Ultrastructural Study of Yam Tuber as Related to Postharvest Hardness

Usually, parenchyma cell walls of monocotyledons do not develop secondary walls; however a few days after harvesting, the yam tuber of Dioscorea dumetorum starts to harden. Two or three weeks Iater, hardness is so pronounced that the tubers cannot be eaten, even after a long cooking time. Cytochemical studies using autofluorescence or some fluorescent dyes, such as phloroglucinol hydrochloride showed that the thin, and flexible cell walls of parenchyma tubers very quickly became fully lignified after harvesting. Ultrastructura 1 stud ies of the hardened ce 11 wa 11 s showed very thick secondary wa 11 s and very deep pit apertures. These secondary walls reacted strong ly with li gn in reactants such as potassium permanganate. The use of a radioactive (l \u27• C) ce llulose precursor, uri dine- 5\u27-d ipho sphateglucose, confirmed the formation of such secondary walls. The lignification started from the corners of the cells around intercellular spaces and proceeded along the walls

La production biologique de porcs en Europe - Gestion de la santé des porcs dans les élevages de production

Les éleveurs de porcs biologiques ont développé en Europe différents systèmes de logement qui dépendent de la disponibilité des terres, des caractéristiques du sol et du climat, des traditions et des schémas de certification. Ce guide décrit les principaux systèmes de logement des porcs biologiques. Il compare les avantages et les inconvénients de chacun et donne des recommandations aux éleveurs pour mieux agir sur la santé des animaux

IEEE European Solid-State Circuits Conference (ESSCIRC)

International audienc

The pectic polysaccharide rhamnogalacturonan II is a major component of the polysaccharides present in fruit-derived products

International audienc