),这种表型迄今还从未发现于另外一个产自克罗地亚拉道博Radoboj植物群和格鲁吉亚阿布哈兹考多儿Kodor植物群的小叶化石种大葛藤(图2. 5~7)。目前,仅在山旺组中发

Figure 2. Leaflet architectures of two fossil Pueraria species 1-4: P. miothunbergiana Hu et Chaney from the Miocene of China and Japan; 1: A terminal leaflet from the Miocene Shanwang (drawn from the holotype UCMP 410001); 2: A lateral leaflet from the Miocene Shanwang (also in Figures 1-4); 3: A trilobed lateral leaflet from the Miocene Shanwang; 4: A trilobed terminal leaflet from the Miocene Takamine of Japan; 5-7: P. maxima (Unger) Wang, Manchester et Dilcher from the Miocene of Croatia and Abkhazia; 5: A lateral leaflet from the Miocene of Croatia (drawn from the lectotype LMJ-76781), showing an intersecondary vein from the upper right of the mid-vein; 6, 7: Two lateral leaflets from the Miocene of Abkhazia (redrawn from Kolakovsky, 1959, pl. 13, fig. 1, pl. 12, fig. 1); 6: Showing a slightly undulate margin and two adjacent secondary veins diverged from the mid-vein at different angles

图2. 葛属2个化石种的小叶结构1~4:中国和日本中新世的鲁葛藤;1:中新世山旺产的顶生小叶(绘自主模式UCMP 410001);2:中新世山旺产的侧生小叶(也见插图1~4);3:中新世山旺产的三裂瓣侧生小叶;4:日本中新世高峰山产的三裂瓣顶生小叶;5~7:克罗地亚和阿布哈兹中新世的大葛藤;5:克罗地亚中新世产的侧生小叶(绘自后选模式LMJ-76781),显示中脉上部右侧有一条间二级脉;6、7:阿布哈兹中新世产的2片侧生小叶(重绘自Kolakovsky, 1959, pl. 13, fig. 1, pl. 12, fig. 1);6:显示了轻微波状的边缘和中脉右侧发出2条挨得很近的、角度不同的二级脉

Figure 3. Leaflet morphology of living P. montana (Lour.) Merr., three leaflets in each line from a trifoliolate compound-leaf, showing the developmental variation

图3. 现生种葛的小叶形态,每排中的3片小叶来自一枚三小叶复叶,显示了发育变异

现了葛属的荚果化石山旺葛藤P. shanwangensis[13],它极有可能和山旺产的小叶化石鲁葛藤来自于相同的母体植物居群。

3.2. 现生种葛的小叶形态和发育变异

现生种葛P. montana的小叶形态变异幅度很大,从全缘叶(有时有些波状)到不同程度的两裂或掌状三裂(见图3),以顶端渐尖的卵形叶片为主,稀顶端钝圆的近圆形、扇圆形或卵形叶片。现生葛的小叶面积在一枚三小叶复叶中也存在一定差异,根据Tsugawa和Tange[40]的观察,42%的三小叶复叶具有较大面积的顶生小叶,25%和33%的三小叶复叶中分别具有较大面积的左侧生小叶和右侧生小叶。

我们分2组观察了攀援于荫闭藤架上和蔓生在开阔地上的栽培葛居群的叶子,对于藤架上的葛叶又分成2小组观察它们的阳生叶sun leaves和阴生叶shade leaves的形态,而蔓生的植株上葛叶大都“华盖状”叶面朝上或斜上方,似乎没有明显的阴生叶。我们在每个居群的藤株上每组随机摘取10枚发育完整的叶(总计90片小叶)进行测量,统计结果发现攀援在藤架上的葛明显比蔓生在开阔地上的葛发育了更多的、具有裂瓣的小叶。总体上,藤架上的阳生小叶比阴生小叶稍小些,而藤架上的小叶比蔓生在开阔地上的小叶要大一些(表1)。

4. 古生态学意义

根据现生种葛与化石种鲁葛藤和大葛藤非常相似的叶结构特征,我们可以推测,控制葛属小叶形态分化的基因组早在中新世就已发挥其内在驱动作用,种内和种间的小叶形态差别总体上可归因于基因调控[41]、发育变异[42]和外界环境条件的变化。就外界环境条件而言,温度(与光照和二氧化碳浓度密切相关)、水分以及支持物是影响葛属生理代谢、生长发育、多样性和丰度以及迁移散布的最重要生态因素。

葛属现生种大多是攀援性藤本植物(稀灌木),它们喜生长在湿润或季节性干旱的热带、亚热带和温带森林、雨林以及灌木丛植被中[2-4,10,12],它们对温度、水分、光照、高浓度水平的二氧化碳和环境污染等生态因素都非常敏感[16,43-47]。通过对现生葛居群的观察,生长在阳光和水分充足的生境以及攀援于支持物(如藤架或其他木本植物)上的植株比生于开阔生境以及蔓生的植株中发育了更多的果实[48]、分枝和冠层[49](本文的观察)。近来的生态学研究表明,随着热带森林的扰动率增加和温带森林碎片化fragmentation的加剧,藤本植物的丰度会增加,而其多样性一般随纬度降低而增加[50-53]。除了鲁葛藤之外,在山旺植物群中还有陶氏紫藤Wisteria taoiana Wang et al.[26]、角苦皮藤Celastrus mioangulata Hu et Chaney、多花藤Berchemia miofloribunda Hu et Chaney、山旺蛇葡萄Ampelopsis shanwangensis Hu et Chaney、山东岩爬藤Tetrastigma shantungensis Hu et Chaney和秋葡萄Vitis romanetii Roman等诸多藤本植物[53,54],这暗示着中新世山旺植物群可能发生了一定程度的森林碎片化。此外,山旺中新世火山喷发可能导致了该地区生物大量非正常死亡[55]。总体上,随着中新世到早上新世以来喜马拉雅山—青藏高原的隆起和古地中海的退却[56]、亚洲内陆荒漠化[57]、亚洲季风系统的形成[58]以及地中海地区的旱化[59],曾经在早新生代广阔的欧亚中纬度

Table 1. Developmental variation of living Pueraria montana leaflets in different environmental conditions

表1. 现生葛小叶在不同环境条件下的发育变异

地区分布的森林变得日益碎片化。东亚、巴尔干半岛和高加索地区发现葛属化石的产地可能代表了北半球新近纪亚热带和暖温带植物群和森林中喜湿成分的避难所[13,17,34,35,60-66]。巴尔干半岛和高加索地区的大葛藤居群在中新世之后(灭绝)消失了,而东亚的鲁葛藤居群在日本兜岩Kabutoiwa则一直延续到上新世中期的凉温带植物群中[37,67],或许最后演化成今天生活在东亚地区的葛属居群。

大气二氧化碳浓度在中中新世暖期比现在可能要低些[68-71]。最近的研究表明,现代大气二氧化碳排放速率是古新世–始新世极热事件Paleocene-Eocene Thermal Maximum(PETM)时期的10倍[72]。通过对现生葛的研究发现,大气二氧化碳浓度升高将明显增加葛属植物小叶的生长率和叶片的扩张速率[45]。现生的葛小叶(7 – 26 ´ 5 – 22厘米)比化石种鲁葛藤和大葛藤的小叶(分别为5.2 – 18.5 × 4.8 – 16厘米和8.3 – 15 × 5.5 – 12厘米)都要大些[13],这可能与新近纪以来大气二氧化碳浓度的变化有关。如果暂不考虑化石埋藏学的偏差等因素,现生种似乎比化石种发育了更多的、具有裂瓣的小叶,这一方面可能与当前高浓度的二氧化碳加快葛小叶的扩张速率有关,即同等大小的裂瓣小叶比全缘小叶的扩张速率更快。另一方面,现代生态学研究表明,裂瓣小叶能有效地促进整株植物的叶片和冠层中的光照截取和通风散热[73-77]。现生葛长在荫蔽生境以及攀援于支持物(如藤架或其他木本植物)上的植株比生于开阔生境以及蔓生的植株发育了更多的、具有裂瓣的小叶。据此我们推测,中国和日本中、上新世的鲁葛藤居群可能比克罗地亚和阿布哈兹中新世的大葛藤居群的生态耐受性更加宽泛,它们既可生活在荫蔽的、更多依赖森林的生境中,也能长在开阔、较少依赖森林、甚至蔓生的生境中。

5. 致谢

作者感谢南京地质古生物研究所郭双兴研究员对本文提出宝贵的修改意见、美国佛罗里达自然历史博物馆Steven Manchester教授、加利福尼亚大学古生物博物馆Douglas Erwin教授、日本国立科学博物馆Kazuhiko Uemura博士、奥地利格拉茨大学Provincial Museum Joanneum的Werner Piller教授和Martin Gross博士、北京大学地球与空间科学学院王德明教授提供部分化石照片;中国科学院植物研究所孙英宝绘制精美的小叶化石线条图;美国克莱蒙特学院郭晋燕博士、日本爱知县Haruyuki Ina先生、北京大学地球与空间科学学院熊聪慧博士以及化石网(www.uua.cn)参与者提供一些重要文献。这项工作受到国家自然科学基金项目(批准号40830209)和系统与进化植物学国家重点实验室项目(批准号56176G1044)资助。

参考文献 (References)

[1]       J. A. Lackey. Phaseoleae DC. (1825). In: R. M. Polhill, R. H. Raven, Eds., Advances in Legume Systematics, Part 1. Kew: Royal Botanic Gardens, 1981: 301-327.

[2]       L. J. G. van der Maesen. Revision of the genus Pueraria DC., with some notes on Teyleria Backer. Agricultural University Wageningen Papers 85-1, Netherlands: Agricultural University Wageningen, 1985: 1-132.

[3]       L. J. G. van der Maesen. Pueraria, the kudzu and its relatives: An update of the taxonomy. In: M. Sørensen, Ed., Proceedings of the First International Symposium of Tuberous Legumes, Guadleoupe, FWI, 21-24 April 1992, 1994: 55-86.

[4]       L. J. G. van der Maesen. Pueraria: Botanical characteristics. In: W. M. Keung, Ed., The Genus Pueraria. Medicinal and Aromatic Plants-Industrial Profiles. London: Taylor & Francis, 2002: 1-28.

[5]       C. Niyomdham. Notes on Thai and Indo-Chinese Phaseoleae (Leguminosae-Papilionoideae). Nordic Journal of Botany, 1992, 12(3): 339-346.

[6]       J. M. Lock, J. Heald. Legumes of Indo-China, a check-list. Kew: Royal Botanic Gardens, 1994: 116-118.

[7]       吴德邻, 陈忠毅, 黄向旭. A study of Chinese Pueraria[J]. 热带亚热带植物学报, 1994, 2(3): 12-21.

[8]       张奠湘, 陈忠毅. A cladistic analysis of Pueraria DC. (Leguminosae)[J]. 热带亚热带植物学报, 1995, 3(1): 35-40.

[9]       J. Lee, T. Hymowitz. A molecular phylogenetic study of the subtribe Glycininae (Leguminosae) derived from the chloroplast DNA rps16 intron sequences. American Journal of Botany, 2001, 88(11): 2064-2073.

[10]    B. D. Schrire. Tribe Phaseoleae. In: G. Lewis, B. Schrire, B. Mackinder and M. Lock, Eds., Legumes of the World, Kew: Royal Botanic Gardens, 2005: 393-432.

[11]    Z. F. Le. Pueraria DC. In: X. Y. Zhu, Y. F. Du, J. Wen and B. J. Bao, Eds., Legumes of China: A Checklist. Reading: The University of Reading, 2007: 530-535.

[12]    乐志芳. Taxonomic revision of Pueraria DC. (Leguminosae)[D]. Institute of Botany, Chinese Academy of Sciences, 2008.

[13]    Q. Wang, S. R. Manchester and D. L. Dilcher. Fruits and foliage of Pueraria (Leguminosae, Papilionoideae) from the Neogene of Eurasia, and their biogeographic implications. American Journal of Botany, 2010, 97(12): 1982-1998.

[14]    Z. Y. Li, Q. Dong, T. P. Albright and Q. F. Guo. Natural and human dimensions of a quasi-wild species: The case of kudzu. Biological Invasions, 2011, 13: 2167-2179.

[15]    R. A. Pappert, J. L. Hamrick and L. A. Donovan. Genetic variation in Pueraria lobata (Fabaceae), an introduced, clonal, invasive plant of the southeastern United States. American Journal of Botany, 2000, 87(9): 1240-1245.

[16]    I. Forseth, A. Innis. Kudzu (Pueraria montana): History, physiology, and ecology combine to make a major ecosystem threat. Critical Reviews in Plant Sciences, 2004, 23: 401-413.

[17]    H. H. Hu, R. W. Chaney. A Miocene flora from Shantung Province, China, part 1. Introduction and systematic considerations. Carnegie Institution of Washington Publication, 1938, 507: 1-82.

[18]    吴征镒. The areal-types of Chinese genera of seed plants[J]. 云南植物研究, 1991, 4(增刊): 1-139.

[19]    G. W. Liu, E. B. Leopold. Paleoecology of a Miocene flora from the Shanwang Formation, Shandong Province, Northern East China. Palynology, 1992, 16: 187-212.

[20]    H. Yang, S. P. Yang. The Shanwang fossil biota in eastern China: A Miocene Konservat-Lagerstätte in lacustrine deposits. Lethaia, 1994, 27(4): 345-354.

[21]    Q. Wang, D. L. Dilcher and T. A. Lott. Podocarpium A. Braun ex Stizenberger 1851 (formerly Podogonium Heer 1857) from the middle Miocene of eastern China, and its paleoecology and biogeography. Acta Palaeobotanica, 2007, 47(1): 237-251.

[22]    孙博. Shanwang plant fossils[M]. Ji’nan: Shandong Science and Technology Press, 1999: 1-167.

[23]    杨式溥, 孙博. Palaeoecology of Miocene Shanwang biota in Shandong Province, East China[J]. 古地理学报, 2000, 2(4): 1- 11.

[24]    李浩敏. The geological age of Shanwang flora[A]. In: Palaeontological Society of China, Ed., Selected Papers of the 12th Annual Meeting of the Palaeontological Society of China[C]. Beijing: Science Press, 1981: 158-162.

[25]    王祺. On the identity of Podogonium Heer 1857, nom. illeg. (Leguminosae) from the Miocene Shanwang flora of Shandong[J]. 植物分类学报, 2006, 43(2): 197-203.

[26]    Q. Wang, D. L. Dilcher, X. Y. Zhu, Y. L. Zhou and T. A. Lott. Fruits and leaflets of Wisteria (Leguminosae, Papilionoideae) from the Miocene of Shandong Province, eastern China. International Journal of Plant Sciences, 2006, 167(5): 1061-1074.

[27]    张静, 王祺. Further observations on the pod fossils of Wisteria (Leguminosae) from the Middle Miocene Shanwang Formation of Linqu, Shandong Province[J]. 古生物学报, 2010, 49(1): 87- 95.

[28]    W. M. Wang, T. Yamanoi. New data on Miocene pollen floras of the Oga Peninsula, Northeast Honshu of Japan, with comparison to those of Northern China. Japanese Journal of Palynology, 1996, 42(1): 1-13.

[29]    T. Deng. Chinese Neogene mammal biochronology. Vertebrata PalAsiatica, 2006, 44(2): 143-163.

[30]    C. A. E. Strömberg, E. M. Friis, M. M. Liang, L. Werdelin and Y. L. Zhang. Palaeoecology of an Early-Middle Miocene lake in China: Preliminary interpretations based on phytoliths from the Shanwang basin. Vertebrata PalAsiatica, 2007, 45(2): 145-160.

[31]    王祺. Pulvini of Cercis leaves from the Miocene Shanwang Formation of Shandong Province and the early evolution of the pulvinus in Leguminosae[J]. 古生物学报, 2012, 51(1): 1-13.

[32]    Q. Wang. Fruits of Hemitrapa (Trapaceae) from the Miocene of eastern China, their correlation with Sporotrapoidites erdtmanii pollen and paleobiogeographic implications. Journal of Paleontology, 2012, 86(1): 156-166.

[33]    B. Ellis, D. C. Daly, L. J. Hickey, et al. Manual of leaf architecture. Ithaca & New York: Cornell University Press, 2009: 1-190.

[34]    T. Hayashi. Fossils from Chōjabaru, Iki Island, Japan. Nagasaki: Shima-No-Kagaku Kenkyusho, Ishida-Cho, 1975: 1-120.

[35]    K. Uemura. Late Miocene floras in Northeast Honshu, Japan. Tokyo: National Science Museum, 1988: 1-197.

[36]    K. Ozaki. Miocene floras of the Pacific side of central Japan 1. In kyoyama flora. Science Reports of the Yokohama National University, Section 2. Biological and Geological Sciences, 1974, 21: 1-21.

[37]    K. Ozaki. Late Miocene and Pliocene floras in central Honshu, Japan. Bulletin of Kanagawa Prefectural Museum Natural Science Special Issue, Yokohama: Kanagawa Prefectural Museum, 1991: 1-244.

[38]    H. Ina. Miocene fossils of the Mizunami group, central Japan 1. Plants of the Kani and Mizunami basins. Monograph of the Mizunami Fossil Museum, 1981, 2: 1-20.

[39]    T. Tanai. The revision of the so-called Alangium leaves from the Paleogene of Hokkaido, Japan. Tokyo: Bulletin of the National Science Museum, Series C, 1989, 15(4): 121-149.

[40]    H. Tsugawa, M. Tange. Prediction equation for estimating leaflet area of kudzu vines (Pueraria lobata Ohwi). Science Reports of Faculty of Agriculture, Kobe University, 1981, 14(2): 249-252.

[41]    M. Barkoulas, C. Galinha, G. S. P. rigg and M. Tsiantis. From genes to shape: Regulatory interactions in leaf development. Current Opinion in Plant Biology, 2007, 10(6): 660-666.

[42]    T. McLellan. Development and morphometrics of leaves. In: M. H. Kurmann, A. R. Hemsley, Eds., The Evolution of Plant Architecture. Kew: Royal Botanic Gardens, 1999: 169-182.

[43]    G. K. Sharma, C. Chandler and L. Salemi. Environmental pollution and leaf cuticular variation in kudzu (Pueraria lobata Willd.). Annals of Botany, 1980, 45(1): 77-80.

[44]    T. W. Sasek, B. R. Strain. Effects of carbon dioxide enrichment on the growth and morphology of kudzu (Pueraria lobata). Weed Science, 1988, 36(1): 28-36.

[45]    T. W. Sasek, B. R. Strain. Effects of carbon dioxide enrichment on the expansion and size of kudzu (Pueraria lobata) leaves. Weed Science, 1989, 37(1): 23-28.

[46]    T. D. Sharkey, F. Loreto. Water stress, temperature, and light effects on the capacity for isoprene emission and photosynthesis of kudzu leaves. Oecologia, 1993, 95(3): 328-333.

[47]    A. E. Wiberley, A. R. Linskey, T. G. Falbel and T. D. Sharkey. Development of the capacity for isoprene emission in kudzu. Plant, Cell and Environment, 2005, 28(7): 898-905.

[48]    王红, 蔡永立, 王亮等. Influence on the sexual reproduction of Pueraria lobata (Willd.) Ohwi in different habitats and with different scramble manner in Tiantong National Forest Park, Zhejiang[J]. 石河子大学学报(自然科学版), 2005, 23(5): 601- 605.

[49]    H. Tsugawa, T. Shimuzu, T. W. Sasek and K. Nishikawa. The climbing strategy of kudzu-vine (Pueraria lobata Ohwi). Science Reports of Faculty of Agriculture, Kobe University, 1992, 20(1): 1-6.

[50]    S. A. Schnitzer, F. Bongers. The ecology of lianas and their role in forests. Trends in Ecology & Evolution, 2002, 17(5): 223-230.

[51]    R. A. Londré, S. A. Schnitzer. The distribution of lianas and their change in abundance in temperate forests over the past 45 years. Ecology, 2006, 87(12): 2973-2978.

[52]    陈亚军, 陈军文, 蔡志全. Lianas and their functions in tropical forests[J]. 植物学通报, 2007, 24(2): 240-249.

[53]    R. J. Burnham. An overview of the fossil record of climbers: Bejucos, sogas, trepadoras, lianas, cipós, and vines. Revista Brasileira de Paleontologia, 2009, 12(2): 149-160.

[54]    陶君容, 孙博, 杨洪. Plant megafossils of the Shanwang formation[A]. In: B. Sun, Ed., Shanwang Plant Fossils[C]. Ji’nan: Shandong Science and Technology, 1999: 13-89.

[55]    Z. F. Guo, J. Q. Liu and X. Y. Chen. Effect of Miocene basaltic volcanism in Shanwang (Shandong Province, China) on environmental changes. Science in China Series D: Earth Sciences, 2007, 50(12): 1823-1827.

[56]    Z. An, J. E. Kutzbach, W. L. Prell and S. C. Porter. Evolution of Asian monsoons and phased uplift of the Himalayan: Tibetan plateau since late Miocene times. Nature, 2001, 411(6833): 62- 66.

[57]    Z. Guo, W. F. Ruddiman, Q. Hao, et al. Onset of Asian desertification by 22 myr ago inferred from loess deposits in China. Nature, 2002, 416(6877): 159-163.

[58]    X. J. Sun, P. X. Wang. How old is the Asian monsoon system? Paleobotanical records from China. Palaeogeography, Palaeoclimatology, Palaeoecology, 2005, 222(3-4): 181-222.

[59]    S. Fauquette, J.-P. Suc, A. Bertini, et al. How much did climate force the Messinian salinity crisis? Quantified climatic conditions from pollen records in the Mediterranean region. Palaeogeography, Palaeoclimatology, Palaeoecology, 2006, 238(1-4): 281-301.

[60]    F. Unger. Sylloge plantarum fossilium. Denkschriften der Kaiserlichen Akademie der Wissenschaften, MathematischNaturwissenschaftlichte Classe, 1864, 22(1): 1-36.

[61]    A. A. Kolakovsky. A second addition to the Pliocene flora of Kodor. Trudy Sukhumskogo Botanicheskogo Sada, 1959, 12: 209-262.

[62]    A. A. Kolakovsky. A Pliocene flora of the Kodor River. Sukhumskiĭ Botanicheskiĭ Sad Monografii 1. Sukhumi: Izdatel’stvo Akademii Nauk Gruzinskoĭ SSR, 1964: 1-220.

[63]    N. K. Pantic. Über die vergesseneen sarmatischen Floren Radoboj und Sused, ihre paläophytogeographische und biostratigraphische Bedeutung. In: J. Kovar-Eder, Ed., Palaeovegetational Development in Europe and Regions Relevant to Its Palaeofloristic Evolution. Vienna: Museum of Natural History Vienna, 1992: 205-210.

[64]    A. K. Shakryl. Leguminosae species from the Tertiary of Abkhazia. In: P. S. Herendeen, D. L. Dilcher, Eds., Advances in Legume Systematics, Part 4: The Fossil Record. Kew: Royal Botanic Gardens, 1992: 189-206.

[65]    D. H. Mai. Tertiäre vegetationsgeschichte Europas. Jena, Stuttgart & New York: Gustav Fischer Verlag, 1995: 1-691.

[66]    J. Kovar-Eder. Vegetation dynamics in Europe during the Neogene. In: J. W. F. Reumer, W. Wessels, Eds., Distribution and Migration of Tertiary Mammals in Eurasia, A Volume in Honour of Hans de Bruijn. Deinsea, 2003, 10: 373-392.

[67]    S. Kohei. K-Ar age of the Arafune Lava and its bearing on age of the Kabutoiwa fossil fauna and flora. Bulletin of Gunma Museum of Natural History, 2007, 11: 53-61.

[68]    M. Pagani, M. A. Arthur and K. H. Freeman. Miocene evolution of atmospheric carbon dioxide. Paleoceanography, 1999, 14(3): 273-292.

[69]    P. N. Pearson, M. R. Palmer. Atmospheric carbon dioxide concentrations over the past 60 million years. Nature, 2000, 406 (6797): 695-699.

[70]    唐自华. Cenozoic warm intervals and their implications for the anthropogenic warming[J]. 第四纪研究, 2011, 31(6): 1053- 1059.

[71]    D. J. Beerling, D. L. Royer. Convergent Cenozoic CO2 history. Nature Geoscience, 2011, 4: 418-420.

[72]    Y. Cui, L. R. Kump, A. J. Ridgwell, et al. Slow release of fossil carbon during the Palaeocene: Eocene thermal maximum. Nature Geoscience, 2011, 4: 481-485.

[73]    S. Vogel. “Sun leaves” and “shade leaves”: Differences in convective heat dissipation. Ecology, 1968, 49(6): 1203-1204.

[74]    S. Vogel. Convective cooling at low airspeeds and the shapes of broad leaves. Journal of Experimental Botany, 1970, 21(66): 91- 101.

[75]    K. J. Niklas. The effect of leaf-lobing on the interception of direct solar radiation. Oecologia, 1989, 80(1): 59-64.

[76]    D. F. Parkhurst, O. L. Loucks. Optimal leaf size in relation to environment. Journal of Ecology, 1972, 60(2): 505-537.

[77]    H. S. Horn. The adaptive geometry of trees. Princeton & New Jersey: Princeton University Press, 1971: 1-146.

[78]    中国科学院植物研究所、南京地质古生物研究所《中国新生代植物》编写组. Fossil plants of China, 3 Cenozoic plants from China[M]. Beijing: Science Press, 1978: 1-232.

[79]    S. X. Guo, Z. K. Zhou. The megafossil legumes from China. In: P. S. Herendeen, D. L. Dilcher, Eds., Advances in Legume Systematics, Part 4: The Fossil Record. Kew: Royal Botanic Gardens, 1992: 207-223.

NOTES

*基金项目:国家自然科学基金项目(40830209)和系统与进化植物学国家重点实验室项目(56176G1044)。

期刊菜单