Leaf anatomy and eco-physiology of Elymus repens, a temperate loess grassland species, were determined after seven years of exposure to 700 μmol (CO2) mol-1 (EC). EC treatment resulted in significant reduction of stomatal density on both surfaces of couch-grass leaves. Thickness of leaves and that of the sclerenchyma tissues between the vessels and the adaxial surfaces, the area of vascular bundle, and the volumes of phloem and tracheary increased at EC while abaxial epidermis and the sclerenchyma layer between the vessel and the abaxial surface were thicker at ambient CO2 concentration (AC). Stomatal conductance and transpiration rates were lower in EC, while net CO2 assimilation rate considerably increased at EC exposure. Contents of soluble sugars and starch were higher in EC-treated couch-grass leaves than in plants grown at AC. and A. I. Engloner ... [et al.].
The effects of parasitisation by Aphidius ervi on the feeding behaviour of the aphid Acyrthosiphon pisum were studied. There was progressive increase in the time devoted to xylem ingestion (G waveform) and concomitant decrease in time devoted to phloem ingestion (E2 waveform) in parasitized relative to unparasitized aphids, as the time from parasitisation increased. These changes are interpreted as a way aphids compensate for metabolic changes occurring during parasitisation.