INSITU RATES OF NITRATE UPTAKE BY GIANT-KELP, MACROCYSTIS-PYRIFERA (L) C AGARDH - TISSUE DIFFERENCES, ENVIRONMENTAL-EFFECTS, AND PREDICTIONS OF NITROGEN LIMITED GROWTH
INSITU RATES OF NITRATE UPTAKE BY GIANT-KELP, MACROCYSTIS-PYRIFERA (L) C AGARDH - TISSUE DIFFERENCES, ENVIRONMENTAL-EFFECTS, AND PREDICTIONS OF NITROGEN LIMITED GROWTH
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DOI：
10.1016/0022-0981(82)90202-7
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发表时间：
1982-01-01
影响因子：
2
通讯作者：
GERARD, VA
中科院分区：
文献类型：
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作者：
GERARD, VA
采用原位法测定了黄芪（M. pyrifera， L.） 7种成年孢子体组织对NO3-的吸收速率。c . Agardh。冠层成熟叶片的吸收遵循饱和动力学。在接近饱和的浓度下，不同组织的平均吸收率在0.1 - 2.1 μ之间。[原子].cntdot。G wet wt-1 .cntdot。H-1 （7-68 ng-at. .cntdot.）cm-2 .cntdot。h)。相似环境条件下不同组织对NO3-的吸收速率不同，存在生理差异。叶片的吸收速率与组织年龄和营养史没有明显的关系，但受一定的环境因素的影响：叶片在黑暗中的吸收速度比正午环境光照水平慢44-48%，叶片在12 m深度孵育的吸收速度比叶片在水面孵育的慢40%。这些生理和环境差异导致位于水面或水面以下的组织通常快速吸收NO3-，而位于水柱深处的组织吸收较慢。利用基于原位NO3-吸收率的模型预测了嘧霉菌种群的日NO3-吸收率。根据模型预测，NO3-浓度为1 ~ 2 μ m。在整个水柱中需要M来支持海带以4%的速度生长。第1天（湿重量）率典型的近海种群。垂直分层，只有在近底部深度NO3-浓度高，会导致严重的氮限制生长。叶片大小分布的季节变化对氮限生长速率影响不大。该模型还用于评估近海海带养殖场的潜在施肥方法和管理问题。
NO3- uptake rates were measured in situ for 7 types of tissue of adult sporophytes of M. pyrifera (L.) C. Agardh. Uptake by mature blades of canopy fronds followed saturation kinetics. At near-saturation concentrations, mean rates of uptake by different tissues ranged from 0.1 to 2.1 .mu.g-at [atoms] .cntdot. g wet wt-1 .cntdot. h-1 (7-68 ng-at. .cntdot. cm-2 .cntdot. h-1). Different tissues incubated under similar environmental conditions took up NO3- at different rates, indicating physiological differences. Uptake rates showed no apparent relation to tissue age or nutritional history, but were influenced by certain environmental factors: uptake was 44-48% slower in dark than at ambient mid-day light levels, and dark uptake was 40% slower by blades incubated at 12 m depth than by blades incubated at the surface. These physiological and environmental differences resulted in generally rapid NO3- uptake by tissues located at or just below the surface and slower uptake by tissues deeper in the water column. Daily NO3- uptake by M. pyrifera populations was predicted using a model based on in situ NO3- uptake rates. According to predictions of the model, NO3- concentrations of 1-2 .mu.M throughout the water column are required to support kelp growth at the 4% .cntdot. day-1 (wet wt) rate typical of inshore populations. Vertical stratification, with high NO3- concentrations only at near-bottom depths, would result in severe N-limitation of growth. Seasonal changes in frond size distribution do not greatly affect N-limited growth rate. The model was also used to evaluate potential fertilizing methods and problems in management of offshore kelp farms.