ISSN:
1432-2285
Keywords:
Betula
;
Birch
;
Phenolics
;
Triterpenes
;
Deterrents
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Defence-related epithelial structures of juvenile stems and their phytochemistry were compared between six woody species of Betula from different geographical areas. The shoots of B. pendula, B. papyrifera, B. platypylla and B. ermanii are covered by resin droplets secreted by multicellular peltate glands. The seedlings of B. papyrifera and B. pubescens are covered with long epithelial hairs. Closer topical examination also revealed smaller glands on B. papyrifera and B. pubescens. The glands of B. ermanii are oval while the other species have a round shape. Phenol-specific histochemical staining indicated phenolic compounds in the cells in active glands of the resinous birches, but not in those of the pubescent birches. The epithelial hairs were strongly positive to the phenol stain. Analysis of the triterpenoids (3α- and 3β-papyriferic acid and pendulic acid) and a phenolic (platyphylloside) deterrent indicated that the morphological differences are accompanied by chemical ones. Pendulic acid was the main triterpene in B. ermanii instead of the 3α-papyriferic acid of the other resinous species. Concentrations of the triterpenes ranged from about 0.3 to 12 mg/g, while the platyphylloside level was around 0.5 mg/g in all of them. Some triterpenes were also detected in B. papyrifera, but none in B. pubescens. The former contained only about 0.05 mg/g of platyphylloside, but B. pubescens contained 4 mg/g of this compound.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00196627
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