Shibaeva Tatjana G, Sherudilo Elena G, Rubaeva Alexandra A, Shmakova Natalya Yu, Titov Alexander F
Institute of Biology, Karelian Research Center, Russian Academy of Sciences, Petrozavodsk 185910, Russia.
Polar-Alpine Botanical Garden, Kola Scientific Center, Russian Academy of Sciences, Kirovsk 184256, Russia.
Plants (Basel). 2024 Sep 30;13(19):2742. doi: 10.3390/plants13192742.
This study addressed the following questions: How does continuous lighting (CL) impact plant physiology, and photosynthetic and stress responses? Does the impact of CL depend on the source of the light and other environmental factors (natural vs. artificial)? Do responses to CL differ for native and non-native plant species in the subarctic region and, if differences exist, what physiological reasons might they be associated with them? Experiments were conducted with three plants native to the subarctic region L., L., (L.) Raeusch.) and three non-native plant species Klotzsch, Sibth. and Sm., Loddiges ex D. Don) introduced in the Polar-Alpine Botanic Garden (KPABG, 67°38' N). The experimental groups included three species pairs exposed to (1) a natural 16 h photoperiod, (2) natural CL, (3) an artificial 16 h photoperiod and (4) artificial CL. In the natural environment, measurements of physiological and biochemical parameters were carried out at the peak of the polar day (at the end of June), when the plants were illuminated continuously, and in the second week of August, when the day length was about 16 h. Th experiments with artificial lighting were conducted in climate chambers where plants were exposed to 16 h or 24 h photoperiods for two weeks. Other parameters (light intensity, spectrum composition, temperature and air humidity) were held constant. The obtained results have shown that plants lack specific mechanisms of tolerance to CL. The protective responses are non-specific and induced by developing photo-oxidative stress. In climate chambers, under constant environmental conditions artificial CL causes leaf injuries due to oxidative stress, the main cause of which is circadian asynchrony. In nature, plants are not photodamaged during the polar day, as endogenous rhythms are maintained due to daily fluctuations of several environmental factors (light intensity, spectral distribution, temperature and air humidity). The obtained data show that among possible non-specific protective mechanisms, plants use flavonoids to neutralize the excess ROS generated under CL. In local subarctic plants, their photoprotective role is significantly higher than in non-native introduced plant species.
持续光照（CL）如何影响植物生理、光合及应激反应？CL的影响是否取决于光源及其他环境因素（自然光照与人工光照）？亚北极地区本土植物与非本土植物对CL的反应是否存在差异？若存在差异，可能与哪些生理原因相关？实验选用了三种亚北极地区的本土植物（北极柳、矮北极桦、高山虎耳草）以及三种引入极地高山植物园（KPABG，北纬67°38′）的非本土植物（高山勿忘草、高山紫菀、高山报春花）。实验组包括三对物种，分别暴露于（1）自然16小时光周期、（2）自然持续光照、（3）人工16小时光周期和（4）人工持续光照。在自然环境中，于极昼高峰期（6月底）和8月的第二周（日照时长约16小时）测量生理和生化参数，极昼高峰期植物持续受光照。人工光照实验在气候箱中进行，植物在16小时或24小时光周期下处理两周。其他参数（光照强度、光谱组成、温度和空气湿度）保持恒定。所得结果表明，植物缺乏对持续光照的特定耐受机制。保护反应是非特异性的，由光氧化应激诱导产生。在气候箱中，在恒定环境条件下，人工持续光照会因氧化应激导致叶片损伤，其主要原因是昼夜节律失调。在自然环境中，极昼期间植物不会受到光损伤，因为由于多种环境因素（光照强度、光谱分布、温度和空气湿度）的每日波动，植物的内源性节律得以维持。所得数据表明，在可能的非特异性保护机制中，植物利用类黄酮来中和持续光照下产生的过量活性氧。在亚北极地区的本土植物中，其光保护作用显著高于非本土引入植物物种。
