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Made available in DSpace on 2021-06-25T11:13:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Populations of dioecious plants commonly exhibit dissimilarities to the equilibrium expectation of a 1:1 sex ratio. Differential expenditure for reproduction between genders is cited as the primary mechanism responsible for a male-biased sex ratio, with increased effects on long-living species, but these mechanisms are still poorly understood. We explore the sex ratio in the endemic gymnosperm Zamia boliviana (Zamiaceae) populations from the Brazilian savanna (the Cerrado). We aim to investigate what the Z. boliviana sex ratio is, and whether population density and ecological correlates lead to variation in the sex proportion among Cerrado habitats. The study was conducted on ten in situ populations of Z. boliviana at sexual maturity (tertiary sex ratio). We estimated the populations’ sex ratio and performed a redundancy analysis to assess the relationship between biotic traits, such as sex ratio, and associated environmental features. Soil texture classes were used to classify the cycad habitats and were expressed in a ternary phase diagram. The results show a significant male-biased sex ratio in seven of the ten populations surveyed. Environmental factors did not explain the redundancy in the reproductive characteristics. However, the cycad occurs in different habitats in their endemic zone. Our study provides new biological data for Z. boliviana, suggesting that the differential reproductive expenditure of sexes in reproduction is governing the mechanisms of sex ratio variation, compared to local environmental factors in this cycad. The pattern of effective sex ratio found here improves our understanding of mechanisms causing biased sex ratios in cycads and other dioecious species from tropical ecosystems. Instituto Federal de Educação Ciência e Tecnologia de Mato Grosso Campus Cáceres–Prof. Olegário Baldo, Avenida Europa, nº 3000, Vila Real/Distrito Industrial Departamento de Biologia Vegetal Instituto de Biologia Universidade Estadual de Campinas Universidade Federal dos Vales do Jequitinhonha e Mucuri Programa de Pós-Graduação em Ciência Florestal, Campus JK, Rodovia MGT 367 - Km 583, nº 5.000, Alto da Jacuba Laboratório de Fenologia Departamento de Biodiversidade Instituto de Biociências Universidade Estadual Paulista UNESP Laboratório de Fenologia Departamento de Biodiversidade Instituto de Biociências Universidade Estadual Paulista UNESP

Cycads, a primitive group of gymnosperms, are currently facing extinction in many parts of the world. In South Africa, this is largely attributed to the illegal poaching of many threatened species. In the illegal trade of cycads, many highly threatened species are often deliberately misnamed as a more common species. Due to macromorphological similarity between many Encephalartos species, as well as taxonomic uncertainties that exist, species identification is also problematic. This study compared the utility of selected leaflet micromorphological characters as a taxonomic tool to independently identify eight South African cycad species. The characters, which included trichome type (if present), stomatal density and dimensions, stomatal band width and vein band width, were compared within four pairs of macromorphologically similar species. Quantitative and qualitative data on the characters were collected using stereomicroscopy, scanning electron microscopy (SEM) and variable pressure SEM. Results indicated that the majority of these characters varied significantly (p

Temperature of sporophylls from excised male cones of three species from the Zamiaceae family (Ceratozamia miqueliana, Zamia fairchildiana, and Zamia pumila) and from one species from the Cycadaceae family (Cycas siamensis) was recorded over several days in an environmental chamber. Each species exhibited a different temperature profile. C. miqueliana and Z. fairchildiana were highly thermogenic, whereas C. siamensis and Z. pumila were weakly thermogenic. In C. miqueliana, the temperature of one sporophyll rose to 10 °C above ambient while other sporophylls on the same cone only reached temperatures of 0–3 °C above ambient. Temperature rates among the different cones varied between ≈ 0.01 and 0.09 ∆ °C/h. Temperature profiles of sporophylls of Z. fairchildiana and C. siamensis were reported for the first time. Studies of thermogenesis of single sporophylls in a controlled environment provide accurate temperature measurements. Furthermore, sporophylls can be exposed to different environments and thus improve our understanding of the mechanism of thermogenesis in vivo.

Early endosymbiotic interactions are recorded only from a Cretaceous termite and a cockroach. Mesoblatta maxi Hinkelman, gen. et sp. nov. is the second representative of the dominant, cosmopolitan Mesozoic family Mesoblattinidae known from Cenomanian northern Myanmar amber, and the fourteenth from both amber and sedimentary rocks. Unique characters are rare (n = 19), symplesiomorphies are frequent (n = 140), and foremost is a standard maxillary palp, an irregular area between forewing veins radius and media, central ocellus, and multisegmented styli, suggesting an ancestral position with respect to Blattidae. Autapomorphies of this otherwise conservative taxon are only its large size and a short probasitarsus. Two nymphs with fecal pellets protruding from their body, Blattocoprolites mesoblattamaxi Hinkelman, ichogen. et ichnosp. nov., represent the first cockroaches with formalized coprolites (along with Blattocoprolites blattulidae Hinkelman, ichnosp. nov. established herein from Lebanese amber) and provide evidence of burial defecation. Subhomogenic consistency of coprolites with mucous components, "pseudoinclusions," leaf, trichia, wood debris, cycad pollen, endosymbiotic protists, and epibiotic bacteria directly document pollen transfer through the digestive tract and the earliest coevolution with protists and bacteria. Other post-burial fecal bacteria at the surface are documented for the first time in the Mesozoic, directly indicating structured dung processing. Reference samples (as well as almost all Myanmar amber samples) contain numerous "pseudoinclusions," probably representing damaged or dead cysts of Chlamydomonas hanublikanus Vršanská et Hinkelman, sp. nov. established on the basis of its reproductive stages (with an origin within the resin inside the tree). These are documented together with green algae, including Spirogyra Nees, 1820; flagellates; and flagellate amoebae, promoting massive future microbiota studies.

Cycads are the most endangered of plant groups based on IUCN Red List assessments; all are in Appendix I or II of CITES, about 40% are within biodiversity ‘hotspots,’ and the call for action to improve their protection is long-standing. We contend that progress in this direction will not be made until there is better understanding of cycad pollen, seed and tissue biology, which at the moment is limited to relatively few (

Zamia lindosensis, a species of cycad from sandy soils of Amazonas, Colombia, is described and illustrated. It is compared to Zamia amazonum, which has similar habitat requirements, petiole morphology and prickles, leaflet margins, and strobili but with very narrow leaflets.

Cycads are considered to be the most threatened plant group on Earth. Thus, the identification of important biological units for conservation is crucial for their management and protection. Taxonomic studies have enormously contributed to cycad conservation, since species descriptions formally recognize biodiversity components that can be considered in conservation. However, because multidisciplinary studies that evaluate the biodiversity within cycad species are almost non-existent intraspecific evolutionarily significant units (ESUs) have not been considered when making conservation plans. The cycad Dioon sonorense (Zamiaceae) has a relatively wide distribution range along a vegetation gradient in Northwest Mexico: the southern populations of D. sonorense occur in tropical forests, whereas the northern populations occur in more xeric environments in the Sonoran Desert. Although both habitats might have promoted important evolutionary trends within D. sonorense, only the southern populations are being conserved. Here, we evaluated whether intrinsic differentiation among populations of D. sonorense exists, and whether northern populations may merit attention in conservation programs. We analyzed the variation of genome-wide loci to evaluate the genetic structure among six populations. We found two clusters, northern and southern, that can be recognized using 361 neutral loci. Such genetic structure is consistent with the differentiation observed from the variation of 16 macromorphological and 9 epidermal traits. Southern and northern regions are clearly differentiated in genetic, morphological and anatomical analyses. These multidisciplinary results suggest that the northernmost populations of D. sonorense represent an ESU that should be included in conservation programs. This study highlights that the evaluation of intraspecific variation may contribute effective strategies for cycad conservation, and that evolutionary processes should be considered in the delimitation of conservation units.

As an ancient seed plant, cycads are one of the few gymnosperms that develop a root symbiosis with cyanobacteria, which has allowed cycads to cope with harsh geologic and climatic conditions during the evolutionary process. However, the endophytic microbes in cycad roots remain poorly identified. In this study, using next-generation sequencing techniques, we investigated the microbial diversity and composition of both the coralloid and regular roots of Cycas bifida (Dyer) K.D. Hill. Highly diverse endophytic communities were observed in both the coralloid and regular roots. Of the associated bacteria, the top five families were the Nostocaceae, Sinobacteraceae, Bradyrhizobiaceae, Bacillaceae, and Hyphomicrobiaceae. The Nectriaceae, Trichocomaceae, and Incertae sedis were the predominant fungal families in all root samples. A significant difference in the endophytic bacterial community was detected between coralloid roots and regular roots, but no difference was observed between the fungal communities in the two root types. Cyanobacteria were more dominant in coralloid roots than in regular roots. The divergence of cycad root structures and the modified physiological processes may have contributed to the abundance of cyanobionts in coralloid roots. Consequently, the colonization of cyanobacteria inhibits the assemblage of other endophytes. Our results contribute to an understanding of the species diversity and composition of the cycad-endophyte microbiome and provide an abbreviated list of potential ecological roles of the core microbes present.

This study evaluates how a modelling approach to determine areas of suitable habitat for the Critically Endangered Albany cycad Encephalartos latifrons can assist in systematic conservation planning for this and other rare and threatened cycads. A map distinguishing suitable from unsuitable habitat for E. latifrons was produced and important environmental predictors (climate, geology, topography and vegetation) influencing the suitable habitat were estimated. The maximum entropy (MaxEnt) modelling technique was chosen for this study as it has consistently performed well compared with alternative modelling methods and is also an appropriate model choice when the sample size is small and locality records are relatively few. Predicted habitat suitability showed that some locations chosen for translocation and restoration of E. latifrons specimens are not suitable. This revealed that modelling suitable habitat can guide relocation and regeneration of E. latifrons and perhaps other threatened cycads with restricted distributions and few locality records. The species distribution model constructed for E. latifrons is the first reported habitat model for a Critically Endangered cycad in South Africa. The results may be incorporated into conservation planning and structured decision-making about translocations and restoration programmes involving vulnerable cycads, which are among the most threatened organisms globally.

Ceratozamia zaragozae has been considered to be the most threatened cycad species in its genus since only 50 individuals were reported for the only known population in the state of San Luis Potosi, Mexico. In this report we present information on newly discovered populations, as well as data on their population structure and spatial distribution. Six different populations were found, one of which is located in a Natural Protected Area. Population density was low (0.05 ± 0.038 ind/m2) and populations exhibited an unconventional ecological affinity for the genus, occurring on igneous soils in oak and pine-oak forests at elevations over 2000 m. Populations showed heterogeneous growth rates (λ = 0.89 ± 0.49). Spatial clustering patterns in all populations indicated adequate recruitment, low survival of juveniles, and spatial dependence between seedlings/juveniles and reproductive adults. We recommend the ex-situ cultivation of the species and the establishment of corridors between areas of habitat, in order to secure the preservation of the species.

The theory that β-N-methylamino-L-alanine (BMAA), a cyanobacterial toxin, contaminates traditional food supplies of the Chamorro people of Guam is supported by the recent finding that chronic dietary exposure to L-BMAA in vervets (Chlorocebus sabaeus) triggers the formation of neurofibrillary tangles (NFT) and β-amyloid plaques in the brain. In the first experiment, we found that all four vervets receiving a 210 mg/kg dose for 140 days developed NFT and sparse amyloid deposits. In the second experiment, all eight vervets receiving a 210 mg/kg dose for 140 days developed NFT and amyloid deposits, as well as all eight vervets that received only 21 mg/kg. Based on dietary surveys of the Chamorro people, we estimated lifetime chronic BMAA exposure at a high and a low level: 1) adult male Chamorros eating two flying foxes per month plus one 30 g serving of cycad flour per week; and 2) adult male Chamorros eating one 30 g serving of cycad flour per day combined with the consumption of eight flying foxes per month. The resultant cumulative lifetime Chamorro exposures ranged from 1 to 41 g/kg and are comparable to the total lifetime vervet exposures in our experiments of 2 and 22 g/kg, respectively. Furthermore, measured protein-bound BMAA concentrations of vervets fed L-BMAA powder are comparable to measured protein-bound BMAA concentrations in postmortem brain tissues of Chamorros who died with ALS/PDC.

Africa hosts a rich assemblage of cycads: 66 Encephalartos species, Stangeria eriopus and Cycas thouarsii. Most Encephalartos and S. eriopus adults appear to be fire-tolerant, and certain Encephalartos species may be fire-dependent. Four Encephalartos species and S. eriopus are primarily insect-pollinated. African cycad populations typically have sex ratios of 1:1, with very small populations often male-biased. Coning is typically infrequent and erratic, with many species exhibiting mast-seeding. Viable seed production in Encephalartos populations tends to decline with decreasing population size, and seed predation by weevils is common. Seed dispersal in Encephalartos is usually localized, but vertebrates may facilitate dispersal over longer distances. Stem material of 25 Encephalartos species and S. eriopus is used for traditional medicine, primarily in South Africa. Two-thirds of Africa’s cycad species are threatened, with four species already Extinct in the Wild. The illegal acquisition of cycads from wild populations is the principle threat to their persistence. Further research is recommended on seed and fire ecology, population dynamics, and the outcomes of conservation interventions.

The genus Zamia (Zamiaceae: Cycadales) exhibits its greatest diversity in Colombia and is highly threatened by habitat loss, extraction for ornamental plant trade, and mining, among other factors. One of the most important considerations for the effective conservation of Zamia is its highly specialized reproductive biology. Despite the importance of pollination for the populations’ viability, no studies have examined the pollination process of cycads in Colombia. Herein, we describe the pollination process of Zamia incognita A. Lindstr. & Idarraga, in a natural population. Exclusion experiments were performed by selectively excluding wind, beetles, both, or neither, which demonstrated that Pharaxonotha beetles are effective pollinators of Zamia incognita and that wind does not play any role as pollen vector. By following beetles marked with fluorescent dyes and directly observing beetle movements on and into female cones and micropyles, we confirmed that Pharaxonotha sp. is the effective pollinator of Z. incognita. The beetles traveled a maximum dispersal distance from a male to female cone of nearly 22 m and a minimum distance of 5 m. We found Pharaxonotha beetles in male cones, where they complete their life cycle. Cones produce heat in a circadian pattern associated with the elongation of the cones and pollen shedding. The increase in cones’ temperature appears to play an important role in beetle attraction. We suggest that pollination droplets on the micropyles would be a reward to pollinators. We also discuss the relationship of this Zamia species with other insects, which have important consequences for the conservation of web interactions.

Plants have multiple strategies, including phytochemicals that protect their vulnerable tissues against pathogens and herbivores. Dioon edule, like all cycads, possess unique azoxy-type compounds, azoxyglycosides (AZGs) as a chemical defense; however, the ontogenetic variability of these compounds in this long-lived cycad is unknown. Here, we investigated the effects of plant age, sex, genotype and individual heterozygosity on AZG levels in mature leaves of wild D. edule populations from eastern Mexico. Individuals were divided into three ontogenetic stages: seedlings, juveniles and adults. We established overall leaf quality by quantifying pigments associated with photosynthesis; chlorophylla, chlorophyllb and lutein. Leaf chlorophylla levels were higher in seedlings compared to adult cycads. Plants were genotyped using 11 microsatellite markers and foliar AZG levels were quantified by HPLC. AZG levels do not correlate with plant genotype or the individual’s heterozygosity. Genetic analysis identified a distinction between lowland and highland individuals; foliar AZG levels were higher in lowland adult cycads compared to highland individuals. In both populations, the highest AZG levels were found in seedlings compared to adult cycads. These young cycads are highly reliant on their few leaves since seedlings bear one or two leaves for the first years of their life and, thus, are unlikely to recover from defoliation. The results suggest that cycad leaves with a greater nutritive content and a higher value for long-term survival are better protected with higher AZG levels. Female adult cycads have higher AZG levels compared to males, suggesting that the benefits of defense could also be linked to reproductive costs.

Although South African cycads are known to be declining in the wild, there is at present no broad-scale, quantitative analysis to support this view. In this study the fate of 626 individual cycads was assessed from 107 repeat photographs taken at 53 locations over three time-steps (broadly 1940s, mid-1990s and 2014). Of the cycads photographed in the 1940s, 78 % survived to the mid-1990s. By 2014, however, only 16 % of the original cycads remained. The Limpopo Province had the highest rate of cycad loss over the recorded period, followed by the Eastern Cape and KwaZulu-Natal. Gauteng and Mpumalanga had the lowest rate of cycad loss. In general, cycad losses were greatest on land under private ownership when compared to communal land and conservation areas. However, cycad loss as a result of damage sustained due to traditional medicine collection was highest on communal lands. Continued declines in most of the studied cycad populations are a concern due to the potential Allee effects this may introduce. While legislation to protect cycads is in place, enforcement is difficult given the spatially extensive and often remote and patchy distribution of cycad populations. Conservation approaches that work actively with farmers to protect cycads on their property, as well as education about sustainable traditional medicine collection practices in communal areas have the best chance of ensuring the viability of wild cycad populations.

Habitat differences might promote adaptive differentiation among populations that can be evidenced by genotype-by-environment interactions (GxE). I examined GxE in seed germination and seedling survival in demes of a rainforest cycad across their native and degraded-forest habitats, and explored the role of maternal effects and resource availability on the observed GxE. A reciprocal-transplant experiment showed a home-site advantage in terms of establishmen of the demes. Germination in a manipulative greenhouse experiment mirrored the patterns in natural environments, with GxE in response to light and water availability. Overall germination was lower in the degraded-forest habitat and under high-light and low-water conditions in the greenhouse. Several analysis suggested that maternal effects related to size on germination are weak, but maternal effects are suggested by better survival of larger seedlings in the degraded-forest habitat. With weak maternal effects, GxE in establishment of individuals suggest some adaptive differentiation across demes in this cycad, which could have implications for population persistence in its habitats.

Several cycad species in the genus Macrozamia are threatened by habitat loss, fragmentation and pollinator loss including at least 11 that rely on the thrips Cycadothrips chadwicki for pollination and therefore their continued survival. We developed 18 highly polymorphic microsatellite markers (mean alleles per locus = 11.1) by 454 shotgun sequencing and present primer options for an additional 14,219 loci.

We tested for a tradeoff across species between plant maximum photosynthetic rate and the ability to maintain photosynthesis under adverse conditions in the unfavorable season. Such a trade-off would be consistent with the observed trade-off between maximum speed and endurance in athletes and some animals that has been explained by cost-benefit theory. This trend would have importance for the general understanding of leaf design, and would simplify models of annual leaf carbon relations. We tested for such a trade-off using a database analysis across vascular plants and using an experimental approach for 29 cycad species, representing an ancient plant lineage with diversified evergreen leaves. In both tests, a higher photosynthetic rate per mass or per area in the favorable season was associated with a stronger absolute or percent decline in the unfavorable season. We resolved a possible mechanism based on biomechanics and nitrogen allocation; cycads with high leaf toughness (leaf mass per area) and higher investment in leaf construction than in physiological function (C/N ratio) tended to have lower warm season photosynthesis but less depression in the cool season. We propose that this trade-off, consistent with cost-benefit theory, represents a significant physio-phenological constraint on the diversity and seasonal dynamics of photosynthetic rate.

The taxonomic status of the Mexican cycad Ceratozamia brevifrons is reassessed based on information from habitat, herbaria and living collections in the Botanic Garden ‘Jardin Botanico Francisco Javier Clavijero.’ Comparison of gross morphology of C. brevifrons with that of C. mexicana as well as analysis of leaflet anatomy, including that of C. robusta, has provided sufficient evidence for the removal of C. brevifrons from synonymy with C. mexicana. A neotype is designated for C. brevifrons and a description is presented.

Zamia tolimensis , a large arborescent species from the Central Cordillera of Tolima, Colombia, is described and illustrated. It is compared to Z. lindenii and Z. poeppigiana, the two most similar species. From these it is distinguished by leaflets with fewer teeth, sparse prickles on its petioles, beige-yellow ovulate strobili with shorter peduncles, and more microsporangia aggregated into a single group on the abaxial surface of the microsporophyll. Brief descriptions of Z. lindenii and Z. poeppigiana are also provided, as well as a key to separate the three species.

Variations in the chloroplast and mitochondrial DNA of Cycas revoluta Thunb. (Cycadaceae) were examined in 22 populations distributed across the Ryukyu Islands and southern Kyushu. Among the 14,130 bp of sequence examined, only one site mutation and one indel were polymorphic. The identified polymorphisms were located in the spacers between trnS (UGA) and trnfM (CAU) of the chloroplast DNA and between nad1 exon B and exon C of the mitochondrial DNA, respectively. Three haplotypes were identified from the Ryukyu Islands and southern Kyushu. The areas of distribution of the three haplotypes were highly geographically structured. The boundaries of two of the three haplotypes were demarcated by Okinoerabujima Island in the middle Ryukyus. The northern type and southern types lay north and south of the island, respectively. The third haplotype was almost sympatrically distributed with the southern type. The genetic variation within C. revoluta was estimated to be very low (h = 0.641, π = 0.00071) in comparison to its relative in Taiwan, C. taitungensis, which possesses 97 cpDNA haplotypes and 55 mtDNA haplotypes from two relic populations. A reasonable explanation for the low genetic diversity of the cycad on the Ryukyu Islands could be severe bottleneck effects, resulting from the submersion of low islands and the diminished landmass of islands in the interglacial age in the Quaternary period. The geographically restricted nature of the haplotypes could be attributed to vicariance resulting from the land configuration of the Ryukyu Islands, including changes in geography during the interglacial age in the Quaternary.

In the literature there is disagreement about the existence of a coleorhiza in cycad embryos. In this paper the terminology of the cycad ovule, seed and embryo is revised. It was confirmed that the cycad ovule and seed are pachychalazal and that the seed coat is exclusively formed by the pachychalaza. The term ‘pleurotesta’ as a substitute for the so-called ‘endotesta’ is suggested to describe the inner, membranous part of the seed coat. The anatomy of the cycad embryo was studied in comparison with the grass embryo and it was found that a coleorhiza does exist in cycad embryos and derives from the distal part of the suspensor. It is postulated that the coleorhiza in grasses also derives from the distal part of the suspensor and that the two structures are therefore structurally homologous.

Very little is known about the pre- and post-shedding megagametophyte development and utilisation of accumulated reserves, respectively, in cycads (Zamiaceae). In the present study on developing ovules of the recalcitrant-seeded species, Encephalartos natalensis, cells of the megagametophyte were found to become progressively packed with starch and protein as the two main storage reserves, a limited number of discrete lipid bodies, and occasional mitochondria all of which appeared to be embedded in a homogeneous matrix. ER-derived vesicles (and not Golgi-derived vesicles) appeared to be the principal contributors of the primary cell wall components, pectin and xylan, during megagametophyte cellularisation. This was confirmed by the use of enzyme-gold localisation. High-pressure freezing (HPF) and freeze substitution (FS) of samples the following season showed that while the apparently featureless cytomatrix of the megaspore was an artefact of conventional fixation, there was still an insignificant occurrence of Golgi bodies during primary wall formation. When enzyme-gold localisation was employed on the HPF-FS material, label for pectin and xylan was found only in the regions of ER and vesicles and not in any of the few Golgi bodies or their associated vesicles. Immunocytochemistry revealed that pectin and xylan were restricted to the ER and not to any vesicles or to the occasional Golgi body that was found. This suggests that the ER exclusively, is involved in the deposition of these primary cell wall components during the cellularisation of the E. natalensis megagametophyte. While cellularisation took place over approximately 1–2 weeks, subsequent development of the megagametophyte cells involved the accumulation of storage reserves, this phase lasting approximately 8 months—after which the seeds were shed whether pollination/fertilisation had recently occurred, or not.

Zamiapyrophylla, a new species from Choco, Colombia, is described and illustrated. It is compared to Z. amazonum, Z. cunaria, and Z. ipetiensis. It is distinguished by its bright orange and red emerging leaves with leaflets that progressively turn green from the apex to the base as they mature, petioles with branched prickles and with ferruginous pubescence when immature, villous strobilar axes, and adaxial microsporangia.

Foreign plants are usually introduced for food or aesthetic reasons. Most of these plants are non-invasive, but can alter the evolutionary trajectory of the associated native insects or inadvertently spread potential pests. A hitherto poorly documented example is the rapid expansion of Chilades pandava, a Cycas-feeding butterfly. Since about 1990, large numbers of the Sago Palm Cycas revoluta were introduced into Taiwan. Invading or introduced with this hostplant, Ch. pandava has rapidly spread to all major parts of Taiwan. To trace the source of outbreaks, we sampled 810 specimens covering 50 Taiwanese localities and other regions using mitochondrial COII sequences. Overall haplotype diversity was high (h = 0.791), but only 29 haplotypes were found. The haplotype C which dominates outbreak populations from western Taiwan was endemic to the island. This is consistent with the hypothesis of a local range expansion of Ch. pandava, rather than an introduction. In addition, the Taiwanese Central Mountain Ridge may constitute a primary biogeographic barrier restricting gene flow between eastern and western populations. Our study not only flags an important new invasive insect that needs to be monitored and controlled within the horticultural trade and for in situ cycad conservation, but also provides a clearly documented case of the transformation of a native tropical butterfly into a pest via introduced horticultural plants.

A recently discovered megafossil of whole plant cycad is briefly reported here. The specimen is collected from the Yangcaogou Formation (Upper Triassic) in Changheying, Beipiao, Liaoning. The whole plant is preserved intact on a sandstone slab, 89 cm long and 130 cm wide, including leaves up to 82 cm long and a male cone physically attached to the stem apex. Analysis on the morphology, arrangement and venation of leaf and pinna, male cone and its relationship with other parts indicates that the fossil is closely related to living Zamiaceae in Cycadales. This cycad fossil is hitherto most completely preserved cycad specimen including both vegetative and reproductive organs. Its discovery contributes much to our understanding of the morphology and evolution of cycads, palaeoclimate as well as palaeoenvironment.

We developed a set of 12 EST-microsatellite markers (EST-STRs) from Cycas rumphii Miq. and tested them on an ex situ collection of the endangered Cycas micronesica K.D. Hill. The number of alleles per locus in both species ranged from 1 to 15. Observed and expected heterozygosities ranged from 0.000 to 0.842, and 0.000 to 0.883, respectively. All primers amplified in four additional Cycas species. These markers are the first genome-enabled tools for cycad population level studies, and are now available to inform conservation efforts and disentangle the biogeographic history of the genus.

Background Bayesian relaxed-clock dating has significantly influenced our understanding of the timeline of biotic evolution. This approach requires the use of priors on the branching process, yet little is known about their impact on divergence time estimates. We investigated the effect of branching priors using the iconic cycads. We conducted phylogenetic estimations for 237 cycad species using three genes and two calibration strategies incorporating up to six fossil constraints to (i) test the impact of two different branching process priors on age estimates, (ii) assess which branching prior better fits the data, (iii) investigate branching prior impacts on diversification analyses, and (iv) provide insights into the diversification history of cycads. Results Using Bayes factors, we compared divergence time estimates and the inferred dynamics of diversification when using Yule versus birth-death priors. Bayes factors were calculated with marginal likelihood estimated with stepping-stone sampling. We found striking differences in age estimates and diversification dynamics depending on prior choice. Dating with the Yule prior suggested that extant cycad genera diversified in the Paleogene and with two diversification rate shifts. In contrast, dating with the birth-death prior yielded Neogene diversifications, and four rate shifts, one for each of the four richest genera. Nonetheless, dating with the two priors provided similar age estimates for the divergence of cycads from Ginkgo (Carboniferous) and their crown age (Permian). Of these, Bayes factors clearly supported the birth-death prior. Conclusions These results suggest the choice of the branching process prior can have a drastic influence on our understanding of evolutionary radiations. Therefore, all dating analyses must involve a model selection process using Bayes factors to select between a Yule or birth-death prior, in particular on ancient clades with a potential pattern of high extinction. We also provide new insights into the history of cycad diversification because we found (i) periods of extinction along the long branches of the genera consistent with fossil data, and (ii) high diversification rates within the Miocene genus radiations. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0347-8) contains supplementary material, which is available to authorized users.

The genus Cycas (Cycadaceae; gymnosperm) have circumstantially been considered to be wind-pollinated. The cones of Cycas revoluta Thunb., however, emit a strong unpleasant odor. The chemical profiles of floral scents often correlate with various pollination modes (pollinators). We collected and analyzed the volatiles emitted from male and female cones of C. revoluta native to Iriomote and Yonaguni Islands, Japan. The analyses indicated that estragole (4-allylanisole) dominated in the volatiles (67.0-92.7%), with small amounts of other benzenoids, e.g., anethole, methyl salicylate, methyl eugenol, and ethyl benzoate. Several fatty acid esters were also detected in the samples from Iriomote Island. The function of estragole in the reproductive biology of C. revoluta is discussed.

A new cycad species, Cycas annaikalensis, has been discovered from the Malabar Coast of the southern Western Ghats of India. Although geographically distributed in a small population within the range of C. circinalis, it can be distinguished from the other described Indian Cycas species by its distinct habitat, habit, morphology of vegetative and reproductive parts, and anatomy of leaflets.

The cycad Ceratozamia mirandae is endemic to Chiapas, Mexico. Demographic studies were made in two of its populations in the Sepultura Biosphere Reserve under different conservation con- ditions; in the nucleus zone ''Tres Picos'' (conserved) and buffer zone ''La Sombra'' (disturbed and under management). Spatial distribution of C. mirandae was aggregated, showed a clumped local distribution on shallow soils on steep slopes and male and female cones appear to be synchronous in both populations. The population structure was of type I (Bongers) for both sites. Individuals between the sites showed dif- ferences in growth pattern. The oldest plants (80- 90 cm tall) were estimated to be about 490 years at ''La Sombra''. The finite growth rate (k) in the buffer zone population showed a tendency for decrease whilst in the nucleus zone this estimate remained stable. The highest elasticity values lied in the transition of the first three classes of the ''La Sombra'' population, in ''Tres Picos'' this corresponded to adult plants between 20 and 30 cm tall. Given the above, it is proposed that in the nucleus zone, reproductive adults should be of highest conservation priority, whereas in the buffer zone seedling reintroduction should be carried out regularly until the population increases. We recom- mend an IUCN Red List category of Vulnerable (VU C, 2a), largely due to difficult-to-control destructive annual forest fires that occur in this Reserve.

Thermogenically elevated cone temperatures were measured in two Macrozamia cycad species that differ in their daily heating time. Mathematical models of the cones' thermo-physics were tested for their accuracy in predicting these cone temperatures and for comparison of the energetics of both species and the sexes within species. These models accurately predicted temperatures over approximately 8-h periods with average errors of: 0.46 degrees C for Macrozamia lucida, pollinated by the thrips, Cycadothrips chadwicki, that moves during mid-day concurrent with cone heating; and 0.38 degrees C for Macrozamia machinii, pollinated by the weevil, Tranes sp., that moves after sunset during cone heating. The combination of models and experiments revealed a thermogenic sexual dimorphism in both species. For M. lucida, the estimated female mass specific metabolisms, and their theoretically possible and actual temperature increases due to thermogenic metabolism were only 57, 67, and 76% of males. In addition, female thermogenic metabolisms began and peaked much earlier and lasted significantly longer than males (all differences1 h), and female metabolic peaks preceded their temperature peaks by 65 vs. 46 min for males. The timing of almost all male cone metabolic peaks was optimized with respect to the diurnal ambient heating cycle so that cone temperatures achieved a maximum temperature gain, whereas most female metabolic peaks occurred much earlier than optimal. In M. machinii, thermogenic sexual dimorphism is much larger since its male peak metabolisms are larger, and its females' peaks are much smaller compared to those of M. lucida. This study provides new information regarding the energetics of cycad cones that is relevant to understanding the interactions of the plant traits with their obligate pollinators' behavior.

Formation and location of phenolic compounds in apogeotropic roots (coralloid roots) were studied in six cycad species, which belong to the genera Cycas, Encephalartos, and Ceratozamia. Total contents of soluble phenolic compounds in coralloid roots in all species studied varied insignificantly, with except for Ceratozamia mexicana that accumulated three times higher amounts of phenolic compounds. Phenolic compounds were accumulated in cell walls of cortical parenchyma of coralloid roots, in intercellular spaces, and in specialized storage cells, found in all zones of apogeotropic roots. The greatest number of phenol-storing cells was situated in the cortical parenchyma of the central part of coralloid roots, adjacent to a zone where active symbiotic cyanobacteria were localized, and in the coralloid root basal region lacking viable forms of cyanobionts. It was suggested that phenolic compounds affect the formation of symbiosis between cyanobacteria and apogeotropic roots of cycad plants, as well as their metabolism.

I. Abstract We describe the spatial distribution, population structure, and fecundity of Ceratozamia matudai in two populations in the El Triunfo Biosphere Reserve, in Chiapas, Mexico. Three random plots of 20 × 20 m were laid out in a cypress forest habitat of the cycad and six plots in a cloud forest habitat on Mount Ovando. The aggregated spatial pattern of C. matudai showed a clumped local distribution on shallow soils on steep slopes. Individuals between the sites showed differences in leaf production, trunk diameter, height, and growth pattern. A population structure with an inverse “J” curve was obtained in both sites. Emergence of male and female cones appears to be synchronous in both populations, with a predominance of male cones recorded.

I. Abstract Polyxylic columnar stems covered by persistent leaf bases and found in sediments assignable to the Upper Cretaceous of Bajo de Santa Rosa, Rio Negro Province, Argentina, are described as two new generic entities in the Cycadales. Anatomical characters are the basis for their being assigned to the Encephalartoideae of the Zamiaceae. Brunoa santarrosensis gen. et sp. nov. is characterized by the presence of polyxyly, cone domes, mucilage cavities, and uniseriate to triseriate araucaroid, scalariform, or bordered intervascular pitting. Worsdellia bonettiae gen. et sp. nov. has polyxyly, anastomosing medullary vascular bundles, centripetal xylem, mucilage canals, and concentric extraxylary bundles. Some characters (polyxyly, medullary vascular bundles, and cone domes) were used to determine the systematic position, while other characters (mucilage reservoirs and centripetal xylem) were used to establish the relationship between polyxylic and monoxylic forms.

A list of the 305 currently recognized cycad species is given, along with citations of the original place of publication and the location of type specimens when known. Included in the list are currently recognized infraspecific taxa, brief geographical ranges, and a partial list of synonyms for each taxon.

The Mexican cycadDioon edule with its two varieties,edule andangustifolium, range from the states of Tamaulipas and Nuevo Leon in the north to the state of Veracruz in the south. The varietyangustifolium is restricted to the northern portions of the range, while the varietyedule is from the southernmost distribution in central Veracruz. Between the two varieties ofDioon edule there are a number of disjunct colonies that exhibit variations that are undoubtedly the result of an extended period of genetic isolation. These colonies display variation in the maximum size of their stems, morphology and color of leaves and leaflets, distinctions in both male and female cones, color of the sarcotesta, and size and shape of the sclerotesta. These differences are maintained even when specimens are grown in cultivation under identical conditions. Critical investigations of these colonies may ultimately disclose the need for additional species descriptions.

I. Abstract It has been possible to regenerate a few cycad species in vitro by somatic embryogenesis, either from zygotic embryos (Ceratozamia hildae, C. mexicana, Encephalartos cycadifolius, E. dyerianus, E. natalensis, Zamia fischeri, Z. furfuracea, and Z. pumila) or from leaves of mature phase trees (C. euryphyllidia, Ceratozamia hildae, and C. mexicana). This strategy has great potential for the commercial vegetative propagation of certain highly endangered species (e.g., C. euryphyllidia) and should indirectly protect wild populations of these species by discouraging collection in situ. Embryogenic cultures of several cycad species have grown vigorously and are highly morphogenic more than 11 years after induction. The long-term conservation of cycad genetic resources can also be addressed for species that can be regenerated by somatic embryogenesis. Preliminary studies indicate that embryogenic cultures that have been pretreated on plant growth medium containing 0.75 M sucrose for two days, encapsul...

I. Abstract The effect of two light intensities (25 µmol m−2s−1 and 50 µmol m−2s−1) on four developmental stages of Ceratozamia mexicana somatic embryos growing on semisolid plant growth medium at 25oC was measured. Growth parameters included fresh weight, morphology, and invertase and peroxidase activity. Under low light conditions, fresh weight was greater in stages 1 and 2 than in stages 3 and 4. In addition, there was a high frequency of hyperhydricity and polyembryogenesis in stages 1 and 2, whereas stages 3 and 4 were nonhyperhydric and unbranched. Stages 2–4 were green. Under high light conditions, embryos had lower fresh weights and less hyperhydricity, and stages 2–4 were green. Under low light conditions, peroxidase activity was less, although stage 1 embryos under both light conditions showed the highest activity. Stage 1 embryos required three to four months to develop to stage 2 under high light conditions and two to three months under low light conditions. Invertase activity under low light ...

Cone traits (volatile components and thermogenesis) of three cycad species in the genus Macrozamia were examined for differences related to their specific insect pollinators, the weevil, Tranes spp., or the thrips, Cycadothrips chadwicki. Linalool (>80% of emissions) dominated cone volatile components of M. machinii (Tranes-pollinated) and beta-myrcene was a minor component (

I. Abstract It has repeatedly been noted that ready availability of well-grown cycad specimens would substantially reduce collection of plants from their natural habitats. Although some cycads are extensively produced in several countries, there is uncertainty as to their optimal growing conditions and fertilizer requirements. Using Zamia floridana (sensu lato) as a model, one-year-old seedlings were grown in 30% and 50% light-exclusion shadehouses for one growing season. They were fertilized with roughly equivalent nutrient proportions of 20–20–20 (N–P–K) Peters solution at 300 ppm applied biweekly, nine-month 18–6–12 controlled-release Osmocote granules, and 16–8–12 Controlled Release Sierra Tablets plus minors at two and three tablets per container, and in combinations. There was interaction between shade and fertilizer types in all parameters measured. Overall, plants grown in 30% shade had a larger caudex, more leaves, and higher leaf and stem-plus-root fresh and dry weights. Peters fertilizer at 300...

We describe the occurrence of arbuscular mycorrhizae in the roots ofZamia pumila andDioon edule. Seedlings were grown on native, unsterilized soil taken from local pinelands of south Florida, whereZ. pumila occurs naturally. Arbuscules, hyphae, hyphal coils, and vesicles occur in the parenchyma cells of the root cortex, especially the half of the cortex next to the stele. Hyphae of the arbuscular mycorrhizal fungi (AMF) occur mainly in longitudinal intercellular spaces and conform to theAcorus type. The finest, ultimate roots have AMF, but these roots are extremely brittle, detach with the slightest disturbance, and are usually lost when plants are uprooted from the ground. No AMF were found in the cortex of coralloid roots. Open image in new window Vovides (1991) previously reported that AMF occur onDioon edule and Ceratozamia mexicana, and we reconfirm this inD. edule. In this species, AMF appear to be mostly associated with the outer and to a lesser extent the inner cortex. However, roots of a potted plant of C.hildae growing in native soil lacked AMF. When grown on low phosphorus soils, legumes are known to require AMF in order for theirRhizobium nodules to fix nitrogen. Without AMF, the legumes are deficient in phosphorus, which inhibits nodule production and nitrogen fixation. It is probable that cycads, with their nitrogen-fixing coralloid roots containingNostoc, may also require AMF for successful nitrogen fixation when phosphorus is limiting.

The microbial complexes of soil, the rhizosphere, and the rhizoplane of the apogeotropic (coralloid) roots of cycad plants were comparatively studied. The aseptically prepared homogenates of the surface-sterilized coralloid roots did not contain bacterial microsymbiont, indicating that in the root tissues the symbiosis is a two-component one (plant–cyanobacteria). At the same time, associated bacteria belonging to different taxonomic groups were detected in increasing amounts in the cycad rhizoplane, rhizosphere, and the surrounding soil. The bacterial communities found in the cycad rhizoplane and the surrounding soil were dominated by bacteria from the genus Bacillus. The saprotrophic bacteria and fungi colonizing the cycad rhizosphere and rhizoplane were dominated by microorganisms capable of degrading the plant cell walls. The local degradation of the cell wall was actually observed on the micrographs of the thin sections of cycad roots in the form of channels through which symbiotic cyanobacterial filaments can penetrate into the cortical parenchyma.

Somatic chromosomes of Stangeria eriopus (Stangeriaceae, Cycadales) were investigated by fluorescent in situ hybridization (FISH) using an 18S ribosomal DNA (rDNA) probe. Stangeria eriopus showed a chromosome number of 2n = 16 with a karyotype of 12 median-, 2 subterminal-, and 2 terminal-centromeric chromosomes. FISH study of S. eriopus revealed 16 signals made up of rDNA sites located on the terminal regions of the long arms of the 7 median- and 2 subterminal-centromeric chromosomes, on terminal region of the short arm of the 1 median-centromeric chromosome, on the terminal regions of the long and the short arms of 1 median- and 2 terminal-centromeric chromosomes. This result suggests that, not only karyomorphologically but also molecular-cytologically, the genus Stangeria may be more closely related to the genus Ceratozamia than the genus Bowenia or the genus Microcycas previously hypothesized.

The morphology and ultrastructure of associative microsymbiont complexes (AMC) isolated from the ferns Azolla pinnata and Azolla sp. and the apogeotropic roots of the cycad Cycas revoluta were studied. The composition of the AMC obtained includes the cyanobionts (symbiotic cyanobacteria) and satellite bacteria (SB). It was found that two types of cyanobacteria that substantially differ in their morphological organization are likely present as cyanobionts in the coralloids of C. revoluta. The isolated cyanobiont strains exhibited the morphological traits and regularities of development typical of the genus Nostoc; they were characterized by the ability of their cells to divide in mutually perpendicular planes. When isolating AMC from different morphological zones of C. revoluta apogeotropic roots, SB growth was revealed only around the pieces corresponding to the coralloid apical zone. No AMC components were revealed around the segments of the basal growth zone. Pure cyanobiont cultures were obtained from the AMC of C. revoluta coralloids. The AMC isolated from the ferns A. pinnata and Azolla sp. are characterized by obligate mutual dependence of the partners (the cyanobiont and SB).

Robertsonian fusion and centric fission are uniquely detectable in comparative studies of karyotype patterns. They are the most important types of karyotype change in animals but seem to be relatively uncommon in higher plants. Both modify intra- and interchromosomal recombination and linkage relationships and consequently patterns of genetic variation. When differentiating populations or species they can produce postulating barriers to gene flow. The number of reported cases of fusion or fission in higher plants has increased over the years but remains low, and most of these are casual comparisons of karyotypes without any follow-up investigation. This review focuses on more adequate studies made in a few groups. Studies in the Tradescantieae produce the strongest evidence for fusion as a type of orthoselection in the subfamily. Some species ofLycoris are also considered to have evolved their karyotypes in that way. Some genera of slipper orchids and the cycad genusZamia have populations where atypical chromosome number increase can be attributed to fission probably as a result of stressful influences. It is suggested that fusion may have been involved in the evolution of many stable karyotypes and that fission is generally a secondary destabilizing mechanism which may lead to refusion in the long term. Their proven incidence remains making it unwise to suggest that they have been major influences in karyotype evolution in higher plants.

This paper reports the first case of ex situ pollination and multiplication of the Central African giant cycad Encephalartos laurentianus De Wild. (Zamiaceae, Cycadales), a rare and endangered species cultivated at the National Botanical Gardens of Meise, Belgium. A brief description of the discovery, distribution and morphology of the species is given; artificial pollination and seed germination techniques are described. About 160 seeds were produced by each of the two pollinated female cones. While most seeds were stored in order to use them for exchanges, ten seeds were sown; germinability was 60%.

Embryogenic callus was induced from explanted pinnae of newly emerged leaves of mature plants ofCeratozamia mexicana var. Robusta (Gymnospermae, Cycadales) on a modified B5 formulation with 1 mg·liter−1 kinetin and 1 mg·liter−1 2,4-dichlorophenoxyacetic acid. Proembryos developed on induction medium, but they were more numerous after subculture onto phytohormone-free medium, which also enabled suspensors to elongate. For nearly 1.5 yr after explanting, subsequent development of somatic embryos was not observed as suspensors dedifferentiated to form embryogenic callus on phytohormone-free medium. After this time, cotyledonary somatic embryos developed at the distal end of the suspensors. Somatic embryos have germinated on phytohormone-free medium. This is the first report of regeneration by somatic embryogenesis of a gymnosperm species from a mature tree. This technique has great potential for preservation of the highly endangered cycads.

The seeds of cycad plants are a toxic food used by many Aboriginal groups in northern Australia. Acute symptoms produced after consumption of untreated Cycas seeds are due to azoxyglycosides, especially cycasin, although the toxic dose depends on the animal species tested. There are three traditional methods used to treat these seeds: brief leaching in water; prolonged leaching in water; and aging. Aboriginal people living at Donydji outstation in northeast Arnhem Land, most regularly consume aged seeds ofCycas angulata R.Br. Analyses of fresh seeds and seeds prepared at Donydji and in the laboratory indicate that cycasin is effectively removed by all the traditional preparation techniques, although each technique has an end product with different storage and handling properties. The social implications of processing need further elaboration, but these techniques have a long history and archaeological remains of seeds in Australia may date back to the Pleistocene.

Nostoc, a genus of filamentous, heterocystous, cyanobacteria, is widely distributed in the free-living state. It is also the most common phycobiont in N2-fixing lichens and occurs as the N2-fixing symbiont in a small and diverse group of green plants. These include several bryophyte genera (e.g. Anthoceros and Blasia), a pteridophyte genus (Azolla; while the symbiont is referred to asAnabaena azollae, it may be aNostoc spp.), a division of gymnosperms (the 10 cycad genera) and one angiosperm genus (Gunnera). In Gunnera the Nostoc apparently penetrates into the cells of the host. In the other associations Nostoc is extracellular but specific morphological modifications and/or structures of the host plant organs create an environment which fosters interaction and metabolite interchange.