Response of mitochondria to light intensity in the leaves of sun and shade species
Response of mitochondria to light intensity in the leaves of sun and shade species
复制标题
DOI：
10.1111/j.1365-3040.2005.01322.x
复制
发表时间：
2005-06-01
影响因子：
7.3
通讯作者：
Day, DA
中科院分区：
文献类型：
--
作者：
Noguchi, K;Taylor, NL;Day, DA
本研究的作者先前已经证明，在有限的光照条件下，树荫植物海芋叶片的呼吸速率和体内交替氧化酶(AOX)的活性都低于太阳树种，从而优化了能量生产(Noguchi等人，澳大利亚植物生理学杂志28，27-35,2001)。本研究以金线莲叶为材料，对其线粒体进行检测，以探讨其呼吸参数差异的生化基础。在强光和弱光下培养海芋和菠菜，从叶片中分离线粒体，并比较它们的呼吸特性。通过延胡索酶活性和孔蛋白(线粒体膜外膜的电压依赖性阴离子通道)抗体检测，估计了这两种植物叶提取物的线粒体含量。在线粒体蛋白质的基础上，菠菜叶片的细胞色素途径和细胞色素c氧化酶(COX)的能力高于金缕梅叶片。然而，在线粒体蛋白的基础上，奥杜拉表现出更高的AOX能力，当丙酮酸激活时，AOX与泛醌具有很高的亲和力。即使在严重遮荫的条件下，海芋每片叶干重的线粒体蛋白质含量也比菠菜高。较低的生长光照强度导致两个物种中测试的大多数途径和蛋白质的活性降低，特别是甘氨酸依赖的氧摄取。在弱光环境下，金线莲叶片中的AOX蛋白主要以非活性、氧化二聚体的形式存在，但当植物生长在强光下时，AOX蛋白被转化为还原的活性形式。这种转变可能会防止呼吸链在光氧化条件下过度减少。
The present authors have shown previously that both respiration rates and in vivo activities of the alternative oxidase (AOX) of leaves of Alocasia odora, a shade species, are lower than those in sun species, thereby optimizing energy production under limited light conditions (Noguchi et al., Australian Journal of Plant Physiology 28, 27-35, 2001). In the present study, mitochondria isolated from A. odora leaves were examined in order to investigate the biochemical basis for the differences in respiratory parameters. Alocasia odora and spinach plants were cultivated under both high and low light intensities, mitochondria were isolated from their leaves, and their respiratory properties compared. Mitochondrial content of leaf extracts from the two species was estimated using fumarase activities and antibody detection of porin (the voltage-dependent anion channel of the outer mitochondrial membrane). On a mitochondrial protein basis, spinach leaves showed higher capacities of the cytochrome pathway and cytochrome c oxidase (COX) than A. odora leaves. However, on a mitochondrial protein basis, A. odora showed higher capacities of AOX, which had a high affinity for ubiquinone when activated by pyruvate. Alocasia odora also had larger amounts of mitochondrial protein per leaf dry weight, even under severely shaded conditions, than spinach. Lower growth light intensity led to lower activities of most pathways and proteins tested in both species, especially glycine-dependent oxygen uptake. In the low light environment, most of the AOX protein in A. odora leaves was in its inactive, oxidized dimer form, but was converted to its reduced active form when plants were grown under high light. This shift may prevent over-reduction of the respiratory chain under photo-oxidative conditions.