Interspecific variation in photosynthesis and respiration balance of three seagrasses in relation to light availability
Interspecific variation in photosynthesis and respiration balance of three seagrasses in relation to light availability
复制标题
三种海草光合作用和呼吸平衡与光利用率的种间差异
DOI：
10.3354/meps07103
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发表时间：
2007
影响因子：
2.5
通讯作者：
M. Nakaoka
中科院分区：
文献类型：
--
作者：
Yoshiyuki Tanaka;M. Nakaoka
弱光水平是决定沉水植物深度分布的主要因素。在印度-太平洋热带地区，不同的海草物种有特定的地带性模式，从潮间带到潮下带地区沿着深度和光照梯度。Cymoprotea serrulata一般比Thalassia hemprichii和C. rotundata，表明C. serrulata可能具有3种中最低的最小光子需求。通过测定叶片和整个植株的光合-辐射曲线，比较了这3种热带海草的光合和呼吸平衡。在日本西南部的石垣岛进行了2次样本采集和测量（7月和2月）。叶片的光合特性与所观察到的物种的地带性格局不一致。当考虑到根和根茎的呼吸速率时，T. hemprichii的光补偿点（7月为158.1 μ mol photons m-2s-1，2月为187.2 μ mol photons m-2s-1）显著高于C. rotundata（7月47.9，2月41.0）和C.细齿苔属（serrulata）7月85.1，2月40.0。T.出血是引起代偿刺激性变化的主要原因。这一结果与T. hemprichii，在深度或严重淤积造成的低光照条件下稀疏。反之，C.锯叶藓的地下生物量较少，呼吸需求较小，使该物种能够在较低的光照下维持较好的光合/呼吸平衡。C.圆齿龙的饱和辐射、补偿点和呼吸速率均低于其它物种。因此，C.圆齿石首鱼具有最深的水域栖息潜力，但其实际分布范围比圆齿石首鱼浅。serrulata，表明其他因素限制了C.圆形的
Low light levels are a major factor determining the depth distribution of submerged macrophytes. In the Indo-Pacific tropical region, different seagrass species have specific zonation patterns from intertidal to subtidal areas along depth and light gradients. Cymodocea serrulata gen- erally occurs in deeper water than Thalassia hemprichii and C. rotundata, suggesting that C. serru- lata probably has the lowest minimum photon requirement of the 3 species. We compared photosyn- thesis and respiration balances of these 3 tropical seagrasses by examining photosynthesis-irradiance (P-E) curves for leaves and for the whole plant bodies. Sample collection and measurement were conducted on 2 occasions (July and February) on Ishigaki Island, southwestern Japan. Leaf photo- synthetic traits were not concordant with the observed zonation pattern of the species. When respira- tion rates of the root and rhizome were taken into account, T. hemprichii had a significantly higher light compensation point (158.1 µmol photons m -2 s -1 in July, 187.2 in February) than C. rotundata (47.9 in July, 41.0 in February) and C. serrulata (85.1 in July, 40.0 in February). The large amount of belowground respiration in T. hemprichii was a major cause of the variation in the compensation irra- diance. This result is in concordance with the realized distribution pattern of T. hemprichii, which is sparse under low light conditions caused by depth or heavy siltation. Conversely, C. serrulata had less belowground biomass and a smaller respiration demand, enabling the species to maintain a better photosynthetic/respiration balance under lower light. C. rotundata had a lower saturating irra- diance, a lower compensation point and a lower respiration rate than the other species. Thus, C. rotundata has the potential to inhabit the deepest water, although its realized distribution range is shallower than that of C. serrulata, suggesting that other factors limit the depth range of C. rotundata.
热带海草、Cymodocea serrulata 和 C.rotundata 对沉积条件和光衰减的响应的形态变化。
DOI：
--
发表时间：
2006
期刊：
Botanica Marina 49
影响因子：
--
作者：
Tanaka;Y.;Nakaoka;M.
通讯作者：
M.