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Flooding is characterized by saturation of soil pores with water, leading to hypoxic conditions which affect plant root development and metabolism. We investigated the oxygen deficiency tolerance observed in Quercus robur and Quercus petraea and seek to understand whether it can be explained by enhanced efficiency in oxygen use in the roots, as estimated through radial oxygen loss visualization in relation to growth measurements and root apex respiration. The study showed that root growth, under oxygen deficiency conditions, was significantly reduced only in Q. robur seedlings. Root respiration was maintained in Q. robur, whereas it was decreased in Q. petraea. Both species set up a barrier against radial oxygen loss, though measurement of apex oxygen leakage showed greater oxygen efficiency in Q. robur seedlings. This strategy might allow Q. robur to maintain its respiration and thus to survive longer under oxygen deficiency conditions by facilitating the seedling establishment in transient flooded soils.

Chapter 12; International audience; Chemical contamination of fresh produce through pesticide spraying is considered a minor risk for consumer health. As a result, significant responsibility in food safety may be shifted to the private sector by public agencies. The involvement of the private sector is even greater when fresh produce is sold to safety-conscious consumers, given the high exposure of retailers' commercial reputation. This chapter focuses on public and private management of food safety risks, and the determinants thereof in the fresh produce industry of two contrasting Mediterranean countries: Morocco and Turkey. Based on expert surveys and face-to-face interviews with a large number of tomato growers, it provides insight into how and why different players are managing and controlling safety risks. A clear distinction is made between firm-scale factors at growing and shipping levels and country-wide factors, especially recent developments in markets and regulatory institutions. Both significantly influence the level of safety management in greenhouses, the adoption of good agricultural practices and integrated pest management. All factors should be taken into consideration simultaneously to understand the respective contributions of public and private operators in the safety risk management of the fresh produce chain.

International audience; Fresh produce growers are the main source of food contamination by chemical pesticides. In their choice of farming practices, producers are influenced by market forces as well as public and private safety regulations – or “macro-drivers” – as opposed to farm-level micro-drivers. Growers respond to their business and regulatory environment by implementing integrated pest management (IPM) and other good agricultural practices (GAP), where profitable through certification schemes. Our paper attempts to analyse the adoption of sustainable farming practices beyond farm and farmer characteristics, focusing on the role of structural and institutional macro-drivers. The empirical research is based on the comparison between Turkey and Morocco, two Mediterranean countries with high export activity in the fresh tomato sector but with contrasting features in terms of both sustainable farming practices and micro/macro-drivers. With regard to the latter, we simultaneously consider supply-side and demand-side aspects (i.e. the requirements of buyers in importing countries). The analysis draws on the literature examining both IPM/GAP adoption and the impact of food safety regulation on firms’ strategies. We call on face-to-face interviews with a relatively large number of tomato growers in the main production areas (N = 86 in Morocco and N = 186 in Turkey). Our findings show that the average level of sustainable practices is greatly affected by national market and institutional particularities, in particular on the demand side. Moreover the surveys confirm the initial assumption of the major role played by private actors in managing safety risk when there are high business stakes, as in export chains oriented towards rich Western countries.