UV-screening and springtime recovery of photosynthetic capacity in leaves of Vaccinium vitis-idaea above and below the snow pack.
UV-screening and springtime recovery of photosynthetic capacity in leaves of Vaccinium vitis-idaea above and below the snow pack.
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积雪上方和下方越橘叶子光合能力的紫外线屏蔽和春季恢复。
DOI：
10.1016/j.plaphy.2018.09.003
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
T. Robson
中科院分区：
文献类型：
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作者：
T. Solanki;P. Aphalo;S. Neimane;Saara M. Hartikainen;Marta Pieristè;A. Shapiguzov;A. Porcar;J. Atherton;A. Heikkilä;T. Robson
北方生物群落中的常绿植物会经历季节性硬化和去硬化，以调整其光合能力和光保护；适应温度和光照的季节变化。黄酮醇对叶子表皮的紫外线 (UV) 屏蔽作用对太阳辐射作出反应，部分通过增加紫外线 B (UV-B) 辐射来感知，并且是提供交叉光保护的候选特性。在芬兰中部的海蒂亚拉林业站，我们检查了越橘叶子中黄酮醇的积累是否较高。与积雪以下的植物相比，积雪以上的植物生长较快。我们发现，暴露在较低温度和较高太阳辐射下的叶子，靠近小丘顶部的叶子比小丘底部的叶子遭受更大的光抑制。上丘叶的表皮紫外线屏蔽能力最高，尤其是在冬季，当下叶位于积雪之下时。所有叶子的黄酮醇和花青素指数之间也存在负相关关系，这表明用于筛选的类黄酮成分与响应温度和辐照度的抗氧化活性进行微调。然而，光系统 II 光化学的最大量子产率 (Fv/Fm) 与脱硬过程中上部小丘叶片中黄酮醇积累之间的正相关性并没有赋予它们任何比 Fv/Fm 与温度和辐照度（整个小丘）的一般关系所预期的更大的交叉保护。无论融雪时间如何，所有叶子的光合作用都完全恢复，这表明 V. vitis-idaea 有潜力利用芬兰中部生长季节延长的持续趋势，而不会因积雪持续时间缩短而造成重大损害。
Evergreen plants in boreal biomes undergo seasonal hardening and dehardening adjusting their photosynthetic capacity and photoprotection; acclimating to seasonal changes in temperature and irradiance. Leaf epidermal ultraviolet (UV)-screening by flavonols responds to solar radiation, perceived in part through increased ultraviolet-B (UV-B) radiation, and is a candidate trait to provide cross-photoprotection. At Hyytiälä Forestry Station, central Finland, we examined whether the accumulation of flavonols was higher in leaves ofVaccinium vitis-idaeaL. growing above the snowpack compared with those below the snowpack. We found that leaves exposed to colder temperatures and higher solar radiation towards the top of hummocks suffered greater photoinhibition than those at the base of hummocks. Epidermal UV-screening was highest in upper-hummock leaves, particularly during winter when lower leaves were beneath the snowpack. There was also a negative relationship between indices of flavonols and anthocyanins across all leaves suggesting fine-tuning of flavonoid composition for screening vs. antioxidant activity in response to temperature and irradiance. However, the positive correlation between the maximum quantum yield of photosystem II photochemistry (Fv/Fm) and flavonol accumulation in upper hummock leaves during dehardening did not confer on them any greater cross-protection than would be expected from the general relationship ofFv/Fmwith temperature and irradiance (throughout the hummocks). Irrespective of timing of snow-melt, photosynthesis fully recovered in all leaves, suggesting thatV. vitis-idaeahas the potential to exploit the continuing trend for longer growing seasons in central Finland without incurring significant impairment from reduced duration of snow cover.