Urban and periurban areas are often contaminated by several pollutants. Phytoremediation is considered to be an effective and eco-friendly strategy for the restoration of these contaminated lands. For this purpose, the exploitation of ornamental plants could be an additional option, due to their positive impact on the landscape. In this paper, we reviewed a selection of species which have been proposed for utilization in phytoremediation. Several tree species have been introduced in the past into urban environments for parks, gardens and avenues, with a selection studied for their capacity to absorb, tolerate, and translocate contaminants. Shrubby and herbaceous species are also commonly exploited for their ornamental features and are now studied for phytoremediation purposes. The responses of several effective species to the presence of heavy metals or dangerous organic compounds in the growth substrate are examined in this paper.

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.

Salix acmophylla Boiss. has a traditional role in several regions of the Middle East and the Indian subcontinent. As with many other woody species, the development of methods for fast propagation and ex situ conservation of this species is needed. We describe for the first time a micropropagation protocol of three S. acmophylla ecotypes. The best results for shoot proliferation were obtained by culturing the shoot explants on Woody Plant Medium (WPM) containing benzyladenine (BA) 5 μM, but it was also observed that proliferation can be further enhanced by the separation of the shoot tip from the underlying internodes, followed by their respective culture on BA- or activated-charcoal-containing medium. Thidiazuron or zeatin did not enhance shoot proliferation. The rooting of shoots occurred spontaneously, but for the ecotype with a lower propensity for rooting, treatment with 5 μM indolebutyric acid (IBA) increased rooting percentage. Genetic differences were evident in rooting success, but not in shoot development of the tested ecotypes in response to in vitro cultural conditions.