Natural ultraviolet radiation exposure alters photosynthetic biology and improves recovery from desiccation in a desert moss
Natural ultraviolet radiation exposure alters photosynthetic biology and improves recovery from desiccation in a desert moss
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DOI：
10.1093/jxb/erab051
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发表时间：
2021-02-17
影响因子：
6.9
通讯作者：
Mishler, Brent D.
中科院分区：
文献类型：
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作者：
Ekwealor, Jenna T. B.;Clark, Theresa A.;Mishler, Brent D.
旱地生态系统中的植物在光照、温度和水的供应方面经历着极端的每日和季节性波动。我们使用了一个原位现场实验，以揭示自然和降低水平的紫外线辐射（UV）的最大PSII量子效率（F-V/F-M），光合色素和抗氧化剂的相对丰度，和耐干燥的沙漠苔藓Syntrichia caninervis的转录组的影响。我们检验了以下假设：（i）S. caninervis植物经历持续的光[非光化学猝灭（NPQ）]，而干燥和复水后;（ii）减少紫外线将导致改善恢复的F-v/F-m;但（iii）1年的紫外线去除将去硬化植物和增加脆弱性紫外线损伤，减少F-v/F-m。所有现场收集的植物有极低的F-V/F-M初始复水后，但在实验室模拟冬季条件下恢复超过8天。紫外线过滤的植物有较低的F-v/F-m在恢复过程中，较高浓度的光保护色素和抗氧化剂，如玉米黄质和生育酚，和较低浓度的新黄质和ChI B比植物暴露于接近自然的紫外线水平。野生S. caninervis经历了持续的NPQ，需要几天的时间来放松和恢复有效的光合作用。太阳紫外线辐射的减少对复水后F-v/F-m的恢复产生不利影响。
Plants in dryland ecosystems experience extreme daily and seasonal fluctuations in light, temperature, and water availability. We used an in situ field experiment to uncover the effects of natural and reduced levels of ultraviolet radiation (UV) on maximum PSII quantum efficiency (F-v/F-m), relative abundance of photosynthetic pigments and antioxidants, and the transcriptome in the desiccation-tolerant desert moss Syntrichia caninervis. We tested the hypotheses that: (i) S. caninervis plants undergo sustained thermal quenching of light [non-photochemical quenching (NPQ)] while desiccated and after rehydration; (ii) a reduction of UV will result in improved recovery of F-v/F-m; but (iii) 1 year of UV removal will de-harden plants and increase vulnerability to UV damage, indicated by a reduction in F-v/F-m. All field-collected plants had extremely low F-v/F-m after initial rehydration but recovered over 8 d in lab-simulated winter conditions. UV-filtered plants had lower F-v/F-m during recovery, higher concentrations of photoprotective pigments and antioxidants such as zeaxanthin and tocopherols, and lower concentrations of neoxanthin and ChI b than plants exposed to near natural UV levels. Field-grown S. caninervis underwent sustained NPQ that took days to relax and for efficient photosynthesis to resume. Reduction of solar UV radiation adversely affected recovery of F-v/F-m following rehydration.