Annual metabolic carbon balance of the seagrass Posidonia oceanica:: the importance of carbohydrate reserves
Annual metabolic carbon balance of the seagrass Posidonia oceanica:: the importance of carbohydrate reserves
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DOI：
10.3354/meps211105
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发表时间：
2001-01-01
影响因子：
2.5
通讯作者：
Romero, J
中科院分区：
文献类型：
--
作者：
Alcoverro, T;Manzanera, M;Romero, J
我们提出了地中海海草 Posidonia oceanica (L.) Delile 的季节性碳 (C) 平衡，该平衡是根据 C 增加（光合作用）、C 损失（呼吸）和生长的季节性速率计算得出的。我们将平衡与季节性碳储备的演变进行比较，以确定影响植物季节周期的参数（芽：根生物量、储备分配、光合参数等）。此外，我们还研究了年度碳平衡是否可以用作测试海草对光照减少的脆弱性的有效工具。季节性全株碳平衡呈现负值（9 月至 6 月）和正值（7 月和 8 月）交替出现。这种趋势是多种季节性因素相互作用的结果，例如辐照度、水体浊度、光合参数、呼吸速率、芽生长、芽内年龄分布，以及主要的低光合与非光合生物量比率。季节性生长和代谢平衡（碳增益 - 碳需求）之间缺乏显着相关性，无法预测植物生长。相反，碳储存的季节格局与碳正负平衡时期一致。因此，储备动员允许在负碳平衡条件下越冬和重新生长。通过不同的计算，发现 1993 年年度碳余额为负；这与碳水化合物的年际消耗和芽密度下降是一致的。由于Posidonia oceanica正在地中海退化，我们的碳预算可能会对未来的碳模型做出显着贡献，这些模型可以成为定义生存的最低光需求的重要工具。为了充分了解海草对光减少的脆弱性，需要更深入地了解一些明确影响碳预算的参数（例如：根茎/根耗氧量和 O-2 到 C 的转化）的功能。
We present the seasonal carbon (C) balance of the Mediterranean seagrass Posidonia oceanica (L.) Delile calculated from seasonal rates of C gain (photosynthesis), C loss (respiration) and growth. We compare our balance with the evolution of seasonal C reserves in order to determine the parameters (shoot:root biomass, reserve allocation, photosynthetic parameters, etc.) that influence the seasonal cycle of the plant. Additionally, we examine whether the annual C balance can be used as a valid tool for testing the vulnerability of seagrasses to light reduction. The seasonal whole-plant C balance showed alternate negative (from September to June) and positive (July and August) values. This trend was the result of the interplay among several seasonal factors such as irradiance, water turbidity, photosynthetic parameters, respiratory rates, shoot growth, within-shoot age distribution, and principally, the low photosynthetic:non-photosynthetic biomass ratio. The lack of significant correlation between seasonal growth and metabolic balance (C gain - C demand) did not permit the prediction of plant growth. Conversely, the seasonal pattern of carbon storage was consistent with the periods of positive and negative C balance. Consequently, reserve mobilization allows overwintering and re-growth under conditions of negative C balance. Using different calculations the annual C balance was found to be negative during 1993; this is in accordance with the carbohydrate interannual depletion and the shoot density decline. Since Posidonia oceanica is regressing in the Mediterranean, our carbon budget may notably contribute to future carbon models that can be essential tools for defining the minimum light requirements for survival. More insight into the functioning of some of the parameters that definitively influence this carbon budget (e.g.: the rhizome/root oxygen consumption and the O-2 to C conversion) is needed to fully understand the vulnerability of seagrasses to Light reduction.