Leaf optical properties and photosynthetic leaf absorptances in several Australian seagrasses
Leaf optical properties and photosynthetic leaf absorptances in several Australian seagrasses
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DOI：
10.1016/j.aquabot.2007.03.005
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发表时间：
2007-07-01
期刊：
影响因子：
1.8
通讯作者：
Durako, Michael J.
中科院分区：
文献类型：
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作者：
Durako, Michael J.
本研究调查了澳大利亚东西海岸的8种大型海草（Posidonia australis、Posidonia sinuosa、Posidonia coriacea、Posidonia angustifolia、Amphibolis antarctica、Amphibolis griffithii、Zostera tasmanica和Zostera capricorni）和小型Halophila ovalis)叶片光学特性的种内和种间变异。测定叶片光谱透射率[T-L(lambda)]、反射率[R-L(lambda)]和非光合吸收率[AL(NP)]，计算叶片光谱吸收率[AL(lambda)]和叶片光合吸收率[A(L)(PAR)]。海草的叶片光谱形状相似，但大小不同。在绿光波段（500 ~ 600 nm）和近红外波段（700 ~ 750 nm），不同种间叶片光学特性差异最大。这表明，海草叶片光学特性的差异主要是由于叶片附属色素和叶片功能解剖结构（如内部结构、厚壁组织纤维等）的差异。叶片对光合有效辐射（PAR）的反射率[%R-L(PAR)]在4.6 ~ 9.3%之间，平均为6.1 +/- 1.2%。A(L)（NP）比%R-L（PAR）在种间和点间变化更大（16±5%）。在高能量环境下，叶片结构强化程度最高的海草中，马齿苋的%R-L(PAR)（9.3 +/- 1.4%）和a (L)(NP)（29 +/- 8%）值最高。A(L)（PAR）值范围从西澳大利亚州一个浅海（1米）开放海岸遗址的卵形圆蝽的45 +/- 3%到新南威尔士州一个较深（3米）保护遗址的南方圆蝽的68 +/- 3%。这里测量的海草的总体平均A(L)（PAR）为57 +/- 6%，比海草的PAM荧光学研究中常用的84%的吸收系数低30%以上。由于该参数的种内变异性相对较低，8个大体种的A(L)（PAR）显著高于小体种的（53 +/- 5%）。这项对海草叶片光学特性的有限调查表明，在广泛的叶片形态和环境中，海草叶片的光吸收变异性相对较低，这与之前水生植物对光吸收的限制一致。(C) 2007 Elsevier B.V.版权所有
This study investigated within- and among-species variability in the leaf optical properties of eight large-bodied seagrasses, Posidonia australis, Posidonia sinuosa, Posidonia coriacea, Posidonia angustifolia, Amphibolis antarctica, Amphibolis griffithii, Zostera tasmanica, and Zostera capricorni and the small-bodied Halophila ovalis from the east and west coasts of Australia. Leaf spectral transmittance [T-L(lambda], reflectance [R-L(lambda)], and non-photosynthetic absorptance [AL(NP)] were measured in order to calculate leaf spectral absorptance [AL(lambda)] and photosynthetic leaf absorptance [A(L)(PAR)]. Leaf spectra for the seagrasses were similar in shape, but variable in magnitude. Greatest among-species differences in leaf optical properties were present across green (500-600 nm) and near infrared (700-750 nm) wavelengths. This suggests differences in seagrass leaf optical properties are mainly due to variations in accessory pigments and leaf functional anatomy (e.g., internal structure, sclerenchyma fibers, etc.). Reflectance of photosynthetically active radiation (PAR) by leaves [%R-L(PAR)] ranged from 4.6 to 9.3% with a mean of 6.1 +/- 1.2%. A(L)(NP) was more variable (16 +/- 5%) than %R-L(PAR) among species and sites. P. coriacea, a seagrass characteristic of high energy environments with the most structurally reinforced leaves, had the highest values of %R-L(PAR) (9.3 +/- 1.4%) and A(L)(NP) (29 +/- 8%). A(L)(PAR) values ranged from 45 +/- 3% for H. ovalis from a shallow (1 m) open coastal site in Western Australia to 68 +/- 3% for P australis from a deeper (3 m) protected site in New South Wales. The overall mean A(L)(PAR) of 57 +/- 6% for the seagrasses measured here is over 30% lower than the absorption factor of 84%, commonly used in PAM fluorometric studies of seagrasses. Because of the relatively low within-species variability in this parameter, A(L)(PAR) was significantly higher for the eight large-bodied species (59 +/- 6%) compared to the small-bodied H. ovalis (53 +/- 5%). This limited survey of seagrass leaf optical characteristics indicates relatively low variability in light absorption across a wide range of leaf morphologies and environments consistent with previous suggestions of constraints on light absorption by aquatic plants. (C) 2007 Elsevier B.V. All rights reserved.