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Fluorescent lights are typically used as light source in indoor horticultural production, including micropropagation. However, light emitting diodes (LEDs) have been recently used for plant growth under controlled environment. Major advantage of LEDs is wavelength specificity, that allows to adequately adjust the spectra according to plant needs. The possibility of using LED as primary light source for the micropropagation of Pyrus communis L. has been investigated in this work. It was proceeded to the optimization of a protocol of micropropagation using a LED lamp as the primary light source inside of the growth chamber with specific wavelengths, to reduce energy consumption and increase the quality of the micro propagated plants. Explants were maintained in a growth chamber and exposed to three different continuous spectrum LED lamps (AP67, NS1, G2) as a primary light source and fluorescent lamps (control) for 4 weeks. At the end of four weeks period, it was proceeded to the morphometric and biochemical analysis. Shoot and leaf growths were more influenced by LED lamps as compared to fluorescent lamps (control) in both cultivars. The results showed that the shoots of William and San Giovanni cultivars showed significant differences in morphological and physiological traits, as well as in chlorophyll, carotenoid, and MDA contents. Highest number of neo-formed shoots and nodes were observed in the plantlets of cv William under AP67 LED followed by NS1 and G2 LED lights respectively as compared to the white light (control), whereas same trend was observed in cv San Giovanni under AP67 LED, but it showed higher shoots and node numbers under control LED lamps as compared to both NS1 and G2. The photosynthetic pigments were significantly decreased in leaves of both cultivars when grown under LEDs as compared to the control fluorescent lamps. Moreover, the AP67 LED light had also significant effects on the protein and MDA contents in the leaves of both cultivars in comparison to all other treatments. This work underlines the importance of the modulation of light sources in relation with different species and varieties, allowing optimizing the proliferation phase and the efficiency of Pyrus communis L. micropropagation protocol. Moreover, this protocol can be improved with further studies to examine the response of the plantlets to the ex-vitro acclimatization because the possibility of using LED light for the micropropagation of pear can be considered as a valuable alternative for its ecologically sustainable production.

Mediterranean almond growing is increasing, as confirmed in Italy where new almond orchards in areas not previously interested in this nut crop have been recently established. In these new areas, as in the coastal of Latium region, the knowledge of eco-physiological behavior as a complex interaction among cultivars, pedoclimate conditions and orchard management is still poor. Optimizing fertilization strategies according to cultivar needs is one of the main key factors to guarantee high yields and nut quality, as well as to reduce environmental pollution. With this aim, an almond field collection has been established planting medium- and late-bloom cultivars. During the growing seasons 2019–2020, leaf samples were collected at 90 and 120 days after full bloom (DAFB) analyzed for biometrical and eco-physiological traits and leaf nutrients content through foliar diagnostics. Differences in foliar nutrient content depend on both cultivar and phenological stage. According to Pearson correlation heatmap, leaf nitrogen content showed a medium–high positive correlation with Nitrogen Balance Index (NBI) either at 90 or 120 DAFB, highlighting reciprocal influences among leaf nutrient contents and some eco-physiological traits. The findings of this study will help to develop novel environmentally friendly nutrition and fertigation strategies supported by foliar diagnostics which also consider accurate cultivar requirements.

In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock ‘GF677’ on the grafted cultivars ‘Tuono’, ‘Supernova’ and ‘Genco’, in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing “high density” plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks (‘GF677’, ‘Rootpac® 20’ and ‘Rootpac® R’), on the Spanish cultivar ‘Guara’ to identify suitable dwarfing rootstocks for “super high density” plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars ‘Genco’, ‘Supernova’ and ‘Tuono’ could be subject to moderate risk of cold damages. The clonal rootstock ‘GF677’ seems to anticipate flowering and vegetative bud break by a few days in ‘Tuono’ when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on ‘GF677’. The observations carried out in trial B highlighted as the flowering of cultivar ‘Guara’ were affected by the rootstock, with ‘Rootpac® 20’, which postponed its full bloom of about one week when compared to other rootstocks, whereas ‘GF677’ imposed more vigor to the cultivar than ‘Rootpac® 20’ and ‘Rootpac® R’.

Light spectra influence growth, development, and quality of plants and seedlings, that is one of the main aspects engaging the interests of private and public researchers and nursery industries. Propagation of hazelnut (Corylus avellana L.), which in the past has been held in low consideration because of the widespread use of rooted suckers directly collected in the field, today is taking on increasing interest due to the strong expansion of hazelnut cultivation. In order to improve the quality of plants and seedlings in greenhouse acclimatization, the effects of light emitting diodes (LED) lights during the ex vitro growth of two hazelnut cultivars (Tonda di Giffoni and Tonda Gentile Romana) were investigated. Plantlets were maintained in a growth chamber and exposed to three different continuous spectrum LED systems as a primary source of illumination and to fluorescent lamps used as control. LEDs differed in the percentage of some wavelength ranges in the spectrum, being AP673L rich in green and red wavelengths, NS1 in blue and green light, G2 in red and far red wavelengths. After a 4-week experimental period, morphometric, biochemical, and histological analyses were carried out. Shoot and leaf growths were influenced by LEDs more than by fluorescent lamps in both cultivars. G2 positively affected biomass increment more than the other LEDs, by inducing not only cell elongation (increase in shoot length, new internodes length, leaf area) but also cell proliferation (increase in new node number). G2 exposure had negative effects on total chlorophyll content but positively affected synthesis of flavonoids in both varieties; therefore, plants grown under this LED showed the lowest nitrogen balance index. Leaf morpho-anatomical analyzed traits (thickness, palisade cell height, number of chloroplasts, number of palisade cells), were influenced especially by G2 and, to a less extent, by NS1 light. Significant differences in some parameters were observed between the two cultivars in response to a same light source. The results obtained underline the importance of light modulation for hazelnut, providing useful information for ex vitro growth of hazelnut plantlets.