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Atmospheric carbon dioxide (CO2) concentration has continuously increased since pre-industrial times and has currently reached an average growth rate of 2.3 ppm per year. For the majority of plant species elevated CO2 (eCO2) improves photosynthesis and thus plant biomass production. To investigate the effects of eCO2 on leaf physiology and morphological leaf characteristics two Vitis vinifera L. cultivars, Riesling and Cabernet Sauvignon, grown in the VineyardFACE (Free Air Carbon dioxide Enrichment) system were used. The VineyardFACE is located at Geisenheim, Rheingau comparing future atmospheric CO2-concentrations (eCO2, predicted for the mid-21st century) with current ambient CO2-conditions (aCO2). Experiments were operated under rain-fed conditions for two consecutive years (2015 and 2016). For both varieties and CO2 treatments, leaf gas exchange measurements were performed as well as measures of epidermal flavonoid (Flav) and leaf chlorophyll (Chl) indices by using a portable leaf clip. Furthermore, leaves were sampled for spectrophotometric analysis of the leaf pigments chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoid (Car). Additionally, leaf cross-sections were produced as permanent preparations to investigate morphological characteristics of the leaf structure. Both cultivars did not differ in leaf chlorophyll meter readings or leaf pigments between the two CO2 treatments while net assimilation was highly stimulated under elevated CO2 for both seasons. Differences found in leaf cross-sections were detected in palisade parenchyma and epidermal thickness of Cabernet Sauvignon under eCO2, whereas Riesling net assimilation increased by 40% under a 20% CO2 enrichment while remaining unaffected in different leaf layer thickness. The observed results within grapevine leaf tissues provide insights to seasonal adaptation strategies of grapevines under elevated CO2 concentrations predicted in future.

In this paper, large partially connected wireless relay interference networks are considered. The entire network is made up of multiple disjoint groups of source-destination node pairs and relays called subnetworks. Each subnetwork is assumed to be fully connected. The different subnetworks are mutually connected by a few inter-subnetwork links. A two-hop relay-aided interference alignment scheme is applied to achieve interferencefree communication in the whole network. The feasibility conditions for interference alignment in the considered networks are investigated. To this end, we extend the concept of external constraints, which was proposed in [1] for the two-subnetwork case, and characterize the proper relay antenna configurations in large networks with an arbitrary number of subnetworks.

In this paper, a network consisting of several partially connected subnetworks where each subnetwork includes one relay is considered. "Partially connected" means that not all nodes are connected to all relays. Some nodes may be connected to multiple relays. The entire bidirectional pairwise communication between the nodes takes place via the intermediate half-duplex amplify-and-forward relays, considering two-way relaying. The algorithm proposed in this paper is a closed-form solution which requires only local channel state information (CSI) to achieve interference alignment. The properness condition for the proposed algorithm is derived. The process of interference alignment is decomposed into signal alignment, channel alignment and transceive zero forcing. It is shown that all subnetworks can be investigated separately. This means the whole problem can be divided into sub-problems. The simulation results show that the degrees of freedom increase for the considered partially connected network in comparison with the fully connected version of the considered network.

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