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首页> 美国卫生研究院文献>Frontiers in Plant Science >Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn
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Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn

机译：荧光测量结果显示与挪威云杉相比苏格兰松树对光合光反应的冷抑制作用更强春季与秋季相比对春季的抑制作用更强

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We studied the photosynthetic activity of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst) in relation to air temperature changes from March 2013 to February 2014. We measured the chlorophyll fluorescence of approximately 50 trees of each species growing in southern Finland. Fluorescence was measured 1–3 times per week. We began by measuring shoots present in late winter (i.e., March 2013) before including new shoots once they started to elongate in spring. By July, when the spring shoots had achieved similar fluorescence levels to the older ones, we proceeded to measure the new shoots only. We analyzed the data by fitting a sigmoidal model containing four parameters to link sliding averages of temperature and fluorescence. A parameter defining the temperature range over which predicted fluorescence increased most rapidly was the most informative with in describing temperature dependence of fluorescence. The model generated similar fluorescence patterns for both species, but differences were observed for critical temperature and needle age. Down regulation of the light reaction was stronger in spring than in autumn. Pine showed more conservative control of the photosynthetic light reactions, which were activated later in spring and more readily attenuated in autumn. Under the assumption of a close correlation of fluorescence and photosynthesis, spruce should therefore benefit more than pine from the increased photosynthetic potential during warmer springs, but be more likely to suffer frost damage with a sudden cooling following a warm period. The winter of 2013–2014 was unusually mild and similar to future conditions predicted by global climate models. During the mild winter, the activity of photosynthetic light reactions of both conifers, especially spruce, remained high. Because light levels during winter are too low for photosynthesis, this activity may translate to a net carbon loss due to respiration.
机译：我们研究了2013年3月至2014年2月苏格兰松（Pinus sylvestris L.）和挪威云杉（Picea abies [L.] Karst）的光合活性与气温变化的关系。我们测量了每棵约50棵树的叶绿素荧光在芬兰南部生长的物种。每周测量1至3次荧光。我们首先测量了冬季后期（即2013年3月）上出现的芽，然后在春季开始伸长后再添加新芽。到了7月，当春季芽的荧光水平与旧芽相似时，我们开始仅测量新芽。我们通过拟合包含四个参数的S型模型来分析数据，以链接温度和荧光的滑动平均值。定义预测荧光最快速增加的温度范围的参数在描述荧光的温度依赖性方面最有用。该模型对两种物种产生相似的荧光模式，但在临界温度和针头年龄上观察到差异。春天对光反应的下调比秋天强。松树显示出对光合作用光反应的更保守控制，该反应在春季晚些时候被激活，而在秋季更容易衰减。因此，在荧光和光合作用紧密相关的假设下，在温暖的春季，云杉应比松树更多地受益于光合作用潜力的增加，但在温暖的时期突然遭受降温，更可能遭受霜冻损害。 2013-2014年冬季异常温暖，与全球气候模式预测的未来状况相似。在温和的冬季，两个针叶树，特别是云杉的光合作用光反应的活性仍然很高。由于冬季的光照水平太低，无法进行光合作用，因此此活动可能会由于呼吸而转化为净碳损失。

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