Search

Gas chromatography-mass spectrometry (GC/MS) due to high sensitivity and qualifying the volatile compounds is one of the most practical methods for the analysis of essential oils. Accurate identification of trace components and complete separation of overlapped and embedded peaks are difficult to achieve even if precise conditions are imposed on the chromatographic separation process. In this study, the essential oil of Lamium amplexicaule L. (L. amplexicaule) after extraction by the Clevenger apparatus, was analyzed by GC/MS. This study focuses on the characterization of the trace and co-eluted components of essential oils in the mentioned species using chemometric methods. Advanced multivariate curve resolution (MCR) methods were used to overcome the problem of background, baseline offset and overlapping peaks and recognition of the noises from the trace components in GC/MS. The analysis of GC/MS data without chemometric methods revealed that eighteen components exist in the L. amplexicaule essential oil. It is noteworthy that, by a combination of MCR with GC/MS method, this number was extended to more than twenty-five. Using chemometric tools and methods, components with a percent higher than 0.01%, were identified from noises and other overlapped peaks were resolved for 85.56% of the total relative content of the L. amplexicaule essential oil. The most important volatile constituents were identified as hexahydrofarnesyl acetone, spathulenol, caryophyllene oxide, hexadecanoic acid and trans-phytol respectively.

Competition affects mixed-mating strategies by limiting available abiotic or biotic resources such as nutrients, water, space, or pollinators. Cleistogamous species produce closed (cleistogamous, CL), obligately selfed, simultaneously with open (chasmogamous, CH), potentially outcrossed flowers. The effects of intraspecific competition on fitness and cleistogamy variation can range from limiting the production of costly CH flowers because of resource limitation, to favouring CH production because of fitness advantages of outcrossed, CH offspring. Moreover, the effects of competition can be altered when it co-occurs with other environmental variations. We grew plants from seven populations of the ruderal Lamium amplexicaule , originating from different climates and habitats, in a common garden experiment combining drought, interspecific competition, and seasonal variation. All these parameters have been shown to influence the degree of cleistogamy in the species on their own. In spring, competition and drought negatively impacted fitness, but the CL proportion only increased when plants were exposed to both treatments combined. We did not observe the same results in autumn, which can be due to non-adaptive phenotypic variation, or to differences in soil compactness between seasons. The observed responses are largely due to phenotypic plasticity, but we also observed phenotypic differentiation between populations for morphological, phenological, and cleistogamy traits, pointing to the existence of different ecotypes. Our data do not support the hypothesis that CL proportion should decrease when resources are scarce, as plants with reduced growth had relatively low CL proportions. We propose that variation in cleistogamy could be an adaptation to pollinator abundance, or to environment-dependent fitness differences between offspring of selfed and outcrossed seeds, two hypotheses worth further investigation. This opens exciting new possibilities for the study of the maintenance of mixed-mating systems using cleistogamous species as models that combine the effects of inbreeding and reproductive costs. [ABSTRACT FROM AUTHOR]

Gas chromatography-mass spectrometry (GC/MS) due to high sensitivity for quantitying volatile compounds is one of the most practical methods for the analysis of essential oils. Accurate identification of trace components and complete separation of overlapped and embedded peaks are difficult to achieve even if precise conditions are imposed on the chromatographic separation process. In this study, the essential oil of Lamium amplexicaule L. (L. amplexicaule) after extraction by the Clevenger apparatus, was analyzed by GC/MS. This study focuses on the characterization of the trace and co-eluted components of essential oils in the mentioned species using chemometric methods. Advanced multivariate curve resolution (MCR) methods were used to overcome the problem of background, baseline offset and overlapping peaks, and recognition of the noises from the trace components in GC/MS. The analysis of GC/MS data without chemometric methods revealed that eighteen components exist in the L. amplexicaule essential oil. It is noteworthy that, by a combination of MCR with GC/MS method, this number was extended to more than twenty-five. Using chemometric tools and methods, components with a percent age higher than 0.01% were identified from noises, and other overlapped peaks were resolved for 85.56% of the total relative content of the L. amplexicaule essential oil. The most important volatile constituents were identified as hexahydrofarnesyl acetone, spathulenol, caryophyllene oxide, hexadecanoic acid and trans-phytol, respectively. [ABSTRACT FROM AUTHOR]

Since the first record of an anamorph of Neoerysiphe galeopsidis (syn. Erysiphe galeopsidis) on Lamium album subsp. barbatum in Korea in 1992, no scientific information has been added. Seven additional anamorphic samples (2003–2022) and one teleomorphic collection (November 2022) of N. galeopsidis on L. album subsp. barbatum in Korea enabled us to provide holomorph morphology and phylogeny of this powdery mildew for the first time. The presence of aerial hyphae around the chasmothecia was proposed and documented for the first time.

Lamium amplexicaule L. (Family: Lamiaceae) is a cosmopolitan weed whose eradication is challenging. The phenoplasticity of this species is related to its heteroblastic inflorescence, which has not received adequate research worldwide in its morphological and genetic aspects. This inflorescence hosts two flower types, a cleistogamous (CL: closed flower) and a chasmogamous (CH: opened flower). This species subjected to detailed investigation is a model species to clarify: (1) the existence of the CL and CH flowers in relation to the time and individual plants. (2) the predominant flower morphs in Egypt. (3) the morphological and genetic variability between these morphs. Among the novel data retrieved from this work is the Presence of this species in three distinct morphs coexisting during winter. These morphs showed remarkable phenoplasticity, particularly in flower organs. Significant differences were observed between the three morphs in pollen fertility, nutlets productivity and sculpture, flowering time, and seed viability. These differences were extended to the genetic profile of these three morphs assessed by the inter simple sequence repeats (ISSRs) and start codon targeted (SCoT). This work highlights the urgent need to study the heteroblastic inflorescence of crop weeds to facilitate its eradication. [ABSTRACT FROM AUTHOR]

Lamium amplexicaule L. (Family: Lamiaceae) is a cosmopolitan weed whose eradication is challenging. The phenoplasticity of this species is related to its heteroblastic inflorescence, which has not received adequate research worldwide in its morphological and genetic aspects. This inflorescence hosts two flower types, a cleistogamous (CL: closed flower) and a chasmogamous (CH: opened flower). This species subjected to detailed investigation is a model species to clarify: (1) the existence of the CL and CH flowers in relation to the time and individual plants. (2) the predominant flower morphs in Egypt. (3) the morphological and genetic variability between these morphs. Among the novel data retrieved from this work is the Presence of this species in three distinct morphs coexisting during winter. These morphs showed remarkable phenoplasticity, particularly in flower organs. Significant differences were observed between the three morphs in pollen fertility, nutlets productivity and sculpture, flowering time, and seed viability. These differences were extended to the genetic profile of these three morphs assessed by the inter simple sequence repeats (ISSRs) and start codon targeted (SCoT). This work highlights the urgent need to study the heteroblastic inflorescence of crop weeds to facilitate its eradication.

* Background and aims Many angiosperms exhibit cleistogamy, the production of both cleistogamous flowers (CL), which remain closed and obligately self-pollinated, and chasmogamous flowers (CH), which are potentially open-pollinated. The CH proportion can be plastic. Plasticity is adaptive if environmental changes can be reliably assessed and responded to with an appropriate phenotype and if plastic genotypes have higher fitness in variable environments than non-plastic ones. * Methods We studied the plastic response of four natural populations from northern and southern France of an annual cleistogamous plant, Lamium amplexicaule, to predictable seasonal variation. Plants were grown in a semicontrolled environment in spring and in autumn. We assessed the variation in flower number, phenology and cleistogamy-related traits, which were all plastic with respect to season. The CH proportion was higher in spring than in autumn in all four populations. * Key Results We showed significant stabilizing selection for cleistogamy traits, with higher optimal CH proportions and more pronounced stabilizing selection in spring than in autumn. Observed CH proportions were close to the predicted optimal CH proportions in each season except in autumn for southern populations, which do not experience the autumnal growing season in nature. * Conclusions These results are consistent with adaptive plasticity across seasons of cleistogamy in L. amplexicaule. We propose that adaptive plasticity of cleistogamy could be driven by pollination environment variation, with CL flowers providing reproductive assurance when pollinators are scarce and CH flowers reducing the inbreeding depression in offspring when pollinators are abundant. [ABSTRACT FROM AUTHOR]

Premise of the study: Lamium amplexicaule is a cleistogamous plant that produces both closed flowers (obligately self-pollinated) and open flowers (potentially outcrossed). The conditions for the maintenance of such a mating system depend on the outcrossing rate of the open flowers, which can be estimated using neutral microsatellite markers. Methods and Results: Forty primer pairs corresponding to microsatellite motifs obtained by coupling multiplex microsatellite enrichment and next-generation sequencing were tested. Thirteen primers amplified with satisfying results. The polymorphism of these markers was studied in four French populations. Allele number varied from one to eight per locus and per population. Heterozygosity levels were significantly lower than those expected under Hardy-Weinberg equilibrium. Conclusions: Our results are consistent with a partial self-fertilization pattern. These markers will be used to estimate the outcrossing rate as well as population differentiation in L. amplexicaule.

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major soybean-yield-limiting soil-borne pathogen, especially in the Midwestern US. Weed management is recommended for SCN integrated management, since some weed species have been reported to be hosts for SCN. The increase in the occurrence of resistance to herbicides complicates weed management and may further direct ecological–evolutionary (eco–evo) feedbacks in plant–pathogen complexes, including interactions between host plants and SCN. In this review, we summarize weed species reported to be hosts of SCN in the US and outline potential weed–SCN management interactions. Plants from 23 families have been reported to host SCN, with Fabaceae including most host species. Out of 116 weeds hosts, 14 species have known herbicide-resistant biotypes to 8 herbicide sites of action. Factors influencing the ability of weeds to host SCN are environmental and edaphic conditions, SCN initial inoculum, weed population levels, and variations in susceptibility of weed biotypes to SCN within a population. The association of SCN on weeds with relatively little fitness cost incurred by the latter may decrease the competitive ability of the crop and increase weed reproduction when SCN is present, feeding back into the probability of selecting for herbicide-resistant weed biotypes. Therefore, proper management of weed hosts of SCN should be a focus of integrated pest management (IPM) strategies to prevent further eco–evo feedbacks in the cropping system. [ABSTRACT FROM AUTHOR]

Se notifica por primera ocasión la presencia de dos géneros, representados por tres es pecies, en el Valle de México: Kickxie elatine ssp. crinita (Scrophulariaceae), Lamium amplexicaule y L. purpureum (Labiatae). Se incluyen descripciones y claves para estos taxa, que permiten diferenciarlos de otros similares. Se adicionan datos sobre Polygonum convolvulus (Polygonaceae), especie arvense también recientemente detectada.