Effects of Adjustment to Spectral Ratios of Supplemental LED Lighting on Miniature Rose Growth and Morphology

Transcription

1 Effects of djustment to Spectral Ratios of Supplemental Lighting on Miniature Rose Growth and Morphology Jake Holley, Scott Malain, Lola Siboli, Rachel Schuster and Melanie Yelton LumiGrow, th Street, Emeryville, C, 94608, US. Rocket Farms, 2651 Cabrillo Highway North, Half Moon ay, C 94019, US Introduction Winter months in California have a Daily Light Integral (DLI) of 10-20, which is inadequate for optimal plant growth. To address this challenge, Light Emitting Diode () lamps are beginning to be used in preference over High Intensity Discharge (HID) lamps for their higher energy efficiency and longevity. Making up a significant portion of the floriculture market, Mini-roses typically require multiple applications of plant growth regulators (PGRs) in order to prevent elongation, and achieve the targeted market height. PGRs also have been shown to present harmful environmental and health-related effects. It is hypothesized that applying a lower ratio of red:blue light to flowering mini-roses will achieve similar effects as PGRs, decreasing the total plant height without reducing flower count, production time, and quality. In this presentation we present three experiments. The first experiment was done at Rocket Farms in Half Moon ay, California, in the greenhouse environment to examine the effect of both a High Red and High lue light environment for a two to three week period at the end of production. The second two experiments were done at LumiGrow s research facility in Emeryville, California utilizing a sole source environment. In one case we used alone at varying light ratios, but at the same intensity, to determine the response of the plants under all conditions. y contrast, in the other sole source experiment we mimicked winter sunlight conditions to create January in a ox, by using a broad spectrum HID lamp and pairing it with a lamp of varying light ratios LumiGrow, Inc. ll right reserved.

2 Controlling Flowering in Production Treatments HPS Control High Red light ratio of 9R:1W:0 (Final two weeks) Full Spectrum light ratio 7R:1W:2 High lue Light ratio 5R:1W:4 (Gradual Increase over three weeks) Materials and Methods Five week grow period (December 28th February 1st) Two miniature rose varieties, Renata, a pink rose, requiring 4 sprays of onzi (.4% Paclobutrazol) Karina, a red rose, requiring 3 sprays of onzi (.4% Paclobutrazol) 400 Plants nalyzed, 80 Plants per treatment (40 per variety) with duplicate groups of 20 3 inch pots/peat moss media Drip fertigated Measurements: height (cm), width (cm), bud count, wet weight (grams), and dry weights (grams) upon harvest Environmental Parameters Daily Light Intergral ~ mol m-2 d-1 Supplemental radiation HPS µmol m-2 s µmol m-2 s-1 ir Temperature HPS 22.5 C 22.5 C Relative Humidity HPS 72.5% 72.2% Photoperiod 17.6 Hours Conclusion Renata Decreased bud count under High lue (5:1:4) Karina Equivalent bud count between HPS and High Red (9:1: LumiGrow, Inc. ll right reserved.

3 Sole Source Treatments High Red 9R:1W:0 Full Spectrum 7R:1W:2 High lue 5R:1W:4 Materials and Methods Two Miniature Rose Varieties, received from Rocket Farms (Half Moon ay, C) Renata, a pink rose, with a low bud count Karina, a red rose, with a moderately high bud count 96 Plants were analyzed, 16 per treatment, 8 of each variety 3 inch pots peat moss media 4 Week Growth Period (July 4th July 29th) Plants grown in 3ft x 3ft x 9ft grow boxes LumiGrow Pro 650 Fixtures Hung 3.5 ft above canopy pollo Horticulture 4 Inch 190 CFM Inline Duct Fan Fertigated: General Hydroponics 2 Micro: 1 loom: 1 Grow ml/gal Plants were rotated when fertigated Measurements: height (cm), internode length (mm), bud count, flowering time, and fresh weight (g) Environmental Parameters Daily Light Intergral 10.8 mol m-2 d-1 Supplemental radiation 150 µmol m-2 s-1 ir Temperature C Relative Humidity ~50-60% Photoperiod 20 Hours Conclusion oth Renata and Karina responded similarly to sole source s Reduction in bud weight under High lue treatments (5:1:4) Increase in blue light resulted in a reduction in plant height Renata Height C Renata ud Fresh Weight Karina ud Fresh Weight Karina Height C LumiGrow, Inc. ll right reserved.

4 120 Sole-Source 100 μwatts per cm-2 nm Sole Source Treatments High Red 9R:1W:0 + HID Full Spectrum 7R:1W:2 + HID High lue 5R:1W:4 + HID μwatts per cm-2 nm Wavelengths in Nanometers 9:1:0 7:1:2 5:1:4 Materials and Methods Eye Hortilux lue Daylight Super MH Lamp (MH) (For Other Materials and Methods refer to Sole Source ) Wavelength in Nanometers and HID 9:1:0 and HID 7:1:2 and HID 5:1:4 Environmental Parameters Daily Light Intergral MH 5 mol m-2 d mol m-2 d-1 Supplemental radiation MH 175 µmol m-2 s-1 80 µmol m-2 s-1 ir Temperature C Relative Humidity ~50-60% Photoperiod MH 8 Hours 20 Hours Conclusion oth Renata and Karina responded similarly to sole source environments 7:1:2 ratios resulted in taller plants 7:1:2 ratios resulted in a higher bud weight 1 1 Renata ud Fresh Weight Renata Height Karina ud Fresh Weight Karina Height LumiGrow, Inc. ll right reserved.

5 Conclusions In conclusion we have demonstrated that s can control plant morphology under three distinct growth conditions. Initially, in January of 2016 the most dramatic effect we observed in the greenhouse was on the control of bud formation in both of our test varieties Renata and Karina. Other growth parameters we measured were inconclusive. s a result of this experiment we created two tests to inform our further experiments planned for January 2017 in the greenhouse. First we wanted to ascertain how sensitive each variety was to differing ratios of red and blue light in directing plant growth and flowering. We found both miniature rose varieties were influenced by the relative ratio of red to blue light. Under low blue light environments both Karina and Renata resulted in taller plants, while high blue environments resulted in more compact plants with equivalent fresh weights. To evaluate the relative amount and ratios of light that would be required to control plant growth and flowering in the greenhouse, we created a mock environment representing January in Half Moon ay with a DLI of 5 using our broad spectrum metal halide lamp (January in a ox). To our simulated January we added light at 80 µmol m-2 s-1 for a photoperiod of 20 hours of varying red, white, and blue ratios but maintaining the same intensity. We observed an increase in height and fresh bud weight with the light ratio 70% Red:10% White:20% lue. These preliminary results suggest that s at attainable red and blue light levels can be used to control plant phenotype. Can t Get Enough Research? Visit our website. (800) sales@lumigrow.com LumiGrow, Inc. ll right reserved.

6 References Faust J, Logan J, Korezynski P (2002) Mapping Monthly Distribution of Daily Light Integrals across the Contiguous United States. Horttechnology 12(1): Morrow R (2008) Lighting in Horticulture. HortScience 43(7): Nelson J, ugbee (2014) Economic nalysis of Greenhouse Lighting: Light Emitting Diodes vs. High Intensity Discharge Fixtures. PLoS ONE 9(6) e99010 doi: /journal.pone Yeh N, Chung J (2009) High-brightness s-energy efficient lighting sources and their potential in indoor plant cultivation. Renewable and Sustainable Energy Reviews. 13(8): LumiGrow, Inc. ll right reserved.