Photosynthetic Productivity of Mayweed Chamomile (Anthemis cotula)

Weed Science ◽  
1991 ◽  
Vol 39 (1) ◽  
pp. 18-26 ◽  
Author(s):  
David R. Gealy ◽  
Sheila A. Squier ◽  
Alex G. Ogg
Keyword(s):  
Pacific Northwest ◽  
Dark Respiration ◽  
Cropping Systems ◽  
Net Photosynthesis ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Photosynthetic Productivity ◽  
Maximum Net Photosynthesis

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%.

scholarly journals Production and Postproduction Irradiance Affects Acclimatization and Longevity of Potted Chrysanthemum and Poinsettia

1990 ◽  
Vol 115 (2) ◽  
pp. 262-265 ◽  
Author(s):  
Terril A. Nell ◽  
Ria T. Leonard ◽  
James E. Barrett
Keyword(s):  
Flux Density ◽  
Dark Respiration ◽  
Photosynthetic Photon Flux Density ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Euphorbia Pulcherrima ◽  
Total Chlorophyll ◽  
Photosynthetic Photon Flux ◽  
Light Compensation Point

Production irradiance levels on growth, light compensation point (LCP), dark respiration (DR), and interior longevity of potted chrysanthemum (Demfranthema grandiflora Tzvelev. cvs. Iridon and Mountain Peak) and poinsettia (Euphorbia pulcherrima Wind. cvs. Annette Hegg Dark Red and Gutbier V-10 Amy) were determined. LCP and DR were measured at anthesis and during acclimatization to interior conditions (10 μmol·s-1·m-2). Days to flowering, inflorescence diameter, total chlorophyll, and interior longevity of chrysanthemum increased when maintained at a mean maximum photosynthetic photon flux density (PPFD) of 500 μmol·s-1·m-2 compared to plants shifted to 300 or 100 μmol·s-1·m-2 8 weeks after planting. LCP and DR were highest at anthesis and were reduced 38% and 49%, respectively, for chrysanthemum and 19% and 42%, respectively, for poinsettia within 3 days in interior conditions. Chrysanthemum plants shifted to 300 μmol·s1·m-2 during production had lower LCP and DR rates at anthesis and throughout time in interior conditions compared to plants maintained at 500 μmol·s-1·m-2. The acclimatization of chrysanthemum to reduced production PPFD is of little significance because interior longevity is reduced. No differences were found in the LCP or DR of poinsettia or chrysanthemum cultivars that differ in interior performance, demonstrating that these physiological characteristics are not good indicators of interior longevity for chrysanthemum and poinsettia.

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
Keyword(s):  
New Zealand ◽  
Dark Respiration ◽  
Genotypic Variation ◽  
Temperature Response ◽  
Light Response ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Ecosystem Dynamics ◽  
Photon Flux ◽  
Photon Flux Density

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.

Photosynthetic light and temperature responses of Eucalyptus cloeziana and Eucalyptus argophloia

2003 ◽  
Vol 51 (5) ◽  
pp. 573 ◽  
Author(s):  
Michael R. Ngugi ◽  
Mark A. Hunt ◽  
David Doley ◽  
Paul Ryan ◽  
Peter J. Dart
Keyword(s):  
Quantum Yield ◽  
Dark Respiration ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Response Curves ◽  
Growth Environment ◽  
Eucalyptus Cloeziana

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.

Gas Exchange Properties of Jointed Goatgrass (Aegilops cylindrica)

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 482-489 ◽  
Author(s):  
David R. Gealy
Keyword(s):  
Dark Respiration ◽  
Stomatal Density ◽  
Photosynthetic Photon Flux Density ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Aegilops Cylindrica ◽  
Jointed Goatgrass ◽  
Diffusive Resistance ◽  
Leaf Surfaces

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.

scholarly journals Estimation of Global and Diffuse Photosynthetic Photon Flux Density under Various Sky Conditions Using Ground-Based Whole-Sky Images

2019 ◽  
Vol 11 (8) ◽  
pp. 932
Author(s):  
Megumi Yamashita ◽  
Mitsunori Yoshimura
Keyword(s):  
Flux Density ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Diffuse Component ◽  
Photosynthetic Photon Flux ◽  
Physiological Processes ◽  
Sky Conditions ◽  
Mean Square Errors ◽  
Relative Root

A knowledge of photosynthetic photon flux density (PPFD: μmol m−2 s−1) is crucial for understanding plant physiological processes in photosynthesis. The diffuse component of the global PPFD on a short timescale is required for the accurate modeling of photosynthesis. However, because the PPFD is difficult to determine, it is generally estimated from incident solar radiation (SR: W m−2), which is routinely observed worldwide. To estimate the PPFD from the SR, photosynthetically active radiation (PAR: W m−2) is separated from the SR using the PAR fraction (PF; PAR/SR: unitless), and the PAR is then converted into the PPFD using the quanta-to-energy ratio (Q/E: μmol J−1). In this procedure, PF and Q/E are considered constant values; however, it was reported recently that PF and Q/E vary under different sky conditions. Moreover, the diffuse ratio (DR) is needed to distinguish the diffuse component in the global PAR, and it is known that the DR varies depending on sky conditions. Ground-based whole-sky images can be used for sky-condition monitoring, instead of human-eye interpretation. This study developed a methodology for estimating the global and diffuse PPFD using whole-sky images. Sky-condition factors were derived through whole-sky image processing, and the effects of these factors on the PF, the Q/E of global and diffuse PAR, and the DR were examined. We estimated the global and diffuse PPFD with instantaneous values using the sky-condition factors under various sky conditions, based on which the detailed effects of the sky-condition factors on PF, Q/E, and DR were clarified. The results of the PPFD estimations had small bias errors of approximately +0.3% and +3.8% and relative root mean square errors of approximately 27% and 20% for the global and diffuse PPFD, respectively.

scholarly journals Different LED Light Wavelengths and Photosynthetic Photon Flux Density Effect on Colletotrichum acutatum Growth

Plants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 143
Author(s):  
Neringa Rasiukevičiūtė ◽  
Aušra Brazaitytė ◽  
Viktorija Vaštakaitė-Kairienė ◽  
Alma Valiuškaitė
Keyword(s):  
Flux Density ◽  
Photosynthetic Photon Flux Density ◽  
Growth Characteristics ◽  
Colletotrichum Acutatum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Light Emitting ◽  
Led Light ◽  
Fungus Growth

The study aimed to evaluate the effect of different photon flux density (PFD) and light-emitting diodes (LED) wavelengths on strawberry Colletotrichum acutatum growth characteristics. The C. acutatum growth characteristics under the blue 450 nm (B), green 530 nm (G), red 660 nm (R), far-red 735 nm (FR), and white 5700 K (W) LEDs at PFD 50, 100 and 200 μmol m−2 s−1 were evaluated. The effect on C. acutatum mycelial growth evaluated by daily measuring until five days after inoculation (DAI). The presence of conidia and size (width and length) evaluated after 5 DAI. The results showed that the highest inhibition of fungus growth was achieved after 1 DAI under B and G at 50 μmol m−2 s−1 PFD. Additionally, after 1–4 DAI under B at 200 μmol m−2 s−1 PFD. The lowest conidia width was under FR at 50 μmol m−2 s−1 PFD and length under FR at 100 μmol m−2 s−1 PFD. Various LED light wavelengths influenced differences in C. acutatum colonies color. In conclusion, different photosynthetic photon flux densities and wavelengths influence C. acutatum growth characteristics. The changes in C. acutatum morphological and phenotypical characteristics could be related to its ability to spread and infect plant tissues. This study’s findings could potentially help to manage C. acutatum by LEDs in controlled environment conditions.

scholarly journals Response of Oxypetalum caeruleum to Irradiance, Temperature, and Photoperiod

1990 ◽  
Vol 115 (6) ◽  
pp. 910-914 ◽  
Author(s):  
A.M. Armitage ◽  
N.G. Seager ◽  
I.J. Warrington ◽  
D.H. Greer ◽  
J. Reyngoud
Keyword(s):  
Stem Elongation ◽  
Net Photosynthesis ◽  
Stem Length ◽  
Photon Flux ◽  
Vase Life ◽  
Photosynthetic Photon Flux ◽  
Node Number ◽  
Stem Strength ◽  
Flower Abortion ◽  
Reduced Time

Incremental increases in temperature from 14 to 22 to 30C resulted in linear increases in stem length and node number and decreases in stem diameter and stem strength of Oxypetalum caeruleum (D. Don.) Decne. Higher temperatures also resulted in additional flower abortion, reduced time to flowering, and fewer flowering stems per inflorescence. Reduction in the photosynthetic photon flux (PPF) from 695 to 315 μmol·s-1·m-2 had similar effects as increasing the temperature on vegetative characteristics, but had little effect on reproductive ones. The rate of stem elongation was greatest at low PPF for all temperatures and at high temperature for all PPF treatments. Net photosynthesis rose between 14 and 22C and declined at 30C for all PPF treatments. Long photoperiods (12 or 14 hours) resulted in longer internodes, longer stems, and more flowers per cyme than short photoperiods (8 or 10 hours), but photoperiod had little effect on flowering time. Treatments to reduce latex coagulant and silver thiosulfate treatments had no significant effect on vase life.

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