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Embryo development in Arabidopsis (Arabidopsis thaliana) starts off with an asymmetric division of the zygote to generate the precursors of the embryo proper and the supporting extraembryonic suspensor. The suspensor degenerates as the development of the embryo proper proceeds beyond the heart stage. Until the globular stage, the suspensor maintains embryonic potential and can form embryos in the absence of the developing embryo proper. We report a mutant called meerling-1 (mrl-1), which shows a high penetrance of suspensor-derived polyembryony due to delayed development of the embryo proper. Eventually, embryos from both apical and suspensor lineages successfully develop into normal plants and complete their life cycle. We identified the causal mutation as a genomic rearrangement altering the promoter of the Arabidopsis U3 SMALL NUCLEOLAR RNA-ASSOCIATED PROTEIN 18 (UTP18) homolog that encodes a nucleolar-localized WD40-repeat protein involved in processing 18S preribosomal RNA. Accordingly, root-specific knockout of UTP18 caused growth arrest and accumulation of unprocessed 18S pre-rRNA. We generated the mrl-2 loss-of-function mutant and observed asynchronous megagametophyte development causing embryo sac abortion. Together, our results indicate that promoter rearrangement decreased UTP18 protein abundance during early stage embryo proper development, triggering suspensor-derived embryogenesis. Our data support the existence of noncell autonomous signaling from the embryo proper to prevent direct reprogramming of the suspensor toward embryonic fate.

lndirect land use change (iLUC) is considered an important risk of the increasing demand for biomass and bioenergy. Certification of biobased products is discussed as a way to reduce this risk. However, the extension of certification schemes towards a credible and reliable certification approach that takes iLUC into account is still an open question. The work presented here aims to develop an integrated assessment framework for low iLUC risk certification based on (1) a review of additionality practices, (2) a comparison of existing certification instruments with trade-offs that might arise from the use of additionality practices, and (:3) the development of a decision support tool for trade-off assessment methods. So far, the study tias identified five potential additionality practices and twenty trade-offs that are addressed differently by the certification schemes under study. The next step is to develop a knowledge base for dec:ision making on assessment methods for tradeoffs.

The scanning behavior of people with a Visual Field Defect (VFD) is still relatively unexplored, although a VFD can have great impact on the person concerned with it. This study examined the scanning behavior of people with a VFD in a mobility situation by the means of an Eye-Tracker. Participants were asked to watch a video of everyday mobility situations, showing both walking and biking sequences from first person perspective. They were asked to imagine being that person in the video and look around naturally. In the video, 33 objects were defined as regions of interest (ROIs), as they are important to detect in order to walk or bike safely. The Eye-Tracker recorded when and where the participants looked. It was expected, that people with a visual field defect (VIPs) need more time to fixate on relevant ROIs for the first time, detect less ROIs in total, do not look at them as long as sighted people do and fixate more often on the ROIs. The results confirmed that VIPs detect less ROIs and spend less time looking at them. Contrary to what was expected, the results also showed that sighted people fixate more on the ROIs than VIPs. An additional analysis showed that the time until an ROI is first looked at, is significantly shorter for sighted people. These findings showed that there are indeed differences in scanning behavior and they could be used to help VIPs counterbalance their decreased visual field.