Astrophytum Asterias Research Articles

Review of the life history and conservation of federally endangered plant species of the Lower Rio Grande Valley, Texas, U.S.A.

This review aims to summarize information critical to the conservation of the federally listed endangered species of South Texas, which occur along the border of Texas and Mexico. This paper describes the characteristics, habitat, population status, distribution, life history, threats, and restoration of endangered plant species of the Lower Rio Grande Valley, Texas, which includes Cameron, Willacy, Hildago, and Starr County. Seven federally listed species are considered including Ambrosia cheiranthifolia, Asclepias prostrata, Astrophytum asterias, Ayenia limitaris, Manihot walkerae, Lesquerella thamnophila (syn. Physaria thamnophila), and Thymophylla tephroleuca. An eighth species, Physostegia correllii is under consideration for federal listing by the U.S. Fish and Wildlife Service. This paper assembles information on the background, biological status, major threats, and conservation to aid managers and the scientific community in restoring and managing these species.

MICROPROPAGATION AND ORGANOGENESIS OF ASTROPHYTUM ASTERIAS (ZUCC.) LEM. (CACTACEAE JUSS.), BLOSSFELDIA LILIPUTIANA WERDERM. AND STROMBOCACTUS DISCIFORMIS (DC.) BRITTON & ROSE

The research reveals results of the creation of sterile cultures and micropropagation of the species of three unique genera of Cactaceae: Astrophytum asterias (Zucc.) Lem. (І CITES); Blossfeldia liliputiana Werderm. (ІІ CITES); Strombocactus disciformis (DC.) Britton & Rose. (І CITES). The solutions for sterilization were selected, the time of sterilization, and the sterilization procedure of seeds was approbated. The expedience of usage of stems of juvenile plants grown in vitro for propagation of these species of cacti was proved. The possibility of an obtaining of the necessary quantity of plant material by the way of indirect organogenesis is shown. The proper content of nutrient media and favourable conditions of the cultivation for all stages of the micropropagation were approved.

Characterization of Biominerals in Cacteae Species by FTIR

A biomineral is a crystalline or amorphous mineral product of the biochemical activity of an organism and the local accumulation of elements available in the environment. The cactus family has been characterized by accumulating calcium oxalates, although other biominerals have been detected. Five species of Cacteae were studied to find biominerals. For this, anatomical sections and Fourier transform infrared, field emission scanning electron microscopy and energy dispersive x-ray spectrometry analyses were used. In the studied regions of the five species, they presented prismatic or spherulite dihydrate calcium oxalate crystals, as the predominant biomineral. Anatomical sections of Astrophytum asterias showed prismatic crystals and Echinocactus texensis amorphous silica bodies in the hypodermis. New findings were for Ariocarpus retusus subsp. trigonus peaks assigned to calcium carbonate and for Mammillaria sphaerica peaks belonging to silicates.

Evaluation of Antidiabetic, Antioxidant and Other Phytochemical Properties of Thai Fruits, Vegetables and Some Local Food Plants

Antidiabetic, antioxidant, anti-acetylcholinesterase and prebiotic activities, total phenolics and flavonoids of 33 crude ethanolic extracts of Thai local fruits, vegetables and some local food plants were determined. Mangosteen (Garcinia mangostana) fruit peel and Indian gooseberry (Phyllanthus emblica) fruit extracts had highest antioxidant activity. Bamboo grass (Tiliacora triandra) leaf extract had strongest α-amylase inhibitory activity (78.28 % inhibition), while mulberry (Morus alba) fruit extract had strongest α-glucosidase inhibitory activity (59.63 % inhibition). Star cactus (Aloe vera) leaf pulp extract had strongest anti-acetylcholinesteraseVactivity (31.55 % inhibition). Indian gooseberry fruit and mangosteen fruit peel extracts had highest content of total phenolics and flavonoids, respectively. The extract with highest indigestible polysaccharide content was the extract of mangosteen fruit peels (188.62 mg/g extract), while those with relatively high indigestible polysaccharides were the extracts of pineapple fruits (Ananas comosus), lotus seeds (Nelumbo nucifera), black rice grains (Oryza sativa) and pisang mas banana fruits (Musa sapientum). Based on these properties, 5 plant extracts were selected to study for their prebiotic effect on growth and fermentation of Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus in yogurt at 42 °C. Addition of lotus seed extract resulted in highest proliferation of these bacteria with 2.24 logCFU/g increase of total lactic acid bacterial counts in yogurt after 24 h fermentation, while addition of black rice grain, pisang mas banana fruit and pineapple fruit extracts caused good growth of these bacteria with 2.12 - 2.19 logCFU/g increase of total counts.

Reproductive ecology of the threatened "star cactus" Astrophytum ornatum (Cactaceae): a strategy of continuous reproduction with low success

Background. There are no previous studies on the reproductive biology of the endemic and endangered cactus species Astrophytum ornatum. 
 Questions. Is flowering continuous or episodic? What are the breeding and mating systems and what floral visitors are associated? and Does the reproductive success change over time?
 Study species. Astrophytum ornatum (Cactaceae).
 Study site and years of study. Observations from 2010 to 2011, in the highest density population of A. ornatum in Metztitlán Canyon (Hgo.).
 Methods. Monthly surveys and monitoring of reproductive structures. Tracking flowers in anthesis. Controlled pollinations to determine the mating system and determination of the Outcrossing Index (OCI), the pollen /ovule ratio and breeding system.
 Results. Astrophytum ornatum produced flower buds throughout the year, but 89.2% of them were aborted. Four events of ephemeral flowering population were presented per year. The species is self-incompatible and controlled pollinations indicated pollinator limitation of several bee species. The OCI indicates that the species is facultative xenogamy, and pollen/ovule ratio indicates obligate xenogamy. On average there were 54 seeds/fruit and individuals produced 4 fruits/year.
 Conclusions. The continuous production of buds had never been reported phenomenon for cacti. Intrapopulation bloom is one of the shortest recorded for the family and it produces high floral synchrony. The low number of seeds / fruit and flowers / individual, coupled with the narrow niche breadth of species and various anthropogenic factors place Astrophytum ornatum as a susceptible species to be extinct.

Genetic structure and molecular divergence among samples of mandacaru (Cereus spp.; Cactaceae) as revealed by microsatellite markers

Microsatellite transferability was used as a method to differentiate samples of mandacaru cultivated in the South (S), Southeast (SE), Northeast (NE) and Midwest (MW) regions of Brazil. Ten microsatellite primers designed from Polaskia chichipe (Pchi5, Pchi21, Pchi44 and Pchi47), Ariocarpus bravoanus (mAbR05, mAbR28 and mAbR86), Astrophytum asterias (AaB6 and AaD9), and Echinocactus grusonii (mEgR78) were polymorphic. A total of 31 alleles, which makes an average of 2.58 alleles per locus, were detected in mandacaru plants. The analyzed mandacaru cacti from the NE region presented lower polymorphism than their relatives from S, SE, and MW regions. The AMOVA showed a higher genetic variation among than within the analyzed samples. Clustering of the samples determined via Bayesian analysis indicated that the 112 analyzed mandacaru plants were grouped into 3 subpopulations. The highest proportion of plants from the S/SE (80.3%/77.5%), NE (91.5%), and MW (95%) were observed within blue, red, and green groups respectively: the mandacaru cacti form genetically structured populations. Molecular divergence at the SSR loci indicated three species: one species located in the South (S) and Southeast (SE) regions, another species in the Northeast (NE) region, and a third one in the Midwest (MW) region of Brazil.

Survival of planted star cactus,Astrophytum asterias, in southern Texas

We planted 308 star cacti (Astrophytum asterias) in southern Texas on private ranches where existing populations were reduced or destroyed. Overall mortality was 48% with herbivory accounting for 34% of the mortality (50 of 148). Mortality varied among planting sites but was not influenced by initial size, even when cacti killed by herbivory were excluded. Mortality was highest during times with low precipitation or high temperatures. Surviving cacti on two sites increased in average size. Reintroduction through planting is a viable strategy for restoring populations of star cacti.

Are nurse plants always necessary for succulent plants? Observations in northeastern Mexico, including endangered and threatened species

In harsh environments some plant species grow under the shelter of other plants. This spatial association known as nurse-protégé interaction is common in arid and semiarid environments. In here we studied the spatial association of six cacti (Ariocarpus retusus, Astrophytum asterias, Echinocactus texensis, Cylindropuntia leptocaulis, Sclerocactus scheeri and Mammillaria heyderi) and one Asparagaceae (Manfreda longiflora) to other plant species. We determined whether they occurred more often under other plants, if they grew very near them or at an angle that provided shade. Manfreda longiflora always grew under the canopy of other plants. Ariocarpus retusus, Astrophytum asterias, Cylindropuntia leptocaulis, and Mammillaria heyderi occurred equally under nurse plants and in open spaces. Echinocactus texensis and Sclerocactus scheeri occurred more often than expected in open areas, but Sclerocactus scheeri occurred shaded from the afternoon sun. We argue that nurse-protégé interactions are less common in our study site due to higher rainfall than that in other studied environments.

Assessing regional differences in predation of endangered species: Implications from Texas populations of the endangered star cactus (Astrophytum asterias)

Understanding threats to endangered species is one of the most critical components of implementing a successful recovery plan. For the endangered star cactus Astrophytum asterias, both mammalian and insect herbivory have been documented as a major threat to populations in Mexico. Herein, we focus on populations of A. asterias in Texas, examining how mortality threats differ from populations found in Mexico as well as among sites within Texas. Our study supports insect and mammalian herbivory as a major threat to A. asterias in Texas, with reductions in population sizes ranging between 16 and 54%. However, our study highlights that both regional and local differences can influence rates of mortality even in a range-restricted species such as A. asterias and highlights the need to assess threats at both of these levels for effective development and implementation of endangered species recovery plans.

Genetic Structure of a Population of the Endangered Star Cactus (Astrophytum asterias) in Southern Texas

We used data on alleles of seven polymorphic microsatellite loci in 142 individuals of the star cactus Astrophytum asterias from five subpopulations to estimate genetic parameters. Four of the subpopulations had high levels of heterozygosity and allelic diversity compatible with efficient outcrossing, and low FST-values that suggested high rates of gametic gene flow effected by winged-insect pollinators. The fifth subpopulation that was small and occupied the smallest area had low levels of heterozygosity and allelic diversity, which can be caused by small populations, inbreeding, geographic isolation, and founder effect. Our research indicated that all subpopulations, except one, were genetically suitable sources of propagules for reintroduction or for augmentation of other populations.Utilizamos datos de los alelos de siete loci polimórficos de microsatélites en 142 individuos del cactus Astrophytum asterias provenientes de cinco subpoblaciones para estimar los parámetros genéticos. Cuatro de las subpoblaciones mostraron altos niveles de heterozigosidad y diversidad alélica, siendo compatibles con cruzamiento exógeno eficiente, y bajos valores de FST, los cuales sugirieron flujo gamético de genes intermediados por insectos voladores como polinizadores. La quinta subpoblación, que era pequeña y ocupaba el área más pequeña, mostró bajos niveles de heterozigosidad y diversidad alélica, lo que puede ser consecuencia de un pequeño tamaño poblacional, endogamia, aislamiento geográfico y el efecto de fundadores. Nuestra investigación indicó que todas las subpoblaciones, menos una, eran genéticamente apropiadas para servir como fuentes para la reintroducción de la especie o el aumento de otras poblaciones.

Pollen dispersal in star cactus ( Astrophytum asterias)

Gene flow occurs via seeds and pollen in plants. In cases where seed dispersal is limited, pollen dispersal can have a substantial impact on the genetic makeup of plant populations. We examined pollen dispersal in Astrophytum asterias, an endangered cactus occurring in southern Texas and northern Mexico. Fluorescent dye was used in this study as a pollen analogue to track the distribution of pollen dispersal within a 1.9 hectare patch of star cactus. Approximately 80% of all recipient plants were located within 30 m of the source plant. Mean dispersal distance was ∼17 m. The longest dispersal event recorded was 142.2 m. Dispersal distances between source and recipient plants were used to calculate estimates of genetic neighborhood size and area using Wright's neighborhood model. These neighborhood estimates (neighborhood size = 41.8 individuals, neighborhood area = 0.094 hectares) indicate potential for population subdivision within the larger patch due to restricted pollen dispersal.

Effectiveness and Importance of Pollinators to the Star Cactus (Astrophytum asterias)

Astrophytum asterias (star cactus) is an obligate outcrosser that does not reproduce vegetatively, so all reproduction is the result of inter-plant transfer of pollen by insects. By measuring seed set resulting from single pollinator visits, we evaluated effectiveness (mean seed set per visit) and importance of pollinator (effectiveness times frequency of visitation) of insects visiting flowers of A. asterias. Results indicate that the most common visitor, Macrotera lobata, is a relatively ineffective pollinator, while the less common Diadasia rinconis is the most effective and important pollinator. Two behavioral variables (duration of visit, whether or not visitors landed on the stigma) were assessed as possible predictors of fruit set. While duration of visit was not predictive of fruit set, there was a positive correlation between fruit set and the proportion of visits a visitor landed on the stigma when entering the flower.

BREEDING SYSTEM OF ASTROPHYTUM ASTERIAS: AN ENDANGERED CACTUS

Astrophytum asterias is an endangered cactus occurring in southern Texas and northeastern Mexico. The purpose of this study was to provide fundamental information about the reproductive biology of the species. Breeding-system experiments were conducted in Starr County, Texas. Pollination treatments were applied to explore whether the species is self-compatible or self-incompatible and whether plants are experiencing pollinator limitation. Treated (bagged) flowers were self-pollinated or outcrossed by hand, or allowed to naturally self-pollinate. Control flowers were unbagged and unmanipulated (open-pollinated). In each treatment and controls, we calculated mean fruit set and mean seed set per plant. Controls had 18.3% fruit set, with a mean seed set of 13.3 ± 14.7 seeds. The outcross treatment resulted in 88.6% fruit set, with a mean seed set of 95.8 ± 5.9 seeds. Median mean fruit and seed set in the outcross treatment were 1 and 92.7, respectively. Although some controls set fruit and seed, median mean fruit and seed set was 0. No fruit or seed was set in self-pollinated treatments. These results showed that the species is an obligate outcrosser. Reproductive success is, therefore, dependent on a vector to transfer pollen. The fact that fruit set and seed set were higher in hand-outcrossed flowers than in open-pollinated flowers suggests that A. asterias might be experiencing reproductive constraints in terms of availability or effectiveness of pollinators.

Causes of individual mortality in the endangered star cactus Astrophytum asterias (Cactaceae): The effect of herbivores and disease in Mexican populations

Little is known about the causes of mortality in natural populations of threatened cactus species. In particular we focus on the endangered Astrophytum asterias in four populations where most individuals of the species are found. At two sites one of each vegetation type (Tamaulipan thornscrub [TS] and Piedmont thornscrub [PT]) we measured individual mortality by three causes: the plant pathogen Phytophtora infestans, a cerambicid beetle and the terrestrial squirrel Spermophilus mexicanus. We found that damage by the combination of pathogen and herbivore meant a reduction of more than 50% in population size. From these factors, the most important cause of death was S. mexicanus followed by the cerambicid beetle in TS and P. infestans in PT. Mortality was concentrated in the small size categories, even though large size plants were also affected albeit to a lesser extent. More quantitative studies in field conditions are necessary to establish sound conservation efforts that could improve the recovery plans for this endangered plant species.

Development and characterization of microsatellite loci in endangered Astrophytum asterias (Cactaceae)

AbstractWe report the development of polymorphic microsatellite markers for the endangered North American cactus Astrophytum asterias (Cactaceae). Six loci, averaging 8.5 alleles per locus, were found to amplify genomic DNA consistently in 94 individuals from four geographically defined demes in South Texas. These markers will permit the generation of appropriate data for estimating population genetic parameters, population structure and the degree of inbreeding in the small, fragmented populations of A. asterias that currently exist. These are the first microsatellites reported for the genus Astrophytum and for the tribe Cacteae.

Cytophotometric Estimation of 4C DNA Content and Chromosome Analysis in Four Species of Astrophytum Lem. of the Family Cactaceae.

Karyotype analysis including determination of somatic chromosome number, chromosome length and volume, 4C DNA content and Interphase Chromosome Volume (INV) were carried out in Astrophytum asterias, A. capricorne, A. myriostigma var. nudum and A. ornatum of the family Cactaceae. Somatic chromosome number was 2n=22 in each of the studied species. Karyotype analysis showed minute structural alterations in the chromosomes. Total chromosome length varied from 56.65 μM in A. myriostigma cv. nudum to 60.76 μM in A. ornatum and the chromosome volume ranged from 48.12 pM3 in A. ornatum to 66.95 μM3 in A. myriostigma var. nudum. Significant changes on the TF% suggested the formation of the median chromosomes from the sub-median types in A. asterias and A. myriostigma var. nudum that might be due to translocation of chromosomes during evolution. Significant variations in the 4C DNA content were noticed among the species which ranged from 9.23 pg in A. capricorne to 10.12 pg in A. myriostigma var. nudum. Total chromosome volume and INV showed high degree of correlation with the nuclear DNA content of the species. Interspecific variability of the nuclear DNA content might be due to the variations in the repetitive DNA sequences of the genome. The structural alterations in the chromosomes as well as loss or addition of highly repetitive sequences in the genome caused variations in the nuclear DNA at interspecific level indicating a micro-change of nuclear material during evolution.

Matchings in hexagonal cacti

Explicit recurrences are derived for the matching polynomials of the basic types of hexagonal cacti, the linear cactus and the star cactus and also for an associated graph, called the hexagonal crown. Tables of the polynomials are given for each type of graph. Explicit formulae are then obtained for the number of defect‐d matchings in the graphs, for various values of d. In particular, formulae are derived for the number of perfect matchings in all three types of graphs. Finally, results are given for the total number of matchings in the graphs.