Leaf patterns,leaf size and ecologically related traits in high Mediterranean mountain on the Moroccan High Atlas

Leaf traits functional relationship is particularly important in plant ecological strategies, but few data are available from Mediterranean high-altitude environments. We analysed leaf general patterns and leaf trait relationships in 84 perennial species on the High Atlas, Morocco. We examined the correlation amongst leaf size, leaf width and length, plant height and seed size, analysed multi-trait relationships using Structural Equation Models and tested leaf size variation amongst growth forms (functional groups). Species spanned 10³ range of leaf size (sub-lepto- to microphylls). Nanophylls (48.8%) were dominant and over-represented in half-shrubs. Tree and rosette herbs were more likely to have large leaf size (nano-micro- and microphylls), whereas shrubs have medium leaf size (nano-micro- and nanophylls) and cushion and half-shrubs have small (sub-lepto- to nanophylls) and narrow leaves. Small-leaved species synchronized their leaf phenological activity with the dry summer months (May–August), and large-leaved species extended throughout the spring until the end of summer following the similar patterns found in lowland Mediterranean environments. Regarding woody species, our results showed a positive and significant relationship between leaf size and plant height and a non-significant relationship between leaf size and seed size. Structural Equation Models showed that variation in leaf size was triggered chiefly by changes in leaf form (leaf width) and plant height, seed size being of no relevance. In our study area, large-seeded species have a relatively wide range of leaf size. The hypothesis that the combination of large seeds and small leaves is allometrically unlikely (except for leptophyll Conifers) was supported in this study.     

Allometric analysis of the induced flavonols on the leaf surface of wild tobacco (Nicotiana attenuata)

Trichomes excrete secondary metabolites that may alter the chemical composition of the leaf surface, reducing damage caused by herbivores, pathogens and abiotic stresses. We examined the surface exudates produced by Nicotiana attenuata Torr. Ex Wats., a plant known to contain and secrete a number of secondary metabolites that are toxic or a deterrent to herbivorous insects. Extractions specific to the leaf surface, the trichomes, and the laminar components demonstrated the localization of particular compounds. Diterpene glycosides occurred exclusively in leaf mesophyll, whereas nicotine was found in both the trichomes and mesophyll. Neither rutin nor nicotine was found on the leaf surface. Quercetin and 7 methylated derivatives were found in the glandular trichomes and appeared to be excreted onto the leaf surface. We examined the elicitation of these flavonols on the leaf surface with a surface-area allometric analysis, which measures changes in metabolites independent of the effects of leaf expansion. The flavonols responded differently to wounding, methyl jasmonate (MeJA), herbivore attack and UV-C radiation, and the response patterns corresponded to their compound-specific allometries. Finding greater amounts of quercetin on younger leaves and reduced amounts after herbivore feeding and MeJA treatment, we hypothesized that quercetin may function as an attractant, helping the insects locate a preferred feeding site. Consistent with this hypothesis, mirids (Tupiocoris notatus) were found more often on mature leaves sprayed with quercetin at a concentration typical of young leaves than on unsupplemented mature leaves. The composition of metabolites on the leaf surface of N. attenuata changes throughout leaf development and in response to herbivore attack or environmental stress, and these changes are mediated in part by responses of the glandular trichomes.     

Disruption of N-acyl homoserine lactone-mediated cell signaling and iron acquisition in epiphytic bacteria by leaf surface compounds

Since N-acyl homoserine lactones (AHLs) are key mediators of cell density-dependent regulation of traits involved in virulence and epiphytic fitness in gram-negative bacteria such as Pseudomonas syringae, a variety of plant species were examined to determine their production of leaf surface compounds that could interact with these signaling systems. Leaf washings of 17 of 52 plant species tested stimulated or inhibited AHL-dependent traits in at least one of the bacterial reporter strains used. The active compounds from most plants could be distinguished from known AHLs due to different patterns of mobility during C8 and C18 reverse-phase thin-layer chromatography (TLC) and normal-phase TLC compared to the patterns for authentic bacterial AHLs. All plant extracts were also tested to determine their abilities to sequester iron and trigger bacterial siderophore synthesis on a medium containing abundant iron. Leaf washings from 16 of the 52 plant species, as well as tannic acid solutions, stimulated pyoverdine synthesis in P. syringae in a high-iron medium. These preparations also inhibited the growth of a P. syringae mutant unable to produce pyoverdine siderophores but not the growth of the wild-type bacterium. The stimulation of siderophore production and the growth inhibition by plant extracts and purified tannins were both reversed by addition of ferric chloride to culture media, indicating that iron was made unavailable by the compounds released onto the leaf surface.     

根系分泌物对紫云英油菜间作的响应

根系分泌物是植物与土壤进行物质交换和信息传递的重要载体,也是间作体系中作物-土壤-微生物互作的重要调控者。为进一步揭示间作体系中作物之间的互作机制,本研究通过紫云英单作、油菜单作和紫云英油菜间作,重点分析了紫云英油菜间作下根系分泌物的响应特征。结果表明: 共检测到紫云英和油菜根系分泌物391种,定性93种,包括了9种代谢物类型,其中有机氧化物含量最高,主要是以核糖醇的形式存在。不同种植模式中,紫云英、油菜的根系分泌物含量差异显著,紫云英油菜间作时根系分泌物特征与油菜单作相似,与紫云英单作差异较大。不同种植模式的差异根系分泌物中,仅9-芴酮1与其他差异分泌物间呈负相关关系。不同种植模式的差异根系分泌物主要为苯系物、脂类和类脂分子、有机酸及其衍生物、有机氧化物等,其中苯系物、脂类和类脂分子是表征紫云英、油菜根系分泌物变化的重要类型。可见,紫云英油菜间作改变了作物的根系分泌物特征,其变化特征与苯系物、脂类和类脂分子关系密切。     

Disruption of N-Αcyl Homoserine Lactone-Mediated Cell Signaling and Iron Acquisition in Epiphytic Bacteria by Leaf Surface Compounds

Since N-acyl homoserine lactones (AHLs) are key mediators of cell density-dependent regulation of traits involved in virulence and epiphytic fitness in gram-negative bacteria such as Pseudomonas syringae, a variety of plant species were examined to determine their production of leaf surface compounds that could interact with these signaling systems. Leaf washings of 17 of 52 plant species tested stimulated or inhibited AHL-dependent traits in at least one of the bacterial reporter strains used. The active compounds from most plants could be distinguished from known AHLs due to different patterns of mobility during C₈ and C₁₈ reverse-phase thin-layer chromatography (TLC) and normal-phase TLC compared to the patterns for authentic bacterial AHLs. All plant extracts were also tested to determine their abilities to sequester iron and trigger bacterial siderophore synthesis on a medium containing abundant iron. Leaf washings from 16 of the 52 plant species, as well as tannic acid solutions, stimulated pyoverdine synthesis in P. syringae in a high-iron medium. These preparations also inhibited the growth of a P. syringae mutant unable to produce pyoverdine siderophores but not the growth of the wild-type bacterium. The stimulation of siderophore production and the growth inhibition by plant extracts and purified tannins were both reversed by addition of ferric chloride to culture media, indicating that iron was made unavailable by the compounds released onto the leaf surface.     

Plant phenology,leaf traits and leaf litterfall of contrasting life forms in the arid Patagonian Monte,Argentina

Question: Do coexisting plant life forms differ in overall phenology, leaf traits and patterns of leaf litterfall? Location: Patagonian Monte, Chubut Province, Argentina. Methods: We assessed phenology, traits of green and senesced leaves and the pattern of leaf litterfall in 12 species of coexisting life forms (perennial grasses, deciduous shrubs, evergreen shrubs). Results: We did not identify differences in phenology, leaf traits and patterns of leaf litterfall among life forms but these attributes contrasted among species. Independent of the life form, the maintenance of green leaves or vegetative growth during the dry season was mostly associated with leaves with high leaf mass per area (LMA) and high concentration of secondary compounds. Low LMA species produced low litterfall mass with low concentration of secondary compounds, and high N concentration. High LMA species produced the largest mass of leaf litterfall. Accordingly, species were distributed along two main dimensions of ecological variation, the dimension secondary compounds in leaves ‐ length and timing of the vegetative growth period (SC ‐ VGP) and the dimension leaf mass per area ‐ leaf litterfall mass (LMA ‐ LLM). Conclusions: Phenology, leaf traits and leaf litterfall varied among species and overlapped among life forms. The two dimensions of ecological variation among species (SC ‐ VGP, LMA ‐ LLM) represent distinct combinations of plant traits or strategies related to resource acquisition and drought tolerance which are reflected in the patterns of leaf litterfall.     

Seasonal fluctuations in the concentration of UV-absorbing compounds in the leaves of some Mediterranean plants under field conditions

Leaves of 14 representative Mediterranean plant species were collected on a monthly basis and assayed for UV-absorbing compounds concentration, either on an area or a dry mass basis, from 1995 to 1997. Strong seasonal fluctuations were observed in eight species (all evergreens, two phrygana, one deciduous, one summer perennial and one winter perennial). Two different patterns of changing concentrations of UV-absorbing compounds were observed. In the first, concentration of these compounds was higher in young developing leaves and concentration declined during maturation, whereas in other plants, the opposite trend was observed. These differences could be attributed to the particular leaf surface morphology of each plant. The observed seasonal fluctuations of UV-absorbing compounds seem to be more correlated to developmental processes, than to seasonal fluctuations of the naturally occurring UV-B radiation. Most of the winter perennials did not show strong fluctuations during the period of development. The concentration of these compounds varied not only on a seasonal basis among the examined plants, but between different life forms as well: during winter, examination of the leaves of 13 species showed that evergreen sclerophylls and phrygana had at least two-fold higher concentration of UV-B-absorbing compounds on a leaf area basis than winter perennials. In addition, during the same season and irrespective of life form and species, the absorbance at 300 nm per unit of mature leaf area followed an asymptotic exponential decrease when specific leaf area increased. The UV-B radiation screening capacity of the leaves of these plants is discussed in relation to each adaptive strategy.     

Temperature and water relation patterns in subalpine understory plants

Summary The daily temperature and water relations of 7 perennial subalpine, understory species (1 shrub, 1 subshrub, 5 herbs) were compared in the Rocky Mountains of southeastern Wyoming with an emphasis on the effects of natural sun and shade exposure. Field measurements of rainfall; leaf, air, and soil temperatures; stomatal conductance to water vapor diffusion; and plant and soil water potentials were supplemented with leaf and root morphological measurements to evaluate potential adaptive patterns in understory species.Morphologically, all 7 species had relatively broad leaves that were hypostomous and bicolored with the abaxial leaf surface lighter than the abaxial surface. Root systems tended to be shallow (<20 cm), especially for the herbaceous species. Although soil water potentials from 4 to 40 cm depths remained relatively high throughout the summer (>-1.0 MPa), plant xylem water potentials for sunlit plants decreased to below-2.0 MPa during midday. During these sunlit periods, leaf temperatures and conductances increased substantially, leading to severe wilting for 4 of the 5 herbaceous species. Stomatal conductance and density for 6 of the 7 species monitored were much greater on abaxial compared to adaxial leaf sides and substantial stomatal closure occurred when either leaf side was oriented to receive direct sunlight. Moreover, stomatal opening on abaxial leaf sides corresponded to the amount of sunlight incident upon the adaxial rather than abaxial leaf surfaces. The 2 shrubby species did not wilt during these periods and were characterized by the highest leaf temperatures (>30°C). These 2 species also had consistantly lower xylem water potentials throughout the summer growth period. These results are discussed in terms of the possible adaptive significance of midday wilting, leaf hypostomy and bicoloration and stomatal behavior to the water and photosynthetic relations of understory species.     

Root Exudation of Phytochemicals in Arabidopsis Follows Specific Patterns That Are Developmentally Programmed and Correlate with Soil Microbial Functions

Plant roots constantly secrete compounds into the soil to interact with neighboring organisms presumably to gain certain functional advantages at different stages of development. Accordingly, it has been hypothesized that the phytochemical composition present in the root exudates changes over the course of the lifespan of a plant. Here, root exudates of in vitro grown Arabidopsis plants were collected at different developmental stages and analyzed using GC-MS. Principle component analysis revealed that the composition of root exudates varied at each developmental stage. Cumulative secretion levels of sugars and sugar alcohols were higher in early time points and decreased through development. In contrast, the cumulative secretion levels of amino acids and phenolics increased over time. The expression in roots of genes involved in biosynthesis and transportation of compounds represented in the root exudates were consistent with patterns of root exudation. Correlation analyses were performed of the in vitro root exudation patterns with the functional capacity of the rhizosphere microbiome to metabolize these compounds at different developmental stages of Arabidopsis grown in natural soils. Pyrosequencing of rhizosphere mRNA revealed strong correlations (p<0.05) between microbial functional genes involved in the metabolism of carbohydrates, amino acids and secondary metabolites with the corresponding compounds released by the roots at particular stages of plant development. In summary, our results suggest that the root exudation process of phytochemicals follows a developmental pattern that is genetically programmed.     

Effects of Riparian Plant Diversity Loss on Aquatic Microbial Decomposers Become More Pronounced with Increasing Time

We examined the potential long-term impacts of riparian plant diversity loss on diversity and activity of aquatic microbial decomposers. Microbial assemblages were obtained in a mixed-forest stream by immersion of mesh bags containing three leaf species (alder, oak and eucalyptus), commonly found in riparian corridors of Iberian streams. Simulation of species loss was done in microcosms by including a set of all leaf species, retrieved from the stream, and non-colonized leaves of three, two or one leaf species. Leaves were renewed every month throughout six months, and microbial inoculum was ensured by a set of colonized leaves from the previous month. Microbial diversity, leaf mass loss and fungal biomass were assessed at the second and sixth months after plant species loss. Molecular diversity of fungi and bacteria, as the total number of operational taxonomic units per leaf diversity treatment, decreased with leaf diversity loss. Fungal biomass tended to decrease linearly with leaf species loss on oak and eucalyptus, suggesting more pronounced effects of leaf diversity on lower quality leaves. Decomposition of alder and eucalyptus leaves was affected by leaf species identity, mainly after longer times following diversity loss. Leaf decomposition of alder decreased when mixed with eucalyptus, while decomposition of eucalyptus decreased in mixtures with oak. Results suggest that the effects of leaf diversity on microbial decomposers depended on leaf species number and also on which species were lost from the system, especially after longer times. This may have implications for the management of riparian forests to maintain stream ecosystem functioning.     

Primula spectabilis Tratt. aerial parts: morphology, volatile compounds and flavonoids

The vacuolar and epicuticular flavonoids and the volatiles of the leaves and parts of flower of P. spectabilis Tratt., an endemic species in the Italian Oriental Alps, were investigated. From a MeOH extract of the leaves two flavone glycosides, 8-C-β-glucopyranosylluteolin 7-O-α-arabinofuranoside (1) and 6-C-α-arabinofuranosylapigenin (2) were isolated, in addition to a flavone and three flavonols already known from species of Primula. From an EtOH extract of leaf exudates, 7,3',4'-tri-O-methylquercetin was obtained. The structures were elucidated on the basis of their 1D 1H- and 13C NMR data and 2D NMR techniques, as well as of HPLC-MS. The volatiles emitted by the leaves were mainly constituted by non-terpene derivatives, followed by comparable proportions of hemiterpens, oxygenated monoterpenes and sesquiterpene hydrocarbons. In flowers, monoterpene hydrocarbons were the most represented chemical class followed by non-terpene derivatives. Different proportions of compounds were found when individual parts of flowers were examined separately; calyx produced a greater proportion (approx. 49.5%) of non-terpenes as its volatile metabolites. P. spectabilis has glandular trichomes in the hyaline margins of the epidermal depressions, distributed on the adaxial leaf blade. Glandular hairs were also present on the corolla. Correlations of phytochemical data with the morphological features of leaf, flower and glandular hair are discussed, and a hypothesis is proposed on the ecological roles of the flavonoids and volatile compounds on the general fitness of the species and cross-pollination strategies.     

Effects of genetically modified starch metabolism in potato plants on photosynthate fluxes into the rhizosphere and on microbial degraders of root exudates

A high percentage of photosynthetically assimilated carbon is released into soil via root exudates, which are acknowledged as the most important factor for the development of microbial rhizosphere communities. As quality and quantity of root exudates are dependent on plant genotype, the genetic engineering of plants might also influence carbon partitioning within the plant and thus microbial rhizosphere community structure. In this study, the carbon allocation patterns within the plant-rhizosphere system of a genetically modified amylopectin-accumulating potato line (Solanum tuberosum L.) were linked to microbial degraders of root exudates under greenhouse conditions, using (13)C-CO(2) pulse-chase labelling in combination with phospholipid fatty acid (PLFA) analysis. In addition, GM plants were compared with the parental cultivar as well as a second potato cultivar obtained by classical breeding. Rhizosphere samples were obtained during young leaf developmental and flowering stages. (13)C allocation in aboveground plant biomass, water-extractable organic carbon, microbial biomass carbon and PLFA as well as the microbial community structure in the rhizosphere varied significantly between the natural potato cultivars. However, no differences between the GM line and its parental cultivar were observed. Besides the considerable impact of plant cultivar, the plant developmental stage affected carbon partitioning via the plant into the rhizosphere and, subsequently, microbial communities involved in the transformation of root exudates.     

Leaf δ13C reflects ecosystem patterns and responses of alpine plants to the environments on the Tibetan Plateau

Leaf δ¹³C is an indicator of water-use efficiency and provides useful information on the carbon and water balance of plants over longer periods. Variation in leaf δ¹³C between or within species is determined by plant physiological characteristics and environmental factors. We hypothesized that variation in leaf δ¹³C values among dominant species reflected ecosystem patterns controlled by large-scale environmental gradients, and that within-species variation indicates plant adaptability to environmental conditions. To test these hypotheses, we collected leaves of dominant species from six ecosystems across a horizontal vegetation transect on the Tibetan Plateau, as well as leaves of Kobresia pygmaea (herbaceous) throughout its distribution and leaves of two coniferous tree species ( Picea crassifolia, Abies fabri ) along an elevation gradient throughout their distribution in the Qilian Mountains and Gongga Mountains, respectively. Leaf δ¹³C of dominant species in the six ecosystems differed significantly, with values for evergreen coniferous13C values of the dominant species and of K. pygmaea were negatively correlated with annual precipitation along a water gradient, but leaf δ¹³C of A. fabri was not significantly correlated with precipitation in habitats without water-stress. This confirms that variation of δ¹³C between or within species reflects plant responses to environmental conditions. Leaf δ¹³C of the dominant species also reflected water patterns on the Tibetan Plateau, providing evidence that precipitation plays a primary role in controlling ecosystem changes from southeast to northwest on the Tibetan Plateau.     

PLANT SIZE AND FORM IN THE UNDERSTORY PALM GENUS GEONOMA: ARE SPECIES VARIATIONS ON A THEME?

This study addressed the hypothesis that phylogenetic changes in plant size at reproductive maturity may have facilitated adaptive radiation of Geonoma species within rain forest understory habitats. Leaf size, leaf form, plant size, and growth form were compared within and among 23 species of Geonoma from lowland and montane rain forest areas of Costa Rica and Colombia. Leaf size was significantly correlated with crown height in 18 of the 21 species examined, and with stem diameter in 17 of the species. In species characterized by a gradual ontogenetic transition from bifid to dissected leaves, shoots with bifid leaves were significantly smaller than shoots with dissected leaves with respect to rachis length, number of plications, and stem diameter. Among species, stem diameter below the crown explained 74% of the variation in leaf size (rachis length). Crown height and stem diameter were positively correlated among clustered species, but not among solitary species or all species combined. Leaf dissection was correlated with crown height among the 17 species with dissected leaves; species with bifid leaves were significantly smaller than species with dissected leaves with respect to leaf size and stem diameter. Solitary species had larger leaves and larger stem diameters than clustered species at the same crown heights. Morphological patterns among species generally followed within-species trends. These patterns suggest that Geonoma species are variants on a generic theme:within and among species, leaf size and complexity of form increase with stem diameter and crown height. Solitary and clustered growth forms appear to be morphologically convergent; within each of these architectural groups, the generic theme still applies. Evolutionary changes in leaf size, leaf form, and plant size, however, have clearly involved other factors in addition to variation in plant size.     

Phylogeny and the patterns of leaf phenolics in gap-and forest-adapted Piper and Miconia understory shrubs

Summary The types and quantities of defense compounds found in plants occupying ecologically distinct habitats have received much theoretical and little empirical attention. Here we characterize the leaf phenolic chemistry of eight species in two genera of tropical rainforest shrubs; four species in each genus are typical of disturbed sites, and four are typical of mature forest understory. Two Miconia species growing in light gaps had significantly higher leaf tannin and total phenolic contents than congenors growing in the primary forest; this pattern was not found among the gap- and forest-adapted Piper species. Tannin patterns were not mirrored by leaf cinnamic acids. These results indicate that plant phylogeny must be considered when predicting plant defense investment.     

Phytoremediation of anthracene contaminated soils by different plant species

Phytoremediation is perceived as an alternative technology for contaminated site remediation. Yet, the mechanisms plants use to remove organic contaminants have not been fully elucidated. The objective of the current study was, therefore, undertaken to clarify the contribution of plants to the disappearance of organic contaminants in soil. Four plant species, including alfalfa, tall fescue, barley, and orchard grass, were examined for the ability to facilitate the degradation of the polyhydric aromatic hydrocarbon, anthracene. Soil samples were intermittently collected for two months to measure the disappearance of anthracene and bacterial number by GC and epifluorescence microscopy, respectively. Plant exudates were collected to determine their ability to solubilize anthracene. Alfalfa showed a 28% enhancement in the disappearance of anthracene compared to the unplanted control. Root exudates from alfalfa increased the release of soluble anthracene by 25 to 80% compared to the other species and unplanted controls. Among the plants tested, there was a positive correlation between enhancing the disappearance of anthracene by plants grown in soil and increasing the release of anthracene by isolated plant exudates. The results suggest that root exudates facilitate the mobilization of anthracene from soil and that the successful implementation of phytoremediation depends on the plant species. Further, root exudates may be a useful tool in screening plants for possible application in anthracene remediation.     

Natural Occurrence of Enantiomers of Organic Compounds Versus Phytoremediations: Should Research on Phytoremediations Be Revisited? A Mini‐review

Decontamination of polluted soils using plants is based on the ability of plant species (including transgenic plants) to enhance bioavailability of pollutants in the rhizosphere and support growth of pollutant‐degrading microorganisms via root exudation and plant species‐specific composition of the exudates. In this work, we review current knowledge of enantiomers of low‐molecular‐weight (LMW) organic compounds with emphasis on their use in phytoremediation. Many research studies have been performed to search for plants suitable for decontamination of polluted soils. Nevertheless, the natural occurrence of L‐ versus D‐enantiomers of dominant compounds of plant root exudates which play different roles in the complexation of heavy metals, chemoattraction, and support of pollutant‐degrading microorganisms were not included in these studies. D‐enantiomers of aliphatic organic acids and amino acids or L‐enantiomers of carbohydrates occur in high concentrations in root exudates of some plant species, especially under stress, and are less stimulatory for plants to extract heavy metals or for rhizosphere microflora to degrade pollutants compared with L‐enantiomers (organic acids and amino acids) or D‐carbohydrates. Determining the ratio of L‐ versus D‐enantiomers of organic compounds as a criterion of plant suitability for decontamination of polluted soils and development of other types of bioremediation technologies need to be subjects of future research. Chirality 26:1–20, 2013. © 2013 Wiley Periodicals, Inc.     

Taxonomic significance of flavonoid variation in temperate species of Nothofagus

Forty-two flavonoids and a stilbene (pinosylvin) were identified in the leaf exudates of 11 temperate species of Nothofagus from South America, Australia and New Zealand. The flavonoid profiles demonstrate significant taxonomic value at the subgeneric level. Most species of subgenus Fuscospora are characterized by the presence of pinosylvin, galangin and galangin methyl ethers. Kaempferol-type flavonols are abundant in subgenus Lophozonia while these flavonols are largely absent from species of subgenus Fuscospora. The flavonoid patterns are largely in agreement with a recent subgeneric classification of Nothofagus.     

Exudate flavonoids in some Gnaphalieae and Inuleae (Asteraceae)

Three members of the tribe Gnaphalieae and six members of the tribe Inuleae (Asteraceae) were analyzed for their exudate flavonoids. Whereas some species exhibit rather trivial flavonoids, others produce rare compounds. Spectral data of rare flavonoids are reported and their structural identification is discussed. 6-Oxygenation of flavonols is a common feature of two Inula species and Pulicaria sicula. By contrast, flavonoids with 8-oxygenation, but lacking 6-oxygenation, are common in two out of three Gnaphalieae species examined. In addition, B-ring deoxyflavonoids are abundantly present in the leaf exudates of Helichrysum italicum (Gnaphalieae). These distinctive features of the two Asteraceae tribes are in agreement with previous flavonoid surveys of these and related taxa.