Age-related patterns of metabolism and biomass in subterranean tissues of Zostera marina (eelgrass)
Age-related patterns of metabolism and biomass in subterranean tissues of Zostera marina (eelgrass)
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大叶藻（鳗草）地下组织代谢和生物量与年龄相关的模式
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
R. S. Alberte
中科院分区：
文献类型：
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作者：
G. Kraemer;R. S. Alberte
研究了美国加利福尼亚州蒙特雷湾潮下草甸根茎海洋被子植物结缕草的生产和代谢特征，以评估地下系统对整个植物代谢的影响。羊茅地下总生物量与地上(地上)生物量呈正相关。地下系统在组织年龄上呈现出从年轻(近端到出芽)到老年(远端)的梯度。在根生物量不变的情况下，代谢能力指标(呼吸作用、可溶性碳水化合物含量、谷氨酰胺合成酶活性)随着组织年龄的增加而降低。根茎节间生物量和碳水化合物水平受季节和组织年龄的影响，呼吸速率随着组织年龄的增加而下降。沿根茎的前4根(最年轻的)根束占植物总同化潜力的90%，而耗氧量随地下组织的增加而线性增加。一个全植物碳平衡模型预测了4.2~11.6m深度的蒙特利湾鳗草的补偿深度(光合作用=呼吸作用)，给出了瞬时地上部P、：R比为11~4.5。该模型还预测，P、：R和深度(光的可获得性)的微小变化都有可能影响新组织生成率的大变化。虽然地下组织占植物生物量的20-26%，但地下组织呼吸消耗的碳占总光合作用生产量(PG)的5%。在0m深处，该模型预测，地下总呼吸作用将增加到P_1的25%。由于地下组织的呼吸只占植物总呼吸的10%~15%，因此，地上部的碳代谢强烈地控制着羊草的碳平衡。
Production and metabolic features of the rhizomatous marine angiosperm Zostera marina L. (eelgrass) from a subtidal meadow in Monterey Bay, Monterey, California, USA, were examined to assess the impact of the subterranean system on whole plant metabolism. Total subterranean biomass of eelgrass was correlated with above-ground (shoot) biomass. The subterranean system presents a gradient in tissue age, from young (proximal to shoot) to old (distal). While root biomass was constant, indices of metabolic capacity (respiration, soluble carbohydrate content, glutamine synthetase activity) decreased with increasing tissue age. Rhizome internodal biomass and carbohydrate levels were influenced by season and tissue age, and rates of respiration declined with increasing tissue age The first 4 (youngest) root bundles along the rhizome accounted for >90 % of total plant NH,+ assimilatory potential, while O2 consumption increased linearly with increasing amount of subterranean tissue. A model of whole plant carbon balance predicted compensation depths (photosynthesis = respiration) for Monterey Bay eelgrass of 4.2 to 11.6 m depth, given instantaneous shoot P,,,:R ratios of 11 to 4.5. The model also predicted that small changes in both P,,,:R and depth (light availability) have the potential to effect large changes in the rate of new tissue production. Although the subterranean tissues constitute 20 to 26% of plant biomass, carbon consumed by respiration in the subterranean tissue represented < l 5 % of gross photosynthetic production (Pg ) at depths < l 0 m. At the deep edges of the eelgrass bed, the model predicts that total subterranean respiration increases to 25% of P,. Since respiration by subterranean tissues represents only 10 to 15 % of total plant respiration, eelgrass carbon balance is strongly controlled by shoot carbon metabolism.