当前位置: X-MOL 学术Front. Plant Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
It Is Hot in the Sun: Antarctic Mosses Have High Temperature Optima for Photosynthesis Despite Cold Climate.
Frontiers in Plant Science ( IF 5.6 ) Pub Date : 2020-07-21 , DOI: 10.3389/fpls.2020.01178
Alicia V Perera-Castro 1, 2 , Melinda J Waterman 2 , Johanna D Turnbull 2 , Michael B Ashcroft 2 , Ella McKinley 3 , Jennifer R Watling 3, 4 , Jessica Bramley-Alves 2 , Angelica Casanova-Katny 5 , Gustavo Zuniga 6 , Jaume Flexas 1 , Sharon A Robinson 2, 7
Affiliation  

The terrestrial flora of Antarctica’s frozen continent is restricted to sparse ice-free areas and dominated by lichens and bryophytes. These plants frequently battle sub-zero temperatures, extreme winds and reduced water availability; all influencing their ability to survive and grow. Antarctic mosses, however, can have canopy temperatures well above air temperature. At midday, canopy temperatures can exceed 15°C, depending on moss turf water content. In this study, the optimum temperature of photosynthesis was determined for six Antarctic moss species: Bryum pseudotriquetrum, Ceratodon purpureus, Chorisodontium aciphyllum, Polytrichastrum alpinum, Sanionia uncinata, and Schistidium antarctici collected from King George Island (maritime Antarctica) and/or the Windmill Islands, East Antarctica. Both chlorophyll fluorescence and gas exchange showed maximum values of electron transport rate occurred at canopy temperatures higher than 20°C. The optimum temperature for both net assimilation of CO2 and photoprotective heat dissipation of three East Antarctic species was 20–30°C and at temperatures below 10°C, mesophyll conductance did not significantly differ from 0. Maximum mitochondrial respiration rates occurred at temperatures higher than 35°C and were lower by around 80% at 5°C. Despite the extreme cold conditions that Antarctic mosses face over winter, the photosynthetic apparatus appears optimised to warm temperatures. Our estimation of the total carbon balance suggests that survival in this cold environment may rely on a capacity to maximize photosynthesis for brief periods during summer and minimize respiratory carbon losses in cold conditions.



中文翻译:

阳光下很热:尽管气候寒冷,南极的苔藓仍具有光合作用的最佳高温。

南极洲冰冻大陆的陆地植物仅限于稀疏的无冰地区,并以地衣和苔藓植物为主。这些工厂经常与零度以下的温度,极端的风和减少的水利用量作斗争。所有这些都会影响他们的生存和成长能力。但是,南极苔藓的冠层温度可能会大大高于空气温度。在午间,根据苔藓草皮含水量的不同,冠层温度可能会超过15°C。在这项研究中,确定了六个南极苔藓物种的光合作用的最佳温度:假三叉草紫罗兰色球孢菌高山多角金龟刺柏南极血吸虫收集自国王乔治岛(南极海洋)和/或南极东部的风车群岛。叶绿素荧光和气体交换均表明,在高于20°C的冠层温度下,电子传输速率出现最大值。净吸收CO 2的最佳温度并且三种南极东部物种的光保护性散热为20–30°C,并且在低于10°C的温度下,叶肉的电导率并没有显着不同于0。最大的线粒体呼吸速率发生在温度高于35°C且降低约80°C时在5℃下为%。尽管南极苔藓在冬季面临极端寒冷的条件,但光合作用设备似乎已针对高温进行了优化。我们对总碳平衡的估计表明,在这种寒冷环境中的生存可能依赖于在夏季短期内最大化光合作用并在寒冷条件下最大程度减少呼吸碳损失的能力。

更新日期:2020-08-08
down
wechat
bug