Heat generation and dissipation in plants: Can the alternative oxidative phosphorylation pathway serve a thermoregulatory role in plant tissues other than specialized organs?
Heat generation and dissipation in plants: Can the alternative oxidative phosphorylation pathway serve a thermoregulatory role in plant tissues other than specialized organs?
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DOI：
10.1104/pp.114.4.1137
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发表时间：
1997-08-01
期刊：
影响因子：
7.4
通讯作者：
Criddle, RS
中科院分区：
文献类型：
--
作者：
Breidenbach, RW;Saxton, MJ;Criddle, RS
对于植物中的氰化物不敏感替代途径，已经提出了许多假设的生理作用（Palmer，1976; Laties，1982; Meeuse，1984; Purvis和Shewfelt，1994;瓦格纳和Krab，1995）。Raskin及其同事的量热观测（Ordentlich等人，1991; Nevo等人，1992; Moynihan等人，1995年）是显着的贡献，显示了一个有趣的代谢，寒冷诱导的替代途径活动的反应和不同的物种适应不同的气候之间的低温反应。由于不同的氧化途径没有很大的差异焓，和观察到的热速率的增加是不足以导致显着的温度升高的生理重要性在nonthermogenic植物，其他的解释必须开发的电子流的分区和生理条件，如低温之间的关系。替代呼吸途径的诱导和参与参与代谢停滞，在波动或极端温度条件下维持碳流、ATP-ADP比率和电子流之间的适当平衡。如Palmer（1976）、Meeuse（1983）、Lambers（1985）以及瓦格纳和Krab（1995）所讨论的，当ATP需求充分满足时，替代氧化酶就会发挥作用。交替氧化酶的表达和动力学活性受关键代谢物浓度的调节（Day和Wiskich，1995; Sedow和Umbach，1995;瓦格纳和Krab，1995; Day等，1996年）。电子流在Cyt氧化酶和交替氧化酶之间的动态分配取决于两种氧化酶和底物氧化酶的动力学行为（Day和Wiskich，1995; Siedow和Umbach，1995;瓦格纳和Krab，1995; Day等，1996年）。此外，Moynihan等人（1995）发现，与小麦相比，适应热带的Episces cupreata Hook具有非常少的替代氧化酶活性（Nevo等人，1992年），适应大范围的温度气候。这一结果与表观交替氧化酶活性与物种起源气候之间的一般关系是一致的。
A number of hypothetical physiological roles have been proposed for the cyanide-insensitive alternative pathway in plants (Palmer, 1976; Laties, 1982; Meeuse, 1984; Purvis and Shewfelt, 1994; Wagner and Krab, 1995). The calorimetric observations of Raskin and co-workers (Ordentlich et al., 1991; Nevo et al., 1992; Moynihan et al., 1995) are significant contributions showing an interesting metabolic, chilling-induced response of the alternative pathway activity and differences in the low-temperature response among species adapted to different climates. Since different oxidative pathways do not have large differences in enthalpy, and observed heat rate increases are insufficient to cause significant temperature increases of physiological importance in nonthermogenic plants, other explanations must be developed for the relationship between the partitioning of electron flow and physiological conditions such as low temperature. The induction and engagement of the alternative respiratory pathway is involved in metabolic stasis, maintaining proper balance between carbon flow, ATP-ADP ratio, and electron flow during fluctuating or extreme temperature conditions. The alternative oxidase is engaged when ATP requirements are adequately met, as discussed by Palmer (1976), Meeuse (1983), Lambers (1985), and Wagner and Krab (1995). The expression and kinetic activity of the alternative oxidase are regulated by concentrations of key metabolites (Day and Wiskich, 1995; Siedow and Umbach, 1995; Wagner and Krab, 1995; Day et al., 1996). Dynamic partitioning of electron flow between Cyt oxidase and the alternative oxidase depends on the kinetic behavior of the two oxidases and the substrate dehydrogenases (Day and Wiskich, 1995; Siedow and Umbach, 1995; Wagner and Krab, 1995; Day et al., 1996). Furthermore, Moynihan et al. (1995) found that Episces cupreata Hook, adapted to the tropics, has very little alternative oxidase activity compared with wheat (Nevo et al., 1992), adapted to a large range of temperature climates. This results is consistent with the general relation between the apparent alternative oxidase activity and the climate of origin of the species.