THE EFFECT OF PHOTOSYNTHETIC PHOTON FLUX DENSITY ON CUCUMBER AND TOMATO TRANSPLANTS ASSIMILATIVE INDICES

2015 ◽  
Author(s):  
Aistė Bagdonavičienė ◽  
Aušra Brazaitytė ◽  
Julė Jankauskienė ◽  
Pavelas Duchovskis
Keyword(s):  
Solid State ◽  
Leaf Area ◽  
Weight Ratio ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Light Emitting ◽  
Net Assimilation ◽  
Positive Effect

The objective of our studies was to evaluate the assimilative indices of cucumber (‘Pasalimo F1’) and tomato (‘Marissa F1’) transplants, cultivated under various photosynthetic photon flux densities (PPFD) were provided by light-emitting diodes (LEDs). Experiment was performed in phytotron complex of Institute of Horticulture, LRCAF. A system of high-power, solid-state lighting modules with 92 % 638 nm (red) + 665 nm (red) + 731 nm (far red) and 8 % 447 nm (blue) was used in the experiments. The generated PPFD of each type of five solid-state modules was ~200 and ~400 μmol m-2 s-1. Our experiment revealed that increased net assimilation rate (NAR) depended on increased PPFD of cucumber and tomato hybrid. 400 μmol m-2 s-1 LED illumination had positive effect on relative growth rate (RGR). Cucumbers which were grown under 200 μmol m-2 s-1 had bigger leaf area ratio (LAR) and specific leaf area (SLA), their development has been bigger as compared to higher 400 μmol m-2 s-1 PPFD. High PPFD LED illumination had positive effect on leaf weight ratio (LWR), shoot root ratio (SRR) and tomato transplants development. These studies with various photosynthetic photon flux densities (PPFD) and LEDs light should be continued throughout plant vegetation.

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 The Impact of Carbon Dioxide Concentrations and Low to Adequate Photosynthetic Photon Flux Density on Growth, Physiology and Nutrient Use Efficiency of Juvenile Cacao Genotypes

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 397 ◽  
Author(s):  
Virupax C. Baligar ◽  
Marshall K. Elson ◽  
Alex-Alan F. Almeida ◽  
Quintino R. de Araujo ◽  
Dario Ahnert ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Leaf Area ◽  
Nutrient Use Efficiency ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Growth Physiology ◽  
Nutrient Use ◽  
Use Efficiency

Cacao (Theobroma cacao L.) was grown as an understory tree in agroforestry systems where it received inadequate to adequate levels of photosynthetic photon flux density (PPFD). As atmospheric carbon dioxide steadily increased, it was unclear what impact this would have on cacao growth and development at low PPFD. This research evaluated the effects of ambient and elevated levels carbon dioxide under inadequate to adequate levels of PPFD on growth, physiological and nutrient use efficiency traits of seven genetically contrasting juvenile cacao genotypes. Growth parameters (total and root dry weight, root length, stem height, leaf area, relative growth rate and net assimilation rates increased, and specific leaf area decreased significantly in response to increasing carbon dioxide and PPFD. Increasing carbon dioxide and PPFD levels significantly increased net photosynthesis and water-use efficiency traits but significantly reduced stomatal conductance and transpiration. With few exceptions, increasing carbon dioxide and PPFD reduced macro–micro nutrient concentrations but increased uptake, influx, transport and nutrient use efficiency in all cacao genotypes. Irrespective of levels of carbon dioxide and PPFD, intraspecific differences were observed for growth, physiology and nutrient use efficiency of cacao genotypes.

Effects of CO2Enrichment on Competition Between a C4Weed and a C3Crop

Weed Science ◽  
1984 ◽  
Vol 32 (1) ◽  
pp. 101-105 ◽  
Author(s):  
David T. Patterson ◽  
Elizabeth P. Flint ◽  
Jan L. Beyers
Keyword(s):  
Leaf Area ◽  
Relative Yield ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Dry Matter Accumulation ◽  
Leaf Area Expansion ◽  
Leaf Area Duration ◽  
Net Assimilation ◽  
Area Expansion

The C4weed johnsongrass [Sorghum halepense(L.) Pers. ♯3SORHA] and the C3crop soybean [Glycine max(L.) Merr. ‘Ransom’] were grown separately and in inter- and intraspecific competition at 350 and 675 ppm CO2in controlled environment chambers with 29/23 C day/night temperatures and 950 μE·m-2· s-1PPFD (photosynthetic photon flux density). In the absence of competition, the higher CO2concentration stimulated dry matter accumulation, leaf area expansion, net assimilation rate, and leaf area duration of soybean more than that of johnsongrass. The plant relative yield (PRY) of soybean in competition with johnsongrass increased, and the PRY of johnsongrass in competition with soybean decreased, as the CO2concentration was increased from 350 to 675 ppm. Thus, the competitiveness of the C3crop with the C4weed increased with increasing CO2concentration. Relative yield totals were not significantly different from 1.0, indicating that the two species were competing for the same resources. With the increases in global atmospheric CO2concentration predicted for the next 50 to 100 yr, the competitiveness of C3crops with C4weeds could be increased.

scholarly journals Extinction coefficient and interception efficiency of the photosynthetic photon flux density in cherry tomato under levels of nitrogen in greenhouse conditions

2019 ◽  
pp. 1749-1755
Author(s):  
Mariana de Oliveira Pereira ◽  
Gustavo Bastos Lyra ◽  
Guilherme Bastos Lyra ◽  
Leonardo Duarte Batista Silva ◽  
José Leonaldo de Souza ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Flux Density ◽  
Extinction Coefficient ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Cherry Tomato ◽  
Photosynthetic Photon Flux ◽  
Area Index

Cherry tomato (Perinha Água Branca cultivar) was cultivated under organic management in greenhouse conditions set up in the municipality of Seropédica, Rio de Janeiro state, Southeastern Brazil. The crop was subjected to different nitrogen doses (N) ranging from 0 to 400% based on the reference value for the crop (100 kg ha-1) applied by means of dairy cattle wastewater. In order to estimate the extinction coefficient (k) and interception efficiency (Ԑint), weekly measurements of the photosynthetic photon flux density (PPFD) were performed below (PPFDb) and above the canopy (PPFDa) and the Leaf Area Index (LAI) was estimated. The extinction coefficient k for each treatment was obtained based on the model proposed by Monsi and Saeki. Ԑint was estimated by the quotient between PPFD absorbed by the canopy (PPFDabs = PPFDa – PPFDb) and PPFDa. Statistical tests were applied to k and Ԑint to evaluate the distribution of data (Kolmorogov-Smirnov) and their significance (Kruskal-Wallis), considering the treatments applied. No statistically significant differences were observed for k (p<0.05), which indicated canopy structure uniformity. The median k value was 0.792. Similar to k, Ԑint showed no statistically significant differences (p<0.05) between treatments; however, the highest interception efficiency was achieved by treatment with 300% N (Ԑint = 0.825), which coincided with the highest leaf area index and the lowest by treatment with 100% N (Ԑint = 0.521). The nitrogen did not interfere in the plant canopy architecture; however, it provided greater leaf area index to plants submitted to nitrogen doses two and three times above that recommended for the crop. Treatment with three times the recommended nitrogen dose reached in a shorter time interval the maximum efficiency value

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 Use of an Aspen Overstory to Control Understory Herbaceous Species, Bluejoint Grass (Calamagrostis canadensis), and Fireweed (Epilobium angustifolium)

2004 ◽  
Vol 21 (2) ◽  
pp. 74-79 ◽  
Author(s):  
Chris Maundrell ◽  
Chris Hawkins
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Ground Cover ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Calamagrostis Canadensis ◽  
Canopy Opening ◽  
Epilobium Angustifolium

Abstract To enhance white spruce [Picea glauca (Moench) Voss] regeneration and growth, the potential for using an aspen (Populus tremuloides Michx.) overstory to suppress bluejoint grass [Calamagrostis canadensis (Michx.)] and fireweed (Epilobium angustifolium L) was investigated. Response to canopy opening was assessed on 10 treatments where the canopy had been incrementally opened. At the summer solstice, measurements of attenuated light were taken at 1.3 meters (breast height). Bluejoint grass and fireweed both responded with greater ground cover as the photosynthetic photon flux density increased (R2 = 0.84, P = 0.0002; R2 = 0.90, P = 0.0001; respectively). Where aspen has developed an overstory canopy, it may be possible to control competing vegetation to create favorable environmental conditions for spruce re-establishment, growth, and release while encouraging a sustainable mixedwood stand.

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