Nanotechnology is a promising tool to achieve great advancements in the global agricultural systems and food production. The widespread application of nanomaterials in numerous fields of life has led to increase concerns over the potential impacts of these nanoparticles on plants. In the present study, morphophysiological evaluation of the effect of zinc oxide nanoparticles (ZnO-NPs) was assessed in two pomegranate (Punica granatum L.) cultivars (i.e. ‘Manfalouty’ and ‘Wonderful’) under in vitro conditions. ZnO-NPs were added to a Woody Plant Medium (WPM) in six doses, i.e. 0, 1, 2.5, 5, 7.5 and 10 mg/L. Results showed that, ZnO-NPs at 2.5 mg/L induced the best proliferation rate (4.8 and 4.4 shoots/explant) compare to control (4 and 3.2 shoots/explants), while at 5 mg/L it induced the maximum shoot length (2.58 and 2.91 cm vs 2.23 and 2.36 cm in control) and biomass (0.3 and 0.37 g) compared with control (0.18 and 0.23 g) for ‘Wonderful’ and ‘Manfalouty’ cultivars, respectively. Moreover, at 1 and 2.5 mg/L of ZnO-NPs the highest total chlorophyll content (0.58 and 0.61 mg/g fresh weight) was achieved for ‘Manfalouty’ and ‘Wonderful’ cultivars compared with control (0.50 and 0.39 mg/g fresh weight), respectively. However, further increase in ZnO-NPs concentration up to 10 mg/L, did not support plant growth or related physiological parameters. These observations clearly showed the influence of ZnO-NPs on morphological and physiological traits in pomegranate under in vitro conditions, which could help in the optimal utilization of ZnO-NPs to improve pomegranate growth.

Heavy metals are among the most common and dangerous contaminants; their action on plants, as well as the possibility for plants to effectively absorb and translocate them, have been studied for several years, mainly for exploitation in phytoremediation, an environmentally friendly and potentially effective technology proposed and studied for the recovery of contaminated soils and waters. In this work, the analysis has focused on the studies developed using in vitro techniques on the possibilities of mitigating, in plants, the stress due to the presence of heavy metals and/or improving their absorption. These objectives can be pursued with the use of different substances and organisms, which have been examined in detail. The following are therefore presented in this review: an analysis of the role of metals and metalloids; the use of several plant growth regulators, with their mechanisms of action in different physiological phases of the plant; the activity of bacteria and fungi; and the role of other effective compounds, such as ascorbic acid and glutathione.

ElecTIS is a new single container bioreactor which does not require forced air blowing, instead making the culture material mobile and the liquid medium stationary. The timed up-and-down movement of the basket containing the shoot culture ensures periodic contact with the liquid medium positioned at the base of the container. In this study we tested for the first time its use in the recovery of blackberry shoot cultures (Rubus fruticosus L., cvs Thornfree and Chester), coming from 5 months of slow growth storage (SGS), at 4 °C and in the dark. The shoot recovery at standard culture conditions was performed on two different types of ElecTIS, i.e., one with a smaller basket (ElecTIS_S, 234 cm² of culture area), and one with a large basket (ElecTIS_L, 336 cm²), comparing the culture in TIS (cycle of 8 min every 6 h, equal to 32 min/day) with the traditional one in a gelled medium in glass jars (500 cc). After each one of the three 4-week subcultures, the shoot growth parameters and the relative growth rate highlighted a clear superiority of ElecTIS in promoting the recovery of shoot cultures coming from SGS. The analyses of chlorophyll content and stoma functionality confirmed the superior quality of shoots cultured in the ElecTIS bioreactor, and these shoots were afterwards easily rooted and acclimatized ex vitro.

This study developed an efficient protocol for the in vitro propagation of giant reed (Arundo donax L.) biomass, defining a complete cycle of the induction of somatic embryogenesis from immature inflorescences, followed by the maturation of somatic embryos and the subsequent multiplication of the derived shoots in liquid culture in a temporary immersion system (TIS). The best explants were found to be 30 cm long immature inflorescences, preferably collected in spring. Such an explant type was easy to decontaminate, and the spikelets isolated from it provided over 100 embryogenic callus lines. Among the callus induction media tested, gelled MS medium supplemented with 1.1 mg/L 2,4-D provided the highest percentage of responsive spikelets and the highest density of embryogenic callus. Maturation of the embryogenic callus was easily triggered on gelled MS medium devoid of plant growth regulators. The obtained shoots could be further multiplied on previously optimized gelled DKW medium supplemented with 30 g/L sucrose, 5 mg/L BA, 0.1 mg/L IBA, and 6.8 g/L plant agar. Subsequent high multiplication of the developed shoots was achieved in liquid culture in TIS using a Plantform™ bioreactor, with an immersion cycle of 12 min every 8 h.