Salt management strategy defines the stem and leaf hydraulic characteristics of six mangrove tree species
Salt management strategy defines the stem and leaf hydraulic characteristics of six mangrove tree species
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盐管理策略定义了六种红树林树种的茎叶水力特征
DOI：
10.1093/treephys/tpw131
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发表时间：
2017-03-01
期刊：
影响因子：
4
通讯作者：
Cao, Kun-Fang
中科院分区：
文献类型：
--
作者：
Jiang, Guo-Feng;Goodale, Uromi Manage;Cao, Kun-Fang
高盐沿海栖息地中的红树林处于恒定的木质部张力下，面临液压功能障碍的极大风险。为了研究功能性状与盐管理之间的关系，我们在中国南部的四个适应盐（SA）和两个非SA（SA）和两种非SA（NSA）红树林物种中测量了20种液压和光合特征。 SA物种包括两个盐分泌物（SSS），Avicennia Marina（Forsskal）Vierhapper和Aegiceras corniculatum（L.）Blanco和两个盐套公寓（SES），Bruguiera Gymnorrhiza（L.这两种NSA物种是芙蓉（L.）和Pongamia pinnata（L.）Merr。在SES中发现了极高的木质部空化耐药性，以木质部电导率下降50％（PSI（50）； -7.85 MPa）表示，在SES中发现。在SSS中观察到较低的气耐耐药性，可能是由于盐分清除不完全而导致的，从而降低了维持土壤中水吸收所需的木质部张力的幅度。令人惊讶的是，NSA物种P. pinnata的PSI非常低（50）（-5.44 MPa）。与NSA相比，SAS具有较低的光合作用，血管密度，液压电导率和血管直径，但SAPWOOD密度较高。八个特征与物种的盐管理策略密切相关，黎明水潜力（PSI（PD））和平均血管直径为95％的流量（D-95），具有最显着的关联； D-95与NSA和SES分离的SAS具有最低的PSI（PD）。液压性状与碳同化性状之间存在明显的耦合。具有较高安全性的红树林效率更高，Sapwood密度（Rho（Sapwood））而不是被木质部效率损害，而不是液压安全性受到损害，但是Rho（Sapwood）与效率之间没有关系。主成分分析通过在第一轴上加载D，D-95和血管密度，并加载PSI（PD），PSI（50）和水势以12％的木质部电导率损失（PSI（12）），RHO（SAPWOOD）和第二个轴上的量子产率，从而区分了三种盐管理策略的物种。我们的结果提供了具有不同盐管理策略的红树林之间的液压和光合特征的第一个比较表征。
Mangroves in hypersaline coastal habitats are under constant high xylem tension and face great risk of hydraulic dysfunction. To investigate the relationships between functional traits and salt management, we measured 20 hydraulic and photosynthetic traits in four salt-adapted (SA) and two non-SA (NSA) mangrove tree species in south China. The SA species included two salt secretors (SSs), Avicennia marina (Forsskål) Vierhapper and Aegiceras corniculatum (L.) Blanco and two salt excluders (SEs), Bruguiera gymnorrhiza (L.) Savigny and Kandelia obovata (L.) Sheue et al. The two NSA species were Hibiscus tiliaceus (L.) and Pongamia pinnata (L.) Merr. Extremely high xylem cavitation resistance, indicated by water potential at 50% loss of xylem conductivity (Ψ50; -7.85 MPa), was found in SEs. Lower cavitation resistance was observed in SSs, and may result from incomplete salt removal that reduces the magnitude of xylem tension required to maintain water uptake from the soil. Surprisingly, the NSA species, P. pinnata, had very low Ψ50 (-5.44 MPa). Compared with NSAs, SAs had lower photosynthesis, vessel density, hydraulic conductivity and vessel diameter, but higher sapwood density. Eight traits were strongly associated with species' salt management strategies, with predawn water potential (ΨPD) and mean vessel diameter accounting for 95% flow (D95) having the most significant association; D95 separated SAs from NSAs and SEs had the lowest ΨPD. There was significant coupling between hydraulic traits and carbon assimilation traits. Instead of hydraulic safety being compromised by xylem efficiency, mangrove species with higher safety had higher efficiency and greater sapwood density (ρSapwood), but there was no relationship between ρSapwood and efficiency. Principal component analysis differentiated the species of the three salt management strategies by loading D, D95 and vessel density on the first axis and loading ΨPD, Ψ50 and water potential at 12% loss of xylem conductivity (Ψ12), ρSapwood and quantum yield on the second axis. Our results provide the first comparative characterization of hydraulic and photosynthetic traits among mangroves with different salt management strategies.