Search

Cycas megagametophyte resources are translocated to developing seedlings through the persistent green cotyledons. The source activities of cotyledons and megagametophytes following germination are not adequately understood. The decline in megagametophyte weight during seedling development was quantified until ultimate tissue desiccation for two Cycas species. In addition, the influence of illuminating the green cotyledons during germination and initial radicle growth on megagametophyte, root, and cotyledon dry weight (DW) was determined to evaluate the role of cotyledon photosynthesis on growth and megagametophyte source activity. Cycas micronesica megagametophytes declined 64% in DW during initial growth of the radicle and maturation of the first true leaf. The rate of DW decline slowed after this stage but continued for 18 months when the seedlings were supported by six leaves. Cycas edentata megagametophytes exhibited similar patterns with a 72% decline in DW when the first true leaf reached full expansion, and the resources were depleted by ≈14 months when the seedlings had five leaves. Illuminating cotyledons during initial seedling growth reduced the rate of megagametophyte DW decline by up to 20% and increased total seedling DW above that of dark-grown seedlings by up to 21%. The results provide direct evidence for the long-term source activity of the Cycas megagametophyte and provide indirect evidence that photosynthetic contributions of illuminated cotyledons reduce the reliance on gametophytes as a source of resources for initial Cycas seedling growth. Improved design of Cycas nursery germination microenvironments may be enabled by this new knowledge. [ABSTRACT FROM AUTHOR]

Experimental manipulations of the balance between leaves as source organs and reproductive structures as sink organs have contributed greatly to our understanding of the assimilate partitioning and regulation of leaf photosynthesis. In order to add cycads to this research agenda, the full range in natural variation in leaf:seed ratio and incident light level of in situ Cycas micronesica was augmented with the experimental manipulation of leaf:seed ratios of C. micronesica and Cycas edentata in Guam and the Philippines. In every study, individual seed size and concentrations of megagametophyte carbon, starch, and sugars were not influenced by leaf:seed ratio. The leaf net photosynthesis (Pn) and operational efficiency of photosystem II were also quantified for the in situ studies, and leaf:seed ratio did not influence these leaf physiology traits. The natural variation in incident light revealed increased net Pn for C. micronesica trees receiving greater levels of light, but the sink traits of seeds were not influenced by these differences in source strength. The findings indicated that the size and sink activity of individual cycad seeds are constitutive traits that are not influenced by the relative balance between leaf source and seed sink size at the individual plant level. The results also reveal that upregulation or downregulation of cycad leaf Pn is not influenced by sink size or source:sink ratio. The massive amounts of nonstructural carbohydrates in cycad stems and roots may explain these findings, as these organs may be the primary source for strobilus and seed growth independently from leaf Pn. [ABSTRACT FROM AUTHOR]

Premise of research. Cycads in the extant Australian flora span both Cycadaceae and Zamiaceae, with Cycas —the sole genus in Cycadaceae—considered to have dispersed into Australia from East Asia and speciated there since the Miocene. This premise is untested because of the lack of a fossil record for Cycas in Australia. Methodology. We describe a pinnate partial cycad leaf impression from a Miocene fossil site in northern South Australia. Diagnostic characters for potential matches with other taxa, such as pinnate ferns, pinnate palms, and the univeined Podocarpus , were assessed against the fossil and eliminated. Multivariate analyses of morphological data from extant Australian Cycas species and likely morphological matches from Asia are used to interpret the fossil's possible affinities. Pivotal results. The fossil is a pinnate leaf with opposite linear to lanceolate leaflets with a single prominent midvein and no secondary veins, diagnostic of Cycas , and the lamina has few (ca. 20) widely spaced, long, broad leaflets. Apparent parallel veins on two leaflets are interpreted as preservation artifacts. This leaf morphology is more consistent with extant Cycas species of the former section Stangerioides from Southeast Asia than with extant Australian taxa from section Cycas , which are characterized by many (100–410) moderately to closely spaced leaflets with narrow laminae. This fossil is a significant temporal and geographic range extension for Cycas and the first record of a fossil Cycas from Australia. Co-occurring angiosperm taxa from the fossil flora are consistent with this cycad being part of a landscape dominated by sclerophyllous forest or woodland under a wet, though seasonally dry, possibly monsoonal climate. Conclusions. Cycas was present in Australia by the Miocene, although potentially representing a lineage absent from modern Australia, likely under a monsoonal climate consistent with that of extant species of Australian Cycas and Southeast Asian section Stangerioides. [ABSTRACT FROM AUTHOR]

Recent technological advancements in conservation genetics and genomics have resulted in diverse tools for aiding the conservation of species. The precision and resolution of high throughput sequencing technologies provide valuable insights to aid conservation decisions, but these technologies are often financially unfeasible or unavailable in resource constrained countries. Inter-Simple Sequence Repeat (ISSR) markers, when combined with sensitive automated detection systems, provide a simple, cheap means to investigate genetic diversity and discriminate closely related species. Here, we apply this technology to assess genetic diversity and taxonomic delimitation in the Encephalartos eugene-maraisii species complex, a highly threatened, taxonomically dubious group of cycads in South Africa. Our analyses support the taxonomic singularity of E. dyerianus, E. dolomiticus and E. eugene-maraisii. Relationships between E. nubimontanus and E. cupidus remain uncertain. E. middelburgensis samples showed no clustering but had poor amplification success. This study demonstrates the suitability of automated ISSR fingerprinting as a method for plant conservation studies, especially in resource-constrained countries, and we make recommendations as to how this methodology can be effectively implemented. [ABSTRACT FROM AUTHOR]

Cycads have a unique phylogenetic position within the gymnosperms which is most typically recognized by the production of motile sperm. The formation of sperm in Cycas revoluta was discovered in 1896 by Seiichiro Ikeno. This discovery and that of Ginkgo biloba by Sakugoro Hirase represent the first great scientific achievements in Japan after the Meiji Restoration. The role of Seiichiro Ikeno in these achievements is highlighted in this review. Later, he became a pioneer in the introduction of genetics and genetic studies in Japan. Throughout his life, he devoted himself to scientific studies. [ABSTRACT FROM AUTHOR]

Callioratis millari Hampson (Lepidoptera: Geometridae) is a Critically Endangered moth endemic to South Africa. Despite extensive searches, it was previously known only from the Entumeni Nature Reserve in KwaZulu-Natal, where its larvae exclusively feed on the cycad Stangeria eriopus (Kunze) Baill (Cycadales: Stangeriaceae). In July 2022, a new population of C. millari was discovered in the Kabouga section of Addo Elephant National Park in the Eastern Cape. Larvae of C. millari were feeding on the cycad Encephalartos caffer (Thunb.) Lehm (Cycadales: Zamiaceae), which also constitutes a new host record. In June 2023, we determined larval incidence and herbivory at this new locality, offering insights into the ecological requirements of C. millari. Known C. millari localities, although ecologically different, share low altitudes (700–950 m a.s.l.), moderate to high rainfall, and grassy habitats with sparse woody cover. A total of 59 larvae were counted in Kabouga, mostly in the fifth and sixth (final) instars. Herbivory incidence was lower on smaller plants and those covered by other vegetation. The flight period of adult C. millari likely occurs between mid-March and April in Kabouga, but further investigation is needed to clarify this. The peak period of larval occurrence in Kabouga occurs during the driest and coldest months of the year (May–July). Considering limited habitat availability, host plant poaching, and the risk of untimely fires, the species should be considered highly threatened. This study adds to our understanding of the biology of C. millari and provides information on its ecological requirements and may contribute to making informed management decisions. [ABSTRACT FROM AUTHOR]

Translocation of endangered plant species and facilitating in situ regeneration require knowledge of the factors that define suitable habitat characteristics. Four approaches were employed to define how antecedent and contemporary plant identity influenced Cycas seedling growth and survival in Guam, Yap, and the Philippines. Cycas micronesica K.D. Hill or Cycas nitida K.D. Hill & A. Lindstr. seedlings growing beneath the canopy of the maternal parent tree reached 100% mortality in 4 to 8 year. Cycas micronesica seedlings planted beneath a conspecific male adult tree reached 68% mortality in two years while seedlings planted away from a conspecific individual exhibited 100% survival. Cycas micronesica seedlings planted beneath monostands of invasive Leucaena leucocephala (Lam.) de Wit or Vitex parviflora Juss. reached 40% mortality in two years while seedlings planted in adjacent native forest cover exhibited 100% survival. Cycas micronesica seedlings planted in soil conditioned for 9 months by conspecifics, heterospecific native species, Carica papaya L., L. leucocephala, or V. parviflora exhibited the greatest growth in the soils conditioned by heterospecific natives and the least growth in the soils conditioned by the three invasive species. The seedlings growing in soil conditioned by conspecifics exhibited the most coralloid roots and the greatest shoot:root ratio. These studies confirmed that the identity of antecedent and competitive plants strongly influenced the longevity and growth of Cycas seedlings. Conservationists may improve outcomes by avoiding degraded forests that have experienced invasive plant species when positioning translocation projects. Planting Cycas seedlings in biodiverse native forest but away from a conspecific individual may lead to the greatest success in population recovery.

This article examines historical and contemporary evidence for the importance of cycads as sources of psychoactive experiences for ritual and recreational purposes. Methods used include critical analysis and comparison of published and gray literature as well as ethnographic accounts gathered by the author in Mexico and South Africa. The consumption of cycad parts (pollen, coralloid root, and caudex) to derive an intentional psychoactive effect as a drug may implicate the neurotoxic amino acid BMAA, while fermentation and distillation of cycad starch result in intoxication from alcohol. Cycad ingestion is related to medicinal uses, magico-religious practice, and sexual stimulation as an aphrodisiac. Interconnections between these functions, the ceremonial importance of cycads, and conservation implications are discussed. Conclusions include the need to better understand effects on users and on cycad populations, and the potential pitfalls and opportunities psychoactive uses present for community-based conservation. [ABSTRACT FROM AUTHOR]

Translocation of endangered plant species and facilitating in situ regeneration require knowledge of the factors that define suitable habitat characteristics. Four approaches were employed to define how antecedent and contemporary plant identity influenced Cycas seedling growth and survival in Guam, Yap, and the Philippines. Cycas micronesica K.D. Hill or Cycas nitida K.D. Hill & A. Lindstr. seedlings growing beneath the canopy of the maternal parent tree reached 100% mortality in 4 to 8 year. Cycas micronesica seedlings planted beneath a conspecific male adult tree reached 68% mortality in two years while seedlings planted away from a conspecific individual exhibited 100% survival. Cycas micronesica seedlings planted beneath monostands of invasive Leucaena leucocephala (Lam.) de Wit or Vitex parviflora Juss. reached 40% mortality in two years while seedlings planted in adjacent native forest cover exhibited 100% survival. Cycas micronesica seedlings planted in soil conditioned for 9 months by conspecifics, heterospecific native species, Carica papaya L., L. leucocephala, or V. parviflora exhibited the greatest growth in the soils conditioned by heterospecific natives and the least growth in the soils conditioned by the three invasive species. The seedlings growing in soil conditioned by conspecifics exhibited the most coralloid roots and the greatest shoot:root ratio. These studies confirmed that the identity of antecedent and competitive plants strongly influenced the longevity and growth of Cycas seedlings. Conservationists may improve outcomes by avoiding degraded forests that have experienced invasive plant species when positioning translocation projects. Planting Cycas seedlings in biodiverse native forest but away from a conspecific individual may lead to the greatest success in population recovery. [ABSTRACT FROM AUTHOR]

Cycad transplantation and asexual propagation by stem cuttings are highly successful horticultural procedures because the manoxylic stems contain copious nonstructural carbohydrates. The success of these horticultural procedures may be impaired by antecedent abiotic or biotic stress that decreases stem nonstructural carbohydrate content. The armored scale Aulacaspis yasumatsui Takagi has emerged as a global threat to cycad conservation, and the direct influence of A. yasumatsui herbivory on cycad transplantation or asexual propagation outcomes has not been adequately determined. Cycas revoluta Thunb. plants were infested with A. yasumatsui for 0, 20, or 40 weeks to determine the influence of infestation duration on transplantation or asexual propagation success. Following 20 weeks of infestation in one study, 100% of the undisturbed replications but only 60% of the transplanted replications survived. Following 40 weeks, 80% of the undisturbed replications but only 40% of the transplanted replications survived. Following 20 weeks of infestation in a second study, 100% of the intact replications but only 43% of the cuttings survived. Following 40 weeks, 86% of the intact replications and none of the cuttings survived. Leaf number and root, stem, and leaf dry weights followed similar trends, with declines in these metrics occurring with longer infestation durations. These outcomes indicated that adding the stress of asexual propagation or transplantation to C. revoluta plants that were damaged by A. yasumatsui herbivory decreased subsequent plant health and increased mortality. [ABSTRACT FROM AUTHOR]

Zamia integrifolia L.f. (Cycadales), a threatened cycad native to Florida, depends on 2 native beetle species for pollination: Rhopalotria slossoni (Chevrolat; Coleoptera: Belidae) and Pharaxanotha floridana (Casey; Coleoptera: Erotylidae). Both insects are brood-site pollination mutualists, known to live and feed within the pollen (male) cone. However, for pollination to occur, beetles must also visit ovulate (female) cones, which have been assumed to offer no benefits to them as food or nurseries. We tested the potential for beetle pollinator use of ovulate cones by performing no-choice behavior and feeding trials for adults of both beetle species on both ovulate cones and pollen cones of Z. integrifolia. Rhopalotria slossoni beetles showed greater survival on ovulate cone tissues despite showing no significant difference in total tissue mass consumed between cone sexes. Conversely, P. floridana consumed more tissue mass from ovulate cone scales yet showed no difference in survivorship on ovulate vs. pollen cone scales. Although neither beetle species is found in large numbers on ovulate cones in the field, our laboratory study suggests that both species could potentially benefit from feeding on ovulate cone tissues, questioning the standing hypothesis that Z. integrifolia pollination occurs by deceit. Zamia integrifolia L. f. (Cycadales), una cicadácea nativa amenazada en la Florida, depende de 2 especies nativas de escarabajos para la polinización: Rhopalotria slossoni (Chevrolat; Coleoptera: Belidae) y Pharaxanotha floridana (Casey; Coleoptera: Erotylidae). Ambos insectos son mutualistas de la polinización del sitio de cría, y se sabe que viven y se alimentan dentro del cono de polen (macho). Sin embargo, para que ocurra la polinización, los escarabajos también deben visitar conos de ovulación (femeninos), que se supone que no les ofrecen ningún beneficio como alimento o vivero. Probamos el potencial para el uso de conos de ovulación por parte de escarabajos polinizadores, esto mediante la realización de pruebas de alimentación y comportamiento de no elección para adultos de ambas especies de escarabajos tanto en conos de ovulación como en conos de polen de Z. integrifolia. Los escarabajos Rhopalotria slossoni mostraron una mayor sobrevivencia en los tejidos del cono ovulado a pesar de no mostrar diferencias significativas en la masa total de tejido consumido entre los sexos del cono. Por el contrario, P. floridana consumió más masa de tejido de las escamas de los conos de ovulación, pero no mostró diferencias en la sobrevivencia en las escamas de los conos de ovulación frente a las de los conos de polen. Aunque ninguna de las especies de escarabajos se encuentra en grandes cantidades en los conos de ovulación en el campo, nuestro estudio de laboratorio sugiere que ambas especies podrían beneficiarse potencialmente al alimentarse de los tejidos de los conos de ovulación, lo que cuestiona la hipótesis actual de que la polinización de Z. integrifolia se produce por engaño. [ABSTRACT FROM AUTHOR]

This article describes the methods of toxicity removal for Cycas revoluta Thunb., used as food on the islands of Amami and Okinawa in the Ryukyu Arc. Regional differences were found in the method of toxin removal from the trunk, which was perceived to make no difference in previous studies. A map showing the geographic distribution of these toxicity removal methods was generated, and the historical origins of the differences in the techniques were discussed. Then, we compared it with the Guam case, where cycads used to be a daily food source. Cycad is still produced as a traditional delicacy in Amami and Okinawa, where cycad consumption was encouraged by the local government, and safe methods of detoxifying the cycad were well known. Beautiful cycad forests can still be seen here and there, especially in Amami. However, in Guam, cycads have been banned since the time of Spanish governors and are not consumed at all. Consequently, they are on the verge of extinction. [ABSTRACT FROM AUTHOR]

Zamia magnifica (Zamiaceae), a new species endemic to Sierra Norte, Oaxaca, Mexico, is described. Zamia magnifica is characterized by having a rupicolous habit, pendent leaves bearing leaflets that are densely tomentose and pink to caramel in color when emerging, and broad oblong leaflets that are coriaceous in texture with few non-prominent denticulations and ovulate strobili with short (Z. furfuracea and Z. meermanii, the Mesoamerican Zamia species to which it shares the closest morphological resemblance.

A cryptic lineage is a genetically diverged but morphologically unrecognized variant of a known species. Clarifying cryptic lineage evolution is essential for quantifying species diversity. In sympatric cryptic lineage divergence compared with allopatric divergence, the forces of divergent selection and mating patterns override geographical isolation. Introgression, by supplying preadapted or neutral standing genetic variations, can promote sympatric cryptic lineage divergence via selection. However, most studies concentrated on extant species introgression, ignoring the genetic legacy of introgression from extinct or unsampled lineages ("ghost introgression"). Cycads are an ideal plant for studying the influence of ghost introgression because of their common interspecific gene flow and past high extinction rate. Here, we utilized reference‐based ddRADseq to clarify the role of ghost introgression in the evolution of a previously identified sympatric cryptic lineage in Cycas revoluta. After re‐evaluating the evolutionary independency of cryptic lineages, the group‐wise diverged single‐nucleotide polymorphisms among sympatric and allopatric lineages were compared and functionally annotated. Next, we employed an approximate Bayesian computation method for hypothesis testing to clarify the cryptic lineage evolution and ghost introgression effect. SNPs with the genomic signatures of ghost introgression were further annotated. Our results reconfirmed the evolutionary independency of cryptic lineage among C. revoluta and demonstrated that ghost introgression to the noncryptic lineage facilitated their divergence. Gene function related to heat stress and disease resistance implied ecological adaptation of the main extant populations of C. revoluta. [ABSTRACT FROM AUTHOR]

Encephalartos eugene-maraisii is an endangered, endemic plant in the Waterberg Mountain range of South Africa. This is the first report of herbivory by Zerenopsis lepida (Lepidoptera: Geometridae) on natural populations of E. eugene-maraisii. The impact of herbivory by folivorous arthropods on this cycad species has not been studied before. This study aimed to determine the incidence and intensity of Z. lepida herbivory on E. eugene-maraisii under field conditions. Local plant dynamics were studied by recording the plant location, sex, size and phenological stage for each plant. Damage surveys were carried out over two consecutive seasons (2020–2021 and 2021–2022). Leaf damage was assessed on 227 plants comprising 692 stems. Approximately 40% of the stems had signs of leaf herbivory by Z. lepida and 10% of the total leaf area was removed by Z. lepida larvae. Less herbivory was recorded in areas where plants synchronously produced new leaf flushes compared to areas with asynchronous leaf flushes. Greater apparency of plants led to a greater incidence of herbivory and level of damage. Repeated damage to plants may delay future leaf and cone flushing events and contribute to the threat against this cycad species. [ABSTRACT FROM AUTHOR]

Zamia magnifica (Zamiaceae), a new species endemic to Sierra Norte, Oaxaca, Mexico, is described. Zamia magnifica is characterized by having a rupicolous habit, pendent leaves bearing leaflets that are densely tomentose and pink to caramel in color when emerging, and broad oblong leaflets that are coriaceous in texture with few non-prominent denticulations and ovulate strobili with short (<4 cm) peduncles. It is compared to Z. furfuracea and Z. meermanii, the Mesoamerican Zamia species to which it shares the closest morphological resemblance. [ABSTRACT FROM AUTHOR]

Cycas revoluta (Cycadaceae) is commonly cultivated as an ornamental tree in several countries. In April 2015, C. revoluta leaves showing brownish spots with a yellow halo that progressed to leaflet necrosis were observed in Belém, Pará state, Brazil. This study aimed to determine the aetiology of this disease on sago palm in Brazil. Based on DNA sequence‐based phylogeny, morphology, and colony characterization, the fungus was identified as Pseudopestalotiopsis elaeidis. To the best of our knowledge, this is the first report of P. elaeidis associated with leaf spots on C. revoluta worldwide. [ABSTRACT FROM AUTHOR]

• The most comprehensive phylogeny to date of the endangered genus Encephalartos is presented. • Resolution is improved on from previous studies by utilizing additional nuclear and plastid genes. • Five biogeographical patterns of Encephalartos have been observed through Africa. • The results here can provide a foundation for future work on Encephalartos. The African endemic cycad genus Encephalartos consists of 68 extant taxa, that are of great conservation concern as 85% are threatened (CR, EN, or VU) and four, are extinct in the wild (EW). Due to there being no formally published monographs for the genus, there is lack of consensus on taxonomically significant characters. This lack of clarity regarding the species relationships and access to several taxa have made researching this group challenging. Nevertheless, numerous studies have proven that this genus has low levels of genetic variation over a wide distribution. The aim of this study was to produce the most robust phylogenetic reconstruction of Encephalartos to date. This was done by using markers from three different genomes – plastid (rbcL, matK-trnK, trnH-psbA, cab), mitochondrial (nad1) and nuclear (26S, AGAMOUS , NEEDLY, nrITS1) – for all currently accepted taxa. The results obtained show an increase in resolution for both the backbone and species level relationships compared to previous work. This genus can be separated into five new geographic groups – northern African, central African, eastern African, Mozambican-Zimbabwean, and southern African. There is also an indication that the evolution of the southern African group is driven by a form of reproductive isolation. Further studies on this group should be approached systematically based on the foundation provided by the linages that are shown in this study. [ABSTRACT FROM AUTHOR]

The composition of fluids that mediate fertilization in cycads is described for the first time. Using tandem mass spectrometry, proteomes of two stages of fluid production, megagametophyte fluid and archegonial chamber fluid production, are compared in Cycas revoluta. These were compared with the proteome of another sexual fluid produced by ovules, the pollination drop proteins. Cycad ovules produce complex liquids immediately prior fertilization. Compared with the pollination drops that mainly had few proteins in classes involved in defense and carbohydrate modification, megagametophyte fluid and archegonial chamber fluid had larger proteomes with many more protein classes, e.g. proteins involved in programmed cell death. Using high-performance liquid chromatography, megagametophyte fluid and archegonial chamber fluid were shown to have elevated concentrations of smaller molecular weight molecules including glucose, pectin and glutamic acid. Compared to megagametophyte fluid, archegonial chamber fluid had elevated pH as well as higher osmolality. [ABSTRACT FROM AUTHOR]

Zamia inermis is a dioecious cycad endemic to the State of Veracruz that is on the risk extinction. Sex-specific markers are important in understanding the mechanism of sex determination. However, since little is known about the mechanism of sex determination in Z. inermis, we proposed looking for Inter-simple Sequence Repeats (ISSR) markers that could be linked to sexual expression in this species. Using DNA bulk samples of male and female genotypes and 6 ISSR primers, a female marker (~867 bp) was identified with primer ISSR-18, which was present in 66% of the DNA mixtures of the female genotypes analyzed. The results of the Principal Coordinate Analysis performed revealed a tendency for clustering of genotypes of the same sex.

Cycad transplantation and asexual propagation by stem cuttings are highly successful horticultural procedures because the manoxylic stems contain copious nonstructural carbohydrates. The success of these horticultural procedures may be impaired by antecedent abiotic or biotic stress that decreases stem nonstructural carbohydrate content. The armored scale Aulacaspis yasumatsui Takagi has emerged as a global threat to cycad conservation, and the direct influence of A. yasumatsui herbivory on cycad transplantation or asexual propagation outcomes has not been adequately determined. Cycas revoluta Thunb. plants were infested with A. yasumatsui for 0, 20, or 40 weeks to determine the influence of infestation duration on transplantation or asexual propagation success. Following 20 weeks of infestation in one study, 100% of the undisturbed replications but only 60% of the transplanted replications survived. Following 40 weeks, 80% of the undisturbed replications but only 40% of the transplanted replications survived. Following 20 weeks of infestation in a second study, 100% of the intact replications but only 43% of the cuttings survived. Following 40 weeks, 86% of the intact replications and none of the cuttings survived. Leaf number and root, stem, and leaf dry weights followed similar trends, with declines in these metrics occurring with longer infestation durations. These outcomes indicated that adding the stress of asexual propagation or transplantation to C. revoluta plants that were damaged by A. yasumatsui herbivory decreased subsequent plant health and increased mortality.

Premise of research. Numerous large permineralized fossil seeds from the Jurassic of Haida Gwaii, western Canada, provide evidence for the mode and tempo of cycad evolution. Methodology. Fossil seed specimens are studied from external morphology and serially sectioned by the classic cellulose acetate peel technique to reveal anatomical features of the integument, vascular system, nucellus, and gametophyte. Fossils are compared to living cycad seeds that are also examined from external views, dissections, and anatomical preparations. Pivotal results. The fossil seeds are described as Traskia maahlae gen. et sp. nov. Features of the integument and vascular system reveal that T. maahlae is a stem group cycad that shares seed architecture and mode of germination with living Cycas spp. Conclusions. Traskia maahlae adds to a growing body of paleontological data on stem and crown group cycads. Results suggest that modern pollination and postpollination biology and the two contrasting modes of cycad seed germination evolved during the Mesozoic but that crown group cycad species may not have appeared until the Cenozoic. [ABSTRACT FROM AUTHOR]

The bioaccumulation of environmental toxins as possible risk factors in the etiology ofamyotrophic lateral sclerosis and parkinsonism-dementia complex (ALS/PDC) is studied inthree foci of the Western Pacific: Guam, the Kii Peninsula, and West Papua New Guinea. Theobjective of this study was to evaluate the best evidence on the exogenous causes of ALS/PDC, with emphasis on the role of cycads, iron, and manganese in the Western Pacific foci,by performing a systematic review of major electronic databases using predefined criteria, 68of which met the selection criteria. Two major environmental hypotheses are associated withthis enigmatic disease: the vegetal hypothesis, which focuses on the neurotoxic and genotoxicproperties of the cycad, and the mineral hypothesis, which focuses on the neurotoxic propertiesof metals. Although typically studied independently, environmental data suggests these twohypotheses may, in fact, converge. Epidemiologic research investigating the association betweenexposure to environmental toxins and ALS/PDC has proven inconclusive. Nevertheless,possible causal links indicate a need for more holistic research to not only better understandALS/PDC, but also glean new insights regarding the associated neurodegenerative diseases.

Chilinia is an extinct genus of cycads, established by Li and Ye in 1964 based on leaf fossils from the Lower Cretaceous in Jilin Province, China. Morphologically, the genus Chilinia closely resembles Ctenis , another cycad foliage genus, in having pinnately divided leaves with laterally inserted pinnae on the rachis and reticulate venation but differs mainly from the latter in having toothed or irregularly lobed rather than entire-margined pinnae. Fossil records show that up to now, nine species of Chilinia have been reported worldwide, representing an index fossil plant in the Jurassic to Early Cretaceous. In this study, we present a comprehensive overview of all reported Chilinia fossils from a systematic palaeobotanical perspective. Fossil records indicate that Chilinia mainly occurred in the middle–high latitudes of the northern and southern hemispheres in Pangea from the Middle Jurassic to Middle Cretaceous. Combined evidence from the morphology of Chilinia and its floral patterns suggests that the genus probably lived in humid warm-temperate palaeoclimatic conditions with brief seasonal variations. • A comprehensive overview of the extinct cycad Chilinia fossils are performed by morphological and cluster analysis approaches. • Chilinia has 9 species worldwide, represents an index plant taxon during Middle Jurassic to Middle Cretaceous. • Global fossil records show that Chilinia distributed in middle to high latitude of both northern and southern hemispheres in Pangea. • Chilinia lived in humid warm-temperate paleoclimate condition with seasonal variations. [ABSTRACT FROM AUTHOR]

Abstract Epiphytes face several constraints regarding nutrient acquisition: They are disconnected from soil minerals and they have to mainly rely on nutrients leached by precipitation and microbes. The cycad, Zamia pseudoparasitica Yates, is the only known strictly epiphytic gymnosperm, and it is endemic to Panamanian rainforests. Cycads have evolved specialized coralloid roots that host endophytic cyanobacteria specialized in nitrogen fixation. We collected coralloid roots from plants in the Omar Torrijos National Park, Provincia de Coclé. DNA was extracted from fresh inner coralloid roots, and the bacteriome was described using two molecular markers: rbcL‐rbcX (targeting cyanobacteria) and 16S (all bacteria). Sixteen samples were sequenced for rbcL‐rbcX yielding sequences belonging to a monophyletic group within the order Nostocales. One hundred and sixty‐five amplicon sequence variants (ASVs) were found in at least two of our 27 samples amplified for 16S. Nostocales, Rhizobiales, and Acetobacterales were the three most diverse and abundant orders of bacteria found within the coralloid roots, and the candidate phylum WPS‐2 was also found in many samples. We performed a de novo assembly from a single culture of the endophytic cyanobacteria. A phylogenomic analysis of the isolate places the cyanobacterium in a sister clade to mostly symbiotic taxa from mosses, liverworts, and lichens. Additionally, the isolate has genes putatively involved in symbiotic signaling, hormogonium differentiation, ammonium transport, nitrogen fixation, heterocyst differentiation, sulfate transport, and secondary metabolites. Although dominated by organisms with the capacity to fix nitrogen, coralloid roots are also inhabited by a diverse community of other taxa which may also play biologically important roles.

Peter S Spencer Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USACorrespondence: Peter S SpencerOregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 Tel +1 503 209-0986Email spencer@ohsu.eduPurpose: To reexamine the etiology of a unique retinal pathology (linear and vermiform sub-retinal tubular structures) described among subjects with and without neurodegenerative disease in former high-incidence foci of Western Pacific amyotrophic lateral sclerosis and parkinsonism-dementia complex (ALS/PDC) in Guam (USA) and the Kii peninsula of Honshu island (Japan).Methods: Analysis of published and unpublished reports of 1) ALS/PDC and the retinal and cerebellar pathology associated therewith and 2) exogenous neurotoxic factors associated with ALS/PDC and the developing retina and cerebellum.Results: ALS/PDC retinal and cerebellar pathology matches persistent retinal and cerebellar dysplasia found in laboratory animals given single in utero or postnatal systemic treatment with cycasin, the principal neurotoxic component in the seed of cycad plants traditionally used for food (Guam) or oral medicine (Kii-Japan), both of which have been linked to the human neurodegenerative disease.Conclusion: ALS/PDC-associated retinal and cerebellar dysplasia could arise from in utero exposure to methylazoxymethanol, the genotoxic metabolite of cycasin that results from maternal ingestion of this azoxyglucoside. These results support the environmental toxic etiology of retinal and brain pathology in ALS/PDC.Keywords: amyotrophic lateral sclerosis, cycad, DNA damage, Guam, methylazoxymethanol, photoreceptor, retinal development, retinal dysplasia, retinal epitheliopathy, rosettes

The influences of indole-3-butyric acid (IBA) concentrations of 0–30 mg·g−1 on the success and speed of adventitious root development of Zamia furfuracea L.f. and Zamia integrifolia L.f. stem cuttings were determined. Root formation success for both species was greater than 95%. The IBA concentrations did not influence the speed of root development for Z. furfuracea, but the Z. integrifolia cuttings that received IBA concentration of 3 mg·g−1 generated adventitious roots more slowly than the cuttings in the control group. The ending dry weights of the stems, leaves, and roots were not influenced by IBA concentration for either species. Our results indicated that adventitious root formation on stem cuttings of these two Zamia species is successful without horticultural application of IBA. Additional IBA studies are needed on the other 300+ cycad species, especially those that are in a threatened category.

AGAMOUS (AG) is a class C MADS-box gene that plays an important role in the development of reproductive organs in angiosperms and gymnosperms. Here, an AGAMOUS homolog was isolated from male and female Zamia muricata. Lengths of nucleotide sequences were 1,262 and 1,537 bp, respectively, and both represented 672 bp of open reading frame corresponding to 224 amino acid residues of predicted protein. The amino acid sequences showed high similarity to AG protein from Cycas (C. elephantipes, C. nongnoochiae, C. taitungensis, C. pranburiensis and C. edentata) and revealed a conserved region at MADSbox (M) and Keratin-like box (K). A phylogenetic tree based on the amino acid sequences of AG protein of angiosperms and gymnosperms indicated that Zamia and gymnosperms were grouped together with high bootstrap support.

Two ascomycetes, Neofusicoccum sp. and Xylaria sp. , were isolated from healthy leaves of the tropical gymnosperms Zamia pseudoparasitica (Z2) and Zamia nana (Z50) from Panama. The two draft genomes possess a broad predicted repertoire of carbohydrate-degrading CAZymes, peptidases, and secondary metabolites, with more secondary metabolite clusters in the Xylaria isolate., Competing Interests: The authors declare no conflict of interest.

Raising insects in a laboratory for release into the wild is a common conservation practice, but maintaining breeding colonies year‐round can be limited by seasonal food availability. Food availability is particularly challenging for insects which depend on specific host plants. For example, our early efforts to rear the imperiled Atala hairstreak butterfly (Eumaeus atala Poey) resulted in colony failure during winter due to lack of food. To overcome this barrier, we developed a modified freeze‐dried host plant diet to support the colony. The diet consisted of reconstituted freeze‐dried leaves and stems from fresh‐growth coontie (Zamia integrifolia), the host plant for the Atala butterflies. We fed larvae less than 9 mm on this freeze‐dried diet and transferred them to live coontie plants after they were more than 9 mm. We reared a colony of Atala butterflies using these methods for 859 days, resulting in more than 3400 animals released into the wild. Comparing colony counts during that time period to the 548 days we reared them without modified freeze‐dried diet showed a clear benefit in using freeze‐dried diet. A growth trial (N = 40) of larvae fed on only freeze‐dried diet compared to larvae fed on fresh coontie cuttings found no significant difference in larval or pupal development between groups (p = 0.71 and p = 0.47, respectively). We, therefore, conclude that the freeze‐dried diet provided an appropriate alternative for Atala colonies when fresh growth from the host plant is unavailable, and we recommend use of this technique for raising other host plant‐dependent insect species of conservation concern. RESEARCH HIGHLIGHTS: When rearing butterflies ex situ for conservation, many species of butterflies are highly host‐plant specific, and it can be difficult to provide enough food for them during nongrowing seasonsAfter a colony failure due to food shortage, we created a modified freeze‐dried diet for the imperiled Atala hairstreak butterfly (Eumaus atala) using methods that could potentially be replicated for other butterfliesThe diet was highly successful, leading to the rearing and release of over 3800 adult butterflies back into the wildKey to the methods was using pure, new‐growth host plant, and switching larger larvae back to mature leaves [ABSTRACT FROM AUTHOR]

The literature covering the biology, invasion chronology, host plant responses, and control efforts of the armored scale Aulacaspis yasumatsui Takagi (Hempitera: Diaspididae) is reviewed. The small size of this cycad pest and complex surface morphology of the host cycad organs combine to make visual detection of every cryptic infestation difficult or impossible to achieve. The international movement of Cycas revoluta Thunb. nursery plants and the presence of C. revoluta nursery industries in so many countries have enabled this pest to wreak havoc on the international cycad horticulture trade over the last 25 years. The short pre-oviposition period and considerable female fecundity lead to rapid population expansion on the plants initially infested in newly invaded regions. A depletion of non-structural carbohydrates accompanies long-term infestations and precedes plant death. Enemy escape within the invasive range allows the scale population growth to remain unchecked until anthropogenic efforts establish non-native biological control. [ABSTRACT FROM AUTHOR]

Cases of cycad toxicosis have been described in dogs that have presented with gastrointestinal, hematologic, hepatic, neurological, and carcinogenic signs. This case report describes brain magnetic resonance imaging (MRI) lesions in a dog with gastrointestinal and neurological signs secondary to cycad toxicosis. A 5-year-old neutered female Jack Russell terrier presented with a 2-days history of gastroenteric signs, progressive generalized tremors, and altered mentation after possible ingestion of Cycad revoluta. Neurologic examinations revealed disorientation, a wide-based stance, severe spasticity of the four limbs, intention tremors, severe cerebellar ataxia, decreased postural reactions in all four limbs, and intermittent decreased menace response in both eyes—all of which are consistent with a multifocal intracranial disorder involving the forebrain and cerebellum. A brain MRI showed diffuse/ill-defined, intra-axial bilateral and symmetrical changes, predominantly affecting the white matter of the cerebral hemispheres, thalamus, hippocampus, and cerebellum. A presumptive diagnosis of toxic-metabolic encephalopathy was made. Medical management of the clinical signs was performed, and the dog was discharged 7 days after presentation with no neurological abnormalities. Two and 8 weeks later, complete blood count (CBC), chemistry, electrolytes, and 8 weeks later brain MRI were performed, revealing no abnormalities. To the best of the authors' knowledge, this is the first case report describing lesions detected by brain MRI secondary to cycad toxicosis as well as a complete resolution of brain lesions on a follow-up MRI 8 weeks later.

Microcycas calocoma is the monotypic species from the critical endangered and endemic cycad genus Microcycas in Cuba, an important taxon to study the evolution of extant gymnosperms. Here we report the complete chloroplast sequences of M. calocoma and characterize the genome structure of this species. The genome size of M. calocoma is 165,667 bp in length which contains 135 genes, including 88 protein-coding genes, eight ribosomal RNA genes and 39 transfer RNA genes. The GC content of this genome is 39.6%. Phylogenomic study shows M. calocoma is mostly closely related to the cycad genus Zamia, which corresponds to previous studies based on multiple nuclear genes and combined plastid and nuclear evidence. The plastome information of M. calocoma offered by this study can contribute to further comparative chloroplast genome in cycads/gymnosperms as well as conservation genetic studies of M. calocoma.

Zamia inermis is a dioecious cycad endemic to the State of Veracruz that is on the risk extinction. Sexspecific markers are important in understanding the mechanism of sex determination. However, since little is known about the mechanism of sex determination in Z. inermis, we proposed looking for Inter-simple Sequence Repeats (ISSR) markers that could be linked to sexual expression in this species. Using DNA bulk samples of male and female genotypes and 6 ISSR primers, a female marker (~867 bp) was identified with primer ISSR-18, which was present in 66% of the DNA mixtures of the female genotypes analyzed. The results of the Principal Coordinate Analysis performed revealed a tendency for clustering of genotypes of the same sex. [ABSTRACT FROM AUTHOR]

The purpose of this retrospective study is to characterize the clinical signs, laboratory values, treatment modalities and mortality outcomes related to cycad palm toxicosis in dogs and to identify medical interventions that potentially correlate with mortality. Dogs with confirmed cycad palm ingestion were identified by reviewing medical records from two private veterinary referral centres for key terms and phrases indicative of cycad palm toxicosis. Of 130 dogs included, 107 (82.3%) presented with clinical signs. A total of 2 (1.5%) died and 14 (10.8%) were euthanized. Diarrhea, lethargy and mortality were all associated with an elevated initial alanine transaminase (ALT) concentration. Overall mortality was 12.3%, with a significantly higher proportion of dogs with an ALT concentration <125 U/L surviving compared to dogs with an elevated ALT concentration. Treatment with activated charcoal reduced the odds of death among all dogs by 82% and was even more protective among dogs with an elevated initial ALT concentration. Among dogs that had an initial platelet count performed, the presence of thrombocytopenia (<200,000/μL) was a negative prognostic indicator and was associated with a significant increase in mortality. Given the high mortality rates reported for cycad palm toxicosis, it is imperative to identify early clinical indicators of mortality as well as treatments that reduce mortality. [ABSTRACT FROM AUTHOR]

Indigenous societies' interactions with plants may result in contemporary distribution patterns that reflect these relationships, such as concentration of resource species close to occupation sites or transport routes. Seeds of the cycad, Macrozamia dyeri, are food of Nyungar First People of the south‐eastern Southwest Australian Floristic Region. Processing of seeds by leaching in soil or water enables detoxification and preservation of the pre‐colonial staple, a Nyungar technique archaeologically dated to at least 13 000 years BP. We measured the distance of M. dyeri populations to cultural landscape features and registered heritage sites. We also compared within‐population plant distribution characteristics to Nyungar occupation preferences around granite inselbergs. We found evidence of Nyungar influence on contemporary distribution of M. dyeri. Populations of M. dyeri occur close to surface water features in the west and granite outcrops in the east of Nyungar country, which corresponds closely to differential pre‐colonial patterns of Nyungar occupation. M. dyeri population frequency was negatively correlated with distance to registered Nyungar sites, and 75% of all M. dyeri populations occur within 3.2 km of a registered Nyungar site. We found no correlation between habitat availability and size of granite populations, but found that Nyungar occupation preferences in relation to ground surface aspect, slope and landform type correlated with intra‐population M. dyeri plant distribution, suggesting a mutualistic relationship with Nyungar people, has influenced the plant's distribution. We suggest that contemporary M. dyeri distribution is therefore useful for interpreting past location‐specific Nyungar land practices to inform contemporary conservation management. Our findings demonstrate that along with edaphic, climate and other environmental factors, consideration of pre‐colonial human dispersal and land practices is important for plant conservation in Australia, particularly for taxa with prolonged use by humans. Further, we suggest that analyses of long‐lived Macrozamia elsewhere may be useful for interpreting past Aboriginal land practices. [ABSTRACT FROM AUTHOR]

Improved horticultural practices may help to reduce demand for wild cycads threatened by unsustainable collection. We determined the influences of leaf retention with or without anti-transpirants on the success and speed of adventitious root development of Zamia furfuracea L.f. and Zamia integrifolia L.f. stem cuttings. Root formation success for both species was greater than 95%. The experimental treatments did not influence the percentage success or the speed of root development for Z. furfuracea or Z. integrifolia. The ending dry weights of the stems, leaves, and roots were also not influenced by the experimental treatments. Our results indicated that adventitious root formation on stem cuttings of these two Zamia species was highly successful with or without retained leaves, and horticultural application of transpiration-reducing products on retained leaves did not improve success. Our findings add to the growing body of evidence that show how the horticulture nursery industry can meet horticultural demands in an effort to stop wild harvesting of threatened plants. Conservation of cycads as a group would benefit from more horticulture studies such as this, especially if the research includes threatened species. [ABSTRACT FROM AUTHOR]

An understanding of leaf nutrient relations is required for tree conservation and horticulture success. The study of cycad leaf nutrient dynamics has expanded in recent years, but direct comparisons among reports remains equivocal due to varying sampling protocols. We used Cycas micronesica K.D. Hill and Cycas nongnoochiae K.D. Hill trees to determine the influence on leaf nutrient concentrations of in situ versus ex situ locations and orientation of leaves within the tree canopy. Nitrogen, phosphorus, and potassium concentrations of leaves from ex situ plants exceeded those from in situ plants, and the differences were not explained by soil nutrient differences. Calcium concentrations of leaves varied among the site pairs, with differences primarily explained by soil calcium. Magnesium concentrations of leaves were not different among all location pairs even though soil magnesium concentrations varied among the sites more than any of the other elements. Differences in leaf macronutrient concentrations among four C. micronesica provenances were minimal when grown in a common garden. Lateral orientation of leaves did not influence any of the essential elements for either of the species. These findings indicate that the lateral orientation of cycad leaves does not influence leaf nutrient concentrations, leaf nutrient relations of cycad plants in managed ex situ settings do not align with leaf nutrient relations in habitat, and these differences are not explained by soil nutrition for most elements. We suggest that leaf nutrient concentrations should be determined in all niche habitats within the geographic range of a cycad species in order to fully understand the leaf physiology of each species. [ABSTRACT FROM AUTHOR]

Cycas micronesica is a foundation species in several Micronesian islands and its seeds have been a historical source of starch for the island residents. The species has become endangered by invasive specialist insect herbivores and conservationists struggle with the inability to estimate the age of observed seeds. To inform this agenda, we evaluated numerous Cycas micronesica seed traits to determine if any exhibited a relationship with age and a substantial change in absolute value. Of the 30 direct and derived seed traits that we evaluated, most of them were non-linear and exhibited minimal change after about 12 months in age. The only traits that emerged as unambiguous estimators of age were the quotients derived as gametophyte fresh weight/total seed fresh weight and sarcotesta dry weight/sclerotesta dry weight. These two simple metrics can be used to accurately estimate seed age for this arborescent cycad species. [ABSTRACT FROM AUTHOR]

The influences of Cycas micronesica and Zamia integrifolia plants on soil chemistry were determined in Tinian and Florida in order to more fully understand how cycad plants affect the environments in which they grow. The introduction of C. micronesica plants into a karst habitat generated decreases in soil phosphorus after five years and increases in soil nitrogen after six years. The carbon:nitrogen:phosphorus stoichiometry beneath the cycad plants significantly diverged from those of the adjacent native forests with Pisonia grandis, Psychotria mariana, Aglaia mariannensis, Cynometra ramiflora, and Ficus sp. cover after five years. Mineralization traits were determined beneath nine-year-old C. micronesica plants and revealed the plants greatly increased net nitrification and decreased net ammonification when compared to the native forest soils with Bursera simaruba, Pinus elliottii, and Quercus virginiana cover. These flux changes increased the total available nitrogen and percent available nitrogen in the soils beneath the cycad plants. The substrates of two soil series exhibited increased carbon and nitrogen concentrations beneath Z. integrifolia plants when compared with soils away from the cycad plants. No other mineral or metal was influenced by proximity to the Z. integrifolia plants. These gymnosperms exhibit distinct interactions with their subtending soils, and some of these traits improve ecosystems by increasing recalcitrant carbon and nitrogen and increasing spatial heterogeneity of soil chemistry. [ABSTRACT FROM AUTHOR]

Cycad stem cuttings will develop adventitious roots if the open wound is first treated with a sealant to protect the exposed parenchyma tissue. The commercial pruning wound sealant that is often employed for this purpose is not available in many locations. We used commonly available products as a prophylactic sealant on Cycas edentata, Cycas micronesica, and Cycas nitida cuttings to determine efficacy for sealing the wound and enabling adventitious root formation. Success was quantified after 7 months in a sand propagation substrate. Mortality was 100% for control cuttings with no wound sealant and about 60% for cuttings with candle wax as the sealant. Cuttings that received petroleum jelly, lanolin paste, modeling clay, honeycomb wax, or commercial pruning sealant exhibited 100% survival. Success in adventitious root formation ranged from 75% to 92% among the five successful prophylactic treatments and did not differ among the species. The results indicated that four of the products we evaluated were as effective as commercial pruning sealant for treating the exposed parenchyma on Cycas stem cuttings and enabling asexual propagation success. The candle wax was less effective because it was brittle and cracked to expose the stem's parenchyma tissue. [ABSTRACT FROM AUTHOR]

Mature Cycas micronesica trees were among the forest trees that were destined to be removed from a 2012 construction site in northern Guam. Forty-nine of these trees were cut at the base and transported to nursery conditions to determine if adventitious root development could be stimulated as a means of saving the trees. Fungicide and auxin were applied to the base of each stem, and perlite was used as the container medium. A nursery maintained by an experienced cycad horticulturist yielded 41% survival, but half of the rooted plants exhibited severe stem dieback. A nursery maintained by general plant nursery specialists without cycad experience resulted in 100% mortality. If numerous caveats are acknowledged, whole-tree stem cuttings may yield moderate success for saving C. micronesica trees from construction sites when adequate resources are appropriated to support the nursery phase with experienced cycad biologists.

Callioratis millari Hampson (Lepidoptera: Geometridae) is a Critically Endangered moth endemic to South Africa. Despite extensive searches, it was previously known only from the Entumeni Nature Reserve in KwaZulu-Natal, where its larvae exclusively feed on the cycad Stangeria eriopus (Kunze) Baill (Cycadales: Stangeriaceae). In July 2022, a new population of C. millari was discovered in the Kabouga section of Addo Elephant National Park in the Eastern Cape. Larvae of C. millari were feeding on the cycad Encephalartos caffer (Thunb.) Lehm (Cycadales: Zamiaceae), which also constitutes a new host record. In June 2023, we determined larval incidence and herbivory at this new locality, offering insights into the ecological requirements of C. millari. Known C. millari localities, although ecologically different, share low altitudes (700-950 m a.s.l.), moderate to high rainfall, and grassy habitats with sparse woody cover. A total of 59 larvae were counted in Kabouga, mostly in the fifth and sixth (final) instars. Herbivory incidence was lower on smaller plants and those covered by other vegetation. The flight period of adult C. millari likely occurs between mid-March and April in Kabouga, but further investigation is needed to clarify this. The peak period of larval occurrence in Kabouga occurs during the driest and coldest months of the year (May-July). Considering limited habitat availability, host plant poaching, and the risk of untimely fires, the species should be considered highly threatened. This study adds to our understanding of the biology of C. millari and provides information on its ecological requirements and may contribute to making informed management decisions., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

The literature covering the biology, invasion chronology, host plant responses, and control efforts of the armored scale Aulacaspis yasumatsui Takagi (Hempitera: Diaspididae) is reviewed. The small size of this cycad pest and complex surface morphology of the host cycad organs combine to make visual detection of every cryptic infestation difficult or impossible to achieve. The international movement of Cycas revoluta Thunb. nursery plants and the presence of C. revoluta nursery industries in so many countries have enabled this pest to wreak havoc on the international cycad horticulture trade over the last 25 years. The short pre-oviposition period and considerable female fecundity lead to rapid population expansion on the plants initially infested in newly invaded regions. A depletion of non-structural carbohydrates accompanies long-term infestations and precedes plant death. Enemy escape within the invasive range allows the scale population growth to remain unchecked until anthropogenic efforts establish non-native biological control.

This study investigates the population structure and life history traits of the Critically Endangered cycad, Encephalartos latifrons. Populations of E. latifrons have been considered functionally extinct because no natural recruitment has been observed in the wild for almost 30 years. The discovery of a previously undocumented population of E. latifrons has made it possible to build on previous research into the life history and regeneration capabilities of the species. This new population was censused annually over 5 years; between 2013 and 2017. Population characteristics of this 'new' population were compared to earlier studies in 2010 of a well-known and intensively managed population. Results of the censuses show that the newly discovered population of E. latifrons appears to be increasing under current environmental conditions through natural recruitment. The discovery of a 'new' E. latifrons population has uncovered many more questions and further research is needed. Information on the life history of E. latifrons , particularly its response to fire, should be used to inform conservation management decisions at a time where the impact of climate change is predicted to have a major influence in the Fynbos Biome. • At least one wild Encephalartos latifrons population is capable of natural recruitment. • At least one E. latifrons population is increasing under present environmental conditions. • Plants in the seedling stage experience the highest levels of mortality. • Of the reproductive individuals present in the population, females outnumbered males. • All stages were significantly clustered in their spatial pattern. [ABSTRACT FROM AUTHOR]

Traditionally the vulnerability of threatened species to extinction has been assessed by studying their environment, genetics and population dynamics. A more comprehensive understanding of the factors promoting or limiting the long-term persistence of threatened species could be achieved by conducting an analysis of their functional responses to changing environments, their ecological interactions, and their role in ecosystem functioning. These less traditional research areas can be unified in a trait-based approach, a recent methodological advance in ecology that is being used to link individual-level functions to species, community and ecosystem processes to provide mechanistic explanations of observed patterns, particularly in changing environments. We illustrate how trait-based information can be translated into well-defined conservation strategies, using the example of Dioon sonorense , an Endangered cycad endemic to north-western Mexico. Scientific information yielded by trait-based research, coupled with existing knowledge derived from well-established traditional approaches, could facilitate the development of more integrative conservation strategies to promote the long-term persistence of individual threatened species. A comprehensive database of functional traits of threatened species would be of value in assisting the implementation of the trait-based approach. [ABSTRACT FROM AUTHOR]

Over the years studies on sporopollenin have reported a wide variety of structures. However, the methods and techniques used to elucidate sporopollenin structures are highly diverse so that much is still unclear with respect to the nature and structural diversity of sporopollenins. In order to investigate the structural diversity in sporopollenin between different taxa, extant sporomorphs of ten different species ranging from a mushroom to a cycad were examined using a relatively simple and fast analytical procedure. Sporomorphs, before and after saponification, were analysed for sporopollenin composition by Thermally assisted Hydrolysis and Methylation (THM) using [13C]tetramethylammonium hydroxide ([13C]TMAH). The sporomorp chemical composition differed markedly between the groups of organisms analysed. Moreover, we not only identified the nature and relative quantities of the well-known sporopollenin constituents p -coumaric acid and ferulic acid but also many other phenolic moieties, such as caffeic acid, which appeared to be the most abundant phenolic constituent in spores of Equisetum palustre, Salvinia molesta, Cyrtomium falcatum and Anemia phyllitidis. Within the two Equisetum species analysed as well as in the closely related Azolla and Salvinia species the same suite of phenolic constituents were observed, but their relative distribution varied largely. We thus demonstrate the existence of a high structural diversity, both qualitatively and quantitatively in sporopollenins enabling future studies related to the evolution, phylogeny and (palaeo)environment of sporopollenin-producing organisms. Furthermore, a better knowledge of sporopollenin and its structural variety is of relevance to the rapidly growing application of spores and pollen as a drug delivery agent in medicine. Image 1 • Spores of 10 species were analysed for their sporopollenin composition. • Spores before and after extraction and saponification were examined. • Thermally assisted Hydrolysis and Methylation using 13C-labeled tetramethylammonium hydroxide was applied. • Caffeic acid appeared to be a major component of sporopollenin. [ABSTRACT FROM AUTHOR]

Premise of research. This study compares the pinnule morphology of three fossil Bowenia species, one Eobowenia (fossil) species, and several Bowenia fossil pinnule fragments with the two extant Bowenia species. Methodology. Pinnule area, stomatal density, and size have been measured on fossil and extant specimens. Measures have been correlated with solar radiation and temperature to ascertain any correlations. Environment and climate variables have been chosen, as they have changed since the Eocene and Lower Cretaceous when the Australian and South American fossils were growing. Pivotal results. Two of the fossil Bowenia species and Eobowenia have significantly smaller pinnules than the living species, and all the fossils have relatively small and sparse stomata compared with the living species. Extant Bowenia pinnule area is positively correlated with daily radiation and temperature. Conclusions. Those fossil species with small pinnules likely lived in relatively dark environments where small pinnules aided the capture of sunflecks and/or facilitated light capture. The smaller and sparser stomata may have limited the potential sites for fungal invasion in the extremely humid growth conditions without hampering overall growth rates in the prevailing very high atmospheric CO2 levels. [ABSTRACT FROM AUTHOR]

A long-term reciprocal garden study was used to determine adaptive variation between Cycas micronesica K.D. Hill plants from north versus south Guam. Half-siblings from each location were planted as one-leaf seedlings in north and south gardens and monitored for 15 years. Stem height and diameter, and leaf number and maximum length were measured yearly. Survival and plant size traits were evaluated using a two-way factorial. In both locations, the local genotypes out-performed the foreign genotypes in terms of survival and growth. Survival of the foreign genotypes began to decline by year 4 and was less than 10% by year 15. Survival of the local genotypes was 70% for the north garden and 100% for the south garden. The north site was more hostile to plant performance because overall survival and plant growth were less than for the south site. The most likely environmental factor provoking local adaptation was highly contrasting soil characteristics between north and south Guam. The results indicates that long-term conservation success for C. micronesica and other cycad species must include the concept of local adaptation into decisions for transplantation and restoration projects.