广东山区的兰科植物及其分布

通过野外调查和广泛收集前人的研究资料,概述了广东山区兰科植物的区系组成特点,分布区类型,水平分布,垂直分布,不同基质上分布的特点和分布格局的形成,文末附有广东山区兰科植物名录。     

CARBOHYDRATE PHYSIOLOGY OF ORCHID SEEDLINGS. II. HYDROLYSIS AND EFFECTS OF OLIGOSACCHARIDES

Orchid seedlings were grown on nutrients containing cold-sterilized sugars as sources of carbon. Action by an extra-cellular invertase was implied from the hydrolysis by seedlings of sugars containing α-D-glucopyranosyl-(1 → 2)-β-D-fructofuranoside bonds. D-galactosides (α and β) were also hydrolyzed, indicating the presence of extracellular galactosidases. Hydrolysis of α-D-fructofuranosides and α-D-galactosides decreased with increasing molecular weight. Seedling damage and growth retardation were paralleled by galactose accumulation in the substrate. Rupture of tonoplast and evagination of the nuclear envelope suggests that this sugar may alter some factor(s) responsible for the maintenance of membrane permeability.     

AN ORCHID SURVEY IN CONGO

Summary. An orchid survey to the Mayombe forest region of the Congo Republic is described; 100 orchid collections were made, mostly epiphytes and representing at least 22 genera, many of them new records for the area.