Assessing the impact of elevated O3 and CO2 on gas exchange characteristics of differently K supplied clonal Norway spruce trees during exposure and the following season

Autor: Hans-Dieter Payer, Thomas Pfirrmann, Michael Lippert, Karl Steiner
Rok vydání: 1997
Předmět:
Zdroj: Trees. 11:306-315
ISSN: 1432-2285
0931-1890
Popis: Well-supplied and K-deficient 4-year-old clonal Norway spruce trees were exposed to combinations of two levels of ozone (20 and 80 nl l – 1 O3) and carbon dioxide (350 and 750 μl l – 1 CO2) to study the effects of possible future climate factors on gas exchange characteristics. The fumigation was performed in environmental chambers for a complete growing season. After the exposure, plants were cultivated outdoors to investigate possible recovery and delayed effects. During the exposure 1-year-old needles responded to the 80 nl l – 1 O3 treatment by a sharp but transient decrease of both apparent carboxylation efficiency (CE) and maximum photosynthetic capacity (A2500). Elevated CO2 also reduced CE and A2500. The effect became stronger in the course of the exposure and was accompanied by decreases of N and P as well as chlorophyll contents. In case of K deficiency, the acclimation response of current-year needles was even more pronounced reflecting lower sink capacities for carbon metabolites. The joint application of elevated O3 and CO2 resulted in the lowest values of gas exchange parameters and chlorophyll contents. At the beginning of the growing season after the exposure and under outdoor conditions, all these treatment effects disappeared in the needles which had developed during the fumigation. In the course of the development of the new flush, however, the well-supplied 1-year-old needles which had been treated with 80 nl l – 1 O3 and 350 μl l – 1 CO2 in the year before, exhibited a sharp decline of CE and A2500. Simultaneously, chlorotic mottle and bands developed. These delayed symptoms are discussed in the context of the previously published “memory” effect for O3 (Sandermann et al. 1989). Additionally, evidence is presented that shoot development is altered in plants which had been exposed to elevated O3.
Databáze: OpenAIRE
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