Studio delle variazioni morfometriche e biochimiche di alcune specie forestali mediterranee sottoposte a differenti tipologie di diodi ad emissione luminosa
Author(s)
Ortolani, Maria Raffaella
Date Issued
June 28, 2016
Type
Doctoral Thesis
Abstract
The need to ensure the success of environmental restoration and reforestation programs contributes to increase the request for high quality plants. To this end, the purpose of the forest nursery is the production of plants with higher capability of engraftment, adaptation and rapid growth. Therefore, new breeding methods and new technologies could surely improve the quality and quantity of the forest seedlings.
Recently, it has been introduced the pre-cultivation phase which provides a sustainable production of forest seedlings in growth chambers with artificial lights for a short period, but sufficient to guarantee a high seed germination and development of the species.
Fluorescent light is typically used as light source in plant growth chambers. However, light emitting diodes (LEDs) have been recently proposed as an attractive low-cost alternative technology for plant growth in controlled environment. Major advantage of LEDs is wavelength specificity, that allows to adequately adjust the spectra according to plant needs.
Aim of this research was to analyse the morphometric and physiological responses of Arbutus unedo L. Quercus ilex L., Myrtus communis L., Punica granatum L. and Fagus sylvatica L. plants cultivated in growth chambers and exposed to different LED lights, comparing the results with those obtained from the same species grown under fluorescent lamps. During the period in growth chamber were evaluated morphometric parameters such as: stem height, stem diameter, stem, roots, leaves fresh and dry weight, and leaves area. In addition, were analysed the total content of chlorophyll and β-carotene, the activity of two enzymes involved in the assimilation of N (nitrate reductase and glutamine synthetase) and, finally, the plant response to photodamage evaluating the concentration of malondialdehyde (MDA).
At the end of the pre-cultivation period, the plants were transferred in the greenhouse for one season, to evaluate the response mechanisms of the plants when exposed to natural light. Finally, at the end of the period in the greenhouse Quercus ilex L plants were transplanted in the open field to verify the capacity of engraftment.
The research showed the effectiveness of LED lights to support the growth and the development of plants in artificial environment. The next step in the greenhouse and in the open field showed good results for the plants cultivated under light emitting diodes, suggesting that the conditions adopted during the pre-cultivation have been appropriate. The results indicate that the introduction of LEDs in the pre-cultivation phase could be good alternative to fluorescent lamps.
Furthermore, during the research period it has developed an experimental growth chamber (prototype) able to reconcile the need of seedlings high production with a low energy consumption. The prototype consists of 10 shelves running under three LED lamps. A PLC control is used to set the experimental
conditions (temperature, photoperiod and light intensity) and to control the automatic irrigation. The aim was to compare the application of traditional growth chambers with LED lighting with innovative growth chamber (prototype) using strawberry tree as model plant. To evaluate the effects of the growth of forest seedlings in the Prototype, compared to a traditional growth chamber, it has been evaluated the same growth parameters previously described. Thereafter, the seedlings were transferred to the greenhouse for one growing season.
Results showed that both chlorophyll and β-carotene contents were higher in plants grown in the prototype than in the traditional growth chamber. Furthermore, the MDA levels were lower in myrtle plants cultured in the prototype, suggesting that pulsed light due to the shelves’ rotation most likely reduces photodamage. Finally, the prototype performance, in terms of number of plants obtained (equivalent to five traditional growth chambers), energy saving and high mechanization seems to point out such a technology as a promising innovation for the quali-quantitative improvement of plants production in forest nursery.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
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