Analysis of genetic diversity and structure in Ethiopian populations of Phytolacca dodecandra using RAPD

The genetic diversity and structure in 17 wild populations (249 individuals) of Phytolacca dodecandra (endod) sampled along altitudinal gradients of 1600-3000 meters above sea level (m.a.s.l.) in Ethiopia was studied using random amplified polymorphic DNA (RAPD). A total of 70 polymorphic loci (P) scored from 12 RAPD primers were used to calculate different diversity indices within and between populations, habitats, geographical regions, climatic zones and altitude groups. The number of polymorphic loci and overall Shannon information measure (H) in the populations varied from 30 to 55 and from 0.228 to 0.418, respectively. In general, differences in population variability were found significantly correlated to effective population size. Both P and H were significantly higher in an undisturbed than in a disturbed habitat, and in the lowland and central-highland than in the highland altitude group. However, for both parameters the differences were not statistically significant between regions and climatic zones. Genetic distance between populations varied from 0.301 to 0.628. Cluster analysis performed using the genetic distance matrix revealed a clear separation of the highland populations (2501-3000 m.a.s.l.) from those of the lowland/central-highlands (1600-2500 m.a.s.l.) irrespective of their geographical regions and climatic zones. Analysis of molecular variance (AMOVA) indicated that differences in habitat, geographical regions and climatic zones explained 4.6%, 2.5% and 4.6%, respectively. But none of these differences were significant. Altitude explained 17.2% of the total variance and was highly significant. The data, therefore, clearly indicated the association of genetic structure in endod with altitude. The proportion of RAPD variation found among populations (21.2-35.0%) was somewhat intermediate between values reported for selfing and outcrossing species. The fixation index (FST) values (0.350 to 0.384) indicated very high genetic differentiation among populations.     

RAPD polymorphism of wild emmer wheat populations, Triticum dicoccoides, in Israel

 Genetic diversity in random amplified polymorphic DNAs (RAPDs) was studied in 110 genotypes of the tetraploid wild progenitor of wheat, Triticum dicoccoides, from 11 populations sampled in Israel and Turkey. Our results show high level of diversity of RAPD markers in wild wheat populations in Israel. The ten primers used in this study amplified 59 scorable RAPD loci of which 48 (81.4%) were polymorphic and 11 monomorphic. RAPD analysis was found to be highly effective in distinguishing genotypes of T. dicoccoides originating from diverse ecogeographical sites in Israel and Turkey, with 95.5% of the 100 genotypes correctly classified into sites of origin by discriminant analysis based on RAPD genotyping. However, interpopulation genetic distances showed no association with geographic distance between the population sites of origin, negating a simple isolation by distance model. Spatial autocorrelation of RAPD frequencies suggests that migration is not influential. Our present RAPD results are non-random and in agreement with the previously obtained allozyme patterns, although the genetic diversity values obtained with RAPDs are much higher than the allozyme values. Significant correlates of RAPD markers with various climatic and soil factors suggest that, as in the case of allozymes, natural selection causes adaptive RAPD ecogeographical differentiation. The results obtained suggest that RAPD markers are useful for the estimation of genetic diversity in wild material of T. dicoccoides and the identification of suitable parents for the development of mapping populations for the tagging of agronomically important traits derived from T. dicoccoides. Received: 13 July 1998 / Accepted: 13 August 1998     

Microsatellite polymorphism in natural populations of wild emmer wheat,Triticum dicoccoides,in Israel

Diversity in 20 microsatellite loci of wild emmer wheat, Triticum dicoccoides, was examined in 15 populations (135 genotypes) representing a wide range of ecological conditions of soil, temperature, and water availability, in Israel and Turkey. An extensive amount of diversity at microsatellite loci was observed despite the predominantly selfing nature of this plant species. The 20 Gatersleben wheat microsatellites (GWM), representing 13 chromosomes of genomes A and B of wheat, revealed a total of 364 alleles, with an average of 18 alleles per GWM marker (range: 5–26). The proportion of polymorphic loci per population averaged 0.90 (range: 0.45– 1.00); genic diversity, He, averaged 0.50 (range 0.094– 0.736); and Shannon’s information index averaged 0.84 (range 0.166–1.307). The coefficients of genetic distance between populations were high and averaged D=1.862 (range 0.876–3.320), an indication of sharp genetic divergence over short distances. Interpopulation genetic distances showed no association with geographic distance between the population sites of origin, which ruled out a simple isolation by distance model. Genetic dissimilarity values between genotypes were used to produce a dendrogram of the relationships among wild wheat populations by the unweighted pair-group method with arithmetic averages (UPGMA). The results showed that all the wild emmer wheat populations could be distinguished. Microsatellite analysis was found to be highly effective in distinguishing genotypes of T. dicoccoides, originating from diverse ecogeographical sites in Israel and Turkey, with 88% of the 135 genotypes correctly classified into sites of origin by discriminant analysis. Our present microsatellite results are non-random and in agreement with the previously obtained allozyme and RAPD patterns, although the genetic-diversity values obtained with microsatellites are much higher. Significant correlates of microsatellite markers with various climatic and soil factors suggest that, as in allozymes and RAPDs, natural selection causes adaptive microsatellite ecogeographical differentiation, not only in coding, but most importantly in non-coding genomic regions. Hence, the concept of ”junk DNA” needs to be replaced by at least partly regulatory DNA. The obtained results suggest that microsatellite markers are useful for the estimation of genetic diversity in natural populations of T. dicoccoides and for the tagging of agronomically important traits derived from wild emmer wheat. Received: 27 February 2001 / Accepted: 22 March 2001     

Detection and analysis of genetic variation in Hordeum spontaneum populations from Israel using RAPD markers

Randomly amplified polymorphic DNA (RAPD) markers were used to analyse genetic diversity within and between Hordeum spontaneum populations sampled from Israel. Nei's index of genetic differentiation was used to partition diversity into within and between population components. Fifty-seven per cent of the variation detected was partitioned within 10 H. spontaneum populations. Using principal component and multiple regression analysis, part of the variation detected between populations was seen to be associated with certain ecogeographical factors. Fifty-eight per cent of the distribution of the phenotypic frequencies of three RAPD phenotypes detected using a single primer in 20 H. spontaneum populations could be accounted for by four ecogeographical variables, suggesting adaptive variation at certain RAPD loci.     

Genetic diversity and differentiation of cultivated amochi (Arisaema schimperianum Schott) in Ethiopia as revealed by AFLP markers

Amochi (Arisaema schimperianum Schott) is an off-season crop plant in southern Ethiopia, grown during the dry season on residual moisture, for its edible tubers. It has gained importance as a "security crop" especially during the years of moisture stress and food shortage. Amochi is irritating in contact to the skin. Removal of this effect is an important question for breeding. As the first step, however we attempt to establish base line information of its breeding system and genetic variability using AFLPs. The extent of genetic differentiation among 11 populations (96 individuals) of amochi sampled along altitudinal gradients that varied from 1700 to 3200 m a.s.l. was investigated. The populations were classified in to three altitudinal groups: lowland (1700 to 2200 m a.s.l.), central-highland (2201 to 2600 m a.s.l.) and highland (2601 to 3200 m a.s.l.). Polymorphic loci (167) scored from four primer pair combinations, were used for principal component analysis (PCA), and analysis of molecular variance (AMOVA). Both PCA and unweighed pair group with arithmetic mean (UPGMA) clearly differentiated populations into their respective altitude groups, with large genetic distances. AMOVA analysis revealed 70.5%, 16.7% and 12.8% variability between altitude groups, between populations and within populations respectively. Average diversity indices within populations were also low. Since the largest proportion of variation is located between altitude groups, rather than within populations, we suggest future studies on the chemical composition, low irritation, and other desirable traits should consider populations from different altitude ranges.     

Effects of roads on alpine and subalpine plant species distribution along an altitudinal gradient on Mount Norikura, central Japan

We investigated the effects of roads on alpine and subalpine plant species distribution along an altitudinal gradient on Mount Norikura (3026 m a.s.l.), Japan. We examined the vegetation of herb and tree species shorter than 1.3 m along roadsides and adjacent natural vegetation at 200 m intervals between 1600 and 3000 m a.s.l. The timberline was at 2500 m a.s.l. Although the canopy opening was greater at the roadsides than in the natural vegetation, it was similar above the timberline. Soil cover and litter depth of the soil surface were less at roadsides than the natural vegetation, and gravel and rock cover were greater at roadsides. Species composition changed in similar directions from natural vegetation to roadsides along the altitudinal gradient. This direction was related to canopy opening and litter depth. Liliaceae, Ericaceae and Pinaceae were dominant families in the natural vegetation, and Asteraceae and Poaceae were greatest at the roadsides. Roadside plants were mostly herb species, while tree species increased in natural vegetation. Five exotic species were also observed at the roadsides. Sunny plant species gradually increased with altitude in the natural vegetation, indicated by the increase in canopy opening. By contrast, roadside plants were mostly sunny plant species irrespective of altitude. The number of lowland and montane species increased at the roadsides in the subalpine zone. Thus, roads strongly altered species composition of the natural vegetation along the altitudinal gradient probably because of changes in light and soil-surface conditions for growth and seedling establishment.     

Genetic and biochemical differentiation in Vitis vinifera (Kabarcik) populations grown at different altitudes in Coruh Valley

We examined genetic differences of four Vitis vinifera populations (A, B, C, D) including local Kabarcik cultivar grown along an altitude gradient of 800, 900, 1000, and 1150 m above sea level in the Coruh Valley (800 m: A population; 900 m: B population; 1000 m: C population; 1150 m: D population). Leaf samples were used for both RAPD and fatty acid analysis. A total of 60 individuals with 15 individuals per population were included in this study. RAPD analyses showed various band sizes, which ranged from 250 to 3000 bp. Mean polymorphic locus ratios were determined as 96.29% considering four populations. The highest percentage of polymorphic loci (97.8%) was produced by the highest altitude. Thirty-two different fatty acids were found; linoleic acid was the most common in all four populations. According to the dendograms obtained from statistical analyses of RAPD and fatty acid profiles the populations that were close to each other in terms of geographical distance also were similar genetically.     

The impact of elevated UV-B (280–320 nm) radiation levels on the reproduction biology of a highland and a lowland population of Silene vulgaris

A highland (altitude 1600 m) and a lowland (altitude –2 m) population of the perennial herb Silene vulgaris were tested on the effects of elevated levels of UV-B radiation on their reproductivity. Highland populations receive higher natural UV-B doses than lowland populations. Therefore adaptation to high UV-B levels of the highland population is to be expected. The lowland population showed a decrease in the number of seed producing flowers and the number of seeds produced per plant under elevated UV-B levels. The highland population increased the number of seeds per plant under elevated UV-B levels. In both populations individual seed mass as well as seed germination percentages were unaffected by the UV-B flux received by the parental plant. Possible effects of UV-B induced alterations in reproductivity on the geographical distribution of the different populations are discussed.     

Microsatellite diversity associated with ecological factors in Hordeum spontaneum populations in Israel

Microsatellite diversity at 18 loci was analysed in 94 individual plants of 10 wild barley, Hordeum spontaneum (C. Koch) Thell., populations sampled from Israel across a southward transect of increasing aridity. Allelic distribution in populations was not distributed randomly. Estimates of mean gene diversity were highest in stressful arid-hot environments. Sixty-four per cent of the genetic variation was partitioned within populations and 36% between populations. Associations between ecogeographical variables and gene diversity, H(e), were established in nine microsatellite loci. By employing principle component analysis we reduced the number of ecogeographical variables to three principal components including water factors, temperature and geography. At three loci, stepwise multiple regression analysis explained significantly the gene diversity by a single principal component (water factors). Based on these observations it is suggested that simple sequence repeats are not necessarily biologically neutral.     

Seed weight increases with altitude in the Swiss Alps between related species but not among populations of individual species

Seed weight is a crucial plant life history trait, determining establishment success and dispersal ability. Especially in stressful environments, larger seeds may be selected at the expense of seed number, because larger seeds have a better chance of giving rise to an established offspring. We tested the hypotheses that between related species-pairs and among populations of single species a similar trend for increasing seed weight with increasing altitude should be present. Firstly, we measured seed weights from 29 species-pairs, with one species occurring in lowland areas and a congeneric species from high altitudes. Seeds of the alpine species were 28±8% larger than seeds from lowland species (P<0.01). Compared to the related lowland species, 55% of the alpine species had heavier seeds, 3% (one species) had lighter, and 41% had seeds of approximately equal weight. Secondly, we compared seed weights among populations of four species from different habitats and with different life histories. Seeds from between 11 and 34 populations per species were sampled along altitudinal gradients of 800–1,500 m (ca. 800 m in Scabiosa lucida, ca. 1,000 m in Saxifraga oppositifolia, ca. 1,000 m in Epilobium fleischeri, and ca. 1,500 m in Carex flacca). In all the four species, we found no indication for heavier seeds at higher altitudes. Our results indicate a selection pressure for species with heavier seeds at higher altitude, but the trend does not seem to operate across all cases. Phylogenetic constraints may limit the correlation among altitude and seed weight, operating particularly against selection for larger seed size, the closer populations and species are related to each other.     

Distribution of plant life forms along an altitudinal gradient in the semi‐arid valley of Zapotitlán,Mexico

Abstract. Plant life‐form abundance along a 600 m altitudinal gradient (1600–2200 m a.s.l.) in the semi‐arid valley of Zapotitlán, México was correlated with soil characteristics and climatic variables. One mixed soil sample was taken and analysed for each of six elevations, temperature was estimated using a terrestrial thermal gradient, and precipitation using a linear regression between total annual precipitation and the elevation of the weather stations in the valley. Rosettes, microphanerophytes, therophytes and nanophanerophytes were well represented throughout the gradient. Columnar cacti were restricted to the 1600–1800 m range, and geophytes to the 1700–1800 m range. In general, abundance of life forms was inversely associated with altitude. Multiple regression analysis did not show parameters to significantly explain the abundance of rosettes, nanophanerophytes, epiphytes, geophytes and hemiparasites; altitude and nitrogen proved significant for columnar cacti, succulents and chamaephytes; altitude, pH, electrical conductivity and nitrogen were significant for globose cacti; pH was significant for therophytes; and altitude was significant for microphanerophytes.     

The distribution of random amplified polymorphic DNA (RAPD) diversity amongst populations of Isotoma petraea (Lobeliaceae)

RAPDs were generated from plants of six populations of Isotoma petraea F. Muell. The species occurs on rock outcrops in southern and western Australia, with populations exhibiting different breeding systems, including complete autogamy, varying levels of outbreeding and complex hybridity. Non-metric multidimensional scaling (nMDS) analysis of the random amplified polymorphic DNA (RAPD) data set clearly resolved all populations. The Pigeon Rock population, which is home to both complex hybrid and structural homozygote plants, was divided into those two groups by the nMDS analysis. There was little diversity in highly autogamous populations, but levels were higher in the outbred Yackeyackine population. All complex hybrid populations and plants possessed numerous genetic system-specific RAPDs, some of which were shown to be held in fixed heterozygosity. Estimating G _ST using RAPDs has been problematical due to their dominance, and analytical methods usually rely on knowledge of the selfing rate or assume Hardy–Weinberg equilibrium. This assumption does not hold when populations exhibit fixed heterozygosity, and an alternative method, Shannon's Index, was used to partition genetic diversity. The distribution of genetic diversity fit expectations for an inbreeding species, with most of the variation (87.5%) occurring between populations. This compares to an average RAPD-based G _ST of 59.6% for inbreeding species generally and 15.5% for outbreeding species.     

Genetic structure and differentiation of Psathyrostachys huashanica populations detected with RAPD markers

Psathyrostachys huashanica Keng is a perennial grass and belongs to genus Psathyrostachys under Triticeae. sathyrostachys is found in the center of Middle Asia and the Caucasus Mountain, while P. huashanica, a species endemic to China, is only located in Mt. Hua in the Shaanxi province, China. At present, the population of this species is decreasing, and reaching the edge of extinction. Due to the limitation in distribution and the importance as breeding material for germplasm storage, it has been considered as first class among the national protected rare plants. For this reason, the present study is significant in probing plant flora, origin and evolution of Triticeae, and crop breeding. Randomly amplified polymorphic DNA (RAPD) markers were used to analyze the genetic structure and differentiation of P. huashanica populations sampled in three valleys (Huangpu, Xian, and Huashan Valleys) in Mt. Hua. One hundred and twenty-two RAPD fragments were obtained in all 266 individuals with 20 primers with a mean of 6.1 (2–10) fragments per primer. The percentage of polymorphic loci (PPB) was 60.66% in Huangpu Valley, 90.98% in Xian Valley, 95.08% in Huashan Valley, and the total PPB was 95.08%, which indicated a highly genetic variability of P. huashanica. The Shannon’s Information index and G _ST were 0.3306 and 0.3263, respectively, indicating that there were more genetic variations within the subpopulations than those among the subpopulations. The gene flow among the subpopulations of P. huashanica (Nm = 1.0322) was much less than that of the common anemophytes (Nm = 5.24). Mean genetic distance is 0.1 571 (range: 0.0022–0.2901). The highest value of genetic distance was found between the subpopulation (hp1) of Huangpu Valley and the highest altitude subpopulation (h8) of Huashan Valley. Correlation analysis detected significant correlation between genetic distance and vertical distance of altitude. Clustering analysis and principal coordinate analysis revealed the genetic differentiation among the populations of P. huashanica. Differentiation mainly occurred between the higher altitude subpopulations and the lower altitude subpopulations, suggesting that altitude might be the major factor that restricted the gene flow between different altitude subpopulations and resulted in differentiation of subpopulations. Translated from Acta Ecologica Sinica, 2005, 25(4): 719–726 [译自: 生态学报]     

Spatial variability in woody species richness along altitudinal gradient in a lowland-dryland site, Lokapel Turkana, Kenya

The woody species richness patterns in three 2–4 km long transects, approximately 1–3 km apart in a lowland (600–700 m) dryland around Lokapel in Turkana northern Kenya was analyzed in 2003 at 200–500 m intervals using the Point-Centred Quarter (PCQ) method involving 51 observation points. Transect 1 and 2 were set along ephemeral runoff channels locally known as lagga with wet season flow westwards from the Lokapel Hills to the Turkwell River. Transect 3 was a cross-cutting profile dissecting the area initially downhill from the Lokapel Hills and later gently uphill eastwards towards Lokichar. The altitude at each of the 51 observation sites was recorded using a GPS and the woody species identified through local knowledge and taxonomic aids. The results showed that the overall integrated altitudinal gradient for the three transects was approximately 100 m. A total of 43 species of trees and shrubs were identified. The Shannon index showed that Transect 2 had the highest diversity of woody species followed by Transect 1 and Transect 3 while the Sorensen’s index indicated qualitative dissimilarity between all the transects. The results of regression analysis indicated that woody species richness increased linearly with elevation in only one transect but regression analysis of height of woody plants and altitude indicated that only about 20% of the variation in the height of woody plants was accountable by altitude. The spatial analysis of woody species-richness and altitudinal gradient showed a dual peak pattern with the main richness peak in low lying areas below 700 m which was mainly within or close to the riparian floodplain environment of the Turkwell River. A minor richness peak was also identified in higher lying areas around the Lokapel hills. The species richness pattern was similar to the hump-shaped altitudinal species-richness pattern which has been recorded widely around the world but mainly in large-scale studies.     

Developmental responses to UV-B radiation in common frog <Emphasis Type="Italic">Rana temporaria</Emphasis> embryos from along an altitudinal gradient

Solar ultraviolet radiation (UV) is harmful for developing amphibians. As UV increases with altitude and latitude, it is suggested that high altitude and latitude populations have evolved tolerance to high levels of UV. Using laboratory experiments, we tested the hypothesis that Rana temporaria populations from several altitudes (438–2,450 m above sea level) were adapted to UV by assessing the effects of artificial UV on embryos mortality rate, malformations, and body length at hatching. We also tested the protective role of the jelly surrounding the embryos. Without artificial UV exposure, hatching success decreased with altitude of the population. Malformation rates were low for all populations (mean 1.36%), and hatching size increased with altitude. The artificial UV (UV-B, UV-A, and visible) used was similar to the solar spectrum received at high altitude. Exposed embryos had performance similar to that of embryos without exposure: a decreased hatching success with altitude and a low malformation rate (mean 0.85%). However, hatching size did not vary with altitude, and UV-exposed embryos tended to be smaller at hatching than non-exposed embryos. Removal of the protective jelly envelope greatly decreased the performance of UV-exposed embryos: hatching success strongly decreased with altitude and embryos of the highest population (2,450 m asl) did not develop. Malformation reached 4.98%, without population differences, and hatching size of embryos without jelly was smaller than hatching size of non-manipulated embryos with no population effect. This study demonstrates that lowland jellyless embryos were less sensitive (i.e., exhibited a higher survival rate) than highland embryos and, on the other hand, that the jelly envelope was a more efficient protection for embryos in highland than in lowland populations. A trade-off hypothesis is presented to explain this difference in UV tolerance and protection among populations: in a harsh, highland environment (i.e., with a curtailed activity period), embryos have to invest in development and growth and, thus, embryo protection should be a female investment (via the jelly). In a lowland environment, embryonic growth and development are less constrained and embryos are able to invest and use protection or repair mechanisms inherited from their parents.     

Ecomorphological and genetic divergence between lowland and montane forms of the Pieris napi species complex (Pieridae, Lepidoptera)

The present study aimed to investigate the morphological and genetic differentiation of lowland and montane populations of the Pieris napi species complex in Norway and to make inferences about the subspecific status of Pieris napi adalwinda and Pieris napi napi . We measured 22 morphological characters on 228 individuals from eight populations in Central Norway (20–1100 m a.s.l.). In addition, lowland and mountain animals were reared at a high altitude locality. Half the animals from either locality were reared on mountain plant, and the other half on a lowland plant. Finally, a fragment of the mitochondrial cytochrome b gene was sequenced for individuals from Central and South-eastern Norway and Germany. Principal component analysis of morphological characters showed a zone of abrupt change from lowland to mountain morphological character states between populations at 506 m and 730 m a.s.l., respectively. The transplant experiment showed that the morphological differences have a genetic basis and that food plants have no impact on morphology. Limited, but significant, molecular genetic differentiation was found between lowland and mountain animals, but the phylogenetic analysis, however, showed that the lowland form ( P. n. napi ) is paraphyletic and the montane form ( P. n. adalwinda ) is monophyletic. Further study is required before taxonomic recognition can be applied.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 727–745.     

Winter water relations of timberline larch (Larix leptolepis Gord.) on Mt. Fuji

 A krummholz mat of larch, Larix leptolepis, is the predominant growth form near the upper limit (near 2500 m) of the timberline ecotone on the south slope of Mt. Fuji, Japan. On the south-eastern slope, the tree line is lowered to 1600 m because of the last volcanic eruption. The extent and causes of winter desiccation were compared in timberline larch between 2500 m and 1600 m elevation over two winters. Bark abrasion due to wind-blown fine volcanic gravels caused a decrease in bark resistance to water loss and resulted in severe desiccation damage to current-year shoots of krummholz larches in the winter of 1986 – 87 at 2500 m, whereas abraded shoots at 1600 m maintained high water content during both winters. In the winter of 1985 – 86, shoots of krummholz larches at 2500 m did not experience bark abrasion and high water contents were maintained. Experimental abrasion of shoot surfaces resulted in similar results at each elevation. Thus, in timberline larch at 2500 m, abrasion by wind-blown fine volcanic gravels is the primary factor causing winter desiccation damage and krummholz formation. Based on field experiments, the estimated amount of water movement to non-abraded shoots was the same for the two elevations. At 2500 m, water movement to abraded shoots was less than to non-abraded shoots, but the reverse situation was noted at 1600 m. Water supply to abraded shoots at 2500 m was limited and insufficient to compensate for water loss. A cause of limited water supply at 2500 m may be xylem embolism. Received: 13 January 1995 / Accepted: 31 January 1996     

Molecular phylogeny of mangroves. VI. Intraspecific genetic variation in mangrove species Excoecaria agallocha L. (Euphorbiaceae).

Genomic DNA from 84 individuals of Excoecaria agallocha from seven mangrove populations were analysed for random amplified polymorphic DNAs (RAPDs) using 16 random 10-mer primers. Polymorphism within populations varied from 20% to 31%. At the interpopulation level, 111/149 (74%) of RAPDs were polymorphic. Restriction fragment length polymorphism (RFLP) analysis of 21 individuals (3 individuals randomly selected from the 7 populations) using 30 probe-enzyme combinations revealed a high level of interpopulation polymorphism (62.2%) indicating interpopulation genetic divergence. The polymorphic RAPDs and RFLPs were pooled, and clustering was carried out based on mean similarity for individual populations. The dendrogram showed groupings of populations from the West and East Coasts of India into separate clusters, at 60% similarity level. Further, RAPD and RFLP analysis of male and female plants showed approximately the same level of variation in both sexes, and no sex-linked markers were found. These results demonstrate that considerable intrapopulation and interpopulation genetic variations exist in E. agallocha, and that lack of genetic variation is not the reason for the morphological uniformity observed across the range of the species.     

Patterns of seasonal activity in a Mediterranean lizard along a 2200 m altitudinal gradient

Ectothermy in reptiles involves strong environmental temperature dependence to maintain body temperature. High mountains are extreme habitats which, because of their marked temperature decrease with altitude, impose difficulties for reptile thermoregulation, as the number of optimum-temperature days diminish in altitude. We studied the activity patterns of the lizard Psammodromus algirus, which has a wide altitudinal distribution, at six sampling stations that spanned an altitudinal range from 300 to 2500 m asl in Sierra Nevada (SE Iberian Peninsula). We performed censuses of the species during the seasonal and daily activity period, and measured lizard body temperature and environmental temperature in the six sampling plots along the altitude gradient. The body temperature of the lizards remained closely the same even though environmental temperature decreased around 9°C along that gradient. Seasonal activity peaked at the beginning of the activity period in highlands, but in the middle of the season in middle and lowland regions. However, newborns appeared in the field almost at the same time along the altitude gradient. We suggest that the thermoregulatory strategies of the lizards must vary along this altitudinal gradient, permitting lizards to keep their body temperature close to a very similar optimum and thus, develop very similar circa-annual activity patterns.     

Altitudinal variations in germination and growth responses ofReynoutria japonica populations on Mt Fuji to a controlled thermal environment

The authors examined altitudinal variations in the thermal responses of seed germination and seedling growth inReynoutria japonica (=Polygonum cuspidatum) under controlled environmental conditions. Seed populations were collected from different altitudes on Mt Fuji in Japan. The mean seed weight of the upland populations (above 1500 m) was significantly (1.5-fold) heavier than that of the lowland populations (below 1400 m). Under the lowest temperature regime of 15/10°C (day/night) the upland populations showed a significantly higher percentage and speed of germination than the lowland populations; this was not significant under higher temperature regimes. These results indicate that the germination traits of the upland populations on Mt Fuji are favorable for colonization in their cold habitats (low temperature and short growing season). Growth and shoot development were compared between the seedlings grown from seeds collected at altitudes of 700 and 2420 m. The upland seedlings showed a significantly larger biomass and leaf area than the lowland seedlings at 15°C, but there was no difference at 25°C. The difference in biomass at 15°C was attributed to the difference in seed weight. The upland seedlings produced a significantly larger number of branches with smaller and more numerous leaves at both 15°C and 25°C. these developmental traits of the upland seedlings were considered to represent the adaptation of the life form to upland environments. It was concluded that theR. japonica populations along an altitudinal gradient on Mt Fuji can be classified into two ecotypes, whose distribution border lies at an altitude of about 1400–1500m. In this study, the seed weight and germination traits of twoR. japonica seed populations collected in Chiba Prefecture were briefly compared with those of the lowland populations on Mt Fuji.