Nocturnal versus diurnal CO2 uptake: how flexible is Agave angustifolia?
Nocturnal versus diurnal CO2 uptake: how flexible is Agave angustifolia?
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DOI：
10.1093/jxb/eru097
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发表时间：
2014-07
影响因子：
6.9
通讯作者：
Holtum JA
中科院分区：
文献类型：
--
作者：
Winter K;Garcia M;Holtum JA
在CAM种的幼嫩和成熟植株中，在一系列环境条件下，CO2交换的昼夜模式是高度保守的。龙舌兰表现出涵养水源的景天酸代谢(CAM)光合作用途径。一些物种是潜在的生物燃料原料，因为它们在季节性干旱的地貌中具有很高的生产力。在有CAM的植物中，当条件有利时，高生长速率通常被认为与C3光合作用对总碳增益的显著贡献有关。甚至有报道称，由于给一种龙舌兰浇水过多，这种植物从CAM转变为C3。我们研究了从巴拿马自然栖息地采集的幼龄和成熟期狭叶龙舌兰，C3光合作用是否能显著促进其碳吸收和生长。在浇水充足的植物中，黑暗中的二氧化碳吸收贡献了每日碳增量的约75%。这种CO2交换的昼夜模式在一系列环境条件下是高度保守的，对密集浇水不敏感。高浓度的二氧化碳(800ppm)主要在光照下刺激二氧化碳的固定。夜间暴露于无CO_2的空气中，在接下来的光照期显著增加了对CO_2的吸收，但在接下来的24小时内，当供应CO_2时，CO_2交换迅速恢复到其标准模式。虽然狭叶沙枣一直以CAM作为其主要的光合作用途径，但其相对有限的光合可塑性并不排除它占据从巴拿马相对温和的热带环境到墨西哥较干燥的生境。
In young and mature plants of the CAM species Agave angustifolia, the day/night pattern of CO2 exchange was highly conserved under a range of environmental conditions. Agaves exhibit the water-conserving crassulacean acid metabolism (CAM) photosynthetic pathway. Some species are potential biofuel feedstocks because they are highly productive in seasonally dry landscapes. In plants with CAM, high growth rates are often believed to be associated with a significant contribution of C3 photosynthesis to total carbon gain when conditions are favourable. There has even been a report of a shift from CAM to C3 in response to overwatering a species of Agave. We investigated whether C3 photosynthesis can contribute substantially to carbon uptake and growth in young and mature Agave angustifolia collected from its natural habitat in Panama. In well-watered plants, CO2 uptake in the dark contributed about 75% of daily carbon gain. This day/night pattern of CO2 exchange was highly conserved under a range of environmental conditions and was insensitive to intensive watering. Elevated CO2 (800 ppm) stimulated CO2 fixation predominantly in the light. Exposure to CO2-free air at night markedly enhanced CO2 uptake during the following light period, but CO2 exchange rapidly reverted to its standard pattern when CO2 was supplied during the subsequent 24h. Although A. angustifolia consistently engages in CAM as its principal photosynthetic pathway, its relatively limited photosynthetic plasticity does not preclude it from occupying a range of habitats, from relatively mesic tropical environments in Panama to drier habitats in Mexico.
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影响因子：
5.6
作者：
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通讯作者：
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影响因子：
64.8
作者：
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通讯作者：
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影响因子：
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作者：
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DOI：
10.1073/pnas.0400366101
发表时间：
2004-03-09
影响因子：
11.1
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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