Love, D. | bioRxiv Science

bioRxiv2021

The 3D construction of leaves is coordinated with water use efficiency in conifers

O_LIConifers prevail in the canopies of many terrestrial biomes, holding a great ecological and economic importance globally. Current increases in temperature and aridity are imposing high transpirational demands and resulting in conifer mortality. Therefore, identifying leaf structural determinants of water use efficiency is essential in predicting physiological impacts due to environmental variation. C_LIO_LIUsing synchrotron-generated microCT imaging, we extracted leaf volumetric anatomy and stomatal traits in 34 species across conifers with a special focus on Pinus, the richest conifer genus. C_LIO_LIWe show that intrinsic water use efficiency (WUEi) is positively driven by leaf vein volume. Needle-like leaves of Pinus, as opposed to flat leaves or flattened needles of other genera, showed lower mesophyll porosity, decreasing the relative mesophyll volume. This led to increased ratios of stomatal pore number per mesophyll or intercellular airspace volume, which emerged as powerful explanatory variables, predicting both stomatal conductance and WUEi. C_LIO_LIOur results clarify how the three-dimensional organization of tissues within the leaf has a direct impact on plant water use and carbon uptake. By identifying a suit of structural traits that influence important physiological functions, our findings can help to understand how conifers may respond to the pressures exerted by climate change. C_LI

plant biology↗

bioRxiv2019

Microbial Food Safety in the Maryland Direct-to-Consumer Poultry Supply Chain

Direct-to-consumer food marketing is a growing niche in the United States food supply chain. Food animal producers who use direct marketing may employ different production models and standard practices from producers selling animal products to the conventional food system. Direct-to-consumer food supply chains (generally and specifically regarding food animal products) are relatively unexplored in food safety and health research. We conducted a cross-sectional, market-basket analysis of the Maryland direct-to-consumer poultry supply chain to assess food safety. We analyzed 40 direct-to-consumer commercial poultry meat products (one product per farm) for Escherichia coli, Staphylococcus aureus and Salmonella spp. using culture-based methods. Isolates underwent antimicrobial susceptibility testing. E. coli and S. aureus were recovered from 9/40 (23%) and 12/40 (30%) of poultry meat samples, respectively. Of interest for comparing direct-market and mainstream supply chains for food safety risks, no Salmonella isolates were recovered from any direct-market sampled poultry products and no multidrug resistance was observed in E. coli and S. aureus isolates. Microbial outcomes were compared to a survey of poultry production and processing practices within the same study population.\n\nImportanceThis study demonstrates substantially lower rates of antimicrobial-resistant (AMR) microbial pathogens in the market-basket products from Maryland direct-market broiler poultry supply chain compared to rates of AMR in the conventional supply chain for similar retail meat products from NARMS. We further describe the landscape of the statewide supply chain for direct-market poultry, focusing on characteristics related to risk management strategies applied to microbial food safety. These findings are of public health significance for both the research and policy communities; these data provide an initial evidence base for more targeted research evaluating potential risk factors for microbial food safety in the direct-to-consumer supply chain. These data will also assist the Maryland Department of Agriculture and other state-level agencies with oversight of food safety issues to guide policy efforts for direct-market poultry production and sales.

microbiology↗