Instituto de Fisiología Vegetal (INFIVE), Facultades de Ciencias Agrarias y Forestales y de Ciencias Naturales y Museo, Universidad Nacional de La Plata, CCT-CONICET La Plata, cc 327, 1900, La Plata, Argentina.
Instituto de Fisiología Vegetal (INFIVE), Facultades de Ciencias Agrarias y Forestales y de Ciencias Naturales y Museo, Universidad Nacional de La Plata, CCT-CONICET La Plata, cc 327, 1900, La Plata, Argentina.
Plant Sci. 2017 May;258:112-121. doi: 10.1016/j.plantsci.2017.01.013. Epub 2017 Feb 7.
This work studied modifications experienced by root mitochondria during whole plant senescence or under light deprivation, using Arabidopsis thaliana plants with YFP tagged to mitochondria. During post-bolting development, root respiratory activity started to decline after aboveground organs (i.e., rosette leaves) had senesced. This suggests that carbohydrate starvation may induce root senescence. Similarly, darkening the whole plant induced a decrease in respiration of roots. This was partially due to a decrease in the number of total mitochondria (YFP-labelled mitochondria) and most probably to a decrease in the quantity of mitochondria with a developed inner membrane potential (ΔΨm, i.e., Mitotracker red- labelled mitochondria). Also, the lower amount of mitochondria with ΔΨm compared to YFP-labelled mitochondria at 10d of whole darkened plant, suggests the presence of mitochondria in a "standby state". The experiments also suggest that small mitochondria made the main contribution to the respiratory activity that was lost during root senescence. Sugar supplementation partially restored the respiration of mitochondria after 10d of whole plant dark treatment. These results suggest that root senescence is triggered by carbohydrate starvation, with loss of ΔΨm mitochondria and changes in mitochondrial size distribution.
这项工作研究了在整个植物衰老或在光照剥夺下，根线粒体经历的修饰，使用 YFP 标记在线粒体上的拟南芥植物。在抽薹后发育过程中，地上器官（即莲座叶）衰老后，根呼吸活性开始下降。这表明碳水化合物饥饿可能诱导根衰老。同样，使整个植物变暗会导致根呼吸减少。这部分是由于总线粒体数量（YFP 标记的线粒体）减少，很可能是由于具有发达内膜电位（ΔΨm，即 Mitotracker red 标记的线粒体）的线粒体数量减少。此外，与 YFP 标记的线粒体相比，在整个黑暗处理 10 天后，具有ΔΨm 的线粒体数量较少，表明存在处于“备用状态”的线粒体。实验还表明，小线粒体对根衰老过程中丧失的呼吸活性做出了主要贡献。糖补充部分恢复了整个植物黑暗处理 10 天后线粒体的呼吸作用。这些结果表明，碳水化合物饥饿触发了根衰老，导致ΔΨm 线粒体丧失和线粒体大小分布的变化。
