scholarly journals Phototaxis of Fungus Gnat, Bradysia sp. nr coprophila (Lintner) (Diptera: Sciaridae), Adults to Different Light Intensities

HortScience ◽  
2007 ◽  
Vol 42 (5) ◽  
pp. 1217-1220 ◽  
Author(s):  
Raymond A. Cloyd ◽  
Amy Dickinson ◽  
Richard A. Larson ◽  
Karen A. Marley
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Photosynthetically Active Radiation ◽  
Management Strategy ◽  
Detection Threshold ◽  
Multiple Choice ◽  
Active Radiation ◽  
Light Intensities ◽  
Fungus Gnats ◽  
Fungus Gnat

Multiple-choice experimental arenas, with sample compartments, were used to assess the response of fungus gnat, Bradysia sp. nr. coprophila (Lintner) (Diptera: Sciaridae), adults to varying light intensities in environmentally controlled walk-in chambers. Each sample compartment contained a yellow sticky card (2.5 × 2.5 cm) to capture fungus gnat adults. Under conditions of darkness, fungus gnat adults migrated randomly with no significant differences among the six sample compartments. Fungus gnat adults were observed to positively respond to light intensities less than 0.08374 μmol·m−2·s−1. In addition, adults responded to light intensities that were below the detection threshold of a photosynthetically active radiation light sensor. A higher percentage of fungus gnat adults (22% to 39%) were captured on yellow sticky cards in the sample compartments that were closest to a directional light source compared with sample compartments that were located further away from the light source (2% to 9%). Fungus gnat adults exhibited a significant response when exposed to two distinct ranges of light intensities (0.12 to 0.26 versus 0.87 to 1.02 μmol·m−2·s−1) with adults significantly more attracted to the highest light intensities (0.87 to 1.02 μmol·m−2·s−1). The results obtained in this study indicate that fungus gnat adults are positively phototactic, and as light intensity increases, they display a preference for those higher light intensities. It is possible that modifications in light intensity may be a feasible management strategy for alleviating problems with fungus gnats in greenhouses.

scholarly journals A comparison and correction of light intensity loggers to photosynthetically active radiation sensors

2012 ◽  
Vol 10 (6) ◽  
pp. 416-424 ◽  
Author(s):  
Matthew H. Long ◽  
Jennie E. Rheuban ◽  
Peter Berg ◽  
Joseph C. Zieman
Keyword(s):  
Light Intensity ◽  
Photosynthetically Active Radiation ◽  
Active Radiation ◽  
Radiation Sensors

scholarly journals A Comparison of Light Acclimatization Methods for Reduction of Interior Leaf Drop in Ficus spp.

1987 ◽  
Vol 5 (3) ◽  
pp. 102-104
Author(s):  
Melanie A. Turner ◽  
David Wm. Reed ◽  
David L. Morgan
Keyword(s):  
Photosynthetically Active Radiation ◽  
Poor Correlation ◽  
Active Radiation ◽  
Ficus Benjamina ◽  
Light Intensities ◽  
Constant Rate ◽  
Leaf Drop ◽  
Post Production ◽  
Interior Environment

Two acclimatization methods at 5 light intensities were investigated for indoor maintenance of Ficus benjamina and F. stricta. Plants were either grown at 5 production shade levels of full-sun (1685 μEm−2s−1) to 80% shade (340 μEm−2s−1) for 8 wks then placed directly into a simulated interior environment for 12 wks, or were grown in full-sun for 8 wks then acclimatized for 6 wks at 5 post-production shade levels prior to placement indoors. Photosynthetically active radiation (PAR) in the interior was set at 10.5 μEm−2s−1 (78 ft-c). For F. benjamina, the full-sun treatment caused the highest degree of defoliation and as production or post-production shade level increased, defoliation decreased. F. stricta showed similar effects under post-production shade, but under production shade levels there was a poor correlation between percent shade and leaf drop. There appeared to be two or three periods of leaf drop after placement indoors as opposed to a constant rate of defoliation.

scholarly journals EARLIER VEGETABLE CROPS WITH NEAR INFRA-RED TRANSMITTING MULCH

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1161d-1161
Author(s):  
Brent Loy ◽  
Otho Wells
Keyword(s):  
Solar Energy ◽  
Light Intensity ◽  
High Temperatures ◽  
Photosynthetically Active Radiation ◽  
Yield Response ◽  
Vegetable Crops ◽  
Active Radiation ◽  
Weed Growth ◽  
Infra Red ◽  
Black Plastic

Near infra-red (NIR)-transmitting plastic mulches transmit between 30 to 50% of the total solar energy to the soil, but block most photosynthetically active radiation (PAR). These mulches warm the soil more effectively than black plastic, but less effectively than clear mulch. Weed growth under NIR-transmitting mulches is suppressed through a combination of lowered light intensity and high temperatures under the mulch surface. With bell pepper and melons, IRT-76, a blue green, NIR-transmitting mulch, enhances growth to about the same extent as black mulch plus a floating rowcover. In turn, rowcover performance is enhanced by IRT-76 as compared to black mulch. In melons, early yield is about doubled and total yields increased by 20 to 30% with IRT-76 as compared to black mulch. Pepper yields are generally higher with IRT-76 as compared to black mulch, but the yield response to IRT-76 is less consistent than with melon.

scholarly journals 357 PHOTOSYNTHETIC RESPONSE OF SELECT RED MAPLE CULTIVARS TO LIGHT INTENSITY

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 482b-482
Author(s):  
Jeff L. Sibley ◽  
D. Joseph Eakes ◽  
Charles H. Gilliam ◽  
William A. Dozier
Keyword(s):  
Stomatal Conductance ◽  
Light Intensity ◽  
Linear Relationship ◽  
Photosynthetically Active Radiation ◽  
Acer Rubrum ◽  
Net Photosynthesis ◽  
Photosynthetic Response ◽  
Red Maple ◽  
Active Radiation ◽  
Use Efficiency

Net photosynthesis (Pn), stomatal conductance (Cs), transpiration (Ts), and water use efficiency (WUE) were determined with a LICOR 6250 Portable Photosynthesis System for four cultivars of Acer rubrum L. under light intensities ranging from 300 to 1950 μmol·m-2·sec-1 photosynthetically active radiation (PAR). As PAR increased, there was a linear relationship for Pn, Cs, and Ts for the cultivars `Franksred' (Red Sunset TM) and `October Glory'. In contrast, the cultivars `Schlesingeri' and `Northwood' had quadratic relationships for Pn and Cs as PAR increased. Ts was quadratic for `Schlesingeri' and had a linear relationship for `Northwood.' WUE was quadratic for each of the four cultivars.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

scholarly journals Effect of chlorophyll biosynthesis-related genes on the leaf color in Hosta (Hosta plantaginea Aschers) and tobacco (Nicotiana tabacum L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingying Zhang ◽  
Changhai Sui ◽  
Huimin Liu ◽  
Jinjiao Chen ◽  
Zhilin Han ◽  
...  
Keyword(s):  
Light Intensity ◽  
Antioxidant Capacity ◽  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Expression Level ◽  
Virus Induced Gene Silencing ◽  
Leaf Color ◽  
Color Changes ◽  
Light Intensities ◽  
Structure Changes

Abstract Background ‘Regal Splendour’ (Hosta variety) is famous for its multi-color leaves, which are useful resources for exploring chloroplast development and color changes. The expressions of chlorophyll biosynthesis-related genes (HrHEMA, HrPOR and HrCAO) in Hosta have been demonstrated to be associated with leaf color. Herein, we isolated, sequenced, and analyzed HrHEMA, HrPOR and HrCAO genes. Subcellular localization was also performed to determine the location of the corresponding enzymes. After plasmid construction, virus-induced gene silencing (VIGS) was carried out to reduce the expressions of those genes. In addition, HrHEMA-, HrPOR- and HrCAO-overexpressing tobacco plants were made to verify the genes function. Changes of transgenic tobacco were recorded under 2000 lx, 6000 lx and 10,000 lx light intensity. Additionally, the contents of enzyme 5-aminolevulinic acid (5-ALA), porphobilinogen (PBG), chlorophyll a and b (Chla and Chlb), carotenoid (Cxc), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), proline (Pro) and catalase (CAT) under different light intensities were evaluated. Results The silencing of HrHEMA, HrPOR and HrCAO genes can induce leaf yellowing and chloroplast structure changes in Hosta. Specifically, leaves of Hosta with HrCAO silencing were the most affected, while those with HrPOR silencing were the least affected. Moreover, all three genes in tobacco were highly expressed, whereas no expression was detected in wild-type (WT). However, the sensitivities of the three genes to different light intensities were different. The highest expression level of HrHEMA and HrPOR was detected under 10,000 lx of illumination, while HrCAO showed the highest expression level under 6000 lx. Lastly, the 5-ALA, Chla, Cxc, SOD, POD, MDA, Pro and CAT contents in different transgenic tobaccos changed significantly under different light intensities. Conclusion The overexpression of these three genes in tobacco enhanced photosynthesis by accumulating chlorophyll content, but the influential level varied under different light intensities. Furthermore, HrHEMA-, HrPOR- and HrCAO- overexpressing in tobacco can enhance the antioxidant capacity of plants to cope with stress under higher light intensity. However, under lower light intensity, the antioxidant capacity was declined in HrHEMA-, HrPOR- and HrCAO- overexpressing tobaccos.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

Sign in / Sign up

Export Citation Format

Share Document