Seasonal photosynthesis and anthocyanin production in 10 broadleaf evergreen species
Seasonal photosynthesis and anthocyanin production in 10 broadleaf evergreen species
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DOI：
10.1071/fp07205
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Smith, William K.
中科院分区：
文献类型：
--
作者：
Hughes, Nicole M.;Smith, William K.
许多常绿物种的叶子在冬季暴露在强烈的阳光下会变红，这是由于产生光保护花青素色素，而其他物种的叶子，缺乏花青素，保持绿色。为什么一些常绿物种合成花青素色素而另一些不合成花青素色素目前尚不清楚。此外，花青素（红色）和无氰（绿色）常绿植物的相对光合性能尚未得到描述。本文报道了5种红绿阔叶常绿植物的季节生理生态数据。我们假设，在冬季叶片中合成花青素的物种对应于那些具有最剧烈的季节性光合作用下降的物种，因为减少的能量汇增加了对光抑制的脆弱性和对光保护的需求。我们的结果不支持这一假设，因为气体交换测量显示红叶和绿叶物种之间的平均季节性光合能力没有差异。与花青素的遮阳作用一致，在冬季，红叶种的叶绿素含量显著高于绿叶种，叶绿素a/b比显著低于绿叶种，PSII的最大光捕获效率（F-v/F-m）显著高于绿叶种，而在夏季（所有叶子都是绿色的时候）则相反。我们得出的结论是，冬季花青素的产生可能与光合能力的减弱无关，而可能只是一些物种在冬季利用的一种替代光保护策略。
Leaves of many evergreen species turn red when exposed to high sunlight during winter due to production of photoprotective anthocyanin pigments, while leaves of other species, lacking anthocyanin, remain green. Why some evergreen species synthesise anthocyanin pigments while others do not is currently unknown. Furthermore, the relative photosynthetic performance of anthocyanic (red) and acyanic (green) evergreens has yet to be described. Here we present seasonal ecophysiological data for five red and green broadleaf evergreen species. We hypothesise that species which synthesise anthocyanins in winter leaves correspond to those with the most drastic seasonal photosynthetic declines, as reduced energy sinks increase vulnerability to photoinhibition and need for photoprotection. Our results did not support this hypothesis, as gas exchange measurements showed no difference in mean seasonal photosynthetic capacity between red- and green-leafed species. Consistent with anthocyanin's shading effect, red- leafed species had significantly higher chlorophyll content, lower chlorophyll a/b ratios, and higher maximum light capture efficiency of PSII (F-v/F-m) than green-leafed species during the winter, but not during the summer (when all leaves were green). We conclude that anthocyanin production during winter is likely not associated with diminished photosynthetic capacity, and may simply represent an alternative photoprotective strategy utilised by some species during winter.