Underwater photosynthesis and respiration in leaves of submerged wetland plants:: gas films improve CO2 and O2 exchange
Underwater photosynthesis and respiration in leaves of submerged wetland plants:: gas films improve CO2 and O2 exchange
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DOI：
10.1111/j.1469-8137.2007.02318.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Pedersen, Ole
中科院分区：
文献类型：
--
作者：
Colmer, Timothy David;Pedersen, Ole
许多湿地植物的叶片表面都有气膜。我们测试的假设，叶片气膜增强CO2吸收的净光合作用（P-N）在光照期间，和增强O-2吸收的呼吸在黑暗时期。还通过用0.05%（v/v）Triton X刷擦来实验性地去除气膜。在不同CO2和O-2浓度下，测定了光照下O-2的净产生量或黑暗中O-2的消耗量，当去除气膜时，黑暗中O-2的吸收量在20.6 kPa（呼吸临界O-2压，COPR >= 284 mmol O-2 m（-3））时已经达到扩散限制，而对于一些有气膜的叶片，O-2的吸收量仅在20.6 kPa（呼吸临界O-2压，COPR >= 284 mmol O-2 m（-3））时下降。4 kPa（COPR 54 mmol O-2 m（-3））。气膜还能促进CO2的吸收，在光照期间，水下P-N增加了6倍，叶片上的气膜能通过气孔进行持续的气体交换，从而绕过角质层阻力，促进O-2和CO2与周围水体的交换，从而促进水下P-N和呼吸作用。
Many wetland plants have gas films on submerged leaf surfaces. We tested the hypotheses that leaf gas films enhance CO2 uptake for net photosynthesis (P-N) during light periods, and enhance O-2 uptake for respiration during dark periods.Leaves of four wetland species that form gas films, and two species that do not, were used. Gas films were also experimentally removed by brushing with 0.05% (v/v) Triton X. Net O-2 production in light, or O-2 consumption in darkness, was measured at various CO2 and O-2 concentrations.When gas films were removed, O-2 uptake in darkness was already diffusion-limited at 20.6 kPa (critical O-2 pressure for respiration, COPR >= 284 mmol O-2 m(-3)), whereas for some leaves with gas films, O-2 uptake declined only at approx. 4 kPa (COPR 54 mmol O-2 m(-3)). Gas films also improved CO2 uptake so that, during light periods, underwater P-N was enhanced up to sixfold.Gas films on submerged leaves enable continued gas exchange via stomata and thus bypassing of cuticle resistance, enhancing exchange of O-2 and CO2 with the surrounding water, and therefore underwater P-N and respiration.