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At least 19 recordsLinked to original sources
PubMed2005

Long-term trends in cellulose delta13 C and water-use efficiency of tropical Cedrela and Swietenia from Brazil.

Elevated CO(2) concentrations ([CO(2)]) affect plant water relations and photosynthesis, and the increase in atmospheric [CO(2)] over the past 100-200 years has been related to changes in stomatal density and the carbon isotope ratio (delta(13)C) in tree rings and leaves from herbarium specimens. Because many tropical trees do not produce annual growth rings and their wood is therefore difficult to date, no trends in delta(13)C of tropical trees have been reported. Wood from Cedrela odorata L. (tropical cedar) and Swietenia macrophylla King (bigleaf mahogany), which do produce annual rings, was collected from a primary rain forest in Aripuanã, Brazil (10 degrees 09' S, 59 degrees 26' W). We measured wood cellulose delta(13)C in 10-year growth increments from 37 Cedrela trees (between 11 and 151 years old in 2001) and 16 Swietenia trees (48-126 years old). A comparison of delta(13)C in cellulose of trees from different decades and of trees of different cambial ages showed that the amount of delta(13)C was largely related to the decade the wood was produced in, and not, or only to a minor extent, to tree age. Cellulose delta(13)C decreased from -26.0 to -27.3 per thousand in Cedrela and from -25.7 to -27.1 per thousand in Swietenia, with the largest changes occurring during the past 50 years. Based on these data and the trends in atmospheric [CO(2)] and delta(13)CO(2), we calculated that the internal [CO(2)] increased from about 220 to 260 ppm and that intrinsic water-use efficiency increased by 34% in Cedrela and by 52% in Swietenia. This may have implications for the water cycle and may explain the trend toward increased tree growth and turnover observed in some tropical forests.

Brazil↗
PubMed2000

Growth inhibitory effects on fall armyworm Spodoptera frugiperda of some limonoids isolated from Cedrela spp. (Meliaceae).

Dichloromethane extracts of Cedrela salvadorensis and Cedrela dugessi afforded a photogedunin epimeric mixture, gedunin and cedrelanolide. These compounds and the photogedunin epimeric acetates 3 and 4 at the 23-OH position were evaluated against Spodoptera frugiperda. Toosendanin, isolated from Melia azedarach, was used as a positive control. When tested for activity on neonate larvae into the no-choice bioassays, gedunin, photogedunin epimeric mixture, and photogedunin acetates mixture caused significant larval mortality with LC(50) of 39.0, 10.0, and 8.0 ppm at 7 days, respectively, as well as growth reduction. All the compounds tested inhibited larval growth, compared to the control, in a concentration-dependent manner. In addition, it was possible to observe significant reduced pupal weights and adult emergence. All the tested compounds except cedrelanolide showed comparable activity to that of toosendanin.

Animals↗
PubMed2005

The tropical cedar tree (Cedrela fissilis Vell., Meliaceae) homolog of the Arabidopsis LEAFY gene is expressed in reproductive tissues and can complement Arabidopsis leafy mutants.

A homolog of FLORICAULA/LEAFY, CfLFY (for Cedrela fissilis LFY), was isolated from tropical cedar. The main stages of the reproductive development in C. fissilis were documented by scanning electron microscopy and the expression patterns of CfLFY were studied during the differentiation of the floral meristems. Furthermore, the biological role of the CfLFY gene was assessed using transgenic Arabidopsis plants. CfLFY showed a high degree of similarity to other plant homologs of FLO/LFY. Southern analysis showed that CfLFY is a single-copy gene in the tropical cedar genome. Northern blot analysis and in situ hybridization results showed that CfLFY was expressed in the reproductive buds during the transition from vegetative to reproductive growth, as well as in floral meristems and floral organs but was excluded from the vegetative apex and leaves. Transgenic Arabidopsis lfy26 mutant lines expressing the CfLFY coding region, under the control of the LFY promoter, showed restored wild-type phenotype. Taken together, our results suggest that CfLFY is a FLO/LFY homolog probably involved in the control of tropical cedar reproductive development.

Arabidopsis↗
PubMed2004

Limonoids from Cedrela sinensis.

Five limonoids were isolated from the leaves of Cedrela sinensis (Meliaceae) and their structures were determined to be 11beta-hydroxy-7alpha-obacunyl acetate, 11-oxo-7alpha-obacunyl acetate, 11-oxo-7alpha-obacunol, 11beta-hydroxycneorin G, and 11-oxocneorin G, by 2D NMR spectroscopic experiments, X-ray crystallographic analysis, and chemical methods.

Cedrela↗
PubMed2006

Hydroxylated gedunin derivatives from Cedrela sinensis.

Four new limonoids, 11alpha-hydroxygedunin (1), 11beta-hydroxygedunin (2), 7-deacetoxy-7alpha,11alpha-dihydroxygedunin (3), and 7-deacetoxy-7alpha,11beta-dihydroxygedunin (4), were isolated from the cortex of Cedrela sinensis, together with three known compounds, gedunin (5), 7-deacetoxy-7alpha-hydroxygedunin (6), and 11-oxogedunin (7). The structures of 1-4 were determined by a combination of 2D NMR experiments and chemical methods and by X-ray crystallography of 1 and 2.

Animals↗
PubMed2003

Chloroplast DNA phylogeography reveals colonization history of a Neotropical tree, Cedrela odorata L., in Mesoamerica.

Spanish Cedar (Cedrela odorata L.) is a globally important timber species which has been severely exploited in Mesoamerica for over 200 years. Using polymerase chain reaction-restriction fragment length polymorphisms, its chloroplast (cp) DNA phylogeography was studied in Mesoamerica with samples from 29 populations in six countries. Five haplotypes were characterized, phylogenetically grouped into three lineages (Northern, Central and Southern). Spatial analysis of ordered genetic distance confirmed deviation from a pattern of isolation by distance. The geographically proximate Northern and Central cpDNA lineages were genetically the most differentiated, with the Southern lineage appearing between them on a minimum spanning tree. However, populations possessing Southern lineage haplotypes occupy distinct moist habitats, in contrast to populations possessing Northern and Central lineage haplotypes which occupy drier and more seasonal habitats. Given the known colonization of the proto-Mesoamerican peninsula by South American flora and fauna prior to the formation of the Isthmus of Panama, it seems most likely that the observed population structure in C. odorata results from repeated colonization of Mesoamerica from South American source populations. Such a model would imply an ancient, pre-Isthmian colonization of a dry-adapted type (possessing the Northern lineage or a prototype thereof), with a secondary colonization via the land bridge. Following this, a more recent (possibly post-Pleistocene) expansion of moist-adapted types possessing the Southern lineage from the south fits the known vegetation history of the region.

Cedrela↗
PubMed2002

The tree Cedrela odorata (Meliaceae): a morphologically subdivided species in Costa Rica.

In Latin America. Cedrela odorata is a wide ranging species that occurs in several environments, where it shows significant morphological variation. A common garden experiment was established with seedlings from 63 families of ten populations from two habitat types (mesic and dry), distributed throughout Costa Rica, to examine the relationships between quantitative variation and site of population origin. Seedlings from dry areas tended to be distinct from those from mesic areas, with climatic grouping of provenance explaining a mean of 52% of the total variance and 80% of the genetic variance. Cluster analysis for seedling traits showed two natural groupings of families, which corresponded for the most part with the regional population groupings into mesic (Atlantic and South Pacific) and dry (North Pacific) groups. Cluster analysis based on seed weight and size also separated populations into mesic and dry climatic groups. Seeds from populations in dry areas were 43% heavier, and seedlings were 61% taller, 117% greater in diameter, and with leaflets 39% longer and 81% wider. These differences may be related to fast growth in the dry zone for taking advantage of early life cycle moisture availability. These findings may indicate incipient speciation in C. odorata in Costa Rica. Evaluation of reproductive isolating mechanisms between populations from the mesic and dry zones, and of clines at potential zones of hybridization would assist in testing a speciation hypothesis.

Analysis of Variance↗
PubMed1995

Immunomodulatory activities of Cedrela tubiflora leaf aqueous extracts.

Human peripheral blood monocytes and polymorphonuclear leukocytes treated with leaf aqueous extracts of the Meliaceae tree Cedrela tubiflora showed a diminution in both their phagocytic and respiratory burst activities. Besides, the extract inhibited the proliferation of Concanavalin A stimulated lymphocytes. A decrease in the hemolytic capacity of the human complement was also observed. The significance of the inhibitory effect observed over some components of the human immune system closely related with the inflammatory process is discussed.

Adjuvants, Immunologic↗
PubMed1999

Neutral polysaccharide from Cedrela tubiflora with anticomplementary activity.

A water-soluble polysaccharide extracted from leaves of the Meliaceae Cedrela tubiflora was separated into neutral and acidic polysaccharide fractions. The best anticomplementary activity was exhibited by the neutral product which was further purified by means of gelpermeation chromatography. The composition and methylation analysis of the purified product were determined.

Animals↗
PubMed2000

Limonoids and phytol derivatives from Cedrela sinensis.

Two new compounds, cedrellin (1) and 2,6,10,15-phytatetraene-14-ol (2), together with five known compounds, 7 alpha-obacunyl acetate, 6-acetoxyobacunol acetate, 7 alpha-acetoxydihydronomilin, 2,6,10-phytatriene-1,14,15-triol and phytol were isolated from leaves of Cedrela sinensis. Their structures were elucidated on the basis of combined one- and two-dimensional spectral techniques.

Drugs, Chinese Herbal↗
PubMed1997

Immunomodulatory activities of Cedrela lilloi and Trichilia elegans aqueous leaf extracts.

The effects of Cedrela lilloi and Trichilia elegans (Meliaceae) aqueous leaf extracts on several parameters of the mouse immune system were studied. Both extracts showed a strong anticomplementary activity and inhibited the phagocytosis of opsonized sheep erythrocytes and the activation of the oxidative metabolism by opsonized zymosan on peritoneal macrophages. The in vitro proliferation of spleen T-lymphocytes was also impaired. Furthermore, treatment of mice with the extracts diminished the delayed-type hypersensitivity response to sheep erythrocytes. These results suggest that both extracts exert a marked immunomodulatory effect on the mouse immune system.

Adjuvants, Immunologic↗
PubMed1999

Four new tetranortriterpenoids from cedrela odorata associated with leaf rejection by exopthalmus jekelianus

Four new tetranortriterpenoids, 3-deoxo-3beta,8beta-epoxy-6, 14alpha-dihydroxy-8,14-dihydromexicanolide (cedrodorin, 1); 3-deoxo-3beta,8beta-epoxy-6-acetoxy-14alpha-hydroxy-8, 14-dihydromexicanolide (6-acetoxycedrodorin, 2); 3-deoxo-3beta, 8beta-epoxy-6-deoxy-9alpha,14alpha-dihydroxy-8, 14-dihydromexicanolide (6-deoxy-9alpha-hydroxycedrodorin, 3); and 3-deoxo-3beta,8beta-epoxy-6,9alpha,14alpha-trihydroxy-8, 14-dihydromexicanolide (9alpha-hydroxycedrodorin, 4), have been isolated from the leaves of Cedrela odorata by HPLC. Their molecular structures were determined by 1D and 2D NMR. Three of the compounds are associated with leaf rejection by the polyphagous, folivorous weevil, Exopthalmus jekelianus. The importance of these compounds as insect deterrents in C. odorata, and their potential value in the selection of insect-resistant clones for timber plantations is discussed.

Journal Article↗
PubMed2001

Plant-growth inhibitory activity of cedrelanolide from Cedrela salvadorensis.

The effect of cedrelanolide, the most abundant limonoid isolated from Cedrela salvadorensis (Meliaceae), was assayed as a plant-growth inhibitory compound against monocotyledonous and dicotyledonous seeds. This compound inhibited germination, seed respiration, and seedling dry weights of some plant species (Lolium multiflorum, var. Hercules, Triticum vulgare, var. Salamanca, Physalis ixocarpa, and Trifolium alexandrinum). Our results indicate that cedrelanolide interferes with monocot preemergence properties, mainly energy metabolism of the seeds at the level of respiration. In addition, the compound inhibits photophosphorylation, H+ uptake, and noncyclic electron flow. This behavior might be responsible for its plant-growth inhibitory properties and its possible role as an allelopathic agent.

Fabaceae↗
PubMed2000

Interaction of nutrient limitation and elevated CO2 concentration on carbon assimilation of a tropical tree seedling (Cedrela odorata).

Carbon assimilation by Cedrela odorata L. (Meliaceae) seedlings was investigated in ambient and elevated CO2 concentrations ([CO2]) for 119 days, using small fumigation chambers. A solution containing macro- and micronutrients was supplied at two rates. The 5% rate (high rate) was designed to avoid nutrient limitation and allow a maximum rate of growth. The 1% rate (low rate) allowed examination of the effect of the nutrient limitation-elevated CO2 interaction on carbon assimilation. Root growth was stimulated by 23% in elevated [CO2] at a high rate of nutrient supply, but this did not lead to a change in the root:shoot ratio. Total biomass did not change at either rate of nutrient supply, despite an increase in relative growth rate at the low nutrient supply rate. Net assimilation rates and relative growth rates were stimulated by the high rate of nutrient addition, irrespective of [CO2]. We used a biochemical model of photosynthesis to investigate assimilation at the leaf level. Maximum rate of electron transport (Jmax) and maximum velocity of carboxylation (Vcmax) did not differ significantly with CO2 treatment, but showed a substantial reduction at the low rate of nutrient supply. Across both CO2 treatments, mean Jmax for seedlings grown at a high rate of nutrient supply was 75 micromol m(-2) s(-1) and mean Vcmax was 27 micromol m(-2) s(-1). The corresponding mean values for seedlings grown at a low rate of nutrient supply were 36 micromol m(-2) s(-1) and 15 micromol m(-2) s(-1), respectively. Concentrations of leaf nitrogen, on a mass basis, were significantly decreased by the low nutrient supply rate, in proportion to the observed decrease in photosynthetic parameters. Chlorophyll and carbohydrate concentrations of leaves were unaffected by growth [CO2]. Because there was no net increase in growth in response to elevated [CO2], despite increased assimilation of carbon at the leaf level, we hypothesize that the rate of respiration of non-photosynthetic organs was increased.

Carbon↗
PubMedDate not supplied

Oleanane trietrpenoids from Cedrela montana (Meliaceae).

Two new oleanane-type triterpenes, characterized as 3-oxo-11alpha,12alpha-epoxy-oleanan-28,13beta-olide and 3-oxo-olean-11-en-28,13beta-olide , were isolated from the fruits and seeds of Cedrela montana (Meliaceae). In addition, the known compounds oleanonic acid, a mixture of beta-sitosterol and stigmasterol, and the limonoid photogedunin were also isolated. The structures of the new compounds were established by spectroscopic methods, including 2D NMR.

Magnetic Resonance Spectroscopy↗
PubMed2000

Photosynthetic nutrient-use efficiency in three fast-growing tropical trees with differing leaf longevities.

Differences in nutrient-use efficiency have been attributed to differences in leaf habit. It has been suggested that evergreens, with their longer-lived leaves, and therefore longer nutrient retention, are more efficient than deciduous species in their use of nutrients. In tropical trees, however, leaf life span is not always a function of whole-tree deciduousness, leading to the proposal that nutrient-use efficiency is better related to leaf life span than to leaf habit. It was predicted that potential photosynthetic nutrient-use efficiency (maximum potential photosynthesis/leaf nutrient content) would decrease with increasing leaf life span, whereas cumulative photosynthetic nutrient-use efficiency (carbon assimilated over a leaf's life span/total nutrients invested in a leaf) would increase with increasing leaf life span. Potential and cumulative photosynthetic nutrient-use efficiencies (with respect to nitrogen and phosphorus) were measured for three fast-growing tropical trees: Cedrela odorata L. (Meliaceae), Cordia alliodora (R. & P.) Cham. (Boraginaceae), and Hyeronima alchorneoides Allemão (Euphorbiaceae). Mean leaf life spans of the three species varied about threefold and ranged from 50 to 176 days. The predictions were partially supported: Cedrela odorata had the shortest-lived leaves and the highest potential nitrogen-use efficiency, whereas Hyeronima alchorneoides had the longest-lived leaves and the highest cumulative nitrogen- and phosphorus-use efficiencies. Potential phosphorus-use efficiency, however, was invariant among species. It is suggested that there are potential tradeoffs between leaf characteristics that lead to high potential and cumulative nutrient-use efficiencies. High potential nutrient-use efficiency may be beneficial in high-nutrient environments, whereas high cumulative nutrient-use efficiency may be of greater benefit to species in low-nutrient environments.

Costa Rica↗