Salinity has little effect on photosynthetic and respiratory responses to seasonal temperature changes in black mangrove (Avicennia germinans) seedlings

2020 ◽  
Author(s):  
Michael J Aspinwall ◽  
Martina Faciane ◽  
Kylie Harris ◽  
Madison O’Toole ◽  
Amy Neece ◽  
...  
Keyword(s):  
Air Temperature ◽  
Seasonal Changes ◽  
Avicennia Germinans ◽  
Model Parameters ◽  
Similar Response ◽  
Seasonal Temperature ◽  
Leaf Respiration ◽  
Black Mangrove ◽  
Photosynthetic Responses ◽  
Respiratory Responses

Abstract Temperature and salinity are important regulators of mangrove range limits and productivity, but the physiological responses of mangroves to the interactive effects of temperature and salinity remain uncertain. We tested the hypothesis that salinity alters photosynthetic responses to seasonal changes in temperature and vapor pressure deficit (D), as well as thermal acclimation _of leaf respiration in black mangrove (Avicennia germinans). To test this hypothesis, we grew seedlings of A. germinans in an outdoor experiment for ~ 12 months under four treatments spanning 0 to 55 ppt porewater salinity. We repeatedly measured seedling growth and in situ rates of leaf net photosynthesis (Asat) and stomatal conductance to water vapor (gs) at prevailing leaf temperatures, along with estimated rates of Rubisco carboxylation (Vcmax) and electron transport for RuBP regeneration (Jmax), and measured rates of leaf respiration at 25 °C (Rarea25). We developed empirical models describing the seasonal response of leaf gas exchange and photosynthetic capacity to leaf temperature and D, and the response of Rarea25 to changes in mean daily air temperature. We tested the effect of salinity on model parameters. Over time, salinity had weak or inconsistent effects on Asat, gs and Rarea25. Salinity also had little effect on the biochemical parameters of photosynthesis (Vcmax, Jmax) and individual measurements of Asat, gs, Vcmax and Jmax showed a similar response to seasonal changes in temperature and D across all salinity treatments. Individual measurements of Rarea25 showed a similar inverse relationship with mean daily air temperature across all salinity treatments. We conclude that photosynthetic responses to seasonal changes in temperature and D, as well as seasonal temperature acclimation of leaf R, are largely consistent across a range of salinities in A. germinans. These results might simplify predictions of photosynthetic and respiratory responses to temperature in young mangroves.

The influence of radical architecture on cadmium bioaccumulation in the black mangrove, Avicennia germinans L

Chemosphere ◽  
2007 ◽  
Vol 67 (2) ◽  
pp. 330-334 ◽  
Author(s):  
D. Gonzalez-Mendoza ◽  
V. Ceja-Moreno ◽  
G. Gold-Bouchot ◽  
R.M. Escobedo-GraciaMedrano ◽  
M. Del-Rio ◽  
...  
Keyword(s):  
Avicennia Germinans ◽  
Black Mangrove ◽  
Radical Architecture ◽  
Cadmium Bioaccumulation

scholarly journals Photosynthetic Responses of Populus alba×glandulosa to Elevated CO2Concentration and Air Temperature

2014 ◽  
Vol 16 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Solji Lee ◽  
Chang-Young Oh ◽  
Sim-Hee Han ◽  
Ki Woo Kim ◽  
Pan-Gi Kim
Keyword(s):  
Air Temperature ◽  
Populus Alba ◽  
Photosynthetic Responses

scholarly journals Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

2010 ◽  
Vol 7 (3) ◽  
pp. 959-977 ◽  
Author(s):  
M. Ueyama ◽  
K. Ichii ◽  
R. Hirata ◽  
K. Takagi ◽  
J. Asanuma ◽  
...  
Keyword(s):  
Air Temperature ◽  
Ecosystem Respiration ◽  
Spatial Scales ◽  
Model Performance ◽  
Limiting Factors ◽  
Model Parameters ◽  
Total Precipitation ◽  
Water Conditions ◽  
Larch Forests ◽  
Water Cycles

Abstract. Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales. The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE), gross primary productivity (GPP), ecosystem respiration (RE), and evapotranspiration (ET). Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values. The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation. Although this study substantially improved the model performance, the uncertainties that remained in terms of the sensitivity to water conditions should be examined in ongoing and long-term observations.

Seasonal Changes in the Germination Responses of Buried Witchgrass (Panicum capillare) Seeds

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 22-24 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seasonal Changes ◽  
Late Summer ◽  
Late Spring ◽  
Seasonal Temperature ◽  
Temperature Changes ◽  
Late Autumn ◽  
Buried Seeds ◽  
Autumn And Winter

Buried seeds of witchgrass (Panicum capillare L., # PANCA) exposed to natural seasonal temperature changes in Lexington, KY, for 0 to 35 months exhibited annual dormancy/nondormancy cycles. Seeds were dormant at maturity in early October. During burial in late autumn and winter, fresh seeds and those that had been buried for 1 and 2 years became nondormant. Nondormant seeds germinated from 76 to 100% in light at daily thermoperiods of 15/6, 20/10, 25/15, 30/15, and 35/20 C, while in darkness they germinated from 1 to 24%. In late spring, seeds lost the ability to germinate in darkness, and by late summer 63 to 100% of them had lost the ability to germinate in light. As seeds became nondormant, they germinated (in light) at high (35/20, 30/15 C) and then at lower (25/15, 20/10, and 15/6 C) temperatures. As seeds reentered dormancy, they lost the ability to germinate (in light) at 15/6 C and at higher thermoperiods 2 to 3 months later.

The Influence of Uncertainty in Air Temperature and Albedo on Snowmelt

1991 ◽  
Vol 22 (2) ◽  
pp. 95-108 ◽  
Author(s):  
G. Blöschl
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Meteorological Data ◽  
Model Parameters ◽  
Local Effects ◽  
Austrian Alps ◽  
Air Temperatures ◽  
Basin Scale ◽  
Simulation Results

Extrapolating meteorological data to the basin scale represents a major problem of spatial snowmelt modelling in alpine terrain. Within this study errors in air temperature introduced by regionalization are analyzed for the Sellrain region in the Austrian Alps. Albedo is simulated using a range of model parameters representing different snow cover conditions. The influence on snowmelt is assessed by simulating water equivalent at the site scale using estimated air temperatures and albedoes. Simulation results indicate that a bias in measured temperatures as produced by local effects may be significantly more important than interpolation errors. Uncertainty in albedo appears to affect snowmelt to a higher degree than air temperature.

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