Articles
Comparing intumescence response and growth of ornamental cuttings propagated indoors or in a greenhouse
Article number
1423_27
Pages
203 – 210
Language
English
Abstract
Propagating cuttings in indoor controlled-environments using light-emitting diode fixtures (LEDs) can improve rooting success compared to greenhouse (GH) propagation.
However, most LEDs lack ultraviolet radiation, creating conducive conditions for intumescence development on susceptible plants.
To assess the effect of far-red radiation on intumescence response and growth, cuttings of ‘Blackie’ sweet potato (Ipomoea batatas) and ‘Firecracker’ cigar plant (Cuphea ignea) were propagated either indoors under broadband white LEDs with or without 20 µmol m‑2 s‑1 of far-red radiation (WF or W, respectively) or in a glass-glazed GH. A total photon flux density of 100 µmol m‑2 s‑1 was provided indoors for 24 h d‑1, whereas cuttings in the GH received an average daily light integral (DLI) of 7.9 mol m‑2 d‑1. Intumescence incidence and severity were 15 and 13% lower in sweet potato under WF than W, respectively, but no differences were measured in cigar plant under the two light-quality treatments.
For both species, cuttings were generally shorter in the GH than under WF. Sweet potato cuttings under W and WF produced up to 20% more root dry mass (DM) than those in the GH. However, no treatment differences were measured for root length or root DM in cigar plant.
To compare environmental responses, cuttings of ‘Arizona Glow’, ‘Orange Wonder’, and ‘Lemon Star’ black-eyed Susan vine (Thunbergia alata) were propagated in another experiment either indoors under 100 µmol m‑2 s‑1 provided for 24 h d‑1 by broadband white LEDs or in a GH receiving an average DLI of 7.8 mol m‑2 d‑1. ‘Orange Wonder’ showed the largest difference in intumescence response between the two environments.
Across cultivars, intumescence severity was up to 200% higher indoors than in the GH, which likely affected growth.
For example, root DM was 13 to 47% lower indoors than in the GH. Overall, our results show that intumescence response and growth of ornamental cuttings vary by species, cultivar, and propagation environment.
However, general susceptibility to the disorder is higher indoors under LEDs compared to the GH.
However, most LEDs lack ultraviolet radiation, creating conducive conditions for intumescence development on susceptible plants.
To assess the effect of far-red radiation on intumescence response and growth, cuttings of ‘Blackie’ sweet potato (Ipomoea batatas) and ‘Firecracker’ cigar plant (Cuphea ignea) were propagated either indoors under broadband white LEDs with or without 20 µmol m‑2 s‑1 of far-red radiation (WF or W, respectively) or in a glass-glazed GH. A total photon flux density of 100 µmol m‑2 s‑1 was provided indoors for 24 h d‑1, whereas cuttings in the GH received an average daily light integral (DLI) of 7.9 mol m‑2 d‑1. Intumescence incidence and severity were 15 and 13% lower in sweet potato under WF than W, respectively, but no differences were measured in cigar plant under the two light-quality treatments.
For both species, cuttings were generally shorter in the GH than under WF. Sweet potato cuttings under W and WF produced up to 20% more root dry mass (DM) than those in the GH. However, no treatment differences were measured for root length or root DM in cigar plant.
To compare environmental responses, cuttings of ‘Arizona Glow’, ‘Orange Wonder’, and ‘Lemon Star’ black-eyed Susan vine (Thunbergia alata) were propagated in another experiment either indoors under 100 µmol m‑2 s‑1 provided for 24 h d‑1 by broadband white LEDs or in a GH receiving an average DLI of 7.8 mol m‑2 d‑1. ‘Orange Wonder’ showed the largest difference in intumescence response between the two environments.
Across cultivars, intumescence severity was up to 200% higher indoors than in the GH, which likely affected growth.
For example, root DM was 13 to 47% lower indoors than in the GH. Overall, our results show that intumescence response and growth of ornamental cuttings vary by species, cultivar, and propagation environment.
However, general susceptibility to the disorder is higher indoors under LEDs compared to the GH.
Authors
S. Lim, C. Gómez
Keywords
edema, far-red, indoor propagation, LEDs, edema
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