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Development of Equipment that Uses Far-Red Light to Impose Seed Dormancy in Arabidopsis for Spaceflight Cover

Development of Equipment that Uses Far-Red Light to Impose Seed Dormancy in Arabidopsis for Spaceflight

Gravitational and Space Research
Volume 4 (2016): Issue 2 (December 2016)
By: Caleb P. Fitzgerald,  Richard J. Barker,  Won-Gyu Choi,  Sarah J. Swanson,  Shawn D. Stephens,  Colleen Huber,  Amit J. Nimunkar and  Simon Gilroy  
Open Access
|Jul 2020

Figures & Tables

Figure 1

(a–b) Initial prototype Petri dish cover design holds a single far-red LED over the center of a 10 cm×10 cm Petri dish using the integral clips. Wiring from the LED wrapped through the tab in the back allowing for a user to remove the entire LED assembly from a Mylar bag that was used to provide a dark environment for the Petri dish after irradiation. (c–d) Second prototype ‘pyramid’ design that held a single far-red LED over the center of a 10 cm×10 cm Petri dish, but allowed for increased convective air flow. All dimensions are in cm.
(a–b) Initial prototype Petri dish cover design holds a single far-red LED over the center of a 10 cm×10 cm Petri dish using the integral clips. Wiring from the LED wrapped through the tab in the back allowing for a user to remove the entire LED assembly from a Mylar bag that was used to provide a dark environment for the Petri dish after irradiation. (c–d) Second prototype ‘pyramid’ design that held a single far-red LED over the center of a 10 cm×10 cm Petri dish, but allowed for increased convective air flow. All dimensions are in cm.

Figure 2

(a–f) Assembly of the portable benchtop darkroom. The tent covers the PVC frame with integral sleeves to allow access to the Petri dishes to be irradiated inside without interference from ambient room lights. Dimensions are 93 cm×62 cm×62 cm.
(a–f) Assembly of the portable benchtop darkroom. The tent covers the PVC frame with integral sleeves to allow access to the Petri dishes to be irradiated inside without interference from ambient room lights. Dimensions are 93 cm×62 cm×62 cm.

Figure 3

Far-red illumination system (a), side view (b), bottom view showing the alternating alignment of the LEDs (c), and mounted LED viewed from under side and custom steel nut (d). CAD drawings for the extruded aluminum and connectors are from the manufacturer. Dimensions in cm unless noted otherwise.
Far-red illumination system (a), side view (b), bottom view showing the alternating alignment of the LEDs (c), and mounted LED viewed from under side and custom steel nut (d). CAD drawings for the extruded aluminum and connectors are from the manufacturer. Dimensions in cm unless noted otherwise.

Figure 4

Temperature profiles recorded below the far-red light treatment device. Data represent mean ± SEM, n=3. Upper trace, stress test for local heat buildup, with the liquid cooling system being activated at 40 min. Lower trace, temperature below the light rail with the liquid cooling system running continuously.
Temperature profiles recorded below the far-red light treatment device. Data represent mean ± SEM, n=3. Upper trace, stress test for local heat buildup, with the liquid cooling system being activated at 40 min. Lower trace, temperature below the light rail with the liquid cooling system running continuously.

Figure 5

(a) Seed morphology after planting on nutrient gel, far-red irradiation for 10 min and storage in the dark for indicated times (days). Seeds were planted, irradiated for 10 min, plates wrapped in foil, and stored at 25°C. Images were taken using an environmental scanning electron microscope. Images are representative of plates from 3 separate experiments; scale bar = 100 μm. Note seed morphology is not obviously altered by the treatment/storage and there is no evidence of germination. (b) Seedling morphology after the indicated days of storage in the dark after far-red irradiation and then induction of germination and growth with white light. Seeds were planted, irradiated for 10 min, plates wrapped in foil, and stored at 25°C for the indicated times and then unwrapped, placed in a growth chamber, and grown on for 11 days. ‘No farred’ represents control samples where the seeds were planted on nutrient gel without far-red irradiation and then immediately moved to germinate under white lights. Representative images of n=3 separate experiments; scale bar = 1 cm. (c) Root length vs. time of growth post germination for plants held dormant by far-red irradiation for 0–21 days as noted. Data represent mean ± SEM, n=3. Values for samples held dormant for 0–21 days are not significantly different from each other at each time post germination (t-test, p>0.05).
(a) Seed morphology after planting on nutrient gel, far-red irradiation for 10 min and storage in the dark for indicated times (days). Seeds were planted, irradiated for 10 min, plates wrapped in foil, and stored at 25°C. Images were taken using an environmental scanning electron microscope. Images are representative of plates from 3 separate experiments; scale bar = 100 μm. Note seed morphology is not obviously altered by the treatment/storage and there is no evidence of germination. (b) Seedling morphology after the indicated days of storage in the dark after far-red irradiation and then induction of germination and growth with white light. Seeds were planted, irradiated for 10 min, plates wrapped in foil, and stored at 25°C for the indicated times and then unwrapped, placed in a growth chamber, and grown on for 11 days. ‘No farred’ represents control samples where the seeds were planted on nutrient gel without far-red irradiation and then immediately moved to germinate under white lights. Representative images of n=3 separate experiments; scale bar = 1 cm. (c) Root length vs. time of growth post germination for plants held dormant by far-red irradiation for 0–21 days as noted. Data represent mean ± SEM, n=3. Values for samples held dormant for 0–21 days are not significantly different from each other at each time post germination (t-test, p>0.05).

Parts list for the light rail, tent, and frame_

Light Rail
QtyItemQtyItem
424” Fractional 10 Series 80/20 (80/20 Inc.)33/32” × ½” × 36” A2 Air Hardening Ground Flat Stock (Drill Rod & Tool Steels, Inc., Franklin Park, IL)
46” Fractional 10 Series 80/202Constant Current LED Drivers 700 mA (RapidLED)
610 Series 2 Hole - Inside Corner Bracket 80/208Barbed Hose Fittings
610 Series 4 Hole - 90 Degree Angled Flat Plate 80/202Plugs without grounding prong
40XP-E Far-red LED (Cree Inc.)1Dynamax 412 Pump, 12 V (Simply Pumps, Manor, PA)
801/4”-20 × 5/16” Machine Screws1½ Gallon Reservoir
N/A¼” Silicone airline tubing (Petsmart, Phoenix, AZ)N/A60/40 Rosin Core Solder
N/ASilicone Heat Sink Compound (Synco Corp., Bohemia, NY)N/A22 gauge hookup wire
N/APTFE Tape
Tent and Frame
1Blackout Fabric with Rubberized Coating (Thorlabs Inc.)N/A½” Schedule 40 PVC pipe (J M Manufacturing, Wilton, IA)
16½” Schedule 40 Tee Fittings (Dura Plastics, Beaumont, CA)8½” Schedule 40 Corner Fittings (J M Manufacturing)
2Flange Extension ring (Sioux Chief, Peculiar, MO)N/A322 Foil Tape (Nashua Corp., Nashua, NH)
N/A2” Industrial Grade Velcro (Velcro Industries, Manchester, NH)N/A1” Velcro (Velcro Industries)

Effect of far-red irradiation on delaying germination and subsequent viability following unwrapping of plates and germination under growth chamber lights_

Irradiation (sec)No Imbibition24 h Pre-Imbibition at 4°C
Germination (%)*Viability (%)**Germination (%)*Viability (%)**
092.5 ± 592.5 ± 5.0095 ± 5.7795 ± 5.77
10 ± 0100 ± 0n.d.n.d.
50 ± 0100 ± 0n.d.n.d.
100 ± 0100 ± 0n.d.n.d.
300 ± 096.77 ± 0n.d.n.d.
602.5 ± 5100 ± 02.5 ± 5100 ± 0
3002.5 ± 5100 ± 00 ± 0100 ± 0
6000 ± 088 ± 3.460 ± 0100 ± 0
36002.5 ± 5100 ± 00 ± 0100 ± 0
DOI: https://doi.org/10.2478/gsr-2016-0008 | Journal eISSN: 2332-7774
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Language: English
Page range: 8 - 19
Published on: Jul 18, 2020
Published by: American Society for Gravitational and Space Research
In partnership with: Paradigm Publishing Services
Publication frequency: 2 issues per year
Keywords:
Seed Dormancy,
Orbital,
Plants,
Phytochrome,
Spaceflight,
Far-red Light
Related subjects:
Life sciences,
Life sciences, other,
Materials sciences,
Materials sciences, other,
Physics,
Physics, other

© 2020 Caleb P. Fitzgerald, Richard J. Barker, Won-Gyu Choi, Sarah J. Swanson, Shawn D. Stephens, Colleen Huber, Amit J. Nimunkar, Simon Gilroy, published by American Society for Gravitational and Space Research
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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