The analysis of photosynthetic performance in leaves under field conditions: A case study using Bruguiera mangroves

In this report, we analyze the photosynthetic capacity and performance of leaves under field conditions with a case study based on the mangroves Bruguiera parviflora and B. gymnorrhiza. Using a tower through a closed canopy at a field sight in North Queensland and portable infra-red gas analyzers, a large data set was collected over a period of 11 days early in the growing season. The set was used to analyze the relationship between net photosynthesis (Pnet) and light, leaf temperature, stomatal conductance and intracellular CO2 (Ci).There are three objectives of this report: (1) to determine photosynthetic potential as indicated by the in situ responses of Pnet to light and stomatal conductance, (2) to determine the extent to which photosynthetic performance may be reduced from that potential, and (3) to explore the basis for and physiological significance of the reduction.The results indicate that even under harsh tropical conditions, the mangrove photosynthetic machinery is capable of operating efficiently at low light and with maximal rates of more than 15 μmol CO2 m-2 s-1. Though stomata were more often limiting than light, in any single measurement the average reduction of Pnet from the maximum value predicted by light or conductance responses was 35%. Analysis of single leaf light and CO2 responses indicated that photosynthetic performance was under direct photosynthetic, or non-stomatal, control at all light and conductance levels. Capacity was adjustable rapidly from a maximum value to essentially nil such that Ci varied inversely with Pnet from ca. 150 μL L-1 at the highest rates of CO2 exchange to ambient at the lowest.

[1]  I. R. Cowan,et al.  Leaf Conductance in Relation to Rate of CO(2) Assimilation: III. Influences of Water Stress and Photoinhibition. , 1985, Plant physiology.

[2]  G. Farquhar,et al.  Some relationships between the biochemistry of photosynthesis and the gas exchange of leaves , 1981, Planta.

[3]  T. Sharkey,et al.  Effects of Irradiance and Methyl Viologen Treatment on ATP, ADP, and Activation of Ribulose Bisphosphate Carboxylase in Spinach Leaves. , 1988, Plant physiology.

[4]  A. Crofts,et al.  Investigation of the limitations to photosynthesis induced by leaf water deficit in field‐grown sunflower (Helianthus annuus L.) , 1990 .

[5]  B. Genty,et al.  Relationship between Photosynthetic Electron Transport and Stromal Enzyme Activity in Pea Leaves : Toward an Understanding of the Nature of Photosynthetic Control. , 1990, Plant physiology.

[6]  G. Marco,et al.  Drought effects on photosynthesis and fluorescence in hard wheat cultivars grown in the field , 1988 .

[7]  I. R. Cowan,et al.  Leaf Conductance in Relation to Rate of CO(2) Assimilation: I. Influence of Nitrogen Nutrition, Phosphorus Nutrition, Photon Flux Density, and Ambient Partial Pressure of CO(2) during Ontogeny. , 1985, Plant physiology.

[8]  J. Leverenz.  Chlorophyll content and the light response curve of shade‐adapted conifer needles , 1987 .

[9]  R. Furbank,et al.  The mechanisms contributing to photosynthetic control of electron transport by carbon assimilation in leaves , 1990, Photosynthesis Research.

[10]  W. Hartung,et al.  Inhibition of photosynthesis of sunflower leaves by an endogenous solute and interdependence of different photosynthetic reactions , 1989, Planta.

[11]  B. Saugier,et al.  Effects of nitrogen deficiency on leaf photosynthetic response of tall fescue to water deficit , 1989 .

[12]  C. R. Ireland,et al.  An integrated portable apparatus for the simultaneous field measurement of photosynthetic CO2 and water vapour exchange, light absorption and chlorophyll fluorescence emission of attached leaves , 1989 .

[13]  I. R. Cowan,et al.  Maintenance of Leaf Temperature and the Optimisation of Carbon Gain in Relation to Water Loss in a Tropical Mangrove Forest , 1988 .

[14]  J. Cheeseman,et al.  Control of Na+ and K+ transport in Spergularia marina I. Transpiration effects , 1986 .

[15]  M. Kirschbaum,et al.  Gas Exchange Analysis of the Fast Phase of Photosynthetic Induction in Alocasia macrorrhiza. , 1988, Plant physiology.

[16]  M. Ball.  Salinity tolerance in the mangroves Aegiceras corniculatum and Avicennia marina. I: Water use in relation to growth, carbon partitioning, and salt balance , 1988 .

[17]  I. R. Cowan,et al.  Stomatal conductance correlates with photosynthetic capacity , 1979, Nature.

[18]  K. Boto.  Nutrient and organic fluxes in Mangroves , 1982 .

[19]  K. Siebke,et al.  Control of photosynthesis in leaves as revealed by rapid gas exchange and measurements of the assimilatory force FA , 1990, Planta.

[20]  M. Kirschbaum.  Recovery of photosynthesis from water stress in Eucalyptus pauciflora: a process in two stages , 1988 .

[21]  G. Farquhar,et al.  Photosynthetic and Stomatal Responses of Two Mangrove Species, Aegiceras corniculatum and Avicennia marina, to Long Term Salinity and Humidity Conditions. , 1984, Plant physiology.

[22]  B. Genty,et al.  The relationship between CO2 assimilation and electron transport in leaves , 1990, Photosynthesis Research.

[23]  G. Farquhar,et al.  Photosynthetic and Stomatal Responses of the Grey Mangrove, Avicennia marina, to Transient Salinity Conditions. , 1984, Plant physiology.

[24]  D. Walker,et al.  Simultaneous measurement of oxygen evolution and chlorophyll fluorescence from leaf pieces. , 1983, Plant physiology.

[25]  M. Ball,et al.  Salinity-Induced Potassium Deficiency Causes Loss of Functional Photosystem II in Leaves of the Grey Mangrove, Avicennia marina, Through Depletion of the Atrazine-Binding Polypeptide , 1987 .

[26]  W. A. Larsen,et al.  The Use of Partial Residual Plots in Regression Analysis , 1972 .

[27]  T. Andrews,et al.  Mangrove Photosynthesis: Response to High-Irradiance Stress , 1988 .

[28]  J. Bunt,et al.  River water salinity and the distribution of mangrove species along several rivers in north Queensland , 1982 .

[29]  J. Seemann,et al.  Photosynthetic induction state of leaves in a soybean canopy in relation to light regulation of ribulose-1-5-bisphosphate carboxylase and stomatal conductance. , 1990, Plant physiology.

[30]  Boyd R. Strain,et al.  Physiological responses in two populations of Andropogon glomeratus Walter B.S.P. to short-term salinity , 1988, Oecologia.

[31]  I. E. Woodrow,et al.  Control of photosynthetic carbon dioxide fixation by the boundary layer, stomata and ribulose 1,5‐biphosphate carboxylase/oxygenase , 1990 .

[32]  P. Tomlinson.  The botany of mangroves , 1987 .

[33]  J. Tenhunen,et al.  Changes in photosynthetic capacity, carboxylation efficiency, and CO2 compensation point associated with midday stomatal closure and midday depression of net CO2 exchange of leaves of Quercus suber , 1984, Planta.

[34]  T. Andrews,et al.  Photosynthetic gas exchange of the mangrove, Rhizophora stylosa Griff., in its natural environment , 1985, Oecologia.