nor-Oleanene type triterpene glycosides from the leaves of Acanthopanax japonicus

Three new (1-3) and two known (4-5) triterpene glycosides were isolated from the leaves of Acanthopanax japonicus (Araliaceae) and elucidated structurally by mass, 1D, and 2D NMR spectroscopy. All the compounds possessed a nor-oleanene triterpene skeleton as the aglycone. The structures of 1-5 were established as 28-O-alpha-L-rhamno-pyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester of 3beta-hydroxy- 30-nor-olean-12,20(29)-diene-23,28-dioic acid, designated as acanjaposide A, 3beta- hydroxy-23-oxo-30-nor-olean-12,20(29)-diene-28-oic acid, named acanjaposide B, 3beta,20alpha-dihydroxy-23-oxo-30-nor-olean-12-en-28-oic acid, named acanjaposide C, and nipponoside E, a known saponin, respectively.     

Flavonol and drimane-type sesquiterpene glycosides of Warburgia stuhlmannii leaves

An investigation of methanolic extract of Warburgia stuhlmannii leaves has led to the isolation of two new drimane-type sesquiterpene glycosides characterized as mukaadial 6-O-beta-D-glucopyranoside, mukaadial 6-O-alpha-L-rhamnopyranoside together with two other novel flavonol glycosides identified as 3',5'-O-dimethylmyricetin 3-O-beta-D-2",3"-diacetylglucopyranoside and 3'-O-methylquercetin 3-O-beta-D-2",3",4"-triacetylglucopyranoside. The known compounds; mukaadial, deacetylugandensolide, quercetin, kaempferol, kaempferol 3-O-alpha-L-rhamnopyranoside, quercetin 3-O-beta-D-glucopyranoside, kaempferol 7-O-beta-D-glucopyranoside, myricetin 3-O-alpha-L-rhamnopyranoside, quercetin 3-O-alpha-L-rhamnopyranoside, quercetin 3-O-sophoroside and isorhamnetin 3-O-beta-D-glucopyranoside were also isolated from the same extract.     

药用植物叶片的碳同位素比和矿质元素含量

36种亚热带季雨林中常见的中草药植物叶片的稳定性同位素比(σ~(13)C 值)为-26.4到-32.6‰,灌木型的σ~(13)C 值最低。表明全部种类都属光合作用C_3途径植物。叶片的7种元素 N、P、K、Ca、Mg、Na、Si 的含量依植物种类、生活型、药效和所用药用部位不同而异。在9个具不同药效的组合中,治疗贫血、高血压和健胃药有较多的 N,治疗蛇伤、癌症的药的叶片含较多 P 和 K,治疗风湿骨痛药含较多 Ca 和 Mg。其他微量元素组成中,治疗贫血的药的叶片含 Fe 多,治疗感冒及高血压药者含 Zn 多,健胃药含 Cu 多。结果认为叶片的矿质元素分布图式反映植株自身的吸收积累特性,且对相应的主要疗效可能有附加的效应。     

Phytomass structure of natural plant communities on spodosols in southern Venezuela: the Bana woodland

Bana, or Low Amazon Caatinga is an evergreen sclerophyllous woodland. It occurs on bleached quartz sands in the lowlands of SW Venezuela, where it occupies relatively small ‘islands’ amidst Tall Amazon Caatinga which is exclusively developed on tropaquods. There is an outer vegetation belt about 20 m in width in which trees over 10 m in height occur (Tall Bana); its structure and floristic composition resemble Tall Amazon Caatinga. Low Bana (maximum tree height usually below 5 m) follows next. The central part is occupied by Open Bana in which even lower trees are very widely spaced. Destructive phytomass sampling was carried out for chemical analyses in seven plots along a 150 m line across the zonation. The total dry matter of living plants including roots of Tall Bana (30–32 kg/m²) compares rather well with 41 kg/m² in Tall Amazon Caatinga. This is only 9–14 kg/m² in Low Bana, and 4–6 kg/m² in Open Bana. The average root % of total phytomass increases from 41% in Tall Bana to 63% in Low Bana, and is 88% in Open Bana. Average total dry dead above-ground phytomass (including standing trees and stumps) declines from 1 kg/m² in Tall Bana to 0.2 kg/m² in Open Bana. An accumulation of dead matter in Low and Open Bana, relative to the above-ground phytomass of living plants, is noted and this contrasts with the general absence of raw humus in the soil. Eighty-two species of woody plants (dbh≥1 cm) were recorded on the total plot area (640 m²); 90% of the species are also known to occur in Tall Amazon Caatinga. The species number declines from 59 in Tall Bana to 18 in Open Bana. Mesophylls sensu strictu dominate in Tall Bana, while notophylls are dominant in Low and Open Bana. Herbaceous species are less numerous: most of them belong to the Araceae, Bromeliaceae, Orchidaceae, Droseraceae, Eriocaulaceae and Xyridaceae.     

Cyclic and noncyclic photophosphorylation during the ontogenesis of high-light and low-light leaves of Sinapis alba

Noncyclic electron transport to ferricyanide and photophosphorylation as well as the methylviologen mediated aerobic and anaerobic photophosphorylation with dichlorophenolindophenol-ascorbate as the electron donor of photosystem I were measured during the development of high-light and low-light adapted leaves of Sinapis alba. Anaerobic methylviologen-catalyzed phosphorylation is more than twice as high as aerobic phosphorylation. The difference between the rates of aerobic and anaerobic phosphorylation is sensitive to dibromothymoquinone. Thus, under anaerobic conditions, methylviologen mediates a cyclic phosphorylation including plastoquinone. All photochemical activities of high-light chloroplasts are about twice as high as that of low-light chloroplasts and show a permanent decline with increasing plant age. The lower activities of low-light chloroplasts correlate with a decrease of electron transport components, such as cytochrome f. This indicates that the number of electron transport chains is decreased under low-light conditions and more chlorophyll molecules interact with one electrontransport chain.Abbreviations Asc ascorbate - Chl chlorophyll a+b - DBMIB 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone - DCMU 3-(dichlorophenyl)-1,1-dimethylurea - DCPIP dichlorophenolindophenol - HL high light - LL low light - MV methylviologen - PhAR photosynthetically active radiation - PS photosystem     

The Occurrence of <Emphasis Type="Italic">p</Emphasis>-coumaric Acid and Ferulic Acid in Fossil Plant Materials and their Use as UV-proxy

The applicability of p-coumaric acid and ferulic acid concentrations or ratios in (sub)fossil plant remnant as UV-B proxies relies on various aspects, which are discussed in this paper and will be illustrated with some experimental data. A newly developed THM-micropyrolysis–gas chromatography–mass spectrometry method was tested on various spores, pollen and other plant remains, which were analysed for the presence of the UV-absorbing compounds p-coumaric acid and ferulic acid. This revealed that these supposed building-blocks of sporopollenin appear to be present in pollen of many plant species but also in moss spores. The development of this micropyrolysis method paved the way for the quantitative analysis of UV-absorbing compounds in case only a small amount of analyte is available, for example for fossil pollen and spores but also other small palynomorphs and plant fossils. The use of this technique will provide a better insight in the plant responses to UV-radiation, the chemistry of pollen and spores, their fossil counterparts and furthermore the means for a further development of a proxy for the reconstruction of past UV-B radiation.     

The flavonoids in leaves of diploidTriticum species (Gramineae)

Leaf flavonoids have been identified in seven species ofTriticum, all of which have been considered at one time as putative parents of the cultivated tetraploid and hexaploid wheats. The major constituents are apigenin- and luteolin-based glycosylflavones, some of which contain various O-glycosidic attachments at the 6-position. Four tricin glycosides are present in minor amount, as is free tricin. The flavonoid patterns link togetherT. searsii, T. speltoides andT. squarrosa, on the one hand, andT. monococcum, T. boeoticum, T. thaoudar andT. urartu, on the other. These results indicate that the first three taxa are more likely to be diploid ancestors to the hexaploidT. aestivum than the latter four species.     

Dihydrozeatin riboside,a minor cytokinin from the leaves of Phaseolus vulgaris L.

Dihydrozeatin riboside has been identified in the leaves of decapitated bean plants by Sephadex LH20 chromatography and combined gas chromatography-mass spectrometry. The relationship between the cytokinins isolated and identified from this system and those previously reported in Phaseolus is discussed.Abbreviations DHZ dihydrozeatin - DHZOG dihydrozeatin-O--D-glucoside - DHZR dihydrozeatin riboside - GCMS combined gas chromatography-mass spectrometry - GLC gas-liquid chromatography - TIC total ion current - TMS trimethylsilyl - Z zeatin - ZR zeatin riboside     

Tannin Dynamics of Propagules and Leaves of Kandelia candel and Bruguiera gymnorrhiza in the Jiulong River Estuary, Fujian, China

Changes in the total phenolics, condensed tannins (CT), protein-precipitable phenolics content and protein precipitation capacity were determined on a series of mangrove leaves from two true viviparous mangrove species (Kandelia candel and Bruguiera gymnorrhiza) at various stages of development and decomposition in the Jiulong River Estuary, Fujian, China. Similar measurements were also done for the propagules at different developmental stages. The results showed that the total phenolics, extractable condensed tannins, total condensed tannins, protein-precipitable phenolics content and protein precipitation capacity in young leaves were higher than those in mature and senescent leaves. Tannin dynamics during leaf decomposition varied with species, and the rapid loss of phenolics observed during decomposition can be ascribed to leaching and degradation. Protein-bound CT and fibre-bound CT tended to increase with leaf decomposition, with CT binding more strongly to protein than to fibre. Protein-bound CT was higher than fibre-bound CT with the exception of mature leaves. Total phenolics, extractable CT and protein-precipitable phenolics contents in flower tissues were relatively lower than those in hypocotyls at different developmental stages. Protein precipitation capacity fluctuated with the development of propagules. Increases in nitrogen in decaying litter, and declines in contents of total phenolics and total condensed tannins of detritus support the general conclusion that decomposing mangrove detritus can be a more palatable heterotrophic substrate than living leaves.     

布迪椰子不同器官热值的季节变化研究

对布迪椰子的幼叶、成熟叶、叶柄和根在不同季节的干重热值、去灰分热值和灰分含量进行了研究,结果表明:干重热值四个季节的平均值为成熟叶(20.65kJg-1)>幼叶(19.84kJg-1)>根(19.55kJg-1)>叶柄(18.77kJg-1),秋季的干重热值明显高于其它三个季节的干重热值,冬季的干重热值最低,去灰分热值与干重热值的变化趋势基本相同。灰分含量四个季节的平均值为根(5.14%)>叶柄(4.33%)>幼叶(4.21%)>成熟叶(3.97%)。成熟叶的灰分含量一直维持在比较低的水平,而幼叶的在秋季明显下降,在冬季明显上升,幼叶灰分含量的季节变化趋势与成熟叶的相同,叶柄灰分含量在冬季明显低于根部。布迪椰子这种不同器官在不同季节的热值和灰分的变化规律显示其具有较强的耐寒适应性。