Altissima Populations Research Articles

Inventarizácia invázneho druhu pajaseňa žliazkatého (Ailanthus altissima) v urbánnom prostredí – prípadová štúdia

Tree of heaven [Ailanthus altissima (Mill.) Swingle] (family Simaroubaceae) is known as an invasive woody species in urban, rural, and natural ecosystems in many parts of the world. In Slovakia, it is accepted as an invasive species included in the list of invasive alien species of the EU concern (Regulation No. 2019/1262). In this study, the spread of the invasive neophyte A. altissima populations was monitored in the immediate vicinity (1 km) of the Slovak University of Agriculture in Nitra in southwestern Slovakia in 2022. We recorded habitat type, GPS coordinates in the centre of the local populations, area of population (m2), average tree height (m), and management measures. The species colonized an area of 1,997 m2. The plant spread mainly in the habitat of extensively cultivated fields such as front gardens of buildings (31%) and in abandoned and unused areas (the species occupied 28% of the total area). We recorded a lower occurrence in the botanical garden (18%), next to the anti-flood dam (16%), along roads (4%) and in the orchard (3%). Approximately 15% (28 shoots) of the total number of 183 shoots were female plants that formed a high number of seeds. There was a high correlation between the area occupied by A. altissima with its above-ground organs and the average plant height (m) (r = 0.88).

Cytogeography of Naturalized Solidago canadensis Populations in Europe.

Autopolyploidization has driven the successful invasion of Solidago canadensis in East Asia. However, it was believed that only diploid S. canadensis invaded Europe, whereas polyploids never did. Here, molecular identification, ploidy level, and morphological traits of ten S. canadensis populations collected in Europe were compared with previously identified S. canadensis populations from other continents and S. altissima populations. Furthermore, the ploidy-driven geographical differentiation pattern of S. canadensis in different continents was investigated. All ten European populations were identified as S. canadensis with five diploid and five hexaploid populations. Significant differences in morphological traits existed among diploids and polyploids (tetraploids and hexaploids), rather than between polyploids from different introduced ranges and between S. altissima and polyploidy S. canadensis. The invasive hexaploids and diploids had few differences in latitudinal distributions in Europe, which was similar to the native range but different from a distinct climate-niche differentiation in Asia. This may be attributed to the bigger difference in climate between Asia and Europe and North America. The morphological and molecular evidences proved the invasion of polyploid S. canadensis in Europe and suggest that S. altissima may be merged into a complex of S. canadensis species. Our study may be concluded that geographical and ecological niche differentiation of an invasive plant driven by ploidy depends on the degree of difference in the environmental factors between the introduced and native range, which provides new insight into the invasive mechanism.

Genome survey sequencing of Ailanthus altissima and identification of simple sequence repeat (SSR) markers

Abstract Ailanthus altissima is a deciduous tree native to China and introduced to other parts of the world as an ornamental plant. It exhibits resistance to both abiotic and biotic stress factors and has various pharmacological effects and strong allelopathy, generating significant research interests. However, the genome sequence of this species has not been reported, limiting its research development. The purpose of the study was to determine the genome size and characteristics of A. altissima to conduct its genomic survey. Next-generation sequencing and K-mer analysis were employed to measure the genome size of A. altissima. Overall, a total of 61.93 Gb high-quality clean data were acquired, representing approximately 64.09× coverage of the A. altissima genome. The genomic characteristics of A. altissima include a genome size of 966.38 Mbp, a heterozygosis rate of 0.78 %, and a repeat rate of 41.22 %. A total of 735,179 genomic SSRs markers were identified based on genome survey sequences. Alignment analysis showed that A. altissima was closely related to Citrus sinensis and Leitneria florida-na. This study provides basic information for future whole-genomic sequencing of A. altissima. This will facilitate a knowledge of the population structure, genetic diversity, long distance-gene transfer, and pollen-based gene flow analyses of A. altissima populations from its known distribution ranges in China, focusing on planted and natural forest stands.

Transcriptome sequencing and microsatellite marker discovery in Ailanthus altissima (Mill.) Swingle (Simaroubaceae).

Ailanthus altissima Swingle, is a tree species native to East Asia and has a great potential in decorative, bioenergy and industrial applications in many countries. To date, despite its commercial importance, the genomic and genetic resources available for this species are still insufficient. In this study, we characterized the transcriptome of A. altissima and developed thirteen EST-SSRs (expressed sequence tag-simple sequence repeats) based on Illumina paired-end RNA sequencing (RNA-seq). Besides, we developed ten polymorphic chloroplast microsatellite (cpSSR) markers using the available chloroplast genome of A. altissima. The transcriptome data produced 87,797 unigenes, of which 64,891 (73.91%) unigenes were successfully annotated in at least one protein database. For cpSSR markers the number of detected alleles (N) per marker varied from three at cpSSR12 to twelve at cpSSR8, the unbiased haploid diversity indices (uh) varied from 0.111 to 0.485, and haploid diversity indices (h) ranged from 0.101 to 0.444 with an average unbiased haploid diversity index (uh) of 0.274. Overall, a total of 65 different cpSSR alleles were identified at the ten loci among 165 individuals of A. altissima. The allele number per locus for EST-SSRs varied from 2.143 to 9.357, and the values of observed and expected heterozygosity ranged from 0.312 to 1.000 and 0.505 to 0.826, respectively. The molecular markers developed in this study will facilitate future genetic diversity, population structure, long distance-gene transfer and pollen-based gene flow analyses of A. altissima populations from its known distribution ranges in China focusing on planted and natural forest stands.

Spatial distribution and interspecific association patterns between Mansonia altissima A. Chev., Ceiba pentandra (L.) Gaertn and Triplochiton scleroxylon K. Schum. in a moist semi-deciduous forest

Mansonia altissima A. Chev. has an aggregated distribution at the juvenile life stage that becomes random at the mature life stage. Ceiba pentandra (L.) Gaertn could play the role of nurse plant in the management of M. altissima populations providing them a moderate forest shade in large gaps for early growth. M. altissima and Triplochiton scleroxylon K. Schum. displayed independent distribution patterns. M. altissima is a species with economic value found in moist semi-deciduous forests of tropical Africa. The analysis of spatial distribution patterns can help to understand the ecology of this species in forest stands dominated by emergent pioneer tree species like C. pentandra and T. scleroxylon. To assess the spatial distribution patterns of M. altissima and spatial relationships with C. pentandra and T. scleroxylon in their natural habitat. We investigated the spatial patterns of the three species during three life stages; juvenile (immature trees), premature (trees with minimum flowering diameter) and mature (trees with minimum fruiting diameter). Diameter at breast height (DBH) was measured and geographical coordinates of trees were recorded within ten one-ha plots, divided into sixteen subplots (625 m2). We computed the L(r) function, normalized from Ripley’s K(r) function to detect aggregated, random or regular distribution patterns. Aggregations were detected in juvenile and premature M. altissima. Size and scales of spatial aggregation were inversely proportional to the DBH size. M. altissima and C. pentandra displayed interspecific association patterns at the similar life stages. Both species were positively associated within a radius ≥ 3 m. No positive association was detected between M. altissima and T. scleroxylon. Interspecific association patterns between M. altissima and C. pentandra suggest that C. pentandra could be used as a nurse tree in reforestation and management practices of M. altissima populations.

Evolutionary and environmental effects on the geographical adaptation of herbivory resistance in native and introduced Solidago altissima populations

To understand rapid evolution in plant resistance to herbivory, it is critical to determine how the genetic correlation among resistances varies genetically and/or environmentally. We conducted a reciprocal transplant experiment of tall goldenrod, Solidago altissima with multiple replicates within the native range (USA) and the introduced range (Japan) to explore the differences in phenotypic traits of resistance to multiple herbivorous insects and their relationships between and within the countries. The Japanese plants were more resistant to the lace bug, Corythucha marmorata, which had recently invaded Japan, but were more susceptible to other herbivorous insects compared to the USA plants. An antagonistic relationship was found between plant resistances to lace bugs and other herbivorous insects in both USA and Japanese plants. In addition, this relationship was more obvious in gardens with a high level of foliage damage than in gardens with a low level of foliage damage by other herbivorous insects. An antagonistic relationship between resistances to aphids and lace bugs was also observed in USA gardens, but not in Japanese garden. These results suggest that the strength of constraints on the evolution of plant resistance due to genetic trade-offs may differ among biotic environments, including community structure of herbivorous insects. Therefore, differences in herbivorous insect communities between the native and introduced ranges can result in the rapid evolution of greater resistance in plants in the introduced range than in the native range.

Multiple and mass introductions from limited origins: genetic diversity and structure of Solidago altissima in the native and invaded range.

Understanding the origins and diversity of invasive species can reveal introduction and invasion pathways, and inform an effective management of invasive species. Tall goldenrod, Solidago altissima, is a herbaceous perennial plant native to North America and it has become a widespread invasive weed in East Asian countries. We used microsatellite and chloroplast DNA markers to obtain information on neutral processes and on genetic diversity in native and invaded populations of S. altissima and to infer how it invaded and spread in Japan. We found that introduced (n = 12) and native (n = 20) populations had similar levels of genetic diversity at nuclear SSR loci. Genetic structure analysis indicated that at least two independent colonization events gave rise to current S. altissima populations in Japan. The majority (68%) of the Japanese S. altissima were genetically similar and likely shared a common origin from a single or a small number of populations from the southern USA populations, while the populations in Hokkaido were suggested to arise from a different source. Our results suggest that multiple and mass introductions have contributed to the persistence and rapid adaptation of S. altissima promoting its widespread establishment throughout Japan.

Genetic structure of the introduced heaven tree (Ailanthus altissima) in Japan: evidence for two distinct origins with limited admixture

The heaven tree, Ailanthus altissima (Mill.) Swingle, was intentionally introduced from China to many temperate areas globally, where it has become successfully established. Here, we investigated the patterns of genetic differentiation between introduced Japanese A. altissima populations using both plastid and nuclear microsatellite markers. Three hundred and eighty-eight trees were sampled from six planted and 12 naturalized populations. Two distinct chloroplastic haplotypes were observed, which allowed us to separate two groups of trees, H1 and H3, containing 128 and 260 trees, respectively. Nine nuclear genetic microsatellites revealed 17.7 alleles per locus on average. These data did not indicate significant isolation-by-distance. Analysis of molecular variance showed the absence of genetic differentiation between the planted and naturalized populations. In contrast, the two groups defined according to the chloroplastic haplotypes (H1 and H3) were differentiated. STRUCTURE analysis showed that, within each haplotype group, most trees were strictly assigned to one cluster, with the exception of a few (ca. 30) trees. Our results indicate that (1) geographical genetic structure was weak, with high genetic variation among populations; (2) a congruent signal was revealed by chloroplastic and nuclear markers, indicating two distinct provenances; and (3) admixture between the two lineages has occurred, but remains limited. Several other invasive plant species have already been reported to exhibit similar trends; hence, future management of A. altissima might be required in Japan.

Development and characterization of polymorphic microsatellite loci in Ficus altissima

Fig trees are keystone resource species in tropical forests. In this study we developed microsatellite loci for Ficus altissima, a common dominant species in tropical China, using an enrichment approach. Nine polymorphic loci were developed, and their characteristics were analyzed in a population. Number of alleles per locus ranged from 2 to 6. The expected and observed heterozygosities were 0.108–0.740 and 0.111–0.800, respectively. These polymorphic microsatellites can be applied to further studies about genetic diversity and structure of F. altissima populations.

An exotic herbivorous insect drives the evolution of resistance in the exotic perennial herb Solidago altissima

Invasive plants often experience rapid changes in biological interactions by escaping from their original herbivores at their new habitats, and sometimes re‐associating with those herbivores afterwards. However, little is known about whether the temporal changes in herbivorous impact work as a selective agent for defensive traits of invaded plants. Solidago altissima (goldenrod) is a North American perennial that has widely invaded abandoned fields in Japan. Recently, an herbivorous insect Corythucha marmorata (lace bug), an exotic insect also from North America, which was first recorded in 2000 in Japan, has been expanding its habitat on S. altissima populations in Japan. In this study, we investigated whether the invasion of C. marmorata had a selective impact on the defensive traits of S. altissima, by conducting a field survey, a common garden experiment and microsatellite analysis. We compared quantitative genetic differentiation of traits (resistance, growth, and reproduction) and neutral molecular differentiation among 16 S. altissima populations with different establishment years of C. marmorata.The common garden experiment, in which plants were grown in a greenhouse and treated to either C. marmorata herbivory or no herbivory, revealed the presence of higher resistance, sexual reproduction, and asexual (rhizome) reproduction in populations subjected to a longer history of C. marmorata pressure. Such phenotypic variability among establishment years of lace bugs was likely driven by natural selection rather than stochastic events such as genetic drift and founder effects. In addition, when plants were exposed to lace bug herbivory, resistance had a positive relationship with sexual and asexual reproduction, although no relationship was found when plants were free from herbivory. These findings suggest that defensive traits in S. altissima have evolved locally in the last decade in response to the selective pressure of C. marmorata.

Geographic variations in phenotypic traits of the exotic herb Solidago altissima and abundance of recent established exotic herbivorous insects

Many invasive plants increase aggressiveness after introduction. Since evolutionary forces such as herbivore pressure may change over different time scales, understanding the changes in biotic interactions in invasive plants through time can clarify the mechanism of their evolution in aggressiveness. In this study, we examined the geographic variation in phenotypic traits of Solidago altissima and the abundance of two exotic herbivorous insect species (the aphid, Uroleucon nigrotuberculatum and the lacebug, Corythucha marmorata), which are recently expanding their habitat on S. altissima populations over Japan. The two exotic insects were present at high density on S. altissima throughout their range. No differences in growth traits (plant height and number of leaves) were found among populations, and all plants examined appear to be exclusively hexaploid. Future studies on population genetics and common garden experiments are necessary to evaluate the potential evolutionary dynamics of the S. altissima after introduction.

Within and between population variation in plant traits predicts ecosystem functions associated with a dominant plant species.

Linking intraspecific variation in plant traits to ecosystem carbon uptake may allow us to better predict how shift in populations shape ecosystem function. We investigated whether plant populations of a dominant old-field plant species (Solidago altissima) differed in carbon dynamics and if variation in plant traits among genotypes and between populations predicted carbon dynamics. We established a common garden experiment with 35 genotypes from three populations of S. altissima from either Tennessee (southern populations) or Connecticut (northern populations) to ask whether: (1) southern and northern Solidago populations will differ in aboveground productivity, leaf area, flowering time and duration, and whole ecosystem carbon uptake, (2) intraspecific trait variation (growth and reproduction) will be related to intraspecific variation in gross ecosystem CO2 exchange (GEE) and net ecosystem CO2 exchange (NEE) within and between northern and southern populations. GEE and NEE were 4.8× and 2× greater in southern relative to northern populations. Moreover, southern populations produced 13× more aboveground biomass and 1.4× more inflorescence mass than did northern populations. Flowering dynamics (first- and last-day flowering and flowering duration) varied significantly among genotypes in both the southern and northern populations, but plant performance and ecosystem function did not. Both productivity and inflorescence mass predicted NEE and GEE between S. altissima southern and northern populations. Taken together, our data demonstrate that variation between S. altissima populations in performance and flowering traits are strong predictors of ecosystem function in a dominant old-field species and suggest that populations of the same species might differ substantially in their response to environmental perturbations.

A field study of potential ecological costs of resistance by ‘stem ducking’ in tall goldenrod, Solidago altissima

AbstractThe maintenance of genetic variation for resistance in a plant population that experiences herbivory suggests that resistance entails costs as well as benefits. Ecological costs – which result from indirect effects that a resistance trait has on other members of the host plant’s community – constitute a potentially widespread but relatively understudied constraint on the evolution of resistance. Here, we tested the hypothesis that ecological costs may act to constrain the evolution of the recently identified ‘stem‐ducking’ resistance trait in Solidago altissima L. (Asteraceae). Previous studies have shown that, although ducking is effective against some harmful apex‐attacking insects, ducking genets are consistently in the minority in S. altissima populations. Potential ecological costs of ducking include increased susceptibility to non‐target herbivores and reduction of attack by the third trophic level (i.e., natural enemies of herbivores). In a field study involving more than 2 100 stems, erect stems of S. altissima were galled about 50% more often than ducking stems by the rosette galler Rhopalomyia solidaginis (Loew) (Diptera: Cecidomyiidae). The two other common stem herbivores in this study – the stem‐boring moths (Lepidoptera) Dichomeris inserrata (Walsingham) (Gelechiidae) and Oidaematophorus kellicottii (Fish) (Pterophoridae) – were equally abundant on ducking and erect‐stemmed plants, suggesting a lack of ecological cost of ducking in terms of susceptibility to other herbivores. Rhopalomyia solidaginis eggs were parasitized by the wasp Platygaster variabilis Ashmead (Hymenoptera: Platygasteridae) at the same rate whether the eggs were laid on ducking or erect stems, suggesting a lack of ecological costs to ducking in terms of reduced attraction of the third trophic level. This study confirmed that ducking is an effective resistance against apex gallers but did not support the hypothesis that ecological costs keep ducking stems in the minority.

To duck or not to duck: resistance advantages and disadvantages of the candy‐cane stem phenotype in tall goldenrod, Solidago altissima

Solidago altissima populations consistently contain a minority of 'ducking', or 'candy-cane', stems. The goals of this study were to investigate whether these candy-cane stems may be an adaptation to resist herbivory, and to look for costs (namely, resistance tradeoffs or reduced reproduction) that might constrain the spread of the ducking trait. In this study, herbivory and seed set were recorded for 272 erect and 272 candy-cane stems in a field population of S. altissima. Candy-cane plants were twice as resistant as erect plants to two common apex-attacking gall midges, but were 26% more susceptible than erect plants to a more abundant apex-boring caterpillar. The two stem morphs were equally resistant to all other herbivores surveyed. Candy-cane plants were 11% less likely to experience apex damage and 3% more likely to set seed than erect-stemmed plants. Damaged candy-cane stems were 9% more likely to produce seeds than damaged erect stems. Although ducking is an effective means of resisting apex-galling herbivores, its spread may be constrained by susceptibility to an apex-boring caterpillar, which may enjoy enemy-reduced space on candy-cane stems. The evolution of ducking does not seem to be constrained by a reduced likelihood of sexual reproduction, or reduced tolerance of apex damage.

Associational resistance, gall-fly preferences, and a stem dimorphism in Solidago altissima

In most populations of Solidago altissima, a small proportion of plants have a growth pattern in which the stem bends early in the season so that the apex is pointing downward (i.e., a “candy-cane” stem) then straightens up again later in the season. The majority of plants, however, do not show this pattern. Instead their stems remain erect from emergence through flowering and senescence. It has recently been shown that the candy-cane stems are a result of a ducking strategy that reduces the risk of attack by apex-attacking herbivores. With such a resistance advantage, it is unclear why the candy-cane morphology is always in the minority, and why the erect morphology persists at all in S. altissima populations. In this study, we tested the hypothesis that the advantage of ducking is inversely frequency dependent and thus will not be an effective resistance strategy when ducking plants are in the majority. In a series of trials, we introduced gall flies ( Eurosta solidaginis) into enclosures with relatively low (15%) and relatively high (85%) frequencies of candy-cane versus erect stems. Candy-cane stems were more resistant than erect stems regardless of relative frequency; thus, the hypothesis was rejected. Overall, attack rates were lower for both stem types in the high candy-cane frequency groups than in the low candy-cane frequency groups. This frequency-dependent attack rate suggests that erect-stemmed plants gain “associational resistance” by having a majority of candy-cane neighbors, while candy-cane plants suffer from “associational susceptibility” when surrounded by erect-stemmed neighbors.

Allozyme variation and population genetic structure of an invasive plant,ageratina altissima(white snake root), in Seoul

Allozyme studies have been widely used to estimate genetic variation and to describe genetic structure in natural populations. In many cases, the genetic diversity of recently established populations is generally lower than that of central populations. In addition, the genetic composition of an invasive species is influenced by its history of introduction as well as its ecological characters. Ageratina altissima (L.) R. King & H. Robinson (white snake root) is a perennial herb native to the eastern United States and Canada, and is currently receiving much attention for its rapid invasion of the Korean forests. Starch gel electrophoresis was used to assess the genetic variability at 11 putative loci in seven introduced populations of A. altissima in Seoul. Populations of A. altissima maintained lower levels of allozyme diversity (expected heterozygosity = 0.063) than those reported for other taxa with similar ecological traits. The degree of differentiation observed among A. altissima populations was consi...