Reproductive strategies of alpine plants

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plantes alpines - alpine plants

When environmental conditions are difficult or peculiar, such as in high mountains, plants must adapt to ensure their reproduction. Two main strategies allow alpine plants to persist generation after generation: the maintenance of sexual reproduction or the use of vegetative reproduction. This diversity will be highlighted through several examples of alpine plants that have adapted to their environment.

 

“Alpine” environments are environments which are found above the natural limit of the forest, in the absence of human intervention, in any part of the world: Alps, Andes Cordillera, Himalayas, New Zealand… These cold environments are often characterized by a very short growing season, with few sites suitable for seed establishment, difficult pollination due to the rarity of insects and violent winds as well as high interannual variability of climatic conditions.

Two main strategies allow alpine plants to persist, generation after generation: maintaining sexual reproduction or the use of vegetative reproduction.

1. Sexual reproduction

Sexual reproduction is a source of genetic diversity that allows animal and plant populations to cope with fluctuations in their environment. In plants, it involves the production of flowers, their pollination, the maturation of seeds and their dissemination and germination, all of which are often hazardous stages in alpine areas. Several strategies can be used to overcome environmental constraints.

1.1. Long life

The Alpine flora has less than 2% of annual alpine plantsPlants that complete their life cycle over a year. [1] (Figure 1) which depend exclusively on the success of sexual reproduction and therefore on the environment. Even if seeds are produced on time, they require new sites for germination, often limited due to the presence of bedrock (rocky areas, screes) and the presence of other species. On the contrary, perennial species can wait for favourable conditions to reproduce (Figure 2). In contrast, in arid and Mediterranean alpine biotopesLiving places with relatively uniform determined physical and chemical characteristics. This environment is home to a set of life forms that make up biocenosis: flora, fauna, micro-organisms. The biotope and the biocenosis it supports form an ecosystem., annual plants are more widespread [2]. The seeds then represent a form of resistance.

Encyclopedie environnement - plantes alpines - plantes vivaces d'altitude - Androsace helvetica - alpine plants
Figure 2. Androsace helvetica All., Primulaceae, is an example of a perennial alpine plant living in an environment without annual species, here at 2800 m altitude, in shale rocks of the Galibier Pass. [Photo © Joseph Fourier Alpine Station/Serge Aubert]
Encyclopedie environnement - plantes alpines - plantes alpines annuelles - alpine plants
Figure 1. Two examples of annual alpine plants. On the left: the winter gentian (Gentiana nivalis L., Gentianaceae). Right: Mucizonia sedoides DC, a Crassulaceae growing in the snowy valleys of the Pyrenees. [Photos © Joseph Fourier Alpine Station/Serge Aubert]
 

 

1.2. Spread reproduction over several years

Encyclopedie environnement - plantes alpines - preformation bourgeons floraux - alpine plants
Figure 3. Examples of alpine plants pre-forming their flower buds in advance. Left: Glacier buttercup (Ranunculus glacialis L., Ranunculaceae. [Photo © Joseph Fourier Alpine Station/Serge Aubert); right: alpine rose (Rhododendron ferrugineum L., Ericaceae; Photo © Irène Till-Bottraud)]
Some species spread seed maturation over several years, or preform flowers in the year before flowering. This allows the flowers to bloom as soon as conditions are favourable. This is the case, for example, of the glacier buttercup (Figure 3), a species that breaks altitude records in the Alps (up to more than 4000 m in Switzerland) and the alpine rose (Figure 3), whose large autumn buds contain all the flowers, allowing it to flower as soon as the snow melts.

1.3. Increase flowering time

Encyclopedie environnement - plantes alpines - Chaetantherapusilla - alpine plants
Figure 4. Chaetanthera pusilla (Asteraceae) an annual plant growing between 2200 and 3500 m above sea level in the Andes. [Photo © Irène Till-Bottraud]
In mountains species, flowering period and blooming duration increases with altitude, which compensates for the relative rarity of pollinators. For example, the annual plant Chaetanthera pusilla (Figure 4), which grows between 2200 and 3500 m above sea level in the Andes, produces many inflorescencesGrouping flowers on the same base. that open one after the other. In addition, each flower head is receptiveCharacterizes the state of a flower or inflorescence likely to be fertilized by pollen from outside. almost twice longer at high altitude than at low altitude: from 7.7 days at 2700 m to 13.4 days at 3500 m [2].

1.4. Playing with colour?

Flowers are said to be more colourful at higher elevations to attract pollinators more effectively (Figure 5). In fact, there is no significant increase in colour, size or other characteristics associated with insect attraction [3]. The mountains of New Zealand are a remarkable example: the vast majority of species have white flowers (Figure 6).

Encyclopedie environnement - plantes alpines - plantes montagnes néo-zelandaises - new zealand mountains
Figure 6. In the New Zealand mountains, white is the dominant colour. From left to right, Raoulia grandiflora Hook. (Asteraceae), Ourisia macrophylla Hook. (Scrophulariaceae), Myosotis pulvinaris Hook. (Boraginaceae). [Photos © Joseph Fourier Alpine Station/Serge Aubert]
Encyclopédie environnement - plantes alpines - floraisons multicolores - alpine plants - colors plants moutains
Figure 5. The multicoloured blooms of plants originating from the Caucasus (here at the Lautaret Alpine Botanical Garden) should not suggest that alpine plants are more colourful than those living in lowlands. [Photo © Joseph Fourier Alpine Station/Serge Aubert]
 

 

 

 

 

 

2. Conquering the territory: vegetative reproduction

To avoid the hazards of sexual reproduction, many alpine plants use vegetative reproductionMode of multiplication allowing plant organisms to multiply without sexual reproduction. It generates new individuals with the same genome and which are therefore clones, we also speak of clonal reproduction.. This is not a specificity of mountain plants; however, the proportion of alpine plants using this reproductive strategy increases with altitude [1]. All vegetative reproduction modes are present in alpine plants: production of rhizomesAn underground stem that carries leaf and root buds. A rhizome can be horizontal and more or less close to the surface, such as the iris, or much deeper, such as the bindweed. or stolonsA creeping stem from the base of the main stem of a plant with leaf and root buds that will become a new plant. This is the case with strawberries formed by the development of an underground bud, the drageon allows a natural propagation of the plant which will thus be reproduced in the same way., formation of dense tufts, stuckers, reproduction by layeringRoots development on a buried branch that allows the production of a new individual. but also viviparityMode of reproduction where seed germination occurs while they are still in the fruit attached to the mother plant. and apomixisProduction of seeds identical to the mother plant without fertilization. Apomixis transmits somatic mutations (mutations occurring in a non-germinal cell), thus allowing the creation of diversity..

2.1. Rhizomes and stolons

Encyclopédie environnement - plantes alpines - reproduction sexuée et clonale - sexual reproduction plants
Figure 7. Sexual and clonal reproduction in the creeping avens (Geum reptans L., Rosaceae). The plant has many flowers, which allows sexual reproduction. Clonal reproduction is ensured by aerial runners (stolons, S) which allow the plant to colonize shale scree (here in Galibier, at an altitude of 2800 m). A ramet (1) is developing at the end of the stolon produced by the initial individual (i). [Photos © Joseph Fourier Alpine Station/Serge Aubert]
They allow to explore the surroundings, for example to settle between the stones of the screes. Figure 7 presents the example of the creeping avens which uses clonal reproduction by aerial runners, which will explore shale screes and produce rametsNatural or artificial clones of a plant multiplied by cuttings. (see Figure 7) that settle between the stones and individualize from the mother plant once the runner is destroyed.

2.2. Stuckers, tufts and layering

Encyclopedie environnement - plantes alpines - Plantes en touffe - tufted plants
Figure 8. Tufted plants. On the left,ciliate bellflower of Mont Cenis, (Campanula cenesia L., Campanulaceae), a rare alpine plant growing in the schists and gypsums of the Col du Galibier (altitude: 2600 m). Right: Alpine sedge (Carex curvula All., Cyperaceae), it dominates in many lawns in the mountains of temperate Europe. [Source: Photo © Joseph Fourier Alpine Station/Serge Aubert]
These types of vegetative reproduction allow a dense space occupancy which has two important consequences on alpine ecosystems: the stabilization of steep soils and the creation of a favourable microclimate in terms of both temperature and humidity. For example, the ciliate bellflower, which forms a compact, slow-growing tuft, is an example of a plant that reproduces by suckering (Figure 8).

Encyclopedie environnement - plantes alpines - marcottage - alpine plants
Figure 9. Example of layering in thyme-leaved willow (Salix serpyllifolia Scop., Salicaceae). [Source: Photo © Joseph Fourier Alpine Station/Serge Aubert]
The Alpine sedge (Figure 8) is an example of a tussock plant. It dominates in many lawns in the mountains of temperate Europe. Recent studies using genotyping methodsLaboratory techniques, such as whole genome sequencing, that classify and compare sequences. (see “DNA Barcode“) have confirmed the genetic similarity of ramets present within the same tuft. Based on an average annual increase of 0.4 mm per year, the age of a clone with 7000 ramets has been estimated at about 2000 years [4]!

In the case of layering, rooting occurs when branches come in contact with the soil as shown in Figure 9 in the thyme-leaved willow. Short bushes of alpine rose (rhododendron moors) or willows can shelter several genets (genetic individuals), each made up of dozens of ramets, all forming a somewhat impenetrable canopy. Only a genetic analysis can allow to distinguish the different genets.

Encyclopedie environnement - plantes alpines - Inflorescence de la renouee vivipare
Figure 10. Inflorescence of the the ‎alpine bistort (Polygonum viviparum L., Polygonaceae) showing sexually reproducing flowers (upper part, 1) and bulbils produced by asexual reproduction (lower part, 2). [Source: Photo © Joseph Fourier Alpine Station/Serge Aubert]

2.3. Viviparity

Viviparity, for example through the production of bulbils that begin to develop on the mother plant, and apomixis ensure dispersion over greater distances. Figure 10 shows the inflorescence of the ‎alpine bistort (Polygonum viviparum L., Polygonaceae), illustrating the combination on the same floral stem of sexually reproducing flowers and bulbils produced by asexual reproduction. Since the stem length available for flowers and bulbils is constant, the proportion of bulbils increases with altitude and latitude. In other words, clonal reproduction is more important when living conditions become more difficult [1].

3. How do plants deal with environmental change?

With their multiple modes of reproduction, alpine plants are adapted to their environment. These modes of reproduction are very effective both for the stability of the environment and for the maintenance of genetic diversity. This genetic diversity may be an opportunity for the alpine flora, which is currently facing major climate change, with a temperature increase expected during this century ranging from 2 to 8°C. This warming, which is very rapid compared to temperature fluctuations during the alternating series of glacial and interglacial periods, will lead to an upslope displacement of vegetation belts and will reduce the sites favourable to alpine flora.

 


References and notes

Cover image. The Meige massif seen from the Lautaret Alpine Garden [Source: © Photo Joseph Fourier Alpine Station/Serge Aubert]

[1] Körner C (1999) Alpine plant life, Functional plant ecology of high mountain ecosystems. Springer-Verlag Publishing

[2] Arroyo MTK et al (1998) The flora of Llullaillaco National Park located in the transitional winter-summer rainfall area of the northern Chilean Andes. Gayana Botanica 55:93-110

[3] Totland Ø et al (2005) Abstract No. 13.10.2. 17th International Botanical Congress, Vienna

[4] Steinger T, Körner C & Schmid B (1996) Long-term persistence in a changing climate: DNA analysis suggests very old ages of clones of alpine Carex curvula. Oecologia 105:307-324

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The Encyclopedia of the Environment by the Association des Encyclopédies de l'Environnement et de l'Énergie (www.a3e.fr), contractually linked to the University of Grenoble Alpes and Grenoble INP, and sponsored by the French Academy of Sciences.

To cite this article: TILL-BOTTRAUD Irène, AUBERT† Serge, DOUZET Rolland (March 9, 2019), Reproductive strategies of alpine plants, Encyclopedia of the Environment, Accessed December 9, 2024 [online ISSN 2555-0950] url : https://www.encyclopedie-environnement.org/en/life/reproductive-strategies-of-alpine-plants/.

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高山植物的繁殖策略

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plantes alpines - alpine plants

  在恶劣的自然环境条件下或者处于类似于高山这种特殊环境中,植物必须适应其所处的环境以确保繁衍后代。植物主要采取两种策略,一代又一代坚守在这里:维持有性生殖或者采用营养生殖。本文以几个适应高山环境的植物为例来展示它们繁殖策略的多样性。

  “高山”环境是指地球上所有海拔超过自然林线、人类干扰很少的地方,它们分布在阿尔卑斯山、安第斯山脉、喜马拉雅山、新西兰……。在这些寒冷的环境里的主要特点是生长季非常短暂,适合种子生存的地点很少,且由于传粉昆虫稀少、盛行强风、气候年际变化大,导致授粉困难。
高山植主要物通过两种策略,一代又一代坚守在这里:保持有性生殖的方式或者采取营养生殖的方式。

1. 有性生殖

  有性生殖是动植物应对环境波动所需的遗传多样性的来源之一。植物的有性生殖包括开花、传粉、种子的形成与散布、萌发等多个阶段,在高山环境中每个阶段都危机四伏,植物可以采取多种策略克服高山环境的限制。

1.1.长寿命

  高山植物区系中一年生植物(完成其生命周期需要一年时间的植物)所占比例不足 2%[1](图 1),一年生植物完全依赖于有性生殖,因而也受制于自然环境。即使能即使产生种子,它们也需要新的萌发地点,但由于基岩(岩石区域、碎石坡)和其他物种的存在,这些地点通常是有限的。相反,多年生植物有时间等待有利于繁殖的条件(图 2)。但在干旱和地中海高山群落生境(具有相对均匀确定的物理和化学特征的生存场所。这个环境是一组生命形式的栖息地,包括植物群、动物群、微生物群。生物群落和它所支持的生物群形成一个生态系统。)中,一年生植物分布更为广泛[2],在这里种子代表着一种抗性。

环境百科全书-高山植物的繁殖策略-植物图1
图1. 两种典型的一年生植物。左边为一种龙胆科龙胆属植物(Gentiana nivalis);右边为一种生长在比利牛斯山脉多雪的山谷中的景天科植物(Mucizonia sedoides)。 [照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]
环境百科全书-高山植物的繁殖-图2
图2. 一种报春花科点地梅属(Androsace helvetica)多年生高山植物,生活在没有一年生植物的环境中,照片地点海拔2800 m,位于加利比尔山口(Galibier Pass)的页岩上。 [照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]
 

 

 

 

 

 

1.2.几年扩散繁殖期

环境百科全书-高山植物的繁殖-图3
图3. 高山植物提前形成花芽的例子。左图:毛茛科高山毛茛属冰川毛茛(Ranunculus glacialis) [照片© 约瑟夫-傅里叶高山站/谢尔盖-奥博特];右图:杜鹃科高山玫瑰杜鹃(Rhododendron ferrugineum);(照片由©艾琳·蒂尔·博特劳德惠赐)。

        有一些植物的扩散种子成熟期跨越几年时间,也有一些植物在开花的前一年先形成花序,这样可以保证一旦环境条件满足开花的要求就可以立即开花。例如冰川毛茛(图 3),这个物种打破了阿尔卑斯山的海拔记录(分布在海拔超过 4000米 的瑞士境内),又如高山玫瑰杜鹃(图 3),它们在秋季形成大量花蕾,包含所有花朵,春天雪一融化就能开花。

1.3. 延长开花期

环境百科全书=高山植物的繁殖-图4
图4. 生长在安第斯山脉海拔2200-3500 米的一种菊科寒绒菊属一年生植物Chaetanthera pusilla。 [照片由©艾琳·蒂尔·博特劳德惠赐]。

        在山地物种中,开花期和花期持续时间随着海拔的增加而延长,这可以弥补传粉媒介的相对稀缺。例如, 生长在安第斯山脉海拔 2200-3500米 的一年生植物Chaetanthera pusilla(图 4)会产生很多花序(在同一基部上聚集花朵),上面的花朵次第开放。同时,花序上的每一朵花能接受外来花粉(描述了一朵花或花序可能受到外部花粉受精的状态。)的时间高海拔地区是处低海拔地区的约 2 倍:2700 米 处约为 7.7 天,3500 米 处约为 13.4 天 [2]

1.4. 运用颜色更艳丽?

  据说海拔越高的地方花的颜色更鲜艳,以便更有效地吸引传粉者(图5)。事实上,花朵的色泽、大小或者与吸引昆虫相关的其他特征都没有随着海拔升高而更显著[3]。新西兰的山地就是一个典型的例子:绝大多数的植物的花朵都是白色的(图6)。

环境百科全书-高山植物的繁殖-图5
图5. 高加索地区植物的花朵五彩缤纷(图为劳累特高山植物园,Lautaret Alpine Botanical Garden),这不意味着高海拔地区的植物比低海拔地区植物花朵更加艳丽。[照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]
环境百科全书-高山植物的繁殖-图6
图6. 在新西兰山地,白色是主要颜色。从左到右依次为菊科植物Raoulia grandiflora Hook.,玄参科植物Ourisia macrophylla Hook.和紫草科Myosotis pulvinaris Hook.。[照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]
 

 

 

 

 

2. 征服领土:营养繁殖

       为了避免依赖有性生殖的风险,许多高山植物采取营养繁殖(植物生物体在无需性繁殖的情况下繁殖的方式。这种方式产生具有相同基因组的新个体,因此它们是克隆体,也称为克隆繁殖。)的方式。营养繁殖不是山地植物特有的繁殖方式,但是随着海拔升高采用营养繁殖的植物比例增加[1]。所有的营养生殖模式都存在高山植物中可以找到所有营养繁殖的类型:产生根状茎(一个地下的茎,带有叶芽和根芽。块茎可以是水平的,或多或少接近地表,比如鸢尾花,也可以更深,比如旋花。)或匍匐茎(从植物主茎的基部蔓延出来的一种匍匐茎,带有叶芽和根芽,将成为一个新的植物。草莓就是这种情况,它通过地下芽的发育形成,草莓芽可以自然繁殖植株,使其以相同的方式进行繁殖。),形成密集的丛生状或根出条,或通过被埋压(这是指在埋藏的树枝上生长出根系,从而产生一个新个体的过程。)、胎生(这种繁殖方式指的是种子在仍然附着在母体植物上的果实内发芽的情况。) 或无融合生殖(这种无需受精就能产生与母本植物相同的种子的繁殖方式称为”无性繁殖”。无性繁殖通过孢子发育而非种子发育,因此新个体与母本植物基本相同。无性繁殖可以传递体细胞突变,即非生殖细胞中发生的突变,因此可以创造出多样性。)等方式繁殖。

2.1. 根状茎和匍匐茎

环境百科全书-高山植物的繁殖-图7
图7. 蔷薇科植物Geum reptans L.的有性生殖和克隆繁殖。这种植物大量开花,能完成有性生殖;同时还通过地表匍匐茎进行克隆繁殖生殖,使其能定植到页岩碎屑上(摄于Galibier海拔2800 米处)。克隆分株(图中1所指示的地方)由实生苗(i指示)产生的匍匐茎的末端发育形成。[照片 © 约瑟夫-傅里叶高山站/谢尔盖-奥博特]

  根状茎和匍匐茎能帮助植物开发利用周围的空间,例如在碎屑堆的石块间生存。如图 7 所示,一种路边青属植物利用匍匐茎进行克隆繁殖,使其到达碎屑堆上,并产生无性系分株(植物的天然或人工克隆体,通过插枝繁殖而成。见图 7),在石块间定植。一旦匍匐茎遭到破坏,它们就会与母株分离,形成独立的个体。

2.2. 根出条、丛生型、压条型

环境百科全书-高山植物的繁殖-图8
图 8. 丛生植物。左图为塞尼斯山(Mont Cenis)的桔梗科风铃草属植物纤毛风铃草(Campanula cenesia L.),高山稀有植物,生长在Galibier山区的片岩和石膏岩中(海拔2600 米)。右图:莎草科植物弯叶莎草(Carex curvula All.),是很多欧洲温带山区草地的优势种。[来源: 照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]

  这些类型的营养繁殖使得植物能够占据密集的空间,对高山生态系统有两个重要的影响。:稳定陡峭的边坡土壤、形成适宜的温湿度微环境。纤毛风铃草就是一个典型例子,它通过根出条形成了一丛丛生长缓慢的紧凑植株(图8)。

环境百科全书-高山植物的繁殖-图9
图9. 杨柳科植物柳属植物百里香叶柳的例子(Salix serpyllifolia Scop.)压条繁殖[来源:照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]

  弯叶莎草(图 8)是一种典型的丛生植物,它是很多欧洲温带山区草地的优势种。最近的研究采用基因分型技术(实验室技术,比如全基因组测序,用于分类和比较基因序列。见“DNA 条形码” 一文)证实同一克隆上各个分株间基因型是相似的。弯叶莎草克隆平均每年增长0.4 毫米,由此推算,一个拥有 7000 个分株的克隆年龄约为 2000 年[4]!
关于压条型营养繁殖,如图 9 所示,百里香叶柳,其枝条与土壤接触处会生根。高山玫瑰杜鹃(杜鹃花属)或百里香叶柳等矮灌丛往往有由多个基株(遗传学上的个体)组成, 每个基株包括几十个分株,形成了一个难以穿透的冠层,只有通过基因型分析才能区分每个基株。

2.3. 胎生

       胎生,例如通过在母本植物上开始发育的鳞茎芽的产生,以及无性生殖确保了更远距离的散布。如图 10 所示,廖科植物珠芽蓼的同一个花序上同时存在有性繁殖的花和无性繁殖产生的珠芽。由于花梗的长度恒定,珠芽部分所占比例随着海拔和纬度的增加而增加,也就是说,无性繁殖的重要性随着环境的恶劣程度增加而增大[1]

环境百科全书=高山植物的繁殖-图10
图10. 蓼科植物珠芽蓼(Polygonum viviparum L.),图中显示了有性繁殖的花(上部分,1)和无性繁殖产生的珠芽(下部分,2)。 [来源:照片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]

3. 植物如何适应环境变化?

       高山植物通过多种繁殖方式适应环境,多样的繁殖方式也是维持高山环境稳定和遗传多样性的有效机制。这种遗传多样性可能给高山植物提供了机会。目前高山植物区系正面临着严峻的气候变化,预计到本世纪内高山地区气温将上升 2-8 ℃,升温速度超过地质历史时期冰川、间冰期交替时温度波动的速度。温度的升高将促使植被带向上迁移,使适宜高山植物区系的环境萎缩。


参考文献和注释

封面图片. 从劳塔雷特高山植物园(Lautaret Alpine Garden)看到的梅格(Meige)群山[来源:图片由©约瑟夫-傅里叶高山站/谢尔盖-奥博特惠赐]

[1] Körner C (1999) Alpine plant life, Functional plant ecology of high mountain ecosystems. Springer-Verlag Publishing

[2] Arroyo MTK et al (1998) The flora of Llullaillaco National Park located in the transitional winter-summer rainfall area of the northern Chilean Andes. Gayana Botanica 55:93-110

[3] Totland Ø et al (2005) Abstract No. 13.10.2. 17th International Botanical Congress, Vienna

[4] Steinger T, Körner C & Schmid B (1996) Long-term persistence in a changing climate: DNA analysis suggests very old ages of clones of alpine Carex curvula. Oecologia 105:307-324

 


The Encyclopedia of the Environment by the Association des Encyclopédies de l'Environnement et de l'Énergie (www.a3e.fr), contractually linked to the University of Grenoble Alpes and Grenoble INP, and sponsored by the French Academy of Sciences.

To cite this article: TILL-BOTTRAUD Irène, AUBERT† Serge, DOUZET Rolland (March 14, 2024), 高山植物的繁殖策略, Encyclopedia of the Environment, Accessed December 9, 2024 [online ISSN 2555-0950] url : https://www.encyclopedie-environnement.org/zh/vivant-zh/reproductive-strategies-of-alpine-plants/.

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