Impact of drought and leaf development stage on enzymatic antioxidant system of twoPopulus deltoides×nigraclones

Abstract

-Impacts of mild and severe water constraints were investigated on leaf protein content and activities of superoxide dismutase (SOD), catalase and peroxidase in young cuttings of two Populus deltoides × nigra clones, 'Luisa_Avanzo' and 'Dorskamp', known to differ in their level of drought tolerance. Expanding and mature leaves were analyzed separately. The effect of water deficit on enzymatic antioxidant system depended on both clone and leaf development stage. For 'Dorskamp', which presents an higher drought tolerance than 'Luisa_Avanzo', activities of SOD and catalase increased in response to the severe water deficit in mature leaves only. For 'Luisa_Avanzo', peroxidase activity increased in response to the mild water deficit in expanding leaves merely. For both clones, three different SOD isoforms, Mn-SOD, Fe-SOD and Cu/Zn-SOD were detected in various amounts depending on drought intensity.water deficit / leaf development stage / catalase / superoxide dismutase / peroxidase Résumé -Impact de la sécheresse et du stade de développement des feuilles sur les systèmes antioxydants enzymatiques de deux clones de Populus deltoides × nigra. L'impact de sécheresses modérée et sévère sur le contenu en protéines des feuilles et sur les activités de la dismutase de superoxyde (SOD), de la catalase et de la peroxydase a été étudié chez de jeunes boutures de deux clones de Populus deltoides × nigra, 'Luisa_Avanzo' et 'Dorskamp', connus pour présenter des niveaux différents de tolérance au déficit hydrique. Les feuilles en croissance et matures ont été analysées séparément. La réponse à la sécheresse des systèmes de protection enzymatiques était différente selon le clone et le stade de développement des feuilles étudiées. Pour le clone 'Dorskamp', réputé plus tolérant que 'Luisa_Avanzo' à la sécheresse, les activités de la SOD et de la catalase augmentaient dans les feuilles matures en réponse à un déficit hydrique sévère. Pour le clone 'Luisa_Avanzo', l'activité de la peroxydase augmentait essentiellement dans les feuilles en croissance en réponse à une sécheresse modérée. Pour les deux clones, trois isoformes différentes de la SOD, la Mn-SOD, la Fe-SOD et la Cu/Zn-SOD ont été détectées en quantités variables chez les deux clones en fonction de l'intensité de la contrainte hydrique. déficit hydrique / stade de développement foliaire / catalase / dismutase de superoxyde / peroxydase

Stress hardening under long-term cadmium treatment is correlated with the activation of antioxidative defence and iron acquisition of chloroplasts in Populus

“…The rise in the activity of APX was observed in parallel to the decline of lipid peroxidation and the increase of Φ PSII . The separated SOD isoforms can be identified as I: MnSOD, II: Cu/ZnSOD, III: FeSOD and IV: Cu/ZnSOD [48][49][50]. As, in contrast to the MnSOD that is present in peroxisomes, mitochondria and cell wall [51], the activities of chloroplast Cu/ZnSOD isoforms (II and IV) did not increase during the experiment, their role in Cd stress alleviation may be less important in poplar.…”

Populus cathayana males exhibit more efficient protective mechanisms than females under drought stress

“…Especially a decreased photosynthetic rate is a common phenomenon in poplars under drought stress (Yin et al, 2005;Xu et al, 2008aXu et al, , 2009. Drought also causes an accumulation of reactive oxygen species (ROS) and, subsequently, induces oxidative stress on plant cells (Lei et al, 2006;Marron et al, 2006;Xiao et al, 2009). To reduce the negative consequences, trees have evolved various protective mechanisms.…”

Antioxidant system is insufficient to prevent cell damages in Euterpe oleracea exposed to water deficit

“…This enzyme is involved in antioxidant protection and maintenance of membrane integrity (Carvalho et al, 2012). Marron et al (2006) showed an increase in CAT activity in leaves of Populus deltoides clones. Slight peaks in the APX enzyme were observed with a subsequent decrease in its activity in both tissues.…”