Leaf Constituents Research Articles

Constituents of the leaf essential oil of Cedrela odorata L. from Nigeria

Constituents of the leaf essential oil of Cedrela odorata L. from Nigeria

Short rotation plantations of aspen and balsam poplar on former arable land in Germany: defoliating insects and leaf constituents

Damage by herbivorous insects to fast-growing clones of aspen ( Populus tremula × P. tremuloides, clone Astria) and balsam poplars ( Populus trichocarpa, clone Muhle Larsen) was estimated on a short rotation plantation which was established on former arable land near Regensburg (Germany). During the first rotation period of 5 years insect pests could not be observed. The present study was carried out in the second year of the second rotation period in which defoliators became obvious. The leaf roller Byctiscus populi (Curculionidae: Coleoptera) and leaf beetles of the genus Chrysomela, especially C. tremulae, and Phratora vitellinae (Chrysomelidae: Coleoptera) were found to be the dominant herbivorous insects. In total, the damages were significantly higher with the aspen clone Astria. In the clone Astria about 50% of the leaves and 37% of the side shoots were damaged by B. populi. Corresponding values with the clone Muhle Larsen amounted to 21% and 20%. Fertilized plots (N or N, P, K, Mg) of the clone Muhle Larsen were less attacked by B. populi. Almost all the remaining leaves not damaged by B. populi were injured by leaf beetles. Chrysomelid-caused damages of the leaf area were classified as follows: class 1 (0% damaged leaf area), 2 (1–5%), 3 (6–25%), 4 (26–50), 5 (51–75), 6 (>75%). About 80% of the investigated leaves of the clone Astria were classified in groups 4–6, while 80% of the clone Muhle Larsen belonged to the classes 1–3. Fertilization resulted in a slight reduction of chrysomelid damage. Biochemical analysis of the leaves revealed that the quantities of proteins and soluble carbohydrates could not explain the increased susceptibility of aspen, but both the clones differed significantly in the amounts of phenolic compounds, indicating a good protection against herbivory by high concentrations of tannins, especially procyanidins, in the clone Muhle Larsen.

Constituents of the Fresh Leaves of Aristolochia cucurbitifolia.

Continuing our investigation on the bioactive compounds from the plant of Aristolochia genus in Taiwan, we isolated one new aristolochic acid derivative, aristolochic acid-VII methyl ester; one new dihydrophenanthrenelactone, aristolide-C; four new benzenoids, 2'-hydroxyethyl 4-hydroxybenzoate, ariscucurbin-A, -B and -C, together with forty-six known compounds from the fresh Aristolochia cucurbitifolia.

Antioxidative systems, pigment and protein contents in leaves of adult mediterranean oak species (Quercus pubescens and Q. ilex) with lifetime exposure to elevated CO2.

The aim of the present study was to investigate the effects of elevated CO2 on the antioxidative systems and the contents of pigments, soluble protein and lipid peroxidation in leaves of adult oaks, Quercus pubescens and Quercus ilex, grown at naturally enriched CO2 concentrations. For this purpose, a field study was conducted at two CO2 springs in Central Italy. Measurements of the pre-dawn water potentials indicated less drought stress in trees close to CO2 springs than in those grown at ambient CO2 concentrations. Most leaf constituents investigated showed significant variability between sampling dates, species and sites. The foliar contents of protein and chlorophylls were not affected in trees grown close to the CO2 vents compared with those in ambient conditions. Increases in glutathione and other soluble thiols were observed, but these responses might have been caused by a low pollution of the vents with sulphurous gases. At CO2 vents, glutathione reductase was unaffected, and superoxide dismutase activity was significantly diminished, in both species. Generally, the activities of catalase, guaiacol peroxidase and ascorbate peroxidase as well as the sum of dehydroascorbate and ascorbate were decreased in leaves from trees grown in naturally CO2 -enriched environments compared with those grown at ambient CO2 concentrations. The reduction in protective enzymes did not result in increased lipid peroxidation, but increased monodehydroascorbate radical reductase and dehydroascorbate reductase activities found in leaves of Q. pubescens suggest that the smaller pool of ascorbate was subjected to higher turnover rates. These data show that changes in leaf physiology persist, even after lifetime exposure to enhanced atmospheric CO2 . The results suggest that the down-regulation of protective systems, which has also previously been found in young trees or seedlings under controlled exposure to elevated CO2 concentrations, might reflect a realistic response of antioxidative defences in mature trees in a future high-CO2 world.

Evidence that Premature Senescence Affects Photosynthetic Decline of Wheat Flag Leaves during Growth in Elevated Carbon Dioxide

Net CO2 exchange (NCE) rates and various flag leaf constituents were measured in wheat plants (Triticum aestivum L.) grown in field chambers at either 350 or 700 p.L L-' CO2. Rates of NCE decreased with leaf age in both CO2 treatments during 1997. A stimulation of NCE initially occurred in response to CO2 enrichment, but this was not observed on the final eight of 33 experimental days. Net photosynthetic rates in response to growth at elevated CO2 were decreased ca. 22% on average for all measurement dates in 1997 and when all NCE rates measured at elevated CO2 for 1995-1997 were averaged (P ' 0.0001). Soluble protein, ct-amino nitrogen, and Chl a + b concentrations were significantly lower (P - 0.0001) in elevated compared with ambient C02-grown wheat flag leaves in 1997. The treatment by date interactions for these flag leaf constituents were nonsignificant (P 2 0.05). Flag leaf storage carbohydrates were measured on 10 dates in 1997, but only starch and sucrose were affected by the elevated CO2 treatment. An increase of acid proteinase activity was observed on the last two measurement dates of this study. However, changes of acid proteinase activity were unaffected by CO2 enrichment (P ? 0.05) and only occurred during late stages of senescence. These findings supported the suggestion that premature senescence contributed to the photosynthetic decline observed in wheat flag leaves during growth at elevated CO2. Changes of ox-amino nitrogen were correlated with photosynthetic decline, but acid proteinase activity probably was under endogenous control.

Relationships between specific leaf weight and mineral concentration among genotypes

Physiological functions are usually expressed on a leaf area basis, whereas leaf mineral concentrations are often expressed on a dry matter basis. If specific leaf weight (SLW; g DM m −2 leaf) differs among genotypes then variability in mineral concentration may depend on the basis of expression. Data from experiments with peanut ( Arachis hypogaea L.) and pearl millet [ Pennisetum glaucum (L.) R. Br.] lines and from the literature were used to examine relationships between leaf mineral concentration and SLW. Peanut and pearl millet were grown in pots in the greenhouse in soil and solution cultures. Specific leaf weight and ash and mineral concentrations were determined at the end of the experiments. Leaf ash concentration on a dry matter basis was negatively correlated with SLW and the correlation coefficients were significant in six of nine comparisons for the two species; r = −0.65 to −0.93. In the one peanut experiment in which mineral elements were determined, the correlations with ash were due mainly to correlations with Ca and Mg, while in pearl millet, correlations were due mainly to K. The slope of a plot of leaf constituents per unit of leaf area against SLW for a range of lines is a measure of the contribution of that leaf constituent to increased SLW. From data in the literature it appears that increased SLW is due mostly to the increase of cell wall components and nonstructural carbohydrates, and sometimes protein. Leaf mineral per unit of leaf area appears to be unrelated or only slightly increased with increased SLW and thus declines on a unit weight basis because of dilution by increased cell wall content or soluble carbohydrate.

Phytotoxic constituents from Bunias orientalis leaves

Aqueous extracts of Bunias orientalis leaves showed considerable germination inhibition in petri-dish bioassays. As major B. orientalis leaf constituents with known allelopathic activity bound forms of p-coumaric, ferulic and sinapic acids as well as two C 13-norisoprenoids, i.e. 3-hydroxy-β-ionone and 3-hydroxy-5,6-epoxy-β-ionone, were identified in XAD-2 isolates. After separation of the glycosidic isolate by counter-current chromatography/HPLC, 3-hydroxy-5,6-epoxy-β-ionyl-β- d-glucoside and the glucose ester of sinapic acid were isolated in pure form and their structures elucidated from 1H and 13C NMR spectral data. The corresponding aglycones were found to be major constituents in leaf leachate solutions of B. orientalis, together with the known allelochemic loliolide.

Relationships between Photosynthetic Activity and the Amounts of Rubisco Activase and Rubisco in Rice Leaves from Emergence through Senescence.

Photosynthetic activity determined as O2 evolution (OER) and the amounts of Rubisco activase, Rubisco, total soluble protein and chlorophyll were investigated in the 10th leaf of rice, Oryza sativa L. cv. Nipponbare, in relation to its aging. The Rubisco activase content increased until the 17th day after leaf emergence, at which time it attained its maximum and accounted for 1.43% of total soluble protein; thereafter, it decreased rapidly. This change was most remarkable compared to the other leaf constituents examined. The Rubisco content had already reached its maximum 3 days after leaf emergence and had begun to decrease earliest among the leaf constituents. The OER depended linearly on the leaf Rubisco content below the value of 3 g m-2, but tended to saturate above this value. On the contrary, the amount of Rubisco activase and OER were linearly correlated during the life span of the leaf. The in vivo Rubisco activity, as the OER per unit Rubisco content, increased exponentially with the increased Rubisco activase/Rubisco ratio. These results show that the amount of Rubisco activase is closely related to the photosynthetic rates in rice leaf from its emergence through senescence, and suggest that in vivo Rubisco activity can be restricted by Rubisco activase content, particularly when the leaf is young and accumulates excess Rubisco.

Constituents of Leaves of Tetradium Glabrifolium

AbstractTwenty‐nine compounds including three alkaloids, live triterpenoids, five coumarins, seven benzenoids, two tannins, five flavonoids, one sugar and one nucleoside are isolated from leaves of Tetradium glabrifolium. Their structures are characterized on comparison of spectral data with literature values.

Methylated C-glycosylflavones as taxonomic markers in orchids of the subtribe ornithocephalinae

In a leaf flavonoid survey of 15 Brazilian orchid species from the subtribe Ornithocephalinae, flavone C-glycosides were found to be the major constituents in all except two Ornithocephalus taxa. In Zygostates cornuta a rare glycoside, apigenin 7,4′-dimethyl ether 6- C-glucoside- 2″- O-rhamnoside, was identified. This also occurred in Z. alleniana, Z. lunata, Z. pellucida and Z. pustulata. Two further similar apigenin 7,4′-dimethyl ether C-glycoside- O-rhamnosides, possibly with different C-linked sugars, were detected in Z. multiflora and Z. grandiflora. In Z. cornuta, apigenin 4′-methyl ether 6- C-glucoside-2″- O-rhamnoside was found to co-occur with the apigenin 7,4′-dimethyl ether derivative. Ornithocephalus myrticola was distinguished by the presence of an apigenin 8- C-methylpentoside and three apigenin 7-methyl ether 8- C-glycoside derivatives. In O. bicornis and O. kruegeri, another apigenin 7,4′-dimethyl ether C-glycoside was found, while from Phymatidum falcifolium, apigenin 7,4′-dimethyl ether and apigenin 7-methyl ether C-glycosides and their O-arabinosides were isolated. Chytroglossa marileoniae also contained an apigenin 7,4′-dimethyl ether C-glycoside, which appeared to be the same as that in P. falcifolium. Rauhiella silvana, on the other hand, could be distinguished from all the other taxa studied by the absence of methylated C-glycosylflavones and presence of isovitexin. 6-Hydroxyflavone O-glycosides, which are characteristic leaf constituents of some Oncidium species in the related subtribe Oncidinae were not detected in the present sample. However, the high frequency of methylated flavone C-glycosides suggests a chemically advanced evolutionary position for the Ornithocephalinae, which is in agreement with evidence from their complex floral and vegetative morphology.

Glycosidically Bound Norisoprenoids from Vitis vinifera cv. Riesling Leaves

HRGC and HRGC-MS identifications of glycosidically bound Riesling leaf constituents were achieved after extraction with MeOH, Amberlite XAD-2 adsorption, and subsequent enzymatic hydrolysis of the glycoconjugates. Among the enzymatically liberated aglycons 23 bound C 13 norisoprenoids were identified. With the aid of multilayer coil countercurrent chromatography (MLCCC) five major C 13 glycosides were purified, and their structures were elucidated by high-field NMR, i.e., the β-D-glucopyranosides of vomifoliol, 4,5-dihydrovomifoliol, 3-hydroxy-5,6-epoxy-β-ionone, grasshopper ketone, and 3-oxomegastigman-9-ol. The latter glucoside with a saturated megastigmane skeleton is reported here for the first time

Constituents of Leaves of Uncaria Hirsuta Haviland

AbstractNine compounds, ursolic acid (1), β‐sitosteryl glucoside (2), umbelliferone (3), uncarine‐A (4), chlorogenic acid (5), rutin (6), neohesperidin (7), quercitrin (8)and afzelin (9) were isolated and characterized from fresh leaves of Uncaria hirsuta. Their structures were elucidated by spectral methods. Among them, uroslic acid (I) exhibited a cytotoxic principle of this plant.

Analyses of Forest Foliage III: Determining Nitrogen, Lignin and Cellulose in Fresh Leaves Using near Infrared Reflectance Data

Near infrared laboratory data of whole fresh leaves were evaluated with respect to leaf chemical composition. Near infrared spectra were measured for 211 foliage samples including both broad- and needle-leaved species. A multiple linear regression analysis was used to determine if reflectance data from fresh leaf samples contains information on nitrogen, lignin and cellulose concentrations. Calibration equations were developed for all three leaf constituents, indicating that information on leaf biochemistry is present in the spectra of fresh as well as dried, ground leaf samples.

Application of multilayer coil countercurrent chromatography for the study of Vitis vinifera cv. Riesling leaf glycosides

The glycosidic fraction violated from Vitis vinifera cv. Riesling leaves by XAD-2 adsorption and methanol elution was separated by multilayer coil countercurrent chromatography (MLCCC) to identify genuine precursors of the off-flavor-causing compound 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). A two-step procedure utilizing preparative MLCCC in combination with analytical MLCCC yielded two major vine leaf glycosides in pure form, i.e., the β-D-glucopyranosides of 3-oxo-7,8-dihydro-α-ionol (Blumenol C) and 3-oxo-4,5-dihydro-α-ionol, respectively. The determination of minor vine leaf constituents in separated MLCCC fractions was achieved after acetylation and subsequent HPLC purification of the per-O-acetylated derivatives

Early detection of effects of acid deposition and automobile exhaust on young spruce [Picea abies (L.) Karst.] trees

Rooted spruce cuttings from three clones were sprayed daily with sulfuric acid at pH 2.5 for one month or treated with automobile exhaust for one hour. Foliage samples were extracted and analyzed by high performance liquid chromatography. Chromatographic peaks representing unidentified leaf constituents from treated and control trees were compared. Discriminant analysis indicated a weak but significant difference and Canonical discriminant analysis indicated clear differences between treatments and control. Similar differences were found between the three clones. Visible symptoms of damage were not evident even four months after treatment. This result is important because it demonstrates the possibility of using unidentified plant constituents to detect damage to plants even before visible symptoms appear.

Osmotic Adjustment and Solute Constituents in Leaves and Roots of Water-stressed Cherry (Prunus) Trees

Tissue osmotic potential(Ψπ) and solute constituents were evaluated in leaves and roots of well-watered and water-stressed Prunus avium L. × pseudocerasus Lindl. `Colt' and Prunus cerasus L. `Meteor'. Osmotic potential at full turgorΨπ,sat decreased in response to water stress for leaves and roots of both cultivars. For `Colt', a cultivar with an indeterminate growth habit,Ψπ,sat decreased by 0.56 MPa and 0.38 MPa for terminal expanding leaves and older expanded leaves, respectively. For `Meteor', a cultivar with a determinate growth habit,Ψπ,sat decreased by ≈0.47 MPa in both terminal and older leaves. RootΨπ,sat was alike for both cultivars and showed a similar decrease of 0.20 MPa in response to water stress. Roots had considerably higherΨπ,sat than did leaves in both cultivars, irrespective of irrigation treatment. Soluble carbohydrates and potassium (K+) were the major solute constituents in both cultivars. Of the soluble carbohydrates, sorbitol was found in the greatest concentration and accounted for the bulk of water stress-induced solute accumulation in both cultivars. Regardless of the irrigation treatment, mature leaves of `Meteor' consistently had lowerΨπ,sat (typically 0.4 MPa) than `Colt'. This variation in Ψπ,sat between Prunus cultivars suggests the potential for selection of cultivars with low Ψπ,sat and possibly superior drought resistance.

Effect of Phloem Interruption on Senescence and Protein Remobilization in the Flag Leaf of Field-grown Wheat

Summary The phloem represents a link between senescing leaves (sources) and maturing (major sinks) in plants characterised by monocarpic senescence such as cereals. The redistribution of nutrients and assimilates might be involved in the control of senescence on a whole plant level. Field-grown winter wheat was steam-girdled at the base of the flag leaf lamina or below the ear in order to interrupt the phloem at these positions and to identify effects on flag leaf senescence. A phloem interruption below the ear delayed senescence of the flag leaf lamina as judged by chlorophyll contents and activities of assimilatory enzymes (phosphoribulokinase, glutamine synthetase). The rate of net photosynthesis was lowered in these leaves during the first week after the treatment, recovered and remained afterwards higher than in those of untreated control plants. Steam-girdling at the base of the leaf initiated its rapid senescence. The rate of photosynthesis declined rapidly after this treatment and was completely lost within one week, while dark respiration was initially slightly stimulated and decreased later than photosynthesis. The good correlations between enzyme activity measurements and immunoblot analyses indicate that not only the activities, but also the quantities of assimilatory enzymes were reduced. The interruption of source/sink relations affected flag leaf senescence, but the effects strongly depended on the position of the treatment. Leaf constituents were rapidly degraded after steam-girdling at the leaf base, although the export of breakdown products became impossible.

Structure Confirmation for an Unusual Flavanone from Encelia stenophylla

Abstract A flavanone with 3′-OH as the sole B-ring substituent has been reported recently as a leaf and stem exudate constituent of Encelia stenophylla. The correctness of this unusual substitution is confirmed by synthesis of this flavanone.

Curvulin and O-Methylcurvulinic acid: Phytotoxic metabolites of Drechslera indica which cause necroses on purslane and spiny amaranth

Curvulin was isolated from Drechslera indica and identified by X-ray crystallography. O-Methylcurvulinic acid was also isolated from this source and identified by NMR and HREIMS. Both compounds are phytotoxic to 2 of the normal hosts of this fungus when applied to detached leaves. Some plants are unaffected by these compounds. Host leaf constituents have some role in regulating the production of these phytotoxins by the fungus.

Terpenoid Chemistry. XXVIII. Furanosesquiterpene β-Ketols From Myoporum betcheanum, M. deserti, M. montanum and Other Myoporaceae

All four of the myodesmoid β-ketols (la) formally derivable from (-)-(S)-myoporone (3a),three of the four myomontanoid β-ketols (2a) from ent-(3a) and two of the four 10,ll-dehydro myodesmoid β-ketols (lb) from (3b), have been found in Myoporaceous plants and characterized by g.1.c. retentions and by Kovats indices and mass spectra of their trimethylsilyl ethers. Five of these ketols have been obtained as crystalline solids whose stereochemistry has been determined in part. All are readily converted into myoporone or 10,11-dehydromyoporone by pyrolysis during distillation or gas chromatography, and by base or alumina. These facile ring-opening reactions have previously concealed the widespread occurrence of these furanosesquiterpene β-ketols in the Myoporaceae. In the few specimens of Myoporum betcheanum, M. deserti and M. montanumwhich have been suitably examined, the β-ketols form a complex mixture of from four to eight ketols differing in carbon skeleton, unsaturation and/or stereochemistry. P-Ketols have been recognized in eight species of Myoporum and three of Eremophila. Both enantiomers of one myodesmoid ketol have been isolated. A mixture of ketols showed a toxicity similar to that of (-)-ngaione. A quick and quantitative micro method for the preparation of g.l.c.-injectable carbon disulfide solutions of volatile leaf constituents is described.