The ecology of Rhizocarpon superficial. II. The seasonal response of net photosynthesis and respiration to temperature, moisture, and light

1983 ◽  
Vol 61 (12) ◽  
pp. 3019-3030 ◽  
Author(s):  
D. S. Coxson ◽  
K. A. Kershaw
Keyword(s):  
Photosynthetic Capacity ◽  
Net Photosynthesis ◽  
Response Matrix ◽  
Operating Environment ◽  
Capacity Change ◽  
Response To Temperature ◽  
Random Fluctuations ◽  
Photosynthesis And Respiration ◽  
Resistance To Heat ◽  
Photosynthetic Adaptation

The seasonal gas-exchange response matrix for the crustaceous lichen Rhizocarpon superficiale (Schaer.) Vain, is presented. Maximum rates for net photosynthesis of ca. 1 mg CO2 g−1 h_1 are generated at 900 μE m−2 s−1 illumination between 50 and 60% relative thallus moisture content and at thallus temperatures of 14 °C down to 1 °C, during all seasons of the year. This broad response to temperature as well as the apparently high resistance to heat stress in Rhizocarpon is discussed in relation to the special characteristics of its boundary-layer habitat. The absence of any seasonal photosynthetic capacity change is discussed in terms of the constraint imposed by the random fluctuations in the thermal operating environment of the lichen. We postulate that the predictability of the operating environment largely determines the extent and the level of any photosynthetic adaptation.

What drives photosynthesis during desiccation? Mosses and other outliers from the photosynthesis–elasticity trade-off

2020 ◽  
Vol 71 (20) ◽  
pp. 6460-6470
Author(s):  
Alicia V Perera-Castro ◽  
Miquel Nadal ◽  
Jaume Flexas
Keyword(s):  
Vascular Plants ◽  
Photosynthetic Capacity ◽  
Net Photosynthesis ◽  
Structural Features ◽  
Current View ◽  
Trade Off ◽  
Linear Dependency ◽  
Co2 Diffusion ◽  
Low Co2 ◽  
Photosynthetic Responses

Abstract In vascular plants, more rigid leaves have been linked to lower photosynthetic capacity, associated with low CO2 diffusion across the mesophyll, indirectly resulting in a trade-off between photosynthetic capacity (An) and bulk modulus of elasticity (ε). However, we evaluated mosses, liverworts, and Chara sp., plus some lycophytes and ferns, and found that they behaved as clear outliers of the An–ε relationship. Despite this finding, when vascular and non-vascular plants were plotted together, ε still linearly determined the cessation of net photosynthesis during desiccation both in species with stomata (either actively or hydro-passively regulated) and in species lacking stomata, and regardless of their leaf structure. The latter result challenges our current view of photosynthetic responses to desiccation and/or water stress. Structural features and hydric strategy are discussed as possible explanations for the deviation of these species from the An–ε trade-off, as well as for the general linear dependency between ε and the full cessation of An during desiccation.

scholarly journals Contributions of leaf photosynthetic capacity, leaf angle and self-shading to the maximization of net photosynthesis in Acer saccharum: a modelling assessment

2012 ◽  
Vol 110 (3) ◽  
pp. 731-741 ◽  
Author(s):  
Juan M. Posada ◽  
Risto Sievänen ◽  
Christian Messier ◽  
Jari Perttunen ◽  
Eero Nikinmaa ◽  
...  
Keyword(s):  
Acer Saccharum ◽  
Photosynthetic Capacity ◽  
Net Photosynthesis ◽  
Leaf Angle

Ecology of Cladonia lichens. II. Comparative physiological ecology of C. mitis, C. rangiferina, and C. uncialis

1974 ◽  
Vol 52 (2) ◽  
pp. 411-422 ◽  
Author(s):  
Martin J. Lechowicz ◽  
Michael S. Adams
Keyword(s):  
Seasonal Variation ◽  
Physiological Ecology ◽  
Net Photosynthesis ◽  
Pine Barrens ◽  
Physiological Tolerance ◽  
Interspecific Differences ◽  
Significant Seasonal Variation ◽  
Relative Water ◽  
Photosynthetic Responses ◽  
Response To Temperature

The net CO2 exchange responses of Cladonia mitis, C. rangiferina, and C. uncialis from the Wisconsin Pine Barrens to irradiance, thallus temperature, and thallus relative water content were statistically compared for fall, spring, and summer. The absolute net photosynthetic rate of C. rangiferina exceeded that of C. uncialis under essentially all conditions and in all seasons; C. mitis's absolute net photosynthesis fluctuated with the seasons between these two contrasting species. Cladonia mitis showed significant intraspecific seasonal variation in net photosynthetic responses to temperature and irradiance. Cladonia rangiferina showed significant seasonal variation in dark respiratory response to temperature. Cladonia uncialis showed no significant intraspecific seasonal variation in net CO2 exchange responses. Significant interspecific differences in net CO2 exchange responses centered on the net photosynthetic responses to thallus temperature and relative water content.Despite its low net photosynthetic rates, C. uncialis is the most prevalent lichen in the Wisconsin Pine Barren ground-layer community. We attribute this not to broad physiological tolerance, but to its significantly slower drying rate. Lichens photosynthesize only when wetted. Cladonia uncialis photosynthesizes at generally lower rates than C. mitis or C. rangiferina, but it photosynthesizes longer under comparable environmental drying regimes. This and other aspects of the physiological ecology of the three species are discussed in relation to microdistribution and microhabitats within the Wisconsin Pine Barrens.

scholarly journals Photosynthetic plasticity of a tropical tree species, Tabebuia rosea, in response to elevated temperature and [CO2]

2021 ◽  
Author(s):  
Martijn Slot ◽  
Sami Rifai ◽  
Klaus Winter
Keyword(s):  
Tree Species ◽  
Photosynthetic Capacity ◽  
Stomatal Density ◽  
Net Photosynthesis ◽  
Tropical Tree ◽  
Measured Temperature ◽  
Tropical Tree Species ◽  
Neotropical Tree ◽  
Photosynthetic Plasticity ◽  
Tabebuia Rosea

Atmospheric and climate change will expose tropical forests to conditions they have not experienced in millions of years. To better understand the consequences of this change we studied photosynthetic acclimation of the neotropical tree species Tabebuia rosea to combined 4°C warming and twice-ambient (800 ppm) CO. We measured temperature responses of the maximum rates of ribulose 1,5-bisphosphate carboxylation (V), photosynthetic electron transport (J), net photosynthesis (P), and stomatal conductance (gs), and fitted the data using a probabilistic Bayesian approach. To evaluate short-term acclimation plants were then switched between treatment and control conditions and re-measured after 1–2 weeks. Consistent with acclimation, the optimum temperatures (T) for V, J and P were 1–5°C higher in treatment than in control plants, while photosynthetic capacity (V, J, and P at T) was 8–25% lower. Likewise, moving control plants to treatment conditions moderately increased temperature optima and decreased photosynthetic capacity. Stomatal density and sensitivity to leaf-to-air vapor pressure deficit were not affected by growth conditions, and treatment plants did not exhibit stronger stomatal limitations. Collectively, these results illustrate the strong photosynthetic plasticity of this tropical tree species as even fully-developed leaves of saplings transferred to extreme conditions partially acclimated.

Photosynthetic Development in Relation to Leaf Expansion in Kiwifruit (Actinidia deliciosa) Vines During Growth in a Controlled Environment

1996 ◽  
Vol 23 (5) ◽  
pp. 541 ◽  
Author(s):  
DH Greer
Keyword(s):  
Leaf Area ◽  
Carbon Balance ◽  
Photosynthetic Capacity ◽  
Photochemical Efficiency ◽  
Net Photosynthesis ◽  
Growth Conditions ◽  
Leaf Expansion ◽  
Actinidia Deliciosa ◽  
Controlled Environment ◽  
Young Leaves

Kiwifruit (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson) vines were grown in constant conditions for 3 months starting from budbreak to measure relationships between leaf development and photosynthesis during leaf expansion. Leaf area, net photosynthesis and fluorescence were repeatedly measured on the same leaves at regular intervals. At the growth conditions, the vines produced 0.5 leaves per day, with the earliest expanding leaves taking about 40 days and later emerging leaves up to 70 days to expand fully. Maximum leaf area increased up to leaf 9 then declined with later emerging leaves. Photosynthesis and photochemical efficiency depended on nodal position but were both highest in the earliest emerging leaves. Maximum photosynthetic capacity of individual leaves generally occurred in concert with leaves reaching full expansion but high rates of photosynthesis were observed within 10 days after budbreak. The early expanding leaves (positions 4 to 9) contributed up to 50% of the total net shoot carbon acquisition over the study period. Young leaves were also resistant to imposed photoinhibitory stresses. Early emerging leaves on kiwifruit vines appear physiologically well adapted to provide carbon in spring, when the plants are in a negative carbon balance.

Inhibition of Metabolic Hydrogen Ion Flux Resulting from Cadmium Stress in Aquatic Microecosystems

1987 ◽  
Vol 19 (11) ◽  
pp. 85-94
Author(s):  
William D. Nicholas ◽  
A. Ray Abernathy
Keyword(s):  
Net Photosynthesis ◽  
Cadmium Stress ◽  
Effective Concentration ◽  
Hydrogen Ion ◽  
Ph Change ◽  
Control Data ◽  
Data Set ◽  
Analysis Techniques ◽  
Photosynthesis And Respiration ◽  
Periodic Changes

Periodic changes in pH were monitored at 30 s intervals in naturally-derived, aquatic microeco-systems. The pH of the system was controlled between two setpoints with a microcomputer. When the upper setpoint was reached a light bank was turned off until the pH dropped to the lower setpoint and the light was again turned on. The cycling of the pH in the microcosms was analyzed using time series analysis techniques. Each experiment resulted in a 24 hour control data set and a 24 hour experimental data set that began with the addition of an inhibitor or toxicant. EC50 values (effective concentration for 50% inhibition) of net photosynthesis and respiration of the community were calculated from slopes of the periodic response to cadmium and compared to literature values. The EC50 for dark induced pH change was 3.8 ppm while the EC50 for light induced pH change was 0.51 ppm. Increasing cadmium concentrations caused dominant peaks in the variance periodograms to be shifted to longer periods.

scholarly journals Photosynthetic Capacity, Stomatal Behavior and Chloroplast Ultrastructure in Leaves of the Endangered Plant Carpinus putoensis W.C.Cheng during Gaseous NO2 Exposure and after Recovery

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 561
Author(s):  
Qianqian Sheng ◽  
Zunling Zhu
Keyword(s):  
Chlorophyll Content ◽  
Photosynthetic Capacity ◽  
Physiological Responses ◽  
Chloroplast Ultrastructure ◽  
Net Photosynthesis ◽  
Spongy Tissue ◽  
High Concentration ◽  
Physicochemical Processes ◽  
Flow Restoration ◽  
Negative Impacts

Foliar uptake of gaseous NO2 mainly occurs through the stomata and disrupts normal plant growth, but no detailed reports about the physiological responses of plants exposed to NO2 are available. In this study, to study leaf physicochemical responses, stomatal characteristics and chloroplast structure, we observed the leaves of Carpinus putoensis W.C.Cheng after exposure to NO2 (6 μL/L) for five time periods (0, 1, 6, 24, and 72 h) and after 30 days of recovery following NO2 exposure. Our results showed that short-duration exposure to a high concentration of NO2 had significant negative impacts (p < 0.05) on the chlorophyll content, photosynthesis and chloroplast-related physicochemical processes of C. putoensis leaves; with the exception of one hour of NO2 exposure, which was helpful for plant physiological responses. Moreover, NO2 exposure significantly increased the thickness of the palisade/spongy tissue and caused swelling of the thylakoids within the chloroplasts; this thylakoid swelling could be reversed by removing the pollutant from the air flow. Restoration of unpolluted air alleviated the toxic effects of NO2, as indicated by an increased chlorophyll content, net photosynthesis, and PSII maximum quantum yield. These results could support the development of a treatment for roadside trees that are exposed to NO2 as a major road pollutant.

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