Oenothera Species Research Articles

A Conspectus of the Family Onagraceae in India

The paper presents a concise account of Onagraceous plants in India. They are represented by 4 genera and 46 species. Five species of the genus OENOTHERA, an American genus, became naturalised, other 8 species are occasionally cultivated. The genus CLARKIA with 3 species and Fuchsia with 8 species are cultivated. Of the hitherto known taxa of EPILOBIUM ONE species is relegated to synonymy, one new species has been added. Original citations, synonymy, reference to taxonomic revisions and Indian floras, types, distribution, ecological notes, phenology etc. have been provided. A key to the genera and species is given. A list of cultivated species has been added.

Prospects and peculiarities of the existence of the genus Oenothera L. species outside the places of cultivation in Odesa region

Cultivated plant species can often become elements of the spontaneous flora fraction of ecotopes of varying degrees of anthropogenic transformation. An example is representatives of the genus Oenothera. Some of them are able to master extreme man-made ecotopes or take root in natural multi-component coenoses. Work with the species of the genus is complicated, since the issues of their hybridization require additional scientific developments. The species Oenothera biennis and O. rubricaulis are the most common spontaneous elements of the flora on the territory of Ukraine. At the same time, the following species were noted for several regions of the northern and central (sometimes–eastern) parts of Ukraine: O. depressa, O. erythrosepala, O. glazioviana, O. hoelscheri, O. villosa. Some species have a limited distribution: O. missuriensis, O. parviflora, O. pycnocarpa, O. fallax, O. speciosa, O. tetragona, O. wienii. According to modern literary data, information on the distribution of Oenothera species for the Odesa region is either absent or critically scarce. In the herbarium collections of the Odesa National University named after I.I. Mechnikov (MSUD), historical and modern, there are some specimens of representatives of this genus. However, all of them relate mainly to the distribution of Oenothera biennis within the borders of Ukraine, or, occasionally, the adjacent territories. The herbarium also contains specimens of other species, but their identification requires the attention of specialists. Literary summaries which contain information about the species of the Oenothera genus (Oenothera biennis) mainly characterize the centuries-old flora of the Odesa region. In general, there are very few cases of spontaneous growth of Oenothera species found in the South of Ukraine. During the floristic survey of ecotopes below the Dniester–Tyligul interfluve, we found several habitats of Oenothera glazioviana. The ecological conditions of the sites differed significantly. In general, most species of the genus Oenothera do not have a high invasive potential, however, monitoring the establishment of species of the genus in ecotopes with different anthropogenic load is advisablе.

Hawkmoth and bee pollinators impact pollen dispersal at the landscape but not local scales in two species of Oenothera.

Animal pollinators play an important role in pollen dispersal. Here, we assessed differences in pollen and seed dispersal and the role of pollinator functional groups with different foraging behaviors in generating patterns of genetic diversity over similar geographic ranges for two closely related taxa. We focused on two members of Oenothera section Calylophus (Onagraceae) that co-occur on gypsum outcrops throughout the northern Chihuahuan Desert but differ in floral phenotype and primary pollinator: Oenothera gayleana (bee) and O. hartwegii subsp. filifolia (hawkmoth). We measured breeding system and floral traits and studied gene flow and population differentiation at the local (<13 km; four populations) and landscape (60-440 km; five populations) scales using 10-11 nuclear (pollen dispersal) and three plastid (seed dispersal) microsatellite markers. Both taxa were self-incompatible and floral traits were consistent with expectations for different pollinators. Seed and pollen dispersal patterns were distinctly different for both species. We found no evidence of genetic structure at the local scale but did at the landscape scale; O. gayleana showed greater differentiation and significant isolation by distance than in O. hartwegii subsp. filifolia. The plastid data were consistent with gravity dispersal of seeds and suggest that pollen dispersal is the principal driver of genetic structure in both species. We demonstrated that pollinator functional groups can impact genetic differentiation in different and predictable ways. Hawkmoths, with larger foraging distances, can maintain gene flow across greater spatial scales than bees.

The evolution of multi-gene families and metabolic pathways in the evening primroses (Oenothera: Onagraceae): A comparative transcriptomics approach.

The plant genus Oenothera has played an important role in the study of plant evolution of genomes and plant defense and reproduction. Here, we build on the 1kp transcriptomic dataset by creating 44 new transcriptomes and analyzing a total of 63 transcriptomes to present a large-scale comparative study across 29 Oenothera species. Our dataset included 30.4 million reads per individual and 2.3 million transcripts on average. We used this transcriptome resource to examine genome-wide evolutionary patterns and functional diversification by searching for orthologous genes and performed gene family evolution analysis. We found wide heterogeneity in gene family evolution across the genus, with section Oenothera exhibiting the most pronounced evolutionary changes. Overall, more significant gene family expansions occurred than contractions. We also analyzed the molecular evolution of phenolic metabolism by retrieving proteins annotated for phenolic enzymatic complexes. We identified 1,568 phenolic genes arranged into 83 multigene families that varied widely across the genus. All taxa experienced rapid phenolic evolution (fast rate of genomic turnover) involving 33 gene families, which exhibited large expansions, gaining about 2-fold more genes than they lost. Upstream enzymes phenylalanine ammonia-lyase (PAL) and 4-coumaroyl: CoA ligase (4CL) accounted for most of the significant expansions and contractions. Our results suggest that adaptive and neutral evolutionary processes have contributed to Oenothera diversification and rapid gene family evolution.

Mutualism has its limits: consequences of asymmetric interactions between a well-defended plant and its herbivorous pollinator.

Concern for pollinator health often focuses on social bees and their agricultural importance at the expense of other pollinators and their ecosystem services. When pollinating herbivores use the same plants as nectar sources and larval hosts, ecological conflicts emerge for both parties, as the pollinator's services are mitigated by herbivory and its larvae are harmed by plant defences. We tracked individual-level metrics of pollinator health-growth, survivorship, fecundity-across the life cycle of a pollinating herbivore, the common hawkmoth, Hyles lineata, interacting with a rare plant, Oenothera harringtonii, that is polymorphic for the common floral volatile (R)-(-)-linalool. Linalool had no impact on floral attraction, but its experimental addition suppressed oviposition on plants lacking linalool. Plants showed robust resistance against herbivory from leaf-disc to whole-plant scales, through poor larval growth and survivorship. Higher larval performance on other Oenothera species indicates that constitutive herbivore resistance by O. harringtonii is not a genus-wide trait. Leaf volatiles differed among populations of O. harringtonii but were not induced by larval herbivory. Similarly, elagitannins and other phenolics varied among plant tissues but were not herbivore-induced. Our findings highlight asymmetric plant-pollinator interactions and the importance of third parties, including alternative larval host plants, in maintaining pollinator health. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.

Testing Pollination Syndromes in &lt;i&gt;Oenothera&lt;/i&gt; (Onagraceae)

Pollinators are considered a major selective force in shaping the diversification of angiosperms. It has been hypothesized that convergent evolution of floral form has resulted in “pollination syndromes” - i.e. suites of floral traits that correspond to attraction of particular pollinator functional groups. Across the literature, the pollination syndrome concept has received mixed support. This may be due to studies using different methods to describe floral traits and/or the pollination syndrome concept being supported more often in species highly reliant on pollinators for reproduction. Here, we assess the predictive ability of pollination syndromes in Oenothera, a species rich clade with pollination systems existing on a gradient of specialization, and in which species are either self-compatible or self-incompatible. We ask the following questions: Do Oenothera species follow the pollination syndrome concept using traditional, categorical floral trait descriptions and/or quantitative floral trait measurements? And, are floral traits more predictive of primary pollinators in species with specialized pollination systems and/or species that are self-incompatible? Mapping floral traits of 54 Oenothera species into morphospace, we do not find support for the pollination syndrome concept using either categorical or quantitative floral trait descriptions. We do not find support for specialization or breeding system influencing the prediction of primary pollinators. However, we find pollination syndromes were more predictive in Oenothera species with moth pollination systems. Collectively, these results suggest that the pollination syndrome concept cannot be generally applied across taxa and that evolutionary history is important to consider when evaluating the relationship between floral form and contemporary pollinators.

Transferability of Microsatellite Markers Developed in Oenothera spp. to the Invasive Species Oenothera drummondii Hook. (Onagraceae)

Oenothera drummondii Hook. (Onagraceae) has life-history traits that make it an invasive species. Native populations are distributed along the coastal dunes from North Carolina in the United States to Tabasco in the Gulf of Mexico. It has been reported as an invasive species in Spain, Israel, and China, where this species can successfully colonize and dominate if the environmental conditions are appropriate. In South Africa, Australia, New Zealand, and France, it is reported to be naturalized. In this study, 28 microsatellite markers developed for other Oenothera species were evaluated for cross-amplification in O. drummondii. Nine primers showed consistent amplification and were polymorphic. Polymorphism was assessed in three populations from both native and invaded areas. Results indicated generalized low genetic variability. Three loci showed significant deviations from the Hardy Weinberg equilibrium, associated with null alleles’ presence. The observed heterozygosity and inbreeding coefficient reflected a generalized excess of homozygotes, particularly in the invaded population “El Dique”, likely due to allele fixation. High genetic differentiation was found between the three populations. These results highlight the accuracy of these markers for future population genetic studies in O. drummondii.

Особливості адаптації окремих видів роду Oenothera L. до посушливо-спекотних умов Правобережного Степового Придніпров'я

Наведено особливості анатомічної адаптації листків двох видів роду Oenothera L. за умов вирощування у Правобережному степовому Придніпров'ї. Здійснено огляд наукових інформаційних вітчизняних і закордонних джерел щодо декоративних якостей представників роду Oenothera, походження, поширення, гібридизації, лікувальних властивостей та переваг використання у ландшафтному дизайні. З'ясовано, що у фітодизайні України їх використовують мало, а в декоративному садівництві м. Кривий Ріг цих видів немає через нестачу інформації щодо їх пластичності у посушливих спекотних умовах Правобережного степового Придніпров'я (ПСП). Для визначення адаптаційного потенціалу видів Oenothera досліджено анатомо-морфологічну структуру листків деяких представників за умов вирощування у ПСП. Матеріалом дослідження слугували рослини O. missuriensis та O. tetragona колекційного фонду квітниково-декоративних трав'яних рослин Криворізького ботанічного саду НАН України, інтродукованих впродовж 20 років. Встановлено особливості анатомо-морфологічної будови листкової пластинки досліджуваних видів. Виявлено специфіку кількісно-якісних адаптаційних пристосувань у структурі листка за умов вирощування в посушливо-спекотних умовах ПСП. З'ясовано, що рослини O. missouriensis та O. tetragona добре адаптовані до зростання в умовах інтенсивної інсоляції, про що свідчить наявність ксероморфних рис в анатомічній будові обох видів, таких як: кутикула та опушення, рафіди оксалату кальцію, диференційований мезофіл, розміщення продихів з адаксільної та абаксіальної сторін. Виявлено, що за умов дефіциту вологи та високих температур у рослин O. missouriensis та O. tetragona сформувалися ксероморфні ознаки, а саме: відбулося значне збільшення шару кутикули, товщини обох епідермісів, зменшилися розміри продихів та їх кількість, ущільнилося розміщення клітин мезофілу, що значно підвищує рівень їх посухостійкості. Кількісна і якісна мінливість елементів структури листкової пластики свідчить про достатній рівень адаптації та пластичність видів в умовах регіону досліджень, що дає підстави рекомендувати їх для застосування у декоративному садівництві в посушливих умовах ПСП.

Pollination biology and breeding system in five nocturnal species of Oenothera (Onagraceae): reproductive assurance and opportunities for outcrossing

The capacity to produce seed, both by selfing and outcrossing, or mixed mating strategies, is considered a mechanism for overcoming unpredictable pollinator availability. In the present study, we investigate breeding system, insect visitations and the role of insect visitors in the pollination of five species of Oenothera subsect. Oenothera. Field experiments showed that autonomous selfing occurs at bud stage, prior to the opening of the flower. Control flowers showed similar seed set to hand-pollinated flowers, whereas emasculated flowers and those subject to open pollination set fewer seed. These results are consistent with the hypothesis that the investigated Oenothera exhibit a great capacity for autonomous selfing and that selfing is selected in order to provide reproductive assurance. Although flowers were visited mostly by nocturnal lepidopterans, these insects did not precipitate pollination and are thus considered nectar thieves. Conversely, analysis of pollen loads and behavior during foraging by diurnal insect visitors revealed that honeybees and bumblebees are the probable pollinators. We conclude that production of flowers capable of autonomous selfing at bud stage, followed by anthesis and opportunities for outcrossing, probably improves the invasive potential of these Oenothera in Europe, together with a rapid increase in their populations, even when pollinators are scarce.

Floral phenology and pollen production in the five nocturnal Oenothera species (Onagraceae)

Blooming phenology and pollen production in the five &lt;em&gt;Oenothera&lt;/em&gt; species were investigated during the period of 2013–2015 in the Lublin area, SE Poland. The blooming period was relatively long, and flowering usually started in the middle or late June and lasted until late July or the middle of August. The &lt;em&gt;Oenothera&lt;/em&gt; species studied exhibited nocturnal anthesis, i.e., the flowers opened in the late evening and lasted overnight until the early morning hours. Plants developed a great number of flowers per individual and per unit area (on average, 158 and 4,136, respectively), and this feature appeared to be species-specific. It was demonstrated that the blooming phase had an impact on the mass of anthers and pollen produced per flower in all &lt;em&gt;Oenothera&lt;/em&gt; species. In general, the greatest mass of anthers and pollen was observed at the beginning of blooming, and with the progress of flowering, the values decreased. However, statistical differences were found for &lt;em&gt;O. flaemingina&lt;/em&gt;, &lt;em&gt;O. paradoxa&lt;/em&gt;, and &lt;em&gt;O. rubricaulis&lt;/em&gt;. The mass of pollen produced per unit area was also a species-specific characteristic and was related to the abundance of flowering. The greatest amount of pollen was produced by &lt;em&gt;O. flaemingina&lt;/em&gt; (30.6 g m&lt;sup&gt;−2&lt;/sup&gt;), which was almost three times more than that produced by &lt;em&gt;O. rubricaulis&lt;/em&gt; (10.9 g m&lt;sup&gt;−2&lt;/sup&gt;). The protein content of pollen grains was relatively low and on average amounted to 15.4%. The &lt;em&gt;Oenothera&lt;/em&gt; species examined in this work may be considered valuable pollen yielding plants. Nevertheless, given the invasive potential of species from subsect. &lt;em&gt;Oenothera&lt;/em&gt;, precautions are suggested during cultivation and/or planting these taxa in bee pastures, in order to prevent uncontrolled spread into new areas.

Complete chloroplast genome of Ulleung Island endemic, Epilobium ulleungensis (Onagraceae), in Korea

The first complete chloroplast genome sequences of Korean endemic Epilobium in Ulleung Island, Epilobium ulleungensis, were reported in this study. The E. ulleungensis plastome was 160,912 bp long, with the large single copy (LSC) region of 88,915 bp, the small single copy (SSC) region of 17,327 bp, and two inverted repeat (IR) regions of 27,335 bp. The plastome contained 131 genes, including 84 protein-coding, eight ribosomal RNA, and 37 transfer RNA genes. The overall GC content was 36.5%. Phylogenetic analysis of nine representative plastomes within the family Onagraceae suggests strongly that E. ulleungensis is sister to the clade containing species of Oenothera in tribe Onagreae.

Distribution of alien species along sand dune plant communities zonation

Background and purpose: For a fairly long period, Velika plaža in Ulcinj, Montenegro has been considered to be one of the best-preserved sites with psammophilous vegetation along the Adriatic coast. In recent years, however, this area has been significantly transformed as a result of various human disturbances (e.g., a non-sustainable approach to touristic development, illegal dumping, sand exploitation etc.), and has become prone to alien plant invasions. We made a transect survey to assess the presence of alien species in the psammophilous communities.Materials and methods: In order to make a survey of the present state of plant life on Velika plaža, its floristic composition and zonation of plant communities, 20 transects were set perpendicular to the coast, regularly every 500 m. Quadrats (2 x 2 m) were laid contiguously in the form of a belt transect starting from the area with the first colonizing plants towards the end of the sand dune system with forest vegetation. This resulted in a matrix of 1124 plots and 196 species (15 alien and 181 native), on which multivariate analysis was performed.Results: Nine plant communities were detected, arranged in zonation from sea to inland. All of them were characterised by the presence of alien species. The least affected was the plant community dominated by Cladium mariscus, while the most affected ones were dominated by Scirpoides holoschoenus and Tripidium ravennae. Psammophilous vegetation is less affected by alien species than wetland communities. Foredunes are dominated by Xanthium orientale ssp. italicum, while Oenothera species are predominant on stable dunes.Conclusions: Sand dunes are a highly invaded ecosystem, with changed plant communities, so conservation measures should be considered.

Floral nectary, nectar production dynamics and chemical composition in five nocturnal Oenothera species (Onagraceae) in relation to floral visitors

Main conclusionThe floral nectars were sucrose-dominant; however, nectar protein and amino acid contents differed, indicating that composition of nitrogenous compounds may vary considerably even between closely related plant species, irrespectively of nectary structure.Numerous zoophilous plants attract their pollinators by offering floral nectar; an aqueous solution produced by specialized secretory tissues, known as floral nectaries. Although many papers on nectaries and nectar already exist, there has been a little research into the structure of nectaries and/or nectar production and composition in species belonging to the same genus. To redress this imbalance, we sought, in the present paper, to describe the floral nectary, nectar production, and nectar composition in five nocturnal Oenothera species with respect to their floral visitors. The structure of nectaries was similar for all the species investigated, and comprised the epidermis (with nectarostomata), numerous layers of nectary parenchyma, and subsecretory parenchyma. Anthesis for a single flower was short (ca. 10–12 h), and flowers lasted only one night. The release of floral nectar commenced at the bud stage (approx. 4 h before anthesis) and nectar was available to pollinators until petal closure. Nectar concentration was relatively low (ca. 27%) and the nectar was sucrose-dominant, and composed mainly of sucrose, glucose and fructose. The protein content of the nectar was also relatively low (on average, 0.31 µg ml−1). Nevertheless, a great variety of amino acids, including both protein and non-protein types, was detected in the nectar profile of the investigated taxa. We noted both diurnal and nocturnal generalist, opportunistic floral insect visitors.

Oenothera Albipercurva – Evening-Primrose Species New To The Flora Of Lithuania

Abstract Oenothera albipercurva Hudziok was reported for the first time in the Lithuanian flora. It is tenth Oenothera species noted in Lithuania. It was found in the association Cladonio-Pinetum nearby Merkinė town in the southern part of the country in 2005. According to the early stage of development (June), fully-flowering plants were very sparse. Oenothera albipercurva is of hybridogenous origin (O. biennis L. × O. ammophila Focke), discovered and reported by Renner in 1937 from Germany, currently distributed in Central and Eastern Europe. It resembles O. ammophila by its narrow leaves and divergent sepal tips, but can be easily distinguished mainly by its clearly larger flowers (petal length 15–26 mm instead of 12–18 mm) and red papillae on the underside of leaves. Some examples of significant mistakes found in the descriptions of this species in literature and main diagnostic characters are given.

Mutational Pressure Drives Evolution of Synonymous Codon Usage in Genetically Distinct Oenothera plastomes

Background: Most of the amino acids are encoded by more than one codon, termed as synonymous codons. Synonymous codon usage is not random as it is unique to species. In each amino acid family, some synonymous codons are preferred and this is referred to as synonymous codon usage bias (SCUB). Trends associated with evolution of SCUB and factors influencing its diversification in plastomes of genetically distinct Oenothera plastomes have not been investigated so far. Objectives: In the present study, major forces that shape SCUB in Oenothera plastomes and putative preferred codons in the protein coding genes (PCG) of plastomes were identified. Materials and Methods: To unravel various features of SCUB across selected Oenothera plastomes, commonly used codon usage indices such as relative synonymous codon usage (RSCU), synonymous codon usage order (SCUO), effective number of codons (ENC) and codon adaptation index (CAI) were calculated. Correspondence analysis (COA) on RSCU was performed to identify various characteristics of SCUB across different PCG in Oenothera plastomes. Spearman’s rank correlation analysis was adopted to correlate nucleotide contents, codon usage indices and major axes of COA to find out critical parameters in shaping SCUB. Results: Mutational bias due to compositional constraints played crucial role in shaping SCUB as T3 and GC3 contents were in strong negative correlation with all axes of COA. Nevertheless, significant negative correlations between axis 1 and 3 with ENC and CAI respectively, in all species, and narrow distribution of GC contents in neutrality plot, indicate the role of natural selection. Hydropathy score of proteins was found to be influencing SCUB in O. glazioviana as it showed strong negative correlation with axis 2. Conclusion: We concluded that mutational pressure coupled with weak selection influenced SCUB in the examined plastomes of Oenothera. In addition, all examined species of Oenothera exist as disjunct populations in different parts of North America and these populations might have experienced genetic drift as random mutations in small populations that have been fixed over a period of time.

Critical size for reproduction and ontogenetic changes in the allocation patterns of wild and domesticated species of evening primrose (Oenothera L.)

Oenothera L. (evening primrose) has been suggested as a new seed-oil crop, source of gamma-linolenic acid, with uses herbal medicine industries. We compared the critical size for reproduction and the biomass allocation patterns during three phenological stages of a wild (O. mendoncinensis) and a domesticated species (O.biennis). Rosettes of O. biennis attained a critical size after two years in the field, while the wild species reproduced during the first year. Early bolting is a comprehensive strategy for indeterminate species growing in a short season environment, because it extends the flowering period but at the same time, the short vegetative period limits carbohydrates stores available for reproductive growth, and therefore, yield. Reproductive effort caused in both species a significant depletion of reserves during the flowering. Leaves and roots biomass declined by senescence after bolting in the wild species. In conclusion, yield improvement of wild species of Oenothera could be obtained by selecting plants with higher accumulation of vegetative biomass and delayed senescence that guarantees greater photosynthetic capacity after flowering.

Effects of functionally asexual reproduction on quantitative genetic variation in the evening primroses (Oenothera, Onagraceae).

It has long been predicted that a loss of sexual reproduction leads to decreased heritable variation within populations and increased differentiation between populations. Despite an abundance of theory, there are few empirical tests of how sex affects genetic variation in phenotypic traits, especially for plants. Here we test whether repeated losses of two critical components of sex (recombination and segregation) in the evening primroses (Oenothera L., Onagraceae) affect quantitative genetic variation within and between populations. We sampled multiple genetic families from 3-5 populations from each of eight Oenothera species, which represented four independent transitions between sexual reproduction and a functionally asexual genetic system called "permanent translocation heterozygosity." We used quantitative genetics methods to partition genetic variation within and between populations for eight plant traits related to growth, leaf physiology, flowering, and resistance to herbivores. Heritability was, on average, 74% higher in sexual Oenothera populations than in functionally asexual populations, with plant growth rate, specific leaf area, and the percentage of leaf water content showing the strongest differences. By contrast, genetic differentiation among populations was 2.8× higher in functionally asexual vs. sexual Oenothera species. This difference was particularly strong for specific leaf area. Sexual populations tended to exhibit higher genetic correlations among traits, but this difference was weakly supported. These results support the prediction that sexual reproduction maintains higher genetic variation within populations, which may facilitate adaptive evolution. We also found partial support for the prediction that a loss of sex leads to greater population differentiation, which may elevate speciation rates.

한반도 미기록 귀화식물: 댕돌보리와 애기분홍낮달맞이꽃

전남 완도군, 경남 양산시에서 한반도 미기록 귀화식물 2분류군을 발견하였다. 댕돌보리로 명명된 Lolium rigidum Gaudin(화본과)는 전남 완도군 보길면 예송리해변과 신지면 명사십리 해변 부근에서 확인되었다. 근연 분류군인 쥐보리(L. mutiflorum Lam)와 비교하여 소수의 길이가 10~20 mm로 짧고, 소화는 2-10(-13)개로 적으며, 호영의 끝부분이 둔하고 까락이 없거나 3-8(-10) mm의 짧은 까락이 있는 특징으로 구별된다. 또한 애기분홍낮달맞이꽃으로 명명된 Oenothera rosea L'H<TEX>$\acute{e}$</TEX>r. ex Aiton(바늘꽃과)는 경남 양산시 원동면 원동배후습지 부근에서 확인되었다. 본 분류군은 비스듬히 자라거나 직립하며, 꽃잎은 길이 5~12 mm, 분홍색부터 연한 보라색으로 달맞이꽃속 다른 분류군들과 구분된다. 주요형질에 대한 두 분류군의 기재 및 해부도와 서식지 식물사진 및 호밀풀속과 달맞이꽃속의 식물에 대한 검색표를 제시하였다. Two unrecorded naturalized species, Lolium rigidum Gaudin (Poaceae) and Oenothera rosea L'H<TEX>$\acute{e}$</TEX>r. ex Aiton (Onagraceae) were newly reported in Korea. L. rigidum, 'Daeng-Dol-Bo-Ri', was found at roadside of Yesong beach, Yesong-ri, Bogil-myeon, and roadside of Myeongsasimni beach, Sin-ri, Sinji-myeon, in Wando-gun, Jeollanam-do. It was distinguished from L. mutiflorum Lam by spikelet 10-20 mm long, florets 2-10(-13), and obtuse lemma, awn absent or up to 3-8(-10) mm. O. rosea, 'Ae-Ki-Bun-Hong-Nat-Dal-Mat-I-Kkot', was found in side of Wondong wetland, Yongdang-ri, Wondong-myeon, Yangsan-si, Gyeongsangnam-do. This taxon was distinguishable from other Oenothera in Korea by following combination of characters, stem erect to ascending, petal 5-12 mm long, pink to bright purple. Descriptions and illustrations of the two taxa and their photographs in the habitat are provided along with a key to the species of Lolium and Oenothera from Korea.

Translocations of Chromosome End-Segments and Facultative Heterochromatin Promote Meiotic Ring Formation in Evening Primroses

Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled end-segments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories.

Macroevolution of plant defenses against herbivores in the evening primroses

Plant species vary greatly in defenses against herbivores, but existing theory has struggled to explain this variation. Here, we test how phylogenetic relatedness, tradeoffs, trait syndromes, and sexual reproduction affect the macroevolution of defense. To examine the macroevolution of defenses, we studied 26 Oenothera (Onagraceae) species, combining chemistry, comparative phylogenetics and experimental assays of resistance against generalist and specialist herbivores. We detected dozens of phenolic metabolites within leaves, including ellagitannins (ETs), flavonoids, and caffeic acid derivatives (CAs). The concentration and composition of phenolics exhibited low to moderate phylogenetic signal. There were clear negative correlations between multiple traits, supporting the prediction of allocation tradeoffs. There were also positively covarying suites of traits, but these suites did not strongly predict resistance to herbivores and thus did not act as defensive syndromes. By contrast, specific metabolites did correlate with the performance of generalist and specialist herbivores. Finally, that repeated losses of sex in Oenothera was associated with the evolution of increased flavonoid diversity and altered phenolic composition. These results show that secondary chemistry has evolved rapidly during the diversification of Oenothera. This evolution has been marked by allocation tradeoffs between traits, some of which are related to herbivore performance. The repeated loss of sex appears also to have constrained the evolution of plant secondary chemistry, which may help to explain variation in defense among plants.