Growth and physiological responses of three seagrass species to elevated sediment nutrients in Moreton Bay, Australia
Growth and physiological responses of three seagrass species to elevated sediment nutrients in Moreton Bay, Australia
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DOI：
10.1016/s0022-0981(97)00060-9
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发表时间：
1997-10-01
影响因子：
2
通讯作者：
Dennison, WC
中科院分区：
文献类型：
--
作者：
Udy, JW;Dennison, WC
海草是一种具有较高初级生产力的海洋被子植物，但其生长往往受到养分供应的限制，尤其是氮和磷。研究了三种海草（Halodule uninervis（Forsk.），大叶藻（Zostera capricorni Aschers）和细齿剑水蚤（Cymoprotea serrulata（r.Br.）Aschers）升高沉积物N（100倍控制）和/或P（10倍控制）在相邻的单种床超过3个月的时间从春天到初夏。每个物种表现出不同的生长和生物量的反应，氮和磷添加。单脉盐藻的生长和生物量增加，响应N和N + P添加，表明排他性的N限制的增长。与此相反，生长和生物量Z。capricorni增加响应N + P添加，表明平衡的N和P限制。Cymoproa serrulata的生长和生物量没有受到任何营养添加的影响。3种海草的生理特性（氨基酸组成、组织养分含量、N-15）对N添加（+ N和N + P）均有响应。与对照相比，海草叶片的总氨基酸含量增加了2至4倍，在N添加。富氮氨基酸谷氨酰胺和天冬酰胺的浓度在氮添加中增加了10-1000倍，表明这些氨基酸可能是氮的代谢储存。叶片、根和根茎的组织N含量增加，叶片的Δ N-15降低。虽然海草的生长和生物量的反应，营养添加物的物种特异性，代谢反应是相似的所有物种。这表明海草的生理特性是有用的，用于确定饱和的营养供应的环境，但不应该被用来确定是否营养的可用性限制海草的生长速度。(C)1997年Elsevier Science B.V.
Seagrasses, marine angiosperms with high rates of primary productivity, are often limited by the supply of nutrients, particularly nitrogen (N) and phosphorus (P). We investigated growth and physiological responses of three seagrass species (Halodule uninervis (Forsk.), Zostera capricorni Aschers and Cymodocea serrulata (r.Br.) Aschers) to elevated sediment N (100X control) and/or P (10x control) in adjacent monospecific beds over a 3 month period from spring to early summer. Each species exhibited different growth and biomass responses to both N and P additions. Halodule uninervis growth and biomass increased in response to N and N + P additions, indicative of exclusive N limitation of growth. In contrast, growth and biomass of Z. capricorni increased in response to N + P additions only, indicative of balanced N and P limitation. Cymodocea serrulata growth and biomass were not affected by any of the nutrient additions. Physiological characteristics (amino acid composition, tissue nutrient content, delta N-15) of all three seagrass species responded to N additions (+ N and N + P). Total amino acid content of seagrass leaves increased by 2 to 4 fold in N additions compared with controls. Concentrations of the N-rich amino acids, glutamine and asparagine, increased by 10-1000 fold in N additions, suggesting that these amino acids may be a metabolic storage for N. Tissue N content of leaves, roots and rhizomes increased and delta N-15 of the leaves decreased in response to N additions. Although seagrass growth and biomass responses to nutrient additions were species specific, metabolic responses were similar for all species. This suggests physiological characteristics of seagrasses are useful for identifying saturating nutrient supply to an environment, but should not be used to determine whether nutrient availability is limiting the seagrass growth rate. (C) 1997 Elsevier Science B.V.