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This research was carried out to determinenutritional content and chemical composition of knotgrass species (Polygonum) consumed as vegetable in theMiddle Black Sea Region. Survey and field studies started in spring of 2011(April-May) and were carried out in Samsun, Amasya, Ordu and Tokat where these species were intense. In the surveystudies, five species were identified in 35 knotgrass samples as Polygonum arenastrum (12 materials), Polygonum aviculare (9 materials), Polygonum salicifolium (9 materials), Polygonum setosum (2 materials) and Polygonum luzuloides (3 materials). Inthe research, the highest amount of dry matter in P. salicifolium (26.68 %), the highest ash content in P. setosum (10.21 %), the highest N andprotein contents in P. luzuloides(3.31 % and 20.70 %) and thehighest Vitamin C in P.aviculare(105.46 mg/100g-1) were determined. The highest K content in P. luzuloides, the highest Zn, Mn and Cacontents in P. setosum, the highest Pand Na contents in P. arenastrum andthe highest Cu, Mg and Fe content in P.salicifolium were determined. Amounts of mineral matter showed variationaccording to plant species, genetic factors and ecology of samples taken from.It was determined that many of nutritional properties studied were richer than some cultivated vegetable species., Buaraştırma, Orta Karadeniz Bölgesi’nde sebze olarak tüketilen madımak türlerininbesin içeriği ve kimyasal bileşimini belirlemek için yürütülmüştür.Sörvey ve arazi çalışmaları 2011 yılının ilkbahar döneminde (Nisan-Mayıs)başlamış olup Samsun, Ordu, Amasya ve Tokat illerinde yürütülmüştür. Sörveyçalışmalarında 35madımak örneğinde 5 tür tespit edilmiş olup bunlar Polygonum arenastrum (12 materyal), Polygonum aviculare (9 materyal), Polygonum salicifolium (9 materyal), Polygonum setosum (2 materyal), ve Polygonum luzuloides (3 materyal)’dir. Araştırmada en yüksek kurumadde miktarı P.salicifolium (% 26.68),en yüksek kül miktarı P. setosum (% 10.21),en yüksek N ve protein miktarı P.luzuloides (% 3.31 ve % 20.70) ve en yüksek C vitamini P. aviculare (105.46 mg/100g)türlerinde belirlenmiştir. En yüksek K miktarı P. luzuloides, en yüksek Zn, Mn ve Ca miktarı P. setosum, en yüksek P ve Na miktarı P. arenastrum ve en yüksek Cu, Mg ve Fe miktarı ise P. salicifolium türlerinde tespitedilmiştir. Mineral madde içerikleri bitki türüne, genetik faktöre ve örneklerin alındığı ekolojiye göre varyasyongöstermiştir. Madımaklarda incelenen besinsel özelliklerin birçoğununbazı kültürü yapılan sebzetürlerine göre daha zengin içeriğe sahip olduklarını tespit edilmiştir.

A herbaceous plant Polygonum arenastrum Bor. (=P. aequele Lindm., Polygonum aviculare ssp. aequale (Lindman) Ascherson & Graebner) (equal-leaved knotgrass), is a widespread, good coloniser, able to survive in wastelands where other species became extinct. Therefore, the bioindication abilities of this species for F, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn were investigated. P.arenastrum was collected from 90 sites affected by six polluting factories: copper smelter, chlor-alkali plant, former ferrous-chromium smelter and active combustion smelter, power plant, cement plant and coke plant. Plant samples were collected at 0.75, 1.5, 3 and 4.5 km from each of these polluters in N, S, W and E directions. For comparison, a control site with 16 sampling points was selected in an area relatively free from pollution. Concentrations of Cr, Cu, Fe, Pb and Zn in shoots and roots positively correlated with those in soil (both total and plant-available). Cu, Pb and Zn in P.arenastrum were within the values reported in literature as toxic for other plants with the highest bioaccumulation factor (BF) from soil to shoots for Cr and the highest translocation factor (TF) from roots to shoots for Co and Pb for more and less polluted and control sites. Polygonum arenastrum has a potential to accumulate Cr even in sites with low chromium concentration in soil. Polygonum arenastrum does not show any form of shoot injury at increased levels of F and metals in its tissues. Based on these characteristics we conclude that the ubiquitous P.arenastrum may be utilised as a relevant indicator of contamination in industrial zones and may function as an early warning system of increased toxicity in the environment.

Habitats that differ in soil resource availability are expected to differ for selection on resource-related plant traits. Here, we examined spatial and temporal variation in phenotypic selection on leaf ecophysiological traits for 10 Helianthus populations, including two species of hybrid origin, Helianthus anomalus and Helianthus deserticola, and artificial hybrids of their ancestral parents. Leaf traits assessed were leaf size, succulence, nitrogen (N) concentration and water-use efficiency (WUE). Biomass and leaf traits of artificial hybrids indicate that the actively moving dune habitat of H. anomalus was more growth limiting, with lower N availability but higher relative water availability than the stabilized dune habitat of H. deserticola. Habitats differed for direct selection on leaf N and WUE, but not size or succulence, for the artificial hybrids. However, within the H. anomalus habitat, direct selection on WUE also differed among populations. Across years, direct selection on leaf traits did not differ. Leaf N was the only trait for which direct selection differed between habitats but not within the H. anomalus habitat, suggesting that nutrient limitation is an important selective force driving adaptation of H. anomalus to the active dune habitat.

Water limitation is one of the most important factors limiting crop productivity world-wide and has likely been an important selective regime influencing the evolution of plant physiology. Understanding the genetic and physiological basis of drought adaptation is therefore important for improving crops as well as for understanding the evolution of wild species. Here, results are presented from quantitative trait loci (QTL) mapping of flowering time (a drought escape mechanism) and carbon stable isotope ratio (¿13C) (a drought-avoidance mechanism) in Arabidopsis thaliana. Whole-genome scans were performed using multiple-QTL models for both additive and epistatic QTL effects. We mapped five QTL affecting flowering time and five QTL affecting ¿13C, but two genomic regions contained QTL with effects on both traits, suggesting a potential pleiotropic relationship. In addition, we observed QTL¿QTL interaction for both traits. Two ¿13C QTL were captured in near-isogenic lines to further characterize their physiological basis. These experiments revealed allelic effects on ¿13C through the upstream trait of stomatal conductance with subsequent consequences for whole plant transpiration efficiency and water loss. Our findings document considerable natural genetic variation in whole-plant, drought resistance physiology of Arabidopsis and highlight the value of quantitative genetic approaches for exploring functional relationships regulating physiology.

Variation at six polymorphic enzymatic loci was studied in 50 populations of the selfing annualPolygonum aviculare from Belgium. The results show that theP. aviculare complex has an allopolyploid origin and comprises two main genetic entities, viz.P. aviculare subsp.depressum (2n = 4x = 40), restricted to urban sites subject to trampling stress, andP. aviculare subsp.aviculare (2n = 4x = 40, 2n = 6x = 60), with a wider ecological amplitude. The latter had a higher genetic diversity and a higher frequency of fixed heterozygosity than the former. WithinP. aviculare subsp.aviculare, genetic diversity and ecological amplitude correlated positively with ploidy level. Additionally, stronger genetic differentiation among and lower variation within populations was found in urban areas than in cultivated fields.

Terrestrial plant photosynthesis may be limited both by stomatal behavior and leaf biochemical capacity. While inferences have been made about the importance of stomatal and biochemical limitations to photosynthesis in a variety of species in a range of environments, genetic variation in these limitations has never been documented in wild plant populations. Genetic variation provides the raw material for adaptive evolution in rates of carbon assimilation. We examined genetic variation in gas exchange physiology and in stomatal and biochemical traits in 16 genetic lines of the annual plant, Polygonum arenastrum. The photosynthesis against leaf internal CO2 (A−ci) response curve was measured on three greenhouse-grown individuals per line. We measured the photosynthetic rate (A) and stomatal conductance (g), and calculated the internal CO2 concentration (ci) at ambient CO2 levels. In addition, the following stomatal and biochemical characteristics were obtained from the A−ci curve on each individual: the degree of stomatal limitation to photosynthesis (Ls), the maximum ribulose 1,5-biphosphate carboxylase-oxygenase (Rubisco) activity (Vcmax) and electron transport capacity (Jmax). All physiological traits were genetically variable, with broad sense heritabilities ranging from 0.66 for Ls to 0.94 for Jmax. Strong positive genetic correlations were found between Vcmax and Jmax, and between g and biochemical capacity. Path analyses revealed strong causal influences of stomatal conductance and leaf biochemistry on A and ci. Path analysis also indicated that Ls confounds both stomatal and biochemical effects, and is an appropriate measure of stomatal influences on photosynthesis, only when biochemical variation is accounted for. In total, our results indicate that differences among lines in photosynthesis and ci result from simultaneous changes in biochemical and stomatal characteristics and are consistent with theoretical predictions that there should be co-limitation of photosynthesis by ribulose-1,5-biphosphate (RuBP) utilization and regeneration, and by stomatal conductance and leaf biochemistry. Gas exchange characteristics of genetic lines in the present study were generally consistent with measurements of the same lines in a previous field study. Our new results indicate that the mechanisms underlying variation in gas exchange include variation in both stomatal conductance and biochemical capacity. In addition, A, g, and ci in the present study tended also to be positively correlated with carbon isotope discrimination (Δ), and negatively correlated with time to flowering, life span, and leaf size based on earlier work. The pattern of correlation between physiology and life span among genetic lines of P. arenastrum parallels interspecific patterns of character correlations. We suggest that the range of trait constellations among lines in P. arenastrum represents a continuum between stress avoidance (rapid development, high gas exchange metabolism) and stress tolerance (slow development, low gas exchange metabolism), and that genetic variation in these character combinations may be maintained by environmental variation in stress levels in the species’ ruderal habitat.

We present evidence of genetic variation in and covariation between leaf-level gas exchange properties and leaf size among family lines of Polygonum arenastrum. This self-fertilizing annual had previously been shown to vary genetically in developmental phenology and in morphology (size of leaves, internodes, flowers and seeds) (Geber 1990). Significant family differences were found in photosynthetic carbon assimilation rate (A), lcaf conductance to water vapor (g), instantaneous water-use efficiency (WUE), and leaf carbon isotope discrimination (Δ). A strong positive genetic correlation between A and g suggested that there was stomatal limitation on A. In addition, higher g led to relatively greater increases in transpiration, E, than in assimilation, A, so that families with high rates of gas exchange had lower instantaneous WUE and/or higher carbon isotope discrimination values. Leaf size and gas exchange were genetically correlated. In earlier studies leaf size was found to be genetically correlated with developmental phenology (Geber 1990). The pattern that emerges is one in which small-leaved families (which also have small internodes, flowers, and seeds) tend to have high gas exchange rates, low WUE, rapid development to flowering and high early fecundity, but reduced life span and maximum (vegetative and reproductive) yield compared to large-leaved families. We suggest that this pattern may have arisen from selection for contrasting suites of characters adapted to environments differing in season length.

Growth and reproduction in higher plants depend on meristems, which have three developmental fates. A meristem can become reproductive, but doing so terminates its activity, it can differentiate vegetatively, or it can remain quiescent for extended periods. The first two fates are mutually exclusive, and only the second leads to the production of additional meristems for subsequent growth and reproduction. In Polygonum arenastrum (frequently referred to as P. aviculare in North American Floras), an annual species lacking quiescent meristems, a quantitative genetic analysis of inbred full-sibling families revealed genetic variation in the developmental pattern of axillary meristem commitment to vegetative growth versus reproduction. Developmental variation resulted in family differences in the age of first reproduction, in age-specific fecundity and growth, and in final plant size and reproductive output. Furthermore, there were strong negative genetic correlations between age-specific growth and fecundity. Early commitment of meristems to reproduction favors high early fecundity, but reduces the number of meristems available for vegetative differentiation, and leads to lowered growth rates and fecundity later in life, when meristems are limiting. Conversely, meristem commitment to vegetative growth early in life results in low early fecundity but high late fecundity and growth. Meristem limitation, like resource limitation, is a proximate mechanism that generates trade-offs between life history traits. Differences between meristem limitation and resource limitation are discussed. Meristem limitation leads automatically to a senescent life history because of the determinate fate of reproductive meristems. Developmental characters were also found to be genetically correlated with metamer characters (leaf size, internode length) and seed size in this selfing species. The pattern of correlation is suggestive of selection for particular suites of life history and morphological characters.

Plant water-use efficiency (WUE) is expected to affect plant fitness and thus be under natural selection in arid habitats. Although many natural population studies have assessed plant WUE, only a few related WUE to fitness. The further determination of whether selection on WUE is direct or indirect through functionally related traits has yielded no consistent results. For natural populations of two desert annual sunflowers, Helianthus anomalus and H. deserticola, we used phenotypic selection analysis with vegetative biomass as the proxy for fitness to test (1) whether there was direct and indirect selection on WUE (carbon isotope ratio) and related traits (leaf N, area, succulence) and (2) whether direct selection was consistent with hypothesized drought/dehydration escape and avoidance strategies. There was direct selection for lower WUE in mesic and dry H. anomalus populations, consistent with dehydration escape, even though it is the longer lived of the two species. For mesic H. anomalus, direct selection favored lower WUE and higher N, suggesting that plants may be "wasting water" to increase N delivery via the transpiration stream. For the shorter lived H. deserticola in the direr habitat, there was indirect selection for lower WUE, inconsistent with drought escape. There was also direct selection for higher leaf N, succulence and leaf size. There was no direct selection for higher WUE consistent with dehydration avoidance in either species. Thus, in these natural populations of two desert dune species higher fitness was associated with some combination direct and indirect selection for lower WUE, higher leaf N and larger leaf size. Our understanding of the adaptive value of plant ecophysiological traits will benefit from further consideration of related traits such as leaf nitrogen and more tests in natural populations.

We examined patterns of genetic variance and covariance in two traits (i) carbon stable isotope ratio delta13C (dehydration avoidance) and (ii) time to flowering (drought escape), both of which are putative adaptations to local water availability. Greenhouse screening of 39 genotypes of Arabidopsis thaliana native to habitats spanning a wide range of climatic conditions, revealed a highly significant positive genetic correlation between delta13C and flowering time. Studies in a range of C3 annuals have also reported large positive correlations, suggesting the presence of a genetically based trade-off between mechanisms of dehydration avoidance (delta13C) and drought escape (early flowering). We examined the contribution of pleiotropy by using a combination of mutant and near-isogenic lines to test for positive mutational covariance between delta13C and flowering time. Ecophysiological mutants generally showed variation in delta13C but not flowering time. However, flowering time mutants generally demonstrated pleiotropic effects consistent with natural variation. Mutations that caused later flowering also typically resulted in less negative delta13C and thus probably higher water use efficiency. We found strong evidence for pleiotropy using near-isogenic lines of Frigida and Flowering locus C, cloned loci known to be responsible for natural variation in flowering time. These data suggest the correlated evolution of delta13C and flowering time is explained in part by the fixation of pleiotropic alleles that alter both delta13C and time to flowering.

The introduced nonmaritime knotweeds have generally been regarded in North America as comprising a single species called P. aviculare L. In recent years cytological and morphological studies have suggested that at least two chromosome races are present and that certain morphological features are correlated with chromosome number. There have been, however, discrepancies in the reports of the distribution and relative abundance of the two races. Studies of the morphology and cytology of introduced knotweeds in eastern Canada confirm the existence of two groups that are recognizable at species rank, and establish that the most common knotweeds in open habitats, e. g., along roadsides and sidewalks, are tetraploid plants distinguishable from their hexaploid relatives by the relatively uniform size of their leaves, the short and narrow free portion of the perianth segments, and by one side of the fruit being very much narrower than the other two. These plants are referable to P. arenastrum Boreau. This species is compared with the heterophyllous hexaploid, usually called P. aviculare sensu stricto, or, if that is considered a nomen ambiguum, P. monspeliense Pers. A table of distinguishing features, illustrations of the two species, and maps of their distribution in eastern Canada are provided.

Increases in size inequalities with time in cohorts of plants have been attributed to two causes: (1) variation in the exponential relative growth rates (RGR) of plants and (2) asymmetry of competitive interactions, whereby large plants can more readily suppress the growth of smaller neighbors than vice versa. It follows, then, that species with a longer exponential growth phase should develop greater size inequality over time. And since asymmetry is thought to be greater when competition is for light than when it is for below—ground resources, competitive interactions should be more asymmetric and size inequality should increase more in response to competition in species whose morphology results in greater between—plant shading. I tested these two hypothesis in greenhouse studies of two annual species, Polygonum arenastrum and P. douglassii, which differ in the duration of exponential growth and the likelihood of between—plant shading as a result of differences in development and morphology. Polygonum arenastrum has a shorter exponential phase of growth because it switches from vegetative growth to reproduction earlier than P. douglassii. It also has a prostrate growth form, more diffuse branching, and smaller leaves than P. douglassii. There should therefore be less shading of one plant by another in P. arenastrum than in P. douglassii. Seedlings from wild—collected seeds were planted in monoculture arrays at four different densities. The plants were harvested at five dates up to 10 wks; growth and branching pattern were measured at each harvest. As expected, in populations of P. douglassii, the species with the longer exponential growth phase, greater size inequality developed over time. In the absence of intraspecific competition, RGR was independent of plant size and size hierarchies were quite permanent. In contrast, P. arenastrum exhibited a period of decelerating growth which resulted in a negative correlation between RGR and plant size, frequent reversals in the size rankings of individuals over time, and declining size inequality through time under noncompetitive conditions. At high densities the morphology and RGRs of plants were size dependent in both species. Large individuals were more branched, had longer branches, and had higher RGRs than small individuals, and these shape and growth—rate differences became more pronounced as competition intensified. Furthermore, the size—dependence of shape and RGR was stronger in P. douglassii at all densities, and became relatively more pronounced as density increased, compared with P. arenastrum. These results are consistent with the expectation of greater competitive asymmetry in the species whose morphology should have led to greater between—plant shading. Size inequality increased with competition in both species. However, contrary to expectation, it did not increase more as density increased in P. douglassii. Reasons for the discrepancy between the morphological, RGR, and size inequality responses of the two species to density are discussed. The link between size inequality and plant development and morphology is examined in light of the effects the latter may have on the size—dependence of RGRs and the asymmetries of competitive interactions.

A total of 183 chromosome counts on plants representing nine species of Polygonum section Polygonum in eastern Canada and the United States is presented. Documented counts are published here for the first time for P. franktonii (2n = 60) and P. neglectum (2n = 40 and 60). In addition, previously unreported counts for P. achoreum (2n = 60), P. aviculare (2n = 40), and P. fowled (2n = 60) are presented. A review of previously published counts and an examination of voucher specimens have revealed a number of errors, negating many reported counts, including all of those for P. erectum and most of those for P. buxiforme. Polygonum arenastrum and P. raii are entirely tetraploid (2n = 40) and P. franktonii and P. ramosissimum entirely hexaploid (2n = 60), whereas the remaining species have both tetraploid and hexaploid elements. In contrast to previous reports, no diploid or octoploid plants have been detected.