Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, South Korea.
Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, South Korea; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, South Korea.
Plant Physiol Biochem. 2019 Aug;141:477-486. doi: 10.1016/j.plaphy.2019.06.004. Epub 2019 Jun 10.
The induction of leaf injuries, including leaf chlorosis and epinasty, by continuous light in tomato plants is one of the most interesting and mysterious phenomena regarding plant interactions with light, the mechanism of which has not yet been revealed. To gain further insights into this particular response of tomato plants, we cultivated tomato seedlings (Solanum lycopersicum cv. Momotaro) for 14 days under continuous light with different ratios of red and blue light and compared their performance to those grown under continuous or 14/10-h photoperiodic white light using novel methods to quantitatively evaluate the level of leaf chlorosis and epinasty. Continuous monochromatic blue light induced severe chlorosis but almost completely alleviated epinasty in tomato leaf. In contrast, continuous monochromatic red light caused a lower level of leaf chlorosis but very severe epinasty. The combination of red and blue light at different ratios significantly reduced both leaf chlorosis and epinasty under continuous light condition. Carbohydrate contents showed no correlation with leaf chlorosis, while glucose and fructose contents showed correlations with the petiole and leaflet curvatures. Histochemical staining with 3,3'-diaminobenzidine and nitro blue tetrazodium chloride also did not reveal any significant buildup of hydrogen peroxide and superoxide anion in monochromatic blue light treatment. Taken together, these results suggest that chlorosis and epinasty are two distinctive leaf injuries caused by continuous light that may follow very different mechanisms, and an overaccumulation of carbohydrates in the leaf may not be the main cause of continuous light-induced leaf chlorosis in tomato.
持续光照诱导番茄叶片损伤，包括叶片黄化和下弯，是植物与光相互作用中最有趣和最神秘的现象之一，其机制尚未揭示。为了更深入地了解番茄对持续光照的这种特殊反应，我们用不同配比的红蓝光连续光照培养番茄幼苗（Solanum lycopersicum cv. Momotaro）14 天，并使用新方法来定量评估叶片黄化和下弯的程度，比较它们在持续光照或 14/10 小时光周期白光下的表现。持续单色蓝光诱导严重的叶片黄化，但几乎完全缓解了番茄叶片的下弯。相比之下，持续单色红光导致较低水平的叶片黄化，但非常严重的叶片下弯。不同配比的红蓝光组合在持续光照条件下显著降低了叶片黄化和下弯的程度。碳水化合物含量与叶片黄化无相关性，而葡萄糖和果糖含量与叶柄和小叶曲率呈相关性。3,3'-二氨基联苯胺和硝基四唑蓝的组织化学染色也未显示在单色蓝光处理中过氧化氢和超氧阴离子有明显的积累。综上所述，这些结果表明，黄化和下弯是持续光照引起的两种不同的叶片损伤，可能遵循非常不同的机制，叶片中碳水化合物的过度积累可能不是番茄持续光照诱导叶片黄化的主要原因。
