Ecophysiological responses of Araucaria angustifoliaseedlings to different irradiance levels.

摘要: Brazilian pine (Araucaria angustifolia [Bert.] O.Ktze.) is an indigenous conifer of the southern region South America, typically regarded as a sun-loving species. However, there insufficient information on species’ behaviour under different irradiances to characterise its plasticity light. The purpose this work was measure some ecophysiological responses seedlings three irradiance levels: 100, 45 and 10% full sunlight. Thirty were grown each treatments and, after 5 months, growth parameters, leaf chlorophyll concentration in vivo nitrate reductase activity, both leaves roots, analysed. There no increase shoot biomass allocation response shading, contrast results from other experiments. Only low-light showed significant specific area, well ratio height biomass. Chlorophyll content b did not vary among treatments. Nitrate activity detected only roots reduced treatment. An overall analysis points normal at high- medium-light sites, least their initial stages development.