Artificial light at night is rapidly spreading and has become an important component of global change. Although numerous studies have focused on its potential ecological impacts, the physiological response mechanisms of landscape plants to artificial light at night have rarely been quantified. With common landscape shrubs in subtropical regions of China, Hydrangea paniculata, Photinia fraseri and Ligustrum japonicum, as test materials, we exa-mined the responses of antioxidant enzyme system and biomass in the light environment at night under different light quality (yellow light, white light) with different light intensities (20, 40, 60 lx) . The results showed that artificial light at night significantly increased the membrane peroxidation, stimulated plant antioxidant protection systems and raised the antioxidant enzyme activities of the three species. The effects of light quality on plant antioxidant enzymes varied across dspecies. The peroxidase (POD) and catalase (CAT) activities of H. paniculata under white light were 1.5 and 1.3 times as that under yellow light, respectively. Both enzyme activities of P. fraseri were 1.1 times as that under white light than under yellow light. The activities of two enzymes in L. japonicum under white light were 88.6% and 99.5% of those under yellow light, respectively. The antioxidant enzyme activities of the three species increased with increasing light intensity at night, whereas the contents of malondialdehyde increased rapidly and the antioxidant enzyme activities decreased when beyond a certain light intensity threshold (at 120 d, the threshold was about 40 lx). The protective enzymes that played the major role under nighttime light stress were different among the three species. For H. paniculata, POD and CAT complemented each other to resist stress-induced oxidative damage, while the main enzyme of L. japonicum was POD. The biomass of the three species increased significantly under artificial light at night. H. paniculata was the most sensitive to nighttime light stress, while L. japonicum had the strongest resistance to the stress. The deciduous shrub H. paniculata could tolerate the white night light lower than 40 lx, while the evergreen shrubs P. fraseri and L. japonicum could tolerate the yellow night light lower than 40 lx.
夜间人工光照正在迅速蔓延,成为全球变化的一个重要组成部分。尽管许多研究关注了它的潜在生态影响,但绿化植物对夜间人工光照的生理响应机制研究相对匮乏。本研究以我国亚热带地区常见的城市绿化灌木圆锥绣球、红叶石楠和金森女贞为对象,模拟不同光质(黄光、白光)下不同光强(20、40和60 lx)的夜间光环境,研究植物抗氧化酶系统以及生物量的响应特征。结果表明: 夜间人工光照显著提高了3种灌木的细胞膜质过氧化程度,激发了植物抗氧化保护系统,显著提高了抗氧化酶活性。光质对植物抗氧化酶的影响因植物种类而异,圆锥绣球在白光下的过氧化物酶(POD)和过氧化氢酶(CAT)活性分别是黄光下的1.5和1.3倍,红叶石楠2种酶活性在白光下均为黄光下的1.1倍,而金森女贞2种酶活性在白光下分别是黄光下的88.6%和99.5%。3种灌木抗氧化酶活性随夜间光强的增加而增加,但超过一定光强阈值(120 d时,阈值约为40 lx)后,丙二醛含量迅速增加,抗氧化酶活性降低。3种灌木在夜光胁迫下起主要作用的保护酶不同,圆锥绣球通过POD与CAT互补来抵御胁迫带来的氧化伤害,金森女贞的主要作用酶为POD。3种灌木在夜间人工光照下生物量均显著增加。圆锥绣球对夜间光胁迫最敏感,金森女贞的抗胁迫能力最强。落叶灌木圆锥绣球可以忍受白光40 lx以下的夜间光照,常绿灌木红叶石楠和金森女贞可以忍受黄光40 lx以下的夜间光照。.
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