We investigated the individual and combined effects of elevated CO2 concentration and fertilization on aboveground growth of three poplar species (Populus alba L. Clone 2AS-11, P. nigra L. Clone Jean Pourtet and P. x euramericana Clone I-214) growing in a short-rotation coppice culture for two growing seasons after coppicing. Free-air carbon dioxide enrichment (FACE) stimulated the number of shoots per stool, leaf area index measured with a fish-eye-type plant canopy analyzer (LAIoptical), and annual leaf production, but did not affect dominant shoot height or canopy productivity index. Comparison of LAIoptical with LAI estimates from litter collections and from allometric relationships showed considerable differences. The increase in biomass in response to FACE was caused by an initial stimulation of absolute and relative growth rates, which disappeared after the first growing season following coppicing. An ontogenetic decline in growth in the FACE treatment, together with strong competition inside the dense plantation, may have caused this decrease. Fertilization did not influence aboveground growth, although some FACE responses were more pronounced in fertilized trees. A species effect was observed for most parameters.
The volume of ecofriendly salicylate internal donors for propylene polymerization has an important impact on the catalyst active centers and microstructure of polypropylene.
An enantioselective synthesis of (-)-(α)-kainic acid in 15 steps with an overall yield of 24% is reported. The pyrrolidine kainoid precursor with the required C2/C3 trans stereochemistry was prepared with complete diastereoselectivity via an unprecedented SmI2-catalyzed intramolecular [3 + 2] cycloaddition reaction of an aryl cyclopropyl ketone and an alkyne. Double bond isomerization was then employed to set the remaining stereochemistry at the C4 position en route to (-)-(α)-kainic acid.
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