Effect of photon flux density on carbon assimilation and chlorophyll a fluorescence of cold-stored white spruce and lodgepole pine seedlings

1993 ◽  
Vol 12 (2) ◽  
pp. 185-194 ◽  
Author(s):  
E. L. Camm ◽  
G. J. Harper ◽  
S. I. Rosenthal ◽  
D. M. Camm
Keyword(s):  
Flux Density ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Lodgepole Pine ◽  
Carbon Assimilation ◽  
White Spruce ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Pine Seedlings

Differential tolerance of coniferous species to the microbially produced herbicide bialaphos. II. Metabolic effects

1994 ◽  
Vol 24 (11) ◽  
pp. 2199-2207 ◽  
Author(s):  
Mikaĭlou Sy ◽  
Hank Margolis ◽  
De Yue ◽  
Robert Jobidon ◽  
Louis-P. Vézina
Keyword(s):  
Flux Density ◽  
White Spruce ◽  
Photosynthetic Photon Flux Density ◽  
Red Pine ◽  
Metabolic Effects ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Ammonium Accumulation ◽  
Higher Doses

The effect of the microbially produced herbicide bialaphos on ammonium accumulation and photosynthesis of white spruce (Piceaglauca (Moench) Voss) and red pine (Pinusresinosa Ait.) seedlings was studied under controlled environmental conditions. Ammonium accumulation increased markedly during the first 48 h for seedlings treated in June and was greater in red pine than in white spruce. Ammonium accumulation also increased with higher doses of bialaphos. In contrast, the accumulation of ammonium following bialaphos application in August was minimal for both species and for doses up to an equivalent of 3.0 kg active ingredient (bialaphos) per hectare. Continuous measurements of photosynthesis for the first 12 h following bialaphos application showed a slight negative effect of the herbicide on photosynthetic activity within 2 h of treatment. The decrease was greater for red pine than for white spruce. Photosynthesis measurements taken under three different levels of photosynthetic photon flux density 24 h after bialaphos application showed a greater decline with increasing photosynthetic photon flux density and with higher doses of bialaphos. Furthermore, the decline was greater in red pine than it was in white spruce. When photosynthesis was followed over a 7-day period, a large decrease was observed during the first 24 h, after which time photosynthesis stayed relatively constant. The decrease was greater with higher doses and was greater for red pine than for white spruce. There was a strong negative correlation between photosynthetic rate at day 7 and both the dose of bialaphos and the development of chlorotic foliage. These results help provide a physiological basis for understanding previously reported morphological and growth responses.

The effect of shade on flowering of Piceaglauca

1984 ◽  
Vol 14 (6) ◽  
pp. 830-832 ◽  
Author(s):  
Robert D. Marquard ◽  
James W. Hanover
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Flux Density ◽  
Tree Height ◽  
White Spruce ◽  
Tree Size ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Spectral Quality ◽  
Active Radiation

Differences in fecundity and tree size of white spruce (Piceaglauca (Moench) Voss) were observed within a mixed Picea plantation differentially shaded by a hardwood stand. To relate environmental factors to tree height and fecundity, the plantation was divided into four regions based on the time of the day each region first received direct solar radiation. Thirty percent of the white spruce in the most shaded and 76% in the sunniest region flowered. Photon flux density, spectral quality, and ambient temperature were measured throughout the plantation. Trees in the most shaded region were significantly shorter and received 18% less photosynthetically active radiation than trees in the sunniest region. Photon flux density within the plantation best explained differences in fecundity and tree size.

scholarly journals Performance Assessment of a Novel Pyramid Photobioreactor for Cultivation of Microalgae Using External and Internal Light Sources

2019 ◽  
Vol 57 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Zahra Khoobkar ◽  
Farshid Pajoum Shariati ◽  
Ali Akbar Safekordi ◽  
Hossein Delavari Amrei
Keyword(s):  
Flux Density ◽  
Chlorophyll A ◽  
Light Emitting Diode ◽  
Biomass Productivity ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Sources ◽  
Chlorella Sp ◽  
Red Led

The cultivation of Chlorella sp., the most abundant microalga in the Persian Gulf, took place in a novel pyramid photobioreactor (PBR), a modified version of plate PBR, consisting of four completely separate equal-volume chambers. In this study we used two light sources incident in each chamber: light-emitting diode (LED) at various wavelengths (red, white and blue) of 108 µmol/(m2·s) photosynthetic photon flux density as internal lighting, and the same photon flux density for external white lighting. PBR served to study the effects of light sources on chlorophyll a production, maximum specific growth rate (µmax), biomass productivity rate (rp) and photon performance. The results showed that the highest chlorophyll a production was obtained under red LED illumination. The highest values for rp, µmax and photon performance were obtained under white light.

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.

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