The potential importance of CO2 derived from host tree respiration at night as a substrate for night time CO2 uptake during CAM was investigated in the subtropical and tropical epiphytic vine Hoya carnosa in a subtropical rainforest in north-eastern Taiwan. Individuals were examined within the canopies of host trees in open, exposed situations, as well as in dense forests. Although night time CO2 concentrations were higher near the epiphytic vines at night, relative to those measured during the day, presumably the result of CO2 added to the canopy air by the host tree, no evidence for substantial use of this CO2 was found. In particular, stable carbon isotope ratios of H. carnosa were not substantially lower than those of many other CAM plants, as would be expected if host-respired CO2 were an important source of CO2 for these CAM epiphytes. Furthermore, laboratory measurements of diel CO2 exchange revealed a substantial contribution of daytime CO2 uptake in these vines, which should also result in lower carbon isotope values than those characteristic of a CAM plant lacking daytime CO2 uptake. Overall, we found that host-respired CO2 does not contribute substantially to the carbon budget of this epiphytic CAM plant. This finding does not support the hypothesis that CAM may have evolved in tropical epiphytes in response to diel changes in the CO2 concentrations within the host tree canopy. and C.-C. Hsu ... [et al.].
The paper summarises basic properties of orthogonal polynomials and their use for approximation of functions representing a surface shape of optical components. The approximation of least-squares is demonstrated including its properties, and a strategy of a generation of orthogonal polynomials on a selected region is shown as well. The second part of the paper deals with mathematical description of aspherical optical surfaces. and Práce shrnuje základní vlastnosti ortogonálních polynomů a jejich využití pro aproximaci funkcí, které vyjadřují tvar ploch v rámci optické praxe. Aproximace funkce je představena ve smyslu nejmenších čtverců, jsou určeny její vlastnosti a možnost generace ortogonálních polynomů na libovolné oblasti. V druhé polovině práce jsou shrnuty možnosti matematického vyjádření asférických ploch v optice.