Light-mediated constraints on leaf function correlate with leaf structure among deciduous and evergreen tree species
Light-mediated constraints on leaf function correlate with leaf structure among deciduous and evergreen tree species
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DOI：
10.1093/treephys/21.18.1341
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发表时间：
2001-12-01
期刊：
影响因子：
4
通讯作者：
Kruger, EL
中科院分区：
文献类型：
--
作者：
Green, DS;Kruger, EL
叶片结构已被证明是叶片光合特性的一个重要决定因素，但这种关系的性质仍然是模糊的。有人认为，叶绿体的叶内遮光可以解释增加叶片厚度/密度对基于质量的光合作用的负面影响。为了进一步探索光介导的功能限制赋予叶结构的重要性，我们研究了光合反应高单向和双向辐照宽和针叶广泛的质量单位面积（LMA）。除最低LMA（< 40 g m（-2））的叶片外，在双向光照下光合作用增加，单向与双向光合作用的比值（A（u）/A（B））与LMA呈显著负相关，最厚/密叶的光合作用比值接近0.5。双向照明也增加气孔导度，但气孔响应的幅度是温和的，与LMA不相关。因此，在单向与双向照射的细胞间CO2分压的比例是呈正相关的LMA。因此，似乎许多C-3叶可能不是“光饱和”下高单向照明。负的，指数A（u）/A（B）-LMA的关系，在这项研究中支持的概念，即随着LMA的增加，越来越多的叶片叶绿体功能在亚饱和辐照下单向光。
Leaf structure has been shown to be an important determinant of leaf photosynthetic characteristics, yet the nature of this relationship remains ambiguous. It has been suggested that intra-leaf shading of chloroplasts may explain the negative influence of increasing leaf thickness/density on mass-based photosynthesis. To explore further the importance of light-mediated functional limitations conferred by leaf structure, we examined photosynthetic responses to high unidirectional and bidirectional irradiances among broad- and needle-leaves ranging widely in mass per area (LMA). Except for leaves with the lowest LMA (< 40 g m(-2)), photosynthesis increased in bidirectional irradiance, and the ratio of unidirectional to bidirectional photosynthesis (A(u)/A(b)) was strongly and negatively related to LMA, approaching 0.5 for the thickest/densest leaves. Bidirectional illumination also increased stomatal conductance, but the magnitude of stomatal response was modest and uncorrelated with LMA. Consequently, the ratio of intercellular CO2 partial pressures during unidirectional versus bidirectional irradiation was positively related to LMA. Hence, it appears that many C-3 leaves may not be "light saturated" under high unidirectional illumination. The negative, exponential A(u)/A(b)-LMA relationship in this study supports the notion that, as LMA increases, an increasing fraction of leaf chloroplasts are functioning at subsaturating irradiance under unidirectional light.