Implications of variation in resin composition among organs, tissues and populations in the tropical legume Hymenaea

Variation in leaf blade, petiole and primary stem resins, composed of sesquiterpene hydrocarbons, is analysed in two contrasting species of the tropical legume Hymenaea. Five populations of the New World H. courbaril, spanning a wide range of ecosystems, are compared with a population of the disjunct African H. verrucosa. Resins in petiole and primary stem tissue are similar, but differ significantly in total composition from leaf blade tissues. The major components, caryophyllene, - and β-selinene and β-copaene vary most significantly among the tissues, but all compounds vary at highly significant levels among populations. The variation patterns in resin composition among the leaf blade and petiole/primary stem tissues are put into a larger context of comparison with the primarily diterpenoid patterns in secondary stem and pod tissues. Although the comparatively minor quantitative differences in the sesquiterpene systems could be attributed solely to developmental and physiological differences among the tissues and populations, the total weight of accumulating evidence regarding quantitative variation and demonstrated toxic and deterrent properties of sesquiterpene resins to insect herbivores leads us to hypothesize a possible role of differential predator pressures.     

Inhibitory effects of Hymenaea and Copaifera leaf resins on the leaf fungus, Pestalotia subcuticularis

Leaf resins in the leguminous genera Hymenaea and Copaifera may play a role in restricting infection by the associated leaf fungus, Pestalotia. We tested this hypothesis by assessing growth of the geographically widespread Pestalotia subcuticularis presented with different compositions of resins. Leaf resins of Hymenaea and Copaifera are composed of the same suite of sesquiterpene hydrocarbons, but these vary quantitatively to form discrete compositional patterns among individuals and populations. Leaf resins may also contain sesquiterpene oxides; caryophyllene oxide, which may have been formed from the caryophyllene precursor common in these resins, inhibited fungal growth in vitro.     

Investigations on radiosensitive and radioresistant populations of Drosophila melanogaster XVI. Adaptation to the mutagenic effects of X-rays in several experimental populations with irradiation histories

Selection responses of the laboratory stock Berlin wild (+60, +K) of Drosophila melanogaster to the mutagenic effects of high, accumulated exposures of X-rays were studied in several sub-populations with long irradiation histories. Interest was focussed on adaptive adjustments of mutation rates. In samples from the populations, radiosensitives of immature oocytes were tested, by using dominant lethals (A), X-chromosome losses (B) and sex-linked recessive lethals (C) as end-points of genetic radiation damage.

Populations RÖ II and RÖ V are similar to the previously studied population RÖ I and were exposed to 2100 R/generation, delivered to oocyte stages 6–14, mature sperm, and spermatids. RÖ II (first tests after 160 generations) is radioresistant relative to +60 (control). The resistance was characterized by dose-reduction factors (DRFs) of 1.72 (with respect to end-points A,B) and 1.53 (C), and these were similar to those previously obtained for RÖ I. The resistance of RÖ II was inherited semidominantly as was that of RÖ I, and the radiosensitivity of the hybrids RÖ I / RÖ II was similar to that of RÖ I and RÖ II with respect to end-points A and B. RÖ V did not become resistant within 25 generations of irradiation history (A).

Populations RÖ III (6000 R/generation) and RÖ IV (7000 R/generation) have histories of irradiations given to oogonia and spermatogonia. Radiosensitivities of immature oocytes of RÖ III did not differ from those of +K after 55 generations, but after 105 and 135 generations of irradiation history, DRFs of 1.2 (A) and 1.44 (B) were observed. RÖ IV was characterized in generations 55–135 by DRFs of 1.31 (A) and 1.72 (B).

Selection for relative radioresistance of immature oocytes was found (1) to be reproducible (RÖ II–RÖ V) (2) not to require genetic pre-adaptation (RÖ V), and (3) to be, in part, also achieved by ‘indirect’ selection (RÖ III, RÖ IV). It is concluded that mutation rates in populations are selectively adjusted to evolutionary requirements.     

Diversity in cyclic sesquiterpene production by Gossypium hirsutum

Major sesquiterpene components of oil of Texas Race Stock 810 of Gossypium hirsutum were - and β-selinene. This is the seventh cyclic terpene type found to date in this genus. Both - and β-selinene, along with aromadendrene, were found but only as minor components of extracts of several domestic cultivars of G. hirsutum.     

Chemotaxonomic significance of flavonoids and phenolic acids in the Hieracium rohacsense group (Hieracium sect. Alpina; Lactuceae, Compositae)

Five apomictic taxa from the Hieracium rohacsense group were studied for their phenolic constituent composition. The following substances represent dominant compounds in the leaves: chlorogenic acid, 3,5-dicaffeoylquinic acid, luteolin 7-O-β- -glucopyranoside, luteolin 4′-O-β- -glucuronopyranoside and apigenin 4′-O-β- -glucuronopyranoside. Within the group only quantitative differences were found, luteolin 7-O-glucoside being the most important chemotaxonomic marker. Each taxon has its own specific quantitative pattern, invariable within the taxon. Based on these characteristic profiles, H. rohacsense can be distinguished from a closely related and still undescribed taxon from Mt. Pip Ivan. The proportion of luteolin 7-O-glucoside to apigenin 4′-O-glucuronoside also clearly separates the individuals of two morphologically close species—H. ratezaticum and H. pseudocaesium, which corresponds to a few slight but recognisable morphological and phenological characteristics. The ontogenetic stage of leaf development and seasonal variation are also important factors, which must be taken into consideration, as the quantity of the substances changes during leaf ontogeny and with season.     

Essential oil composition of two endemic Centaurea species from Turkey, Centaurea mucronifera and Centaurea chrysantha, collected in the same habitat

The essential oils of two endemic Centaurea species from Turkey, C. mucronifera and C. chrysantha, collected in the same habitat, have been studied. The main compounds of the former were germacrene D (29.3%), β-eudesmol (17.4%) and β-caryophyllene (7.3%), while in the latter germacrene D (27.4%), caryophyllene oxide (9.5%) and bicyclogermacrene (5.4%) were detected among its major constituents. The two species produced many similar compounds in their essential oils that could be justified by the similar ecological conditions of their habitat, but also many differences were found that could confirm their taxonomic separation.     

Variation in δC values for the seagrass Thalassia testudinum and its relations to mangrove carbon

Carbon isotope ratios (¹³C/¹²C) were measured for the leaves of the seagrass Thalassia testudinum Banks ex König and carbonates of shells collected at the seagrass beds from seven sites along the coast of southern Florida, U.S.A. The δ¹³C values of seagrass leaves ranged from −7.3 to −16.3‰ among different study sites, with a significantly lower mean value for seagrass leaves from those sites near mangrove forests (−12.8 ± 1.1‰) than those far from mangrove forests (−8.3 ± 0.9‰; P < 0.05). Furthermore, seagrass leaves from a shallow water area had significantly lower δ¹³C values than those found in a deep water area (P < 0.01). There was no significant variation in δ¹³C values between young and mature leaves (P = 0.59) or between the tip and base of a leaf blade (P = 0.46). Carbonates of shells also showed a significantly lower mean δ¹³C value in the mangrove areas (−2.3 ± 0.6‰) than in the non-mangrove areas (0.6 ± 0.3‰; P <0.025). In addition, the δ¹³C values of seagrass leaves were significantly correlated with those of shell carbonates (δ¹³C seagrass leaf = −9.1 + 1.3δ¹³C shell carbonate (R² = 0.83, P < 0.01)). These results indicated that the input of carbon dioxide from the mineralization of mangrove detritus caused the variation in carbon isotope ratios of seagrass leaves among different sites in this study.     

Investigations on radiosensitive and radioresistant populations of Drosophila melanogaster: X. The resistance factor rar 3: genetics

In earlier work, immature oocytes of the irradiated population RÖI₄ of Drosophila melanpgaster were found to be radioresistant relative to those of the basic population RÖI and to those of the control population Berlin wild (+K). The resistance of RÖI₄ relative to RÖI was previously attributed to a hypothetical “factor” rar-3. In the present paper, evidence is presented to show that rar-3 is a single, recessive genetic factor, located on chromosome 3 at a map position of about 49.8. The action of rar-3 is apparently independent of that of rar-1 and rar-2, the factors already present in RÖI.     

Light adaptation and the role of autotrophic epiphytes in primary production of the temperate seagrass, Zostera marina L.

Photosynthetic features of Zostera marina L. and its autotrophic epiphyte community were investigated in a population inhabiting a shallow (1.3 m depth) water meadow in Great Harbor, Woods Hole, MA (U.S.A.). Photosynthesis versus irradiance (P-I) relationships were measured with respect to leaf age determined by the leaf position in the shoot bundle and by location of the tissue along the leaf axis. Therefore both age and light intensity gradients along the leaf axis were considered. The maximum photosynthesis (P_max) per dm² typically increased nearly two-fold along the leaf axis from leaf bases to apices. Photosynthetic rate on a chlorophyll (Chl) basis did not increase as dramatically along the leaf axis, and rates were usually lowest in tissues with the highest Chl content. The P-I relationships of leaves of different ages did not reveal photoinhibition even at light intensities > 1400 μE • m⁻² • s ⁻¹. Furthermore, no photoinhibition was observed in tissues from leaf blade bases, which never experienced high light levels (> 500 μE • m ⁻² • s⁻¹) in situ in Great Harbor. The initial slopes of the P-I curves and light compensation and saturation values varied along the leaf axis in relation to in situ light intensity gradients and in relation to leaf or tissue age. It appeared that leaf and/or tissue age was more important than light environment in determining P-I responses. The contribution of the autotrophic epiphyte community on Z. marina leaves to total photosynthesis per dm² was between 27 and 50%, and between 10 and 44% per mg chlorophyll. These levels of epiphyte photosynthesis can double the primary production of Z. marina leaves. No detrimental effects of epiphyte cover were realized in leaf maximal photosynthesis or P-I relationships. Non-epiphytized leaves and leaves from which epiphytes were removed showed essentially identical photosynthetic features. Light intensity and age gradients along the leaf axis control both the photosynthetic performance of the leaves and epiphyte biomass and photosynthesis.     

Biosynthesis of sesquiterpenes in Hymenaea inferred from their quantitative co-occurrence

Leaf pocket resins of 11 species of the tropical arborescent genus Hymenaea are virtually identical qualitatively, but of widely varying quantitative proportions. Within this large range of variability, several strong positive quantitative correlations between resin constituents were found, especially between caryophyllene and β-humulene and between γ-muurolene and δ-cadinene. These data lead to clarification of sesquiterpene biosynthetic routes in Hymenaea. In addition, quantitative relationships found among caryophyllene, α- and β-selinene, γ-muurolene and δ-cadinene are explained only with difficulty by long accepted biosynthetic pathways, and the intermediacy of germacrenes is suggested.     

Studies on the continuous production of (R)-(−)-phenylacetylcarbinol in an enzyme-membrane reactor

The optimization of a continuous enzymatic reaction yielding (R)-(−)-phenylacetylcarbinol ((R)-PAC), a key intermediate of the (1R,2S)-(−)-ephedrine synthesis, is presented. We compare the suitability of different mutants of the pyruvate decarboxylase (PDC) from Zymomonas mobilis with respect to their application in biotransformation using pyruvate or acetaldehyde and benzaldehyde as substrates, respectively. Starting from 90 mM pyruvate and 30 mM benzaldehyde, (R)-PAC was obtained with a space time yield of 27.4 g/(L·day) using purified PDCW392I in an enzyme-membrane reactor. Due to the high stability of the mutant enzymes PDCW392I and PDCW392M towards acetaldehyde, a continuous procedure using acetaldehyde instead of pyruvate was developed. The kinetic results of the enzymatic synthesis starting from acetaldehyde and benzaldehyde demonstrate that the carboligation to (R)-PAC is most efficiently performed using a continuous reaction system and feeding both aldehydes in equimolar concentration. Starting from an inlet concentration of 50 mM of both aldehydes, (R)-PAC was obtained with a space-time yield of 81 g/(L·day) using the mutant enzyme PDCW392M. The new reaction strategy allows the enzymatic synthesis of (R)-PAC from cheap substrates free of unwanted by-products with potent mutants of PDC from Z. mobilis in an aqueous reaction system.     

Phytosterols from Murraya exotica

From the cyclohexane extract of the leaves of Murraya exotica, five novel phytosterols: (23S)-23-ethyl-24-methyl-cycloart-24(24¹)-en-3β-ol; 3β-methoxy-(23S)-23-ethyl-24-methyl-cycloart-24(24¹)-en-3β-ol; (23 S)-23-ethyl-24-methyl-cycloart-24(24¹)-3β-yl acetate; (23ξ)-23-isopropyl-24-methyl-cycloart-25-en-3β-ol and (23ξ)-23-isopropyl-24-methyl-cycloart-25-en-3β-yl acetate have been isolated. Structural elucidation of the isolated compounds is based on physical, chemical and spectral analysis including IR, ¹H and ¹³CNMR and mass spectrometry.     

η and η olefin complexation by S, S-[Ru(Me2edda)]: a structural change to accommodate bidentate dienes

[Ru^II(Me₂edda)(H₂O)₂] (1), Me₂edda²⁻ = N,N′-dimethylethylenediaminediacetate, exhibits a sterically-controlled molecular recognition in forming η² and η⁴ olefin complexes. 1 exists with an N₂O₂ in-plane set of chelate donors and axial H₂O ligands. The two CH₃ functionalities of Me₂edda²⁻ are poised above and below the N₂O₂ plane of the glycinato rings. Studies herein of the 2,2′-bipyridine complex, [Ru^II(Me₂edda)(bpy)], with bidentate bpy chelation as established via ¹H NMR and electrochemical methods show 1 to be ligated in the S,S configuration with the glycinato rings in-plane as a cis-O form. 1 is sterically discriminating in forming η² complexes with smaller olefins (ethylene, 2-propene, cis-2-butene, methyl vinyl ketone and 3-cyclohexene-1-methanol), but rejects larger decorated ring structures and branched olefins (1,2-dimethyluracil, cyclohexene-1-one 2-methyl-2-propene). η² complexes of 1 have characteristic Ru^II/III DPP waves near 0.55 V which vary slightly with olefin structure. Potentially bidendate dienes (1,3-butadiene, 1,3-cyclohexadiene and 2,5-norbornadiene (nbd) form η⁴ complexes as shown by Ru^II/III waves between 0.94 and 1.30 V, indicate of a highly stabilized Ru^II center by π-backboning. An η²η⁴ ‘equilibrium’ with apparent K = 22 at 25 °C is observed for nbd coordinated to 1. (The η² and η⁴ distribution may be a kinetic one and not a thermodynamic one). To allow formation of the cis η⁴ complexes, 1 must undergo a shift of one or both glycinato donors from the N₂O₂ plane into the axial site away from the dimethyl functionalities. η⁴ chelation by 1,3-butadiene has been confirmed by ¹H NMR spectral assignments of two [Ru^II(Me₂edda)] isomers, one in the axial rans-O glycinato configuration, e.g. 1,3-butadiene is bidentate in the original N₂O₂ plane and a second unsymmetrical glycinato arrangement with in-plane and axial glycinato as well as in-plane and axial η⁴-1,3-butadiene coordination. [Ru^II(hedta)(H₂O)]⁻ (2), hedta³⁻ = N-hydrpxyethylenediaminetriacetate, is less discriminating for olefin structures, forming η² complexes with all eleven olefins and dienes mentioned for studies with 1. However, 2 does not undergo displacement of a carboxylate donor by the second olefin unit of a diene [Ru^II(hedta)(diene)]⁻ complexes possess a pendant non-coordinated olefin and on η²-bound olefin in the complex, indicated by a normal Ru^II(pac)(olefin)Ru^II/III wave near 0.55 V.     

Carotenoids in petals of perennial Medicago species

The carotenoid content in the petals of fourteen Medicago species was examined, together with eight species studied previously, caratenoids in all the known perennials of the genus are reported. The species can be arranged in relationship groups on the basis of their interfertility. No major carotenoid was species- or groupspecific; a few minor pigments, however, were group- or species-specific. The amount of carotenoids ranged from 7 μg/g dry matter in violet-flowered M. sativa to 2120 μg/g in brownish-yellow M. platycarpos. Xanthophylls constituted 76–99% of the total, with lutein as the major component. β-Carotene, lutein and flavoxanthin were ubiquitous in petals. In M sativa leaves β-carotene, lutein, violaxanthin and neoxanthin constituted 88% of the total. The xanthophylls were esterified in petals but not in leaves.     

Flavonoids of Helianthus series Microcephali

Ray flower and leaf flavonoids were investigated for the three species of Helianthus series Microcephali. Ray flowers of all species contain coreopsin, sulphurein, and quercetin 7-O-glucoside; those of H. microcephalus also contain quercetin 3-O-glucoside. A mixture of flavonoid aglycones, mostly methoxylated flavones, occurs in leaves of H. microcephalus, but not in H. glaucophyllus or H. laevigatus which also lack the glandular trichomes that in Helianthus are typically associated with flavonoid aglycones. The presence of compounds with the 6,8,4′ pattern of methoxylation in H. microcephalus suggests that the series is more similar in flavonoids to series Angustifolii than to series Corona-solis.     

Geographic differentiation of monoterpenes from Abies procera and Abies magnifica

Cortical oleoresins from 352 Abies magnifica and A. procera trees, collected in 35 localities, were analysed for composition of their monoterpene fractions. The monoterpenes were composed primarily of -pinene, β-pinene, limonene and β-phellandrene, with camphene and 3-carene appearing only sporadically in larger amounts. Limonene, β-phellandrene, -pinene and 3-cerene were used to study the transitional populations in northern California and southern and central Oregon and the transitional-like populations in southern Sierra Nevada. The populations segregated latitudinally into three related clusters—above 44° (A.procera), between 44° and 40° (transitional), and below 40° (A.magnifica). A.magnifica from southern Sierra Nevada and A.magnifica from Mtn. Shasta differed in a number of parameters, with southern Sierra Nevada populations being chemically much closer to typical A. magnifica from central and northern Sierra Nevada. While monoterpene and morphological data did not allow a clear Interpretation of the status of the transitional and southern populations, the paleobotanical evidence favored the recent evolution over introgression. The desirability of additional studies was indicated.     

The effect of non-protein amino acids from Calliandra plants on the aphid, Aphis fabae

Non-protein amino acids found in the young leaves and stems of Calliandra spp. were assayed for insecticidal activity against the aphid, Aphis fabae. Of the five compounds tested S-(β-carboxyethyl)-cysteine was the most active and combinations of the compounds were more active than single compounds.     

Anti-diabetic properties of the Canadian lowbush blueberry Vaccinium angustifolium Ait.

Incidence of type II diabetes is rapidly increasing worldwide. In order to identify complementary or alternative approaches to existing medications, we studied anti-diabetic properties of Vaccinium angustifolium Ait., a natural health product recommended for diabetes treatment in Canada. Ethanol extracts of root, stem, leaf, and fruit were tested at 12.5 μg/ml for anti-diabetic activity in peripheral tissues and pancreatic β cells using a variety of cell-based bioassays. Specifically, we assessed: (1) deoxyglucose uptake in differentiated C2C12 muscle cells and 3T3-L1 adipocytes; (2) glucose-stimulated insulin secretion (GSIS) in β TC-tet pancreatic β cells; (3) β cell proliferation in β TC-tet cells; (4) lipid accumulation in differentiating 3T3-L1 cells; (5) protection against glucose toxicity in PC12 cells. Root, stem, and leaf extracts significantly enhanced glucose transport in C2C12 cells by 15–25% in presence and absence of insulin after 20 h of incubation; no enhancement resulted from a 1 h exposure. In 3T3 cells, only the root and stem extracts enhanced uptake, and this effect was greater after 1 h than after 20 h; uptake was increased by up to 75% in absence of insulin. GSIS was potentiated by a small amount in growth-arrested β TC-tet cells incubated overnight with leaf or stem extract. However, fruit extracts were found to increase ³H-thymidine incorporation in replicating β TC-tet cells by 2.8-fold. Lipid accumulation in differentiating 3T3-L1 cells was accelerated by root, stem, and leaf extracts by as much as 6.5-fold by the end of a 6-day period. Stem, leaf, and fruit extracts reduced apoptosis by 20–33% in PC12 cells exposed to elevated glucose for 96 h. These results demonstrate that V. angustifolium contains active principles with insulin-like and glitazone-like properties, while conferring protection against glucose toxicity. Enhancement of proliferation in β cells may represent another potential anti-diabetic property. Extracts of the Canadian blueberry thus show promise for use as a complementary anti-diabetic therapy.     

A comparison of measured and calculated net community CO2 exchange: Scaling from leaves to communities

Leaf net photosynthesis is crucial for detecting the mechanism of photosynthesis, whereas community net photosynthesis is useful for understanding the photosynthetic capacity of communities and its relationship with environmental factors. In particular, we need to scale up eco-physiological models from leaf scale to canopy level to study carbon cycling at regional or global scale. We hypothesized that accumulated leaf net photosynthetic rate (P_c) at community scale, i.e., calculated based on leaf net photosynthetic rate (P_n) and leaf area index (LAI), equals to measured net community CO₂ exchange (NCE). The purpose of this study is to verify this hypothesis. Our field study was carried out in Duolun, Nei Mongol, China, where we constructed single-species communities by sowing Medicago sativa ‘Aohan’ seeds in three plots (3 m × 5 m) on May 30, 2012. On August 16, 2014, P_n of five healthy leaves of M. sativa ‘Aohan’ in each plot were measured with a LI-6400 portable photosynthesis system at 10:00, and net ecosystem CO₂ exchange (NEE) in each plot was measured simultaneously with a LI-8100 system connected with a assimilation chamber (0.5 m × 0.5 m × 0.5 m). P_c was calculated based on P_n, number of leaves (n), LAI percentage of healthy leaves (r) and percentage of received effective light by leaves (m). NCE was derived from NEE and ecosystem respiration rate (R_eco). P_c was 3.52 μmol CO₂·m^-2·s^-1, and very close to NCE (3.56 μmol CO₂·m^-2·s^-1), suggesting that leaf-scale photosynthesis may accurately predict community-scale photosynthesis. However, our method could not separate community respiration from soil respiration, and future studies, should be designed to counteract this effect. Scaling up from leaf photosynthesis to community photosynthesis should also consider vertical structure of communities and nonlinear responses of leaf photosynthesis to changes in light quantum.     

基于超声清洗的树木叶面颗粒物粒径分布与吸滞效率研究——以银杏和油松为例

明确在常规叶片清洗方法(泡洗或泡洗+刷洗)上增加超声清洗对叶面各径级颗粒物滞纳量定量评估的影响, 并在此基础上研究叶面颗粒物的粒径分布和吸滞效率, 可进一步提高城市树木大气颗粒物吸滞能力的定量评估精度。该文以城市森林建设常用阔叶树种银杏(Ginkgo biloba)和针叶树种油松(Pinus tabuliformis)为研究对象, 于雨后(降水量>15 mm) 4天(短滞尘时长)和14天(长滞尘时长)分别采集叶样, 并依次对其进行泡洗(WC)、刷洗(BC)、超声清洗(UC)等洗脱程序, 然后对每个清洗步骤下叶片洗脱液中颗粒物的质量和粒径分布进行测试, 并依此估算叶片各径级颗粒物的吸滞效率。结果表明, 以“泡洗+刷洗+超声清洗”清洗流程的测试结果为参照, 若只对叶片进行泡洗, 则银杏和油松对大气颗粒物(PM₁, 粒径d ≤1 µm)、PM_2.5 (d ≤ 2.5 µm)、PM₅ (d ≤ 5 µm)、PM₁₀ (d ≤ 10 µm)吸滞量会分别被低估约一半(54%、53%、53%和53%)和40% (42%、42%、42%和42%); 若只进行“泡洗+刷洗”, 则银杏和油松对相应径级颗粒物的吸滞量仍会分别被低估约15% (17%、16%、15%和15%)和20% (21%、20%、20%和20%)。油松叶面颗粒物粒径分布呈双峰曲线, 而银杏叶面颗粒物粒径则呈单峰分布, 且银杏叶面颗粒物平均粒径在短、长滞尘时长下均大于油松。油松叶片对PM₁、PM_2.5、PM₅、PM₁₀和总悬浮颗粒物的吸滞效率分别为8.96、23.92、23.96、23.96和23.96 mg·m^-2·d^-1, 分别比银杏叶片高112%、73%、34%、37%和42%。