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Josef Musil 《Environmental monitoring and assessment》1995,34(2):137-140
There are some special problems in Central and Eastern European countries connected with environmental assessment, which is a prerequisite for reasonable environmental care. Individual steps of solution of environmental problems are briefly discussed and relevant difficulties are stressed. A new schema is suggested for quality assurance and validity systems of primary data generation and evaluation.The challenge is not so much to discover what must be done to ensure sustainability. The challenge is to discover how to do it.Robert Repetto 相似文献
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The winter ephemeral Dimorphotheca pluvialis was grown in open-top chambers in ambient or elevated CO2 (350 or 650 micromol mol(-1)), combined with ambient (2.39 to 7.59 kJ m(-2) d(-1)) or increased (4.94 to 11.13 kJ m(-2) d(-1)) UV-B radiation. Net CO2 assimilation rate and leaf water use efficiency increased in elevated CO2, but increased UV-B did not affect gas exchange. Leaf biomass was greater under increased UV-B, but vegetative biomass was unaffected in elevated CO2. Initiation of reproduction was delayed, and proportional investment in reproductive biomass at harvest was reduced in elevated CO2. Increased UV-B stimulated reproduction, particularly in ambient CO2, but also in elevated CO2 at a later stage. Changes in reproductive phenology and prolonged development in elevated CO2 during the stressful late season could indirectly be detrimental to reproductive success of D. pluvialis, but stimulation of reproduction by enhanced UV-B may to some extent mitigate this. 相似文献
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