Genotypic Variation in Light and Temperature Response of Photosynthesis in Nothofagus solandri Var. cliffortioides and N. menziesii

1996 ◽  
Vol 23 (4) ◽  
pp. 421 ◽  
Author(s):  
OJ Sun ◽  
GB Sweet

Responses of photosynthesis to light and temperature were studied in two Nothofagus species native to New Zealand: N. solandri var. cliffortioides (Hook. f.) Poole and N. menziesii (Hook. f.) Oerst.. Measurements of leaf photosynthesis were made in a controlled environment growth chamber at photosynthetic photon flux density between 0 and 700 μmol m-2 s-1 with temperatures set for 10, 20 and 25�C, on seedlings previously grown in a glasshouse from seed of three different origins. In both species, pronounced intraspecific variation was shown in dark respiration, light compensation point and light-saturated net photosynthesis (Amax). Seedlings of N. solandri showed higher dark respiration and light compensation levels than N. menziesii seedlings, but the two species did not differ in Amax. Change in temperature resulted in significant change in the response of photosynthesis to light in both N. solandri and N. menziesii. The differences between N. solandri and N. menziesii in light response of photosynthesis are discussed in terms of ecosystem dynamics of Nothofagus forests in New Zealand.

2003 ◽  
Vol 51 (5) ◽  
pp. 573 ◽  
Author(s):  
Michael R. Ngugi ◽  
Mark A. Hunt ◽  
David Doley ◽  
Paul Ryan ◽  
Peter J. Dart

Acclimation of gas exchange to temperature and light was determined in 18-month-old plants of humid coastal (Gympie) and dry inland (Hungry Hills) provenances of Eucalyptus cloeziana F.Muell., and in those of a dry inland provenance of Eucalyptus argophloia Blakely. Plants were acclimated at day/night temperatures of 18/13, 23/18, 28/23 and 33/28�C in controlled-temperature glasshouses for 4 months. Light and temperature response curves were measured at the beginning and end of the acclimation period. There were no significant differences in the shape and quantum-yield parameters among provenances at 23, 28 and 33�C day temperatures. Quantum yield [μmol CO2 μmol–1 photosynthetic photon flux density (PPFD)] ranged from 0.04 to 0.06 and the light response shape parameter ranged from 0.53 to 0.78. Similarly, no consistent trends in the rate of dark respiration for plants of each provenance were identified at the four growth temperatures. Average values of dark respiration for the plants of the three provenances ranged from 0.61 to 1.86 μmol m–2 s–1. The optimum temperatures for net photosynthesis increased from 23 to 32�C for the humid- and from 25 to 33�C for the dry-provenance E. cloeziana and from 21 to 33�C for E. argophloia as daytime temperature of the growth environment increased from 18 to 33�C. These results have implications in predicting survival and productivity of E. cloeziana and E. argophloia in areas outside their natural distribution.


2005 ◽  
Vol 17 (3) ◽  
pp. 341-352 ◽  
Author(s):  
STEFAN PANNEWITZ ◽  
T.G. ALLAN GREEN ◽  
KADMIEL MAYSEK ◽  
MARK SCHLENSOG ◽  
ROD SEPPELT ◽  
...  

Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment.


MAUSAM ◽  
2022 ◽  
Vol 46 (3) ◽  
pp. 303-306
Author(s):  
Y. R. KENJLE ◽  
M. C. VARSHNEYA ◽  
T. R. U. NAIDU

ABSTRACT. The diurnal variation of rate of photosynthesis (l') with photosynthetic photon flux density (PPFD) model of light response curves and the relationship between PPFD and P were studied for two postmonsoon (rabi) sorghum genotypes, viz.. M35- I and RSV-9R under field conditions at Pune. The half maximal values. i.e., PPFD level at which P=Pmax/2 obtained were 1251 and 937 umolm-2s-1 for M35-l and RSV.9R respectively. The potential rates of photosynthesis were 65,79 and 64.52  umolm-2S-1 whereas the observed maximum rates of photosynthesis were lower. 40.93 and 46.66 umolm-2s-1 in M35-1 and RSV-9R Respectively, due to effect of air temperatures under the field conditions, n1e maximum rate of photosynthesis determined from the model decreased with delay in the sowing of the crop. Correlation coefficients between PPFD and rate of photosynthesis were 0,794 and 0,708 for M35-1 and RSV-9R respectively. The PPFD received and rate of photosynthesis decreased significantly with delay in sorghum sowing.    


2019 ◽  
Vol 46 (7) ◽  
pp. 684 ◽  
Author(s):  
Camilo Rey-Sanchez ◽  
Juan M. Posada

Individual leaves have a unique instantaneous photosynthetic photon flux density (PPFD) at which net photosynthetic light use efficiency (ϵL, the ratio between net photosynthesis and PPFD) is maximised (PPFDϵmax). When PPFD is above or below PPFDϵmax, efficiency declines. Thus, we hypothesised that heterogeneous PPFD conditions should increase the amount of time leaves photosynthesise at a PPFD different than PPFDϵmax and result in reduced growth. To date, this prediction has not been rigorously tested. Here, we exposed seedlings of Abatia parviflora Ruiz & Pav to light regimes of equal total daily irradiance but with three different daily time courses of PPFD: constant PPFD (No_H), low heterogeneity (Low_H) and high heterogeneity (High_H). Mean ϵL, leaf daily photosynthesis and plant growth were all significantly higher in No_H and Low_H plants than in High_H plants, supporting our hypothesis. In addition, mean ϵL was positively related to final plant biomass. Unexpectedly, High_H plants had more etiolated stems and more horizontal leaves than No_H and Low_H plants, possibly due to exposure to low PPFD in the morning and afternoon. In conclusion, PPFD heterogeneity had an important effect on average ϵL, photosynthesis and growth, but also on allocation and plant morphology.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 127
Author(s):  
Richard M. Bastías ◽  
Pasquale Losciale ◽  
Camilla Chieco ◽  
Luca Corelli-Grappadelli

There is little information about the role of red and blue light on leaf morphology and physiology in fruit trees, and more studies have been developed in herbaceous plants grown under controlled light conditions. The objective of this research was to evaluate the effect of red and blue screens on morpho-anatomy and gas exchange in apple leaves grown under ambient sunlight conditions. Apple trees cv. Fuji were covered by 40% red and blue nets, leaving trees with 20% white net as control. Light relations (photosynthetic photon flux density, PPFD; red to far-red light ratio, R/FR and blue to red light ratio, B/R), morpho-anatomical features of the leaf (palisade to spongy mesophyll ratio, P/S, and stomata density, SD) and leaf gas exchange (net photosynthesis rate, An; stomatal conductance, gs; transpiration rate, E; and intrinsic water use efficiency, IWUE) were evaluated. Red and blue nets reduced 27% PPFD, reducing by 20% SD and 25% P/S compared to control, but without negative effects on An and gs. Blue net increased gs 21%, leading to the highest E and lowest IWUE by increment of B/R light proportion. These findings demonstrate the potential use of red and blue nets for differential modulation of apple leaf gas exchange through sunlight management under field conditions.


1987 ◽  
Vol 17 (4) ◽  
pp. 273-283 ◽  
Author(s):  
R. Ceulemans ◽  
I. Impens ◽  
V. Steenackers

Several photosynthetic, anatomical, and enzymatic leaf traits were studied on 1- and 2-year-old fast growing Populus clones representing interspecific hybrids of P. deltoides, P. trichocarpa, and P. maximowiczii. Growth performance of the clones was studied with container-grown plants and for 5 years in the field. Considerable variation in photosynthetic, anatomical, and enzymatic leaf traits was found, but variation in growth differences among the clonal groups was minimal. Photosynthetic photon flux density saturated net photosynthesis of 1-year-old container-grown plants was significantly correlated with shoot height growth, but none of the other leaf traits measured showed a significant correlation with any of the growth characteristics. Clonal groups could be segregated by taxonomic and genetic affinities with hierarchical clustering and principal component analysis. Although enzymatic and biochemical traits (area leaf weight, ribulose-bisphosphate carboxylase and phosphoenolpyruvate carboxylase activities, protein content) and adaxial stomatal frequency can be used to discriminate among clonal groups, no significant regression of these leaf traits on growth performance was observed.


Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 482-489 ◽  
Author(s):  
David R. Gealy

Net (apparent) photosynthesis rate (Pn) of jointed goatgrass (Aegilops cylindricaHost # AEGCY) leaves in the greenhouse became light saturated at a photosynthetic photon flux density (PPFD) of about 1000 μE·m–1-2·s–1with a maximum Pn of 27 mg CO2·dm–2·h–1. Diffusive resistance to water vapor (rl) of adaxial leaf surfaces was 43% that of abaxial surfaces, in part, because stomatal density was 50% greater on adaxial leaf surfaces than on abaxial surfaces. Dark respiration rate (Rd) was 1.6 mg CO2·dm−2·h−1. Light compensation point (CPl) was 21 μE·m−2·s−1and CO2compensation point (CPc) was 32 ppmv. In the field, where light intensity and temperature were greater than in the greenhouse, leaves became light saturated for Pn at a higher intensity, and Rd and CPl were three times greater than in the greenhouse. Pn and Rd of spikes at anthesis were at least 30% less and 200% greater, respectively, than the values for leaves.


Weed Science ◽  
1991 ◽  
Vol 39 (1) ◽  
pp. 18-26 ◽  
Author(s):  
David R. Gealy ◽  
Sheila A. Squier ◽  
Alex G. Ogg

Photosynthetic productivity parameters were determined for mayweed chamomile, a troublesome annual weed of the cropping systems in the Pacific Northwest. At a photosynthetic photon flux density of 1800 μE m−2s–1, maximum net photosynthetic rate of greenhouse-grown plants was 35 mg CO2dm−2h–1and maximum transpiration rate was 6.7 μg H2O cm−2s–1. Dark respiration rate was 1.4 mg CO2dm−2h–1and the light compensation point was 17.5 μE m−2s–1. Carbon dioxide compensation point increased from 25 ppm at 15 C to 43 ppm at 30 C. At saturating photosynthetic photon flux densities, optimum leaf temperature for net photosynthesis was about 25 C. Maximum net photosynthesis of leaves of field-grown plants averaged 15.8 mg CO2dm−2h–1. After a 24-h exposure to 0.075 kg ha–1metribuzin, maximum net photosynthesis and transpiration were reduced 85 and 40%, respectively. Soil water deficits reduced maximum net photosynthesis about 50%.


1988 ◽  
Vol 68 (4) ◽  
pp. 1209-1218 ◽  
Author(s):  
ATHANASIOS P. PAPADOPOULOS ◽  
DOUGLAS P. ORMROD

The effect of four equidistant spacings (23, 30, 38, 45 cm) applied to four-row plantings of greenhouse tomato (Lycopersicon esculentum Mill. ’CR-6’) on plant net photosynthesis (P) and transpiration (E) was studied. Closer spacing decreased the leaf-area-based net photosynthesis (Pa) of the lower leaves but had little effect on the Pa of the upper leaves. The exposed parts of a tomato plant could adjust their Pa rates upwards to compensate for the low Pa of their shaded parts. The leaf-weight-based net photosynthesis (Pw) increased with the decrease of plant spacing and it was higher in inside compared to outside plants. The differences between the Pa and Pw results were mostly attributable to the effect of light in increasing the specific leaf weight (SLW). The E rate of plants increased at the closest spacing and there was a higher leaf weight based transpiration (Ew) in inside than outside plants. The leaf area based transpiration (Ea) and stomatal resistance (Rw) were not affected appreciably by light (photosynthetic photon flux density) other than at very low levels (i.e. less than 100 μmol m−2 s−1) where there was a sharp increase in Rw and a corresponding decrease in Ea. The P of plants growing in an environment of gradually declining duration and intensity of solar irradiance declined with the aging of plants. There was no similar effect on E.Key words: Lycopersicon esculentum Mill, plant spacing, photosynthesis, transpiration, tomato


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