Modarelli, Giuseppe Carlo
(2020)
Modulation of light spectrum for controlling plant growth and development of flower species for greenhouse cultivation and leafy vegetables for indoor cultivation.
[Tesi di dottorato]
| Tipologia del documento: |
Tesi di dottorato
|
| Lingua: |
English |
| Titolo: |
Modulation of light spectrum for controlling plant growth and development of flower species for greenhouse cultivation and leafy vegetables for indoor cultivation |
| Autori: |
| Autore | Email |
|---|
| Modarelli, Giuseppe Carlo | giuseppecarlo.modarelli@unina.it |
|
| Data: |
13 Marzo 2020 |
| Numero di pagine: |
137 |
| Istituzione: |
Università degli Studi di Napoli Federico II |
| Dipartimento: |
Agraria |
| Dottorato: |
Scienze agrarie e agroalimentari |
| Ciclo di dottorato: |
32 |
| Coordinatore del Corso di dottorato: |
| nome | email |
|---|
| D'Urso, Guido | durso@unina.it |
|
| Tutor: |
| nome | email |
|---|
| Paradiso, Roberta | [non definito] | | Arena, Carmen | [non definito] |
|
| Data: |
13 Marzo 2020 |
| Numero di pagine: |
137 |
| Parole chiave: |
Photoperiod, Light quality, Plant physiology |
| Settori scientifico-disciplinari del MIUR: |
Area 07 - Scienze agrarie e veterinarie > AGR/04 - Orticoltura e floricoltura |
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| Depositato il: |
20 Mar 2020 15:23 |
| Ultima modifica: |
10 Nov 2021 11:37 |
| URI: |
http://www.fedoa.unina.it/id/eprint/13037 |
Abstract
Light represents a key factor for plant development because it drives photosynthesis, growth and morphogenesis. Optimizing plant growth by modulating the light spectrum is an attractive perspective to obtain specific morphological and physiological traits in different plant species.
The aim of this PhD thesis was to investigate the physiological and morphological effects of light modulation on ornamental and vegetable species, and to contribute to the development of new lighting protocols for plant cultivation.
The ornamental species chosen for these studies, was Rannunculus asiaticus L. a quantitative long day geophyte original from the Mediterranean basin and Asia Minor, cultivated for cut stems and potted plant production. In a preliminary experiment, the photosynthetic process was characterized in R. asiaticus plants to reduce the gap of information on the physiology of this species. Plants were grown in pots under controlled environmental conditions at the Photosynthetic Photon Flux Density, PPFD of 200 µmol m-2 s-1, provided by fluorescent white light lamps. We compared two R. asiaticus hybrids, MDR and MBO, and two tuberous root preparation procedures (rehydration (C), rehydration plus vernalization (V)). The results indicated an intrinsic difference between the two hybrids and a hybrid-specific response to the tuberous root preparation procedures in terms of photosynthetic capacity and plant growth. Moreover, the vernalization treatment promoted starch degradation and increased sucrose and amino acids content in the tuberous roots. These findings were confirmed in a second experiment carried out in a cold greenhouse on the same hybrids under different photoperiodic lighting treatments. The treatments consisted in a day extension, by means of fluorescent light or Red and Far Red Light Emitting Diodes (LEDs) at a ratio of 3:1 and 1:3 compared to a typical natural daylength (NL, short day) in the period December - March.
Compared to the NL treatment, photoperiodic lighting promoted photochemical processes, reducing the thermal dissipation and the time to complete flowering in both MBO and MDR hybrids; furthermore, in MBO anticipated the formation of flower buds. Photoperiodic lighting also modified the metabolic profile in both hybrids, inducing in MDR hybrid higher soluble sugars, polyphenols, proteins and pigment content, while in MBO higher amino acids and starch content. The R:FR 3:1 treatment promoted the photosynthetic pigments in both hybrids.
The experiments on leafy vegetables were carried out to assess 1) the influence of different blue (B): red (R) ratios (25:75; 20:80 and 10:90 ratios) and 2) the effect of increasing far red (FR) intensity (0, 25, 50, 75 µmol μmol m−2 s−1) over a fixed 20:80 ratio BR spectrum on plant growth, photosynthesis and leaf phenolic compounds in Chicorium endivia L. ‘Lindo’ and Lactuca sativa L. ‘Blackhawk’. The results showed that a precise balance between B and R light is needed to promote photosynthetic activity and plant growth in both species. The addition of different FR light intensities reduced photosynthesis in both species. This decrease was likely linked to ETR drop in lettuce whereas in endive to a reduction of photosynthetic pigment pool. FR light favored the biomass partitioning toward aboveground structures in endive, and both B:R light and FR light affected the polyphenol profile in both species.
In conclusion, light modulation can be considered a powerful tool to modulate qualitative attributes in ornamental plants and leafy vegetables.
The results of this study might have scientific as well as practical implication. The optimized growth protocol could be applied on large scale greenhouses or indoor cultivation systems to increase the plant yield and functional attributes.
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