Betula spp

In addition to triterpenoids in the bark of Betula spp., suberin (a biopolyester comprising primarily hydroxy, epoxy and dicarboxylic acids) is also present, as... 

Palo, R. T. (1984). Distribution of birch Betula spp.), willow [Salix spp.) and poplar Popu-lus spp.) secondaiy metabolites and their potential role as chemical defense against herbivores. Journal of ChemicalEcobgy 10,499-520. 

Acer nikoense (Aceraceae), Betula spp. (Betulaceae), Rhododendron chrysanthum, R.fauriae, R.ferrugieum, R. ponticum (Ericaceae)... 

Last, F. T., Pelham, J., Mason, P. A. Ingleby, K. (1979). Influence of leaves on sporophore production by fungi forming sheathing mycorrhizas with Betula spp. Nature,... 

A plant-derived compound with a long history is the lupane-type triterpene, betulinic acid (53), which has been isolated from many taxonomically diverse plant genera. " A major source is the birch tree, Betula spp., which is also a primary source of its C-28 alcohol precursor, betulin, the isolation of which was first reported in 1788. 

Pinus sylvestris Pinus sylvestris Pinus sylvestris Pinus sylvestris Pinus sylvestris Pseudotsuga menziesii Taxus baccata Hardwoods Alnus rubra Betula odorata Betula spp. 

Betula odorata Betula spp. Bischofia polycarpa Fagus spp. 

Birch (bark, leaves) Betula spp 1,3 Methyl salicylate (see p 331), irritant oils causing Gl upset... 

Birch-celery syndrome has been described, with individuals sensitized to birch (Betula spp.) pollen or mugwort Artemisia vulgaris) pollen frequently displaying type I allergic symptoms after ingestion of celery (Breiteneder et al. 1995 Luttkopf et al. 2000). 

As the relative proportions of the woody components vary only within narrow ranges for common commercial species, the EMCs at a given relative humidity and temperature are closely similar for these woods. However, at high relative humidities deviations from mean values can appear. Shubin s data (1990) show, for instance, that at 95% relative humidity the EMC at 42.4°C ranges from 22% for a pine to 33% for an oak. Hoadley (1980) notes that in species with a high extractives content, such as redwood (Sequoia sempervirens) and mahogany (Swietenia mahogani), the fibers remain saturated at 22%-24% moisture content, whereas birch (Betula spp.) may have a moisture content up to 35% at fiber saturation. 

Himanen SJ, Blande JD, Klemola T, Pulkkinen J, Heijari J, Holopainen JK (2010) Birch Betula spp.) leaves adsorb and re-release volatiles specific to neighbouring plants -a mechanism Iot associational herbivore resistance New Phytol 186 722-732... 

A chemometric approach where the /ty-values of forty-seven flavonoids in seven TLC systems were studied using principal component and cluster analyses, has made it possible to choose the minimum number of chromatographic systems needed to perform the best separation (20). Another method (the PRISMA model) based on Snyder s solvent selectivity triangle has been described to aid mobile phase optimization (21). This model is reported to give good separation of flavonol glycosides from Betula spp. (1). When tested in our laboratory no improvements were obtained in comparison with established systems (22) such as the solvent ethyl acetate-formic acid-acetic acid-water (100 11 11 27) on silica support, which can be used for separation of a wide range of flavonoids. 

The separation of flavonoid glucosides in Betula spp. with fluorescence quenching as the detection mode is shown in Fig. 4. 

Figure 4 Separation of flavonol glycosides from Betula spp. Solvent system ethyl acetate-formic acid-acetic-water (100 11 11 27). Stationary phase silica gel 60 F254 (0.25 mm, Merck). Developing distance 8.5 cm. Detection absorbance at 254 nm (fluorescence quenching in reflection mode). Peak identities (1) quercetin-3-O-ara(f) (2) quercetin-3-(7-rha (3) quercetin-3-0-ara(p) (4) quercetin-3-O-gal (5) myricetin-3-O-gal (tentative).

D-Galactose has been found in Siberian larch Larix sibirica) wood (28), the spring sap of birches Betula spp.) (103, 149), the xylem of Scots pine Pinus sylvestris) (27), and red beech Fagus sylvatica) sap (150). D-Mannose has been found in saps (149, 150). Both may be more widespread than indicated. 

The xylem ray cells of the sugar maple (Acer saccharum) contain -10% starch (172). In birch (Betula spp.) stored starch is converted into sucrose when the ambient temperature drops to - 5 °C (50), perhaps to provide cryoprotection. 

Chars Bark chars (such as from Betula spp., Swedish black , and Quercus suberioccidentalis spp., cork black ), fruitstone chars, paper chars, wood chars (such as from Vitis spp., Vine black , etndFagus spp., beech black ). 

According to the Colour Index (1971 Cl 77268/Pigment Black 8), this is a carbon char made from birch bark (Betula spp.). 

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