Esterase polymorphism in remanant populations of Aspidosperma polyneuron Müll.Arg. (Apocynaceae)

The population genetic structure of the endangered tree species Aspidosperma polyneuron Mull.Arg. (Apocynaceae) was reported based on analysis of esterase polymorphism in two remanant populations. Allelic variation was detected at three isoesterase loci (Est-3, Est-9, and Est-10). The proportion of polymorphic loci for both populations was 30% and deviation from Hardy-Weinberg equilibrium was observed for the Est-3 locus observed in the northern population. Segregation distortion and the lower level of observed and expected heterozygosity in this population were attributed to founder genotype. The high genetic identity values for northern and northwestern populations are in accordance with the low levels of interpopulation genetic divergence demonstrated by the F(ST) (0.03) value. The F(IS) value (0.23) indicated moderate levels of inbreeding. A. polyneuron can be indicated as an example of endangered species suggesting high genetic variation in contrast to the low genetic variation reported for endangered species. The esterase isozymes may be a good genetic marker for studies of natural A. polyneuron populations.

Download Full-text

Leaf traits and persistence of relict and endangered tree species in a rare plant community

Functional Plant Biology ◽

10.1071/fp11291 ◽

2012 ◽

Vol 39 (6) ◽

pp. 512

Author(s):

Jian X. Liao ◽

Juan Chen ◽

Ming X. Jiang ◽

Han D. Huang

Keyword(s):

Endangered Species ◽

Plant Community ◽

Tree Species ◽

Leaf Traits ◽

Rare Plant ◽

Low Light ◽

Endangered Tree ◽

Leaf Trait ◽

Endangered Tree Species ◽

High Rainfall

The rare plant communities, located in Houhe Nature Reserve, Hubei, China, are remnant evergreen and deciduous mixed broadleaved forest where many tree species have been identified as Tertiary relict and endangered plants and environmental conditions are typically characterised by low light and high rainfall. Knowledge of their patterns of leaf traits would contribute to our understanding of persistence of relict and endangered species. Here, we measured leaf mass per unit area (LMA), mass-based photosynthetic capacity (Amass), nitrogen content (Nmass), construction cost (CCmass) and photosynthetic nitrogen-use efficiency (PNUE) of 20 major tree species in a typical rare plant community. Correlations among leaf traits in the community were consistent with those from the global dataset, but they had lower Amass at any given Nmass and lower Amass and PNUE at any given LMA. Such results suggested the capacity and efficiency of photosynthetic gain from a unit investment in leaf tissue tend to be lower in the community. Moreover, they had lower LMA, CCmass and PNUE but higher Nmass than global broadleaved tree species. For relict and endangered species, the common limited factors (such as low light and high rainfall), similar leaf traits as coexisting deciduous non-endangered species and significant leaf trait relationships may allow them to persist in the community.

Download Full-text

Genetic variation, breeding structure and taxonomic status of the gummy shark Mustelus antarcticus in southern Australian waters

Marine and Freshwater Research ◽

10.1071/mf9880641 ◽

1988 ◽

Vol 39 (5) ◽

pp. 641 ◽

Cited By ~ 14

Author(s):

CM MacDonald

Keyword(s):

Genetic Variation ◽

Genetic Similarity ◽

Population Studies ◽

Allelic Variation ◽

Taxonomic Status ◽

Breeding Population ◽

Allelic Polymorphism ◽

Gene Exchange ◽

Low Levels ◽

High Degree

Electrophoretic studies of the protein products of 32 presumed gene loci have indicated low levels of allelic variation in Mustelus antarcticus. Only one enzyme, L-lactate dehydrogenase (LDH), exhibited sufficient allelic polymorphism to be useful as a marker for population studies. The distribution of LDH alleles was homogeneous in M. antarcticus sample sets collected from across the range of the species. The LDH data, together with information from earlier tagging studies, suggest that there is sufficient movement and gene exchange for M. antarcticus throughout southern Australian waters to be considered part of a single breeding population. The high degree of genetic similarity observed between all samples also indicates that there is only one Mustelus species (M. antarcticus) in southern Australian waters.

Download Full-text

Floristic Variation of Tree Communities and Their Association with Soil Properties in Pulau Jerejak, Penang, Peninsular Malaysia

Science Letters ◽

10.24191/sl.v14i1.7899 ◽

2020 ◽

Vol 14 (1) ◽

pp. 34

Author(s):

Faezah Pardi

Keyword(s):

Tree Species ◽

Diversity Index ◽

Basal Area ◽

Peninsular Malaysia ◽

Importance Value ◽

Conservation Action ◽

Endangered Tree ◽

Endangered Tree Species ◽

Tree Communities ◽

Floristic Variation

This study was conducted at Pulau Jerejak, Penang to determine the floristic variation of its tree communities. A 0.5-hectare study plot was established and divided into 11 subplots. A total of 587 trees with diameter at breast height (DBH) of 5 cm and above were measured, identified and recorded. The tree communities comprised of 84 species, 63 genera and 32 families. The Myrtaceae was the most speciose family with 10 recorded species while Syzgium glaucum (Myrtaceae) was the most frequent species. The Myrtaceae recorded the highest density of 306 individuals while Syzgium glaucum (Myrtaceae) had the highest species density of 182 individuals. Total tree basal area (BA) was 21.47 m2/ha and family with the highest BA was Myrtaceae with 5.81 m2/ha while at species level, Syzgium glaucum (Myrtaceae) was the species with the highest total BA in the plot with value of 4.95 m2/ha. The Shannon˗Weiner Diversity Index of tree communities showed a value of 3.60 (H'max = 4.43) and Evenness Index of 0.81 which indicates high uniformity of tree species. The Margalef Richness Index (R') revealed that the tree species richness was 13.02. Myrtaceae had the highest Importance Value of 20.4%. The Canonical Correspondence Analysis (CCA) showed that Diospyros buxifolia (Ebenaceae) and Pouteria malaccensis (Sapotaceae) were strongly correlated to low pH. Dysoxylum cauliflorum (Meliaceae) and Eriobotrya bengalensis (Rosaceae) were correlated to phosphorus (P) and calcium ion (Ca2+), respectively. Therefore, the trees species composition at Pulau Jerejak showed that the biodiversity is high and conservation action should be implemented to protect endangered tree species. Keywords: Floristic variation; Tree communities; Trees composition; Pulau Jerejak; Species diversity

Download Full-text

Genetic diversity of central and peripheral populations of Toona ciliata var. pubescens, an endangered tree species endemic to China

Chinese Journal of Plant Ecology ◽

10.3724/sp.j.1258.2013.00006 ◽

2013 ◽

Vol 37 (1) ◽

pp. 52-60 ◽

Cited By ~ 2

Author(s):

Jun LIU ◽

Jing-Min JIANG ◽

Jun ZOU ◽

Jin-Liang XU ◽

Han SHEN ◽

...

Keyword(s):

Genetic Diversity ◽

Tree Species ◽

Peripheral Populations ◽

Endangered Tree ◽

Endangered Tree Species ◽

Toona Ciliata

Download Full-text

Genetic Analysis of Chinese Cucumber Collections in the U.S. National Germplasm Collection

HortScience ◽

10.21273/hortsci.33.3.534e ◽

1998 ◽

Vol 33 (3) ◽

pp. 534e-534 ◽

Cited By ~ 1

Author(s):

J. Staub ◽

Felix Sequen ◽

Tom Horejsi ◽

Jin Feng Chen

Keyword(s):

Genetic Diversity ◽

Principal Component Analysis ◽

Genetic Variation ◽

Genetic Analysis ◽

Allelic Variation ◽

Germplasm Collection ◽

Principal Component ◽

Isozyme Loci ◽

National Plant Germplasm System ◽

The U.S

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.

Download Full-text

Population Genetics ofCaenorhabditis elegans: The Paradox of Low Polymorphism in a Widespread Species

Genetics ◽

10.1093/genetics/163.1.147 ◽

2003 ◽

Vol 163 (1) ◽

pp. 147-157 ◽

Cited By ~ 6

Author(s):

Arjun Sivasundar ◽

Jody Hey

Keyword(s):

Genetic Variation ◽

Microsatellite Loci ◽

Population Expansion ◽

Widespread Species ◽

C Elegans ◽

Model Research ◽

The World ◽

Natural Isolates ◽

History Of ◽

Low Levels

AbstractCaenorhabditis elegans has become one of the most widely used model research organisms, yet we have little information on evolutionary processes and recent evolutionary history of this widespread species. We examined patterns of variation at 20 microsatellite loci in a sample of 23 natural isolates of C. elegans from various parts of the world. One-half of the loci were monomorphic among all strains, and overall genetic variation at microsatellite loci was low, relative to most other species. Some population structure was detected, but there was no association between the genetic and geographic distances among different natural isolates. Thus, despite the nearly worldwide occurrence of C. elegans, little evidence was found for local adaptation in strains derived from different parts of the world. The low levels of genetic variation within and among populations suggest that recent colonization and population expansion might have occurred. However, the patterns of variation are not consistent with population expansion. A possible explanation for the observed patterns is the action of background selection to reduce polymorphism, coupled with ongoing gene flow among populations worldwide.

Download Full-text