Rahoui Sondès, Martinez Yves, Sakouhi Lamia, Ben Cécile, Rickauer Martina, El Ferjani Ezzeddine, Gentzbittel Laurent, Chaoui Abdelilah
Laboratoire de Toxicologie Végétale et Biologie Moléculaire des Microorganismes, Faculté des Sciences de Bizerte, Université de Carthage, 7021, Jarzouna, Tunisia.
INP, UPS, Ecolab (Ecologie Fonctionnelle et Environnement), ENSAT, Université de Toulouse, 18, Chemin de Borde Rouge, 31326, Castanet-Tolosan, France.
Protoplasma. 2017 Jan;254(1):473-489. doi: 10.1007/s00709-016-0968-9. Epub 2016 Apr 7.
Defense pathways and stress responses induced under Cd stress were illustrated in roots of hydroponically grown Medicago truncatula seedlings. Actually, the ascorbate-glutathione and antioxidative system, secondary metabolism events including peroxidases, phenolic compounds, and lignification launching, and developmental modifications were described. Cd (100 μM) initially increased reactive oxygen species, enhanced antioxidative (total SOD, CAT, and PRX) and ascorbate-glutathione-related metabolism enzymes (APX and MDAR), except in A17 and TN1.11. In agreement with peroxidase enhancement, physiological measurement and in situ observation illustrated soluble phenolic compound accumulation under Cd treatment. However, lignification was restricted to recently created protoxylem elements established in the root tip area, usually constituting the elongation zone. Cell death was increased. In the absence of necrotic reactions, developmental changes including lignin deposition, increase in cellulose and pectin contents, intercellular meatus, and condensed and deformed hairs were noticed in Cd-treated roots.
水培生长的蒺藜苜蓿幼苗根系中展示了镉胁迫下诱导的防御途径和应激反应。实际上，描述了抗坏血酸-谷胱甘肽和抗氧化系统、包括过氧化物酶、酚类化合物和木质化启动在内的次生代谢事件，以及发育变化。镉（100 μM）最初增加了活性氧，增强了抗氧化（总超氧化物歧化酶、过氧化氢酶和过氧化物酶）和抗坏血酸-谷胱甘肽相关代谢酶（抗坏血酸过氧化物酶和苹果酸脱氢酶），但A17和TN1.11除外。与过氧化物酶增强一致，生理测量和原位观察表明镉处理下可溶性酚类化合物积累。然而，木质化仅限于根尖区域新形成的原生木质部元素，通常构成伸长区。细胞死亡增加。在没有坏死反应的情况下，在镉处理的根系中观察到包括木质素沉积、纤维素和果胶含量增加、细胞间隙以及浓密和变形的毛状体在内的发育变化。
