Munné-Bosch Sergi
Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, E-08028 Barcelona, Spain.
Vitam Horm. 2007;76:375-92. doi: 10.1016/S0083-6729(07)76014-4.
alpha-Tocopherol, which belongs to the vitamin E group of compounds, is a lipophilic antioxidant that has a number of functions in plants. Synthesized from homogentisic acid and isopentenyl diphosphate in the chloroplast envelope, alpha-tocopherol is essential to maintain the integrity of photosynthetic membranes and plays a major role in photo- and antioxidant protection. alpha-Tocopherol scavenges lipid peroxy radicals, thereby preventing the propagation of lipid peroxidation, and protects lipids and other membrane components by physically quenching and reacting chemically with singlet oxygen. Moreover, given that alpha-tocopherol increases membrane rigidity, its concentration, together with that of the other membrane components, may be regulated to afford adequate fluidity for membrane function. Furthermore, recent studies on tocopherol-deficient plants indicate that alpha-tocopherol may affect cellular signaling in plants. Evidence thus far indicates that the effects of this compound in plant cellular signaling may be linked to the control of redox homeostasis. alpha-Tocopherol may influence cellular signaling by controlling the propagation of lipid peroxidation in chloroplasts, therefore modulating the formation of oxylipins such as the phytohormone jasmonic acid.
α-生育酚属于维生素E类化合物，是一种亲脂性抗氧化剂，在植物中具有多种功能。α-生育酚在叶绿体包膜中由尿黑酸和异戊烯基二磷酸合成，对于维持光合膜的完整性至关重要，并且在光保护和抗氧化保护中发挥主要作用。α-生育酚清除脂质过氧自由基，从而防止脂质过氧化的传播，并通过物理猝灭单线态氧以及与单线态氧发生化学反应来保护脂质和其他膜成分。此外，鉴于α-生育酚会增加膜的刚性，其浓度以及其他膜成分的浓度可能会受到调节，以便为膜功能提供足够的流动性。此外，最近对生育酚缺乏植物的研究表明，α-生育酚可能会影响植物中的细胞信号传导。迄今为止的证据表明，这种化合物在植物细胞信号传导中的作用可能与氧化还原稳态的控制有关。α-生育酚可能通过控制叶绿体中脂质过氧化的传播来影响细胞信号传导，从而调节氧脂类（如植物激素茉莉酸）的形成。
