Zhao Qing-Ping, Lv Qian-Yi, Fu Xiang-Lin, Wu Qi-Qi, Liu Yan-Fei, Xue Lin-Lin, Zhao Xiang
National Key Laboratory of Cotton Bio-Breeding and Integrated Utilization, School of Life Sciences, Henan University, Kaifeng 475004, China; and College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, China.
National Key Laboratory of Cotton Bio-Breeding and Integrated Utilization, School of Life Sciences, Henan University, Kaifeng 475004, China.
Funct Plant Biol. 2024 Dec;51. doi: 10.1071/FP24246.
Plant stems grow towards the incident light in response to unilateral blue light to optimize photosynthesis. However, our findings reveal that unilateral high-intensity blue light (HBL) triggers backlit lodging in etiolated cotton (Gossypium hirsutum ) hypocotyls when they are pulled approximately 1.5cm from the soil. Phenotypic analysis indicated that stomata on the lit side were open, while those on the shaded side were closed under unilateral HBL. To investigate the relationship between stomatal movement and backlit lodging, we applied abscisic acid (ABA), hydrogen peroxide (H2 O2 ), and lanthanum chloride (LaCl3 ) to the lit side, and cytokinins (6-BA) and ascorbic acid (ASA) to the shaded side. Results showed that all these treatments inhibited the backlit lodging phenomenon, specifically, ABA, H2 O2 , and LaCl3 reduced stomatal opening on the lit side, while 6-BA and ASA enhanced stomatal opening on the shade side. These results demonstrate that HBL-induced asymmetrical stomatal opening on the lit and shade side of hypocotyl supports the backlit lodging phenomenon. Notably, maize (Zea mays ), which lack stomata in the hypocotyl did not exhibit HBL-induced backlit lodging, whereas soybean (Glycine max ), which has stomata in its etiolated hypocotyl, displayed a similar phenotype to that of cotton. Additionally, while both red light and low-intensity blue light (LBL) can induce stomatal opening, they do not trigger the backlit lodging phenomenon. These findings suggest that backlit lodging is a unique HBL-dependent response, but the mechanism need further investigation.
植物茎会朝着入射光生长，以响应单侧蓝光，从而优化光合作用。然而，我们的研究结果表明，当黄化的棉花（陆地棉）下胚轴从土壤中拔出约1.5厘米时，单侧高强度蓝光（HBL）会引发背光倒伏现象。表型分析表明，在单侧HBL条件下，受光侧的气孔开放，而背光侧的气孔关闭。为了研究气孔运动与背光倒伏之间的关系，我们在受光侧施加脱落酸（ABA）、过氧化氢（H2O2）和氯化镧（LaCl3），在背光侧施加细胞分裂素（6-BA）和抗坏血酸（ASA）。结果表明，所有这些处理都抑制了背光倒伏现象，具体而言，ABA、H2O2和LaCl3减少了受光侧的气孔开放，而6-BA和ASA增加了背光侧的气孔开放。这些结果表明，HBL诱导的下胚轴受光侧和背光侧气孔不对称开放支持了背光倒伏现象。值得注意的是，下胚轴没有气孔的玉米（Zea mays）没有表现出HBL诱导的背光倒伏现象，而黄化下胚轴有气孔的大豆（Glycine max）则表现出与棉花相似的表型。此外，虽然红光和低强度蓝光（LBL）都能诱导气孔开放，但它们不会引发背光倒伏现象。这些发现表明，背光倒伏是一种独特的依赖HBL的反应，但其机制有待进一步研究。
