Comparison of the performance of native and invasive plants of

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Comparison of the performance of native and invasive plants of Senecio vulgairs L.

Dandan Cheng1, *, Viet Thang Nguyen 2,3, Noel Ndihokubwayo 2,4

1 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences,

Wuhan, Hubei, 430074, China

2 School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan, Hubei, 430074,

China

3 Faculty of Biology, Thai Nguyen University of Education, No. 20, Luong Ngoc Quyen Street, Thai

Nguyen City, Vietnam

4 Ecole Normale Supérieure, Département des Sciences Naturelles, Boulevard du 28 Novembre, B.P

6983 Bujumbura, Burundi

* Corresponding author, E-mail:[email protected]

PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.2012v1 | CC-BY 4.0 Open Access | rec: 2 May 2016, publ: 2 May 2016

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Abstract

According to the Evolution of Increased Competitive Ability (EICA) hypothesis and Enemy

Release Hypothesis (ERH), comparing the plants from the same species, individuals from the

invasive range will outperform those from the native range. However, not all recent studies

support the prediction of these two hypotheses. In this study, we sought to test the prediction

by comparing the performance of common groundsel (Senecio vulgaris) taken from native

(Europe) and invasive (China) ranges. Those plants were grown in a greenhouse and in a

common garden, and harvested with various vegetative and reproductive traits measured. We

found that although the plants grown in the common garden grew and reproduced better than

those grown in the greenhouse, the invasive plants outperformed the native plants in relation

to most vegetation parameters (except plant height) and reproduction in both experiments; and

generally, the invasive plants allocated more proportion of biomass to root than the native

plants. However, the proportion of biomass allocated to reproductive organ and relative dry

matter content were the same between the native and invasive plants, no matter among the

plants grown in the greenhouse or in the common garden. Our study partially supported the

predictions of the EICA and ERH and indicated that evolution might have happened to S.

vulgaris invasive to China.

Key words: Evolution of Increased Competitive Ability (EICA) hypothesis, Enemy Release

Hypothesis (ERH), reproductive allocation, root/shoot ratio, dry matter content.


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1. Introduction

Biological invasions are currently one of the most important environmental issues brought by

globalization (Miller et al., 2010) and one of the major threats to biological diversity (Wilcove

et al., 1998). Facilitated by human activities intentionally or unintentionally, the biological

invasions have been the result of species exchanges between many regions throughout the

world (Rejmánek 1996; McKinney & Lockwood 1999; Garcia-Serrano et al., 2007). The

increase in threats caused by invasive species on ecosystems have led to many studies focused

on why some species significantly succeed in new environments where they are not native

(Callaway & Ridenour 2004; van Kleunen et al., 2010; Firn et al., 2011). A number of

hypotheses about invasive mechanism have been put forward from the aspects of the

interactions between plants and the biotic factors in the environments.

The Enemy Release Hypothesis (ERH) postulated that invasive plants benefit from a direct

release from natural enemies resulting in an increase in distribution and abundance (Keane &

Crawley 2002). In the absence of specialist herbivores in introduced ranges, exotic plants are

also less likely to be attacked by generalist herbivores in introduced ranges (Inderjit 2012).

Hence, resources previously allocated to plant defense in the native range might reallocate to

growth or reproduction of the exotic plant, so leading to enhanced competitiveness, as

suggested by the Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey &

Notzold 1995). Moreover, the EICA emphasize that the different reallocation pattern could be

kept when the native and invasive plants of the same species were under identical growing

conditions. These combining of the two hypotheses (ERH/EICA) would improve

understanding of the phenomenon of biological invasions (Joshi & Vrieling 2005; Kambo &

Kotanen 2014).

To test the EICA hypothesis, comparative studies between native and introduced populations

of the same species are useful (McKenney et al., 2007; Handley et al., 2008; Zou et al., 2008;

Turner et al., 2014). The plant performance can be measured by various traits such as dry

biomass and plant height (Blossey & Notzold 1995), growth rate (Daehler 2003; Traveset et

al., 2008), fecundity, survival (Daehler 2003), etc. Studies in line with the EICA found that

invasive species performed better than the invasive ones (Leger & Rice 2003; Wolfe et al.,

2004; Blumenthal & Hufbauer 2007; Caño et al., 2008; Oduor et al., 2011; Turner et al. 2014).

However, some studies found that the performance of invasive plants depends mainly on the

identity of the species (Traveset et al. 2008), and the pattern that invasive species perform

better than the native one in their new ranges is not universal (Parker et al., 2013; Seipel et al.,


4

2015). Therefore, the EICA does not hold for all cases of invasive plant species (van Kleunen

& Schmid 2003; Bossdorf et al., 2004; McKenney et al. 2007). It still remains unanswered

questions related to what attributes make some species more invasive.

Common groundsel (Senecio vulgaris, Asteraceae), a herbaceous plant native to Europe, is

suggested to be of autotetraploid originating from Senecio vernalis (2n = 20) in southern

Europe (Kadereit 1984). Senecio vulgaris can complete its life cycle in a short time, 8 weeks;

and an average of 38300 seeds are produced in each of its generation (Kempen & Graf 1981).

Genetic variability, short generation time, the capacity for large – scale seed production and

rapid germination throughout the year, are all characteristics of successful weed invaders

(Holzmueller & Jose 2009 and references therein). The ingestion of S. vulgaris and other

species of this genus has been implicated as a possible cause of liver toxicity in livestock

(Wiedenfeld 2011), because the plants of S. vulgaris contains high amount of pyrrolizidine

alkaloids which cause liver toxicity in livestock and human beings (Borstel et al., 1989).

Some biotype of S. vulgaris can resist herbicides such as simazine, atrazine (Radosevich &

Devilliers 1976), atrazine, bromacil, pyrazon, buthidazole (Fuerst et al., 1986) and linuron

(Beuret 1989). Therefore, S. vulgaris is considered as a troublesome weed, especially in

horticulture where frequent cultivation occurs (Holt & Lebaron 1990).

Senecio vulgaris, first recorded in China in 19th century, mainly distributes in north – eastern

and south – western China, and may cause great damages to agricultural plants (barley, rape,

strawberry, etc.), fruit trees and lawns in low latitudes in central China (Li & Xie 2002; Xu et

al., 2012). The morphology of S. vulgaris plant is similar to some other Senecio species used

as Chinese traditional medicinal plants, so it could bring high risk to health if they are used as

medicine by mistake (Yang et al., 2011).

In this study, we carried out experiments in a greenhouse and in a common garden with S.

vulgaris plants from the native (Europe) and invasive (China) range. We investigated whether

the hypotheses ERH and EICA can explain the biological invasion of S. vulgaris in China by

comparing the performance between native and invasive S. vulgaris plants under the identical

growing conditions. We addressed the following questions: (1) Do invasive S. vulgaris plants

grow and reproduce better than the native ones? (2) Are there any differences between native

and invasive plants in relation to reproduction and underground/above ground allocation? (3)

Are there any differences between native and invasive plants in relation to dry matter content?


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2. Materials and Methods

2.1. Plant resources

Six native and six invasive populations of S. vulgaris were sampled in Europe and China in

2012 and 2013 (Table 1). Three mother plants were chosen from each population, and the

seeds were collected from the mother plants. The seeds were air – dried and stored at room

temperature in paper bags until sowing. The collected seeds were grown for the second

generation in a climate room, and resulting seeds of the first flower head per plant were used

in the experiment. The maternal effects in S. vulgaris would be strong and influence seeds

germination and plant size (Aarssen & Burton 1990; Figueroa et al., 2010). . We would like to

remove the maternal effects by using the seeds from second generation plants grown in the

climate room, instead of those collected from field.

2.2. Experimental design

We used 24 good seeds for each mother plant in this study. The total of selected seeds was 24

× 12 × 3 = 864. Four seeds of each mother plant were sown in one cell of the 12 cell boxes

(size of one cell: 3.7 × 3.7 × 6 cm) filled with a moistened substrate of coconut peat

(Zhenjiang Jingkou District Green Island Horticultural Development Center, Zhenjiang,

Jiangsu, China) mixed with sand (1:1 by volume). The sowed seeds were moistened every day

by using a small sprayer, and were germinated in a climate chamber (12h dark/12h light at

24oC, relative humidity 80%). The first seedlings appeared two days after seed sowing.

Seedlings emergence was carefully observed and recorded every day. The seedlings were

transferred to the greenhouse at the fourth day after sowing. Then, one week later, seedlings

that had two true leaves were transplanted, each seedling was grown in one pot (8 × 8 × 9 cm)

filled with substrate prepared as described above.

The 0.5 liter pots containing seedlings were randomly put in blocks under a roof of net to

protect them from insects (Figure S1). The seedlings were watered one time within two days.

When plants had 5 – 8 leaves, two groups of seedlings similar in size were formed. To form

each group, 3 plants from each mother plant were chosen (Figure S2). The total plants were

108 and were randomly placed in each group. One group was left in the greenhouse and the

other one was placed in the common garden. The plants were watered 3 times every week.

The plants in the greenhouse were treated with a solution of liquid pesticide Leguo 0.19%

(Lianyungang Dongjin Chemical Co., Ltd., Jiangsu, China) 2 – 3 times per week with a small

sprayer.


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The experiment was conducted from 2nd April to 4th June in 2014. The average daily

temperature of this period was: 21.2oC with a maximum of 32oC on sunny days and minimum

of 11oC during night. The rainfall averaged 156 mm in April, 114 mm in May, and 51 mm in

June; with the total of 31 rainy days, 27 cloudy days and 6 sunny days.

2.3. Plant harvesting and measurement

Plants were harvested individually when each of them had the first matured capitulum, or

when any plants were died because of rain or disease. Various vegetative and reproductive

characters were measured at harvest. We counted the number of leaves and branches of each

plant, measured height (the distance from the base of the stem to the apical meristem of a

plant). Each plant was cut into three parts: (1) stem and leaves, (2) root and (3) capitula. The

stem and root of each plant were separated from its root crown by scissors. The capitula were

separated at their stalks. The fresh weights of the three parts of each plant were separately

measured at harvest by using a scale (AdventureTM OHAUS). The plant samples were dried at

50oC in 2 consecutive days by a heat dry machine and then the dry weight of each samples

were separately measured by another scale (METTLER TOLEDO) due to its high sensitivity

to low weight.

2.4 Data analysis

The vegetative characters analyzed in this study were: height, number of branches and leaves;

fresh and dry weight of shoot, root, and whole plant. The reproductive characters were: the

number of capitula, fresh and dry weight of capitula. The ratio between root fresh/dry weight

and shoot fresh/dry weight were computed to assess how the plants allocated their resources

to biomass of shoot and root. The proportions between capitula fresh/dry weight and whole

plant fresh/dry weight were also calculated to assess how the plants allocated their biomass to

reproductive organ. The dry matter content of the plant was analyzed by using the percentage

of shoot/root dry weight to shoot/root fresh weight.

To check the differences between ranges, populations and mother plants, plant trait

parameters were analyzed with a three – level nested ANOVA with range, population nested

within range, and mother plant nested within population. The nested ANOVA tests were

conducted for plants grown inside the greenhouse and in the common garden, separately.

The data on the vegetative and reproductive characters were analyzed with Principal

component analysis (PCA) to show the differences between plants grown in the greenhouse

and those grown in the common garden. The results of the PCA also showed the differences

between the native and invasive plants grown in the identical conditions.


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All analyses were performed in R version 3.1.2 (R Core Team 2014).

3. Results

3.1. Difference between the greenhouse and common garden experiments

We used Principal component analysis (PCA) to examine the difference between plants

grown in the greenhouse and in the common garden. PC1 explained 51%, PC2 explained 23%

and PC3 explained 9% of the variation in the data. More than 90% of the total variation was

accounted for the first 5 PCs. The plot with PC1 and PC2 and loading plots showed that plants

grown in the two places are different in relation to most performance parameters (Figure 1).

In general, the plants grown in the common garden perform better than those grown in the

greenhouse.

3.2. Greenhouse experiment

Among the plants grown in the greenhouse, the invasive plants were bigger than the native

ones, because the plants from the invasive populations produced more number of branches

and leaves, and more vegetative biomass (fresh/dry weight of shoot, root, and whole plant)

than those from native populations. Actually, of all the vegetative parameters, only height was

not significantly different between the native and invasive plants. Moreover, the invasive

plants had more reproduction output than the native ones in relation to the number and

fresh/dry weight of capitula (Table 2, Figure 1).

The invasive and native plants did not differ in respect of reproductive allocation (the

proportion of biomass allocated to reproductive organs), root/shoot ratio in fresh biomass, and

dry matter content. However, the invasive plants had significantly higher root/shoot ratio in

dry biomass than the native ones (Table 2).

Generally, significant differences were found at the population level but not at the mother

plant level. Plants from each population were different in vegetative parameters (height,

number of branches and leaves, fresh/dry weight of shoot, root and whole plant) and

reproductive output (number of capitula and fresh/dry weight of capitula). However, those

trait parameters did not differ between mother plants within populations (Table 2).

3.3. Common garden experiment

The native and invasive S. vulgaris plants did not differ again in relation to their height. The

number of branches leaves and capitula were not significantly different between the invasive

and native plants as well. However, the invasive plants produced more vegetative and

reproductive biomass than the native ones.


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No significant difference was found between the native and invasive plants in respect of

reproductive allocation or relative dry matter content. However, the invasive plants had

significantly higher root/shoot ratio than the native ones (Table 3).

4. Discussion

Although the plants grown in the common garden performed better than those grown in the

greenhouse, when we compared the native and invasive plants for the two experiments

separately, the trends pattern are the same: higher vegetative, reproductive biomass and

root/shoot ratio was found in invasive plants, and no significant difference were found in

relation to the reproduction allocation and dry matter content.

Generally, biomass is a good parameter to investigate plant performance and competitive

ability of plant (Gaudet & Keddy 1988; Zou et al. 2008). . Hence, increasing of the vegetative

and reproductive biomass in invasive S. vulgaris plants indicates that the invasive plants

performed better and had higher competitive ability than the native plants. Higher vegetative

and reproductive biomasses in invasive populations have been also reported in some previous

studies on Senecio genus. For instance, in the climate room and experimental garden, invasive

populations of S. jacobaea (from North America, Australia, and New Zealand) displayed

significantly higher vegetative and reproductive biomass compared to the native S. jacobaea

populations (from Europe) (Joshi & Vrieling 2005). The invasive genotypes of S. pterophorus

from Spain showed higher dry biomass than those from native range (from South Africa)

(Caño et al. 2008).

The greater root/shoot ratio of the invasive plants suggests that they could probably have

higher potential of regrowth than the native ones. And it also indicated that the invasive plants

could produce more pyrrolizidine alkaloids (PAs), because PAs are known to be produced in

root of S. vulgaris before they are translocated to other parts of a plant (Hartmann et al., 1989;

Sander & Hartmann 1989). Hence, it is predicted that the invasive populations could have

higher potential of regrowth and defense against generalist herbivores compared to the native

ones.

Reproductive allocation (proportion of biomass allocated to reproductive organs) was not

different between ranges in both experiments, suggesting that although the invasive

populations reproduced more vigorous than the native ones, the invasive populations focused

on increasing the competitive ability rather than the reproductive organs. Dry matter content

is considered as a mechanical defense product (Doorduin & Johanna 2012). Hence, dry matter

content of plants is considered as quantitative defense against herbivores. The result shows


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that there was no difference in the quantitative defense between the two origins. This

suggested that there might be no shifting defense evolution happened in invasive S. vulgaris

in China.

The genetic variation happened to S. vulgaris in introduced ranges in relation to habitat type

and population size (Müller-Schärer & Fischer 2001); and S. vulgaris originated from

different habitats also revealed a genetic differentiation among habitats (Leiss & Müller-

Schärer 2001). The species used in the present study, Senecio vulgaris, was first recorded in

China in 19th century (Xu et al. 2012). This long period of time could provide a chance for

natural selection to act on S. vulgaris in the invasive range. The native S. vulgaris also

underwent natural selection in the native range which is different from the natural selection in

the invasive range. In addition, its short life – span in 8 weeks in good conditions (Kempen &

Graf 1981) could bring a good chance for the natural selection with a strong effect on the S.

vulgaris. The difference in natural selection between ranges led to the genetic differentiation

in some characteristics of plants. In our study case, the significant difference in vegetative,

reproductive characters and proportion of biomass allocated to root/shoot among ranges could

be a result of genetic differentiation which may play an important role in the invasion success.

Therefore, it is expected that a possible chance of evolution happened to the invasive

populations of S. vulgaris.

Results of this study are consistent with the predictions of the EICA and ERH, suggesting that

S. vulgaris in China might evolve to grow and reproduce vigorously, which contributes to the

invasion success of S. vulgaris in introduced ranges. Further studies would confirm this by

genetic analysis of the origination of the invasive populations of S. vulgaris in China and the

genetics base of performance, especially of growth of this species. We also plan to investigate

the PA variation and the resistance to herbivories among the native and invasive S. vulgaris.

Acknowledgements

Colleagues are thanked for their help during the experiment carried out at Hubei Academy of

Forestry, Wuhan city, Hubei province, China. Colleagues and students in the School of

Environmental Studies in CUG and Institution of Biology in Leiden University are also

thanked for their help in seed collecting, plant rearing and harvesting plants.


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References

Aarssen L, and Burton S. 1990. Maternal effects at four levels in Senecio vulgaris (Asteraceae)

grown on a soil nutrient gradient. American Journal of Botany 77:1231-1240.

Beuret E. 1989. A new problem of herbicide resistance: Senecio vulgaris L. in carrot crops

treated with linuron. Rev Suisse Vitic Arboric Hortic 21:349-352.

Blossey B, and Notzold R. 1995. Evolution of increased competitive ability in invasive

nonindigenous plants: a hypothesis. Journal of Ecology 83:887-889.

Blumenthal DM, and Hufbauer RA. 2007. Increased plant size in exotic populations: A

common-garden test with 14 invasive species. Ecology 88:2758-2765.

Borstel KV, Witte L, and Hartmann T. 1989. Pyrrolizidine alkaloid patterns in populations of

Senecio vulgaris, S. vernalis and their hybrids. Phytochemistry 28:1635-1638.

Bossdorf O, Prati D, Auge H, and Schmid B. 2004. Reduced competitive ability in an

invasive plant. Ecology Letters 7:346-353.

Callaway RM, and Ridenour WM. 2004. Novel weapons: invasive success and the evolution

of increased competitive ability. Frontiers in Ecology and the Environment 2:436-443.

Caño L, Escarré J, Fleck I, Blanco-Moreno J, and Sans F. 2008. Increased fitness and

plasticity of an invasive species in its introduced range: a study using Senecio

pterophorus. Journal of Ecology 96:468-476.

Daehler CC. 2003. Performance comparisons of co-occurring native and alien invasive plants:

implications for conservation and restoration. Annual Review of Ecology, Evolution,

and Systematics 34:183-211.

Doorduin, and Johanna L. 2012. Rapid evolution or preadaptation in invasive Jacobaea

vulgaris PhD Thesis. Institute of Biology Leiden, Faculty of Science, Leiden

University.

Figueroa R, Herms DA, Cardina J, and Doohan D. 2010. Maternal Environment Effects on

Common Groundsel (Senecio vulgaris) Seed Dormancy. Weed Science 58:160-166.

Firn J, Moore JL, MacDougall AS, Borer ET, Seabloom EW, HilleRisLambers J, Harpole WS,

Cleland EE, Brown CS, and Knops JM. 2011. Abundance of introduced species at

home predicts abundance away in herbaceous communities. Ecology Letters 14:274-

281.

Fuerst EP, Arntzen CJ, Pfister K, and Penner D. 1986. Herbicide cross-resistance in triazine-

resistant biotypes of four species. Weed Science Society of America 34:344-353.

Garcia-Serrano H, Sans F, and Escarre J. 2007. Interspecific competition between alien and

native congeneric species. Acta Oecologica 31:69-78.

Gaudet CL, and Keddy PA. 1988. A comparative approach to predicting competitive ability

from plant traits. Nature 334:242-243.

Handley RJ, Steinger T, Treier UA, and Mueller-Schaerer H. 2008. Testing the evolution of

increased competitive ability (EICA) hypothesis in a novel framework. Ecology

89:407-417.

Hartmann T, Ehmke A, Eilert U, von Borstel K, and Theuring C. 1989. Sites of synthesis,

translocation and accumulation of pyrrolizidine alkaloid N-oxides in Senecio vulgaris

L. Planta 177:98-107.

Holt JS, and Lebaron HM. 1990. Significance and distribution of herbicide resistance. Weed

Technology 4:141-149.

Holzmueller EJ, and Jose S. 2009. Invasive plant conundrum: What makes the aliens so

successful? J Trop Agric 47:18-29.

Inderjit. 2012. Exotic plant invasion in the context of plant defense against herbivores. Plant

Physiol 158:1107-1114.


11

Joshi J, and Vrieling K. 2005. The enemy release and EICA hypothesis revisited:

incorporating the fundamental difference between specialist and generalist herbivores.

Ecology Letters 8:704-714.

Kadereit JW. 1984. The origin of Senecio vulgaris (Asteraceae). Plant Systematics and

Evolution 145:135-153.

Kambo D, and Kotanen PM. 2014. Latitudinal trends in herbivory and performance of an

invasive species, common burdock (Arctium minus). Biological Invasions 16:101-112.

Keane RM, and Crawley MJ. 2002. Exotic plant invasions and the enemy release hypothesis.

Trends Ecol Evol 17:164-170.

Kempen H, and Graf J. 1981. Weed seed production. Proceedings of the Western Society of

Weed Science 34:78-81.

Leger EA, and Rice KJ. 2003. Invasive California poppies (Eschscholzia californica Cham.)

grow larger than native individuals under reduced competition. Ecology Letters 6:257-

264.

Leiss KA, and Müller-Schärer H. 2001. Adaptation of Senecio vulgaris (Asteraceae) to

ruderal and agricultural habitats. American Journal of Botany 88:1593-1599.

Li Z, and Xie Y. 2002. Invasive alien species in China. Beijing: China Forestry Publishing

House 1:54.

McKenney JL, Cripps MG, Price WJ, Hinz HL, and Schwarzländer M. 2007. No difference in

competitive ability between invasive North American and native European Lepidium

draba populations. Plant Ecology 193:293-303.

McKinney ML, and Lockwood JL. 1999. Biotic homogenization: a few winners replacing

many losers in the next mass extinction. Trends Ecol Evol 14:450-453.

Miller TK, Allen CR, Landis WG, and Merchant JW. 2010. Risk assessment: Simultaneously

prioritizing the control of invasive plant species and the conservation of rare plant

species. Biological Conservation 143:2070-2079.

Müller-Schärer H, and Fischer M. 2001. Genetic structure of the annual weed Senecio

vulgaris in relation to habitat type and population size. Molecular Ecology 10:17-28.

Oduor AMO, Lankau RA, Strauss SY, and Gomez JM. 2011. Introduced Brassica nigra

populations exhibit greater growth and herbivore resistance but less tolerance than

native populations in the native range. New Phytologist 191:536-544.

Parker JD, Torchin ME, Hufbauer RA, Lemoine NP, Alba C, Blumenthal DM, Bossdorf O,

Byers JE, Dunn AM, and Heckman RW. 2013. Do invasive species perform better in

their new ranges? Ecology 94:985-994.

R Core Team. 2014. R: A language and environment for statistical computing. Available at

[WWW document] http://www.R-project.org/2014).

Radosevich S, and Devilliers O. 1976. Studies on the mechanism of s-Triazine resistance in

Common Groundsel. Weed Science Society of America 24:229-232.

Rejmánek M. 1996. A theory of seed plant invasiveness: the first sketch. Biological

Conservation 78:171-181.

Sander H, and Hartmann T. 1989. Site of synthesis, metabolism and translocation of

senecionine N-oxide in cultured roots of Senecio erucifolius. Plant cell, tissue and

organ culture 18:19-31.

Seipel T, Alexander JM, Daehler CC, Rew LJ, Edwards PJ, Dar PA, McDougall K, Naylor B,

Parks C, and Pollnac FW. 2015. Performance of the herb Verbascum thapsus along

environmental gradients in its native and non-native ranges. Journal of Biogeography

42:132-143.


http://www.r-project.org/2014)

12

Turner KG, Hufbauer RA, and Rieseberg LH. 2014. Rapid evolution of an invasive weed.

New Phytol 202:309-321.

Traveset A, Brundu G, Carta L, Mprezetou I, Lambdon P, Manca M, Médail F, Moragues E,

Rodríguez-Pérez J, and Siamantziouras A-SD. 2008. Consistent performance of

invasive plant species within and among islands of the Mediterranean basin.

Biological Invasions 10:847-858.

van Kleunen M, Dawson W, Schlaepfer D, Jeschke JM, and Fischer M. 2010. Are invaders

different? A conceptual framework of comparative approaches for assessing

determinants of invasiveness. Ecology Letters 13:947-958.

van Kleunen M, and Schmid B. 2003. No evidence for an evolutionary increased competitive

ability in an invasive plant. Ecology 84:2816-2823.

Wiedenfeld H. 2011. Plants containing pyrrolizidine alkaloids: toxicity and problems. Food

Additives & Contaminants: Part A 28:282-292.

Wilcove DS, Rothstein D, Dubow J, Phillips A, and Losos E. 1998. Quantifying threats to

imperiled species in the United States. BioScience 48:607-615.

Wolfe LM, Elzinga JA, and Biere A. 2004. Increased susceptibility to enemies following

introduction in the invasive plant Silene latifolia. Ecology Letters 7:813-820.

Xu H, Qiang S, Genovesi P, Ding H, Wu J, Meng L, Han Z, Miao J, Hu B, and Guo J. 2012.

An inventory of invasive alien species in China. NeoBiota 15:1-26.

Yang X, Yang L, Xiong A, Li D, and Wang Z. 2011. Authentication of Senecio scandens and

S. vulgaris based on the comprehensive secondary metabolic patterns gained by

UPLC–DAD/ESI-MS. Journal of pharmaceutical and biomedical analysis 56:165-172.

Zou J, Rogers WE, and Siemann E. 2008. Increased competitive ability and herbivory

tolerance in the invasive plant Sapium sebiferum. Biological Invasions 10:291-302.


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Table 1. Information of the locations and collected times for Senecio vulgaris seeds

Range Country Location Coordinates Collected time

Native

Spain Barcelona Lat 41.67 Lon 2.73 06/2012

Switzerland Fribourg Lat 46.79 Lon 7.15 07/2012

The Netherlands Leiden Lat 52.17 Lon 4.48 10/2013

Germany Potsdam Lat 52.40 Lon 13.07 06/2012

Poland Puławy Lat 51.40 Lon 21.96 07/2012

Scotland St. Andrews Lat 56.33 Lon -2.78 05/2012

Invasive China

Fuyuan, Heilongjiang Lat 48.37 Lon 134.28 06/2013

Hegang, Heihongjiang Lat 47.33 Lon 130.30 06/2013

Siping, Jilin Lat 43.17 Lon 124.38 07/2013

Tongjiang, Heihongjiang Lat 47.98 Lon 133.17 06/2013

Yichun, Heihongjiang Lat 47.72 Lon 128.79 07/2013

Lijiang, Yunnan Lat 26.89 Lon 100.23 09/2013


14

Table 2. Results of nested ANONA tests and mean values for the growth and reproductive traits measured on the native and invasive Senecio

vulgaris plants grown in the greenhouse.

F value of source of variation Mean value for each

parameter

Range Population (in range) Mother Plant (in population) Invasive Native

Height (cm) 1.98 ns 4.44*** 1.33 ns 28.38 27.02

Branches 23.48*** 5.03*** 1.37 ns 10.17 6.81

Number of Leaves 24.09*** 5.44*** 0.72 ns 39.20 28.52

Capitula 14.81*** 6.55*** 1.11 ns 44.37 33.13

Capitula 13.55*** 2.41* 0.97 ns 1.20 0.84

Fresh weight Shoot 26.07*** 3.14** 0.56 ns 7.66 5.38

(g) Root 37.75*** 4.11*** 1.03 ns 1.81 1.16

Whole plant 28.70*** 3.46*** 0.59 ns 10.67 7.38

Capitula 17.01*** 2.67** 1.13 ns 0.20 0.13

Dry weight Shoot 36.86*** 4.07*** 0.81 ns 0.70 0.46

(g) Root 43.15*** 4.60*** 0.94 ns 0.13 0.08

Whole plant 34.76*** 3.93*** 0.80 ns 1.03 0.68

Proportion Fresh weight: Capitula/ whole plant 0.53 ns 1.82ns 2.28** 0.11 0.11

Dry weight: Capitula/whole plant 1.46 ns 3.26** 1.75* 0.19 0.18

Ratio Fresh weight: Root/shoot 1.75 ns 1.27 ns 1.14 ns 0.24 0.22

Dry weight: Root/shoot 5.51* 1.44 ns 1.89* 0.19 0.17

Percentage

(%)

Shoot dry weight /shoot fresh weight 0.67 ns 1.69 ns 1.13 ns 9.35 8.96

Root dry weight/root fresh weight 0.01 ns 0.2 ns 0.3 ns 8.16 10.43

Level of significance: *p < 0.05. **p < 0.01. ***p < 0.001; ns: not significant

Degree freedom of source of variation (Df): Range: 1; Population (in range): 10; Mother Plant in population): 24.


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Table 3. Results of nested ANONA tests and mean values for the growth and reproductive parameters of the native and invasive Senecio vulgaris

plants grown in the common garden.

F value of source of variation Mean value for each

parameter

Range Population (in range) Mother Plant (in population) Invasive Native

Height (cm) 0.28 ns 1.94 ns 1.74* 26.11 26.65

Branches 0.32 ns 2.43* 1.06 ns 8.72 9.06

Number of Leaves 3.12 ns 1.67 ns 1.13 ns 28.91 25.93

Capitula 1.24 ns 1.67 ns 1.20 ns 32.35 29.98

Capitula 8.60** 1.75 ns 1.27 ns 1.66 1.34

Fresh weight Shoot 14.16*** 1.52 ns 1.98* 5.45 4.56

(g) Root 31.79*** 3.81*** 1.47 ns 3.06 2.13

Whole plant 22.04*** 2.43* 1.67* 10.17 8.02

Capitula 9.64** 2.28* 1.44 ns 0.34 0.28

Dry weight Shoot 23.34*** 1.69 ns 1.76* 0.89 0.71

(g) Root 57.61*** 3.83*** 1.52 ns 0.33 0.22

Whole plant 26.59*** 2.58** 1.84* 1.54 1.20

Proportion Fresh weight: Capitula/Whole plant 0.09 ns 0.95 ns 1.57 ns 0.16 0.16

Dry weight: Capitula/Whole plant 0.05 ns 1.80 ns 1.42 ns 0.22 0.22

Ratio Fresh weight: Root/shoot 13.06*** 3.21** 1.43 ns 0.57 0.47

Dry weight: Root/shoot 12.82*** 1.95 ns 1.40 ns 0.38 0.31

Percentage

(%)

Shoot dry weight/shoot fresh weight 0.31 ns 1.11 ns 1.14 ns 15.99 15.77

Root dry weight/root fresh weight 0.00006 ns 0.003 ns 0.012 ns 10.92 10.77

Level of significance: *p < 0.05. **p < 0.01. ***p < 0.001; ns: not significant

Degree freedom of source of variation (Df): Range: 1; Population (in range): 10; Mother Plant (in population): 24.


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Figure 1. The scoring and loading plots of the Principle component analysis (PCA) of all variables measured from Senecio vulgaris plants

grown in a greenhouse and common garden. a: Scoring plot with PC1 and PC2; b: loading plot. Empty dots: plants grown in the greenhouse; solid

dots: plants grown in the common garden. red dots: invasive plants; black dots: native plants. Propotion1: biomass of capitula in whole plant by

fresh weight; Propotion2: biomass of capitula in whole plant by dry weight. Ratio1: root/shoot ratio in fresh weight; Ratio2: root/shoot ratio in dry

weight.


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Supplementary Materials

Figure S1. Seedlings prepared for the study


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(A)

(B)

Figure S2. Senecio vulgaris grown in the two different conditions

A: group treated with a solution of liquid pesticide in a greenhouse

B: group grown outside the greenhouse


Documents

Comparison of the performance of native and invasive plants of