Maurizio Micheli

Encapsulation of In Vitro-Derived Explants: An Innovative Tool for Nurseries

The encapsulation technology consists of the inclusion of some millimeter-long plant portions in a nutritive and protective matrix. This technology represents a further and promising tool for exchange of plant material between private and public plant tissue culture laboratories, for short- and medium-term storage of valuable plant material and for use of in vitro-derived or micropropagated propagules directly in farm or in nurseries. After encapsulation, transport, storage and sowing in aseptic conditions, the enclosed explants (capsules) may evolve in shoots (regrowth) and be employed for subsequent micropropagation or culture in vitro. When the encapsulated explant evolves in plantlet (conversion) in in vitro or in vivo conditions, the product of the encapsulation is defined as synthetic seed or artificial seed or synseed. The different evolution of the encapsulated plant material depends on tissue or plant material, genotype, nutritive and culture conditions, and treatments before or after encapsulation. In order to make economical the application of the encapsulation technology in the commercial nursery, research is looking for efficient automation or mechanization of the procedure and for preparation of the encapsulable explants.

Effects of tree shelters on young olive (Olea europaea) tree growth and physiology

Abstract A 3‐year study was conducted to evaluate the effects of tree shelters on young olive (Olea europaea) tree growth and physiology. The trial was carried out in the Apulia region in southern Italy using 1‐year‐old plants of the cultivar ‘Coratina’. Four different types of polypropylene shelters were tested: 75‐cm‐high brown; 90‐cm‐high brown; 75‐cm‐high green; 120‐cm‐high light‐green vented, with holes in their basal part. Both green shelters significantly increased the vertical growth of the trees, especially the 120‐cm light‐green vented ones. Shelters did not increase the amount of dry matter produced, but they modified its allocation within the tree, favouring vertical growth and the development of shoots in the apical parts of the trees.

Perspectives of the encapsulation technology in the nursery activity of Citrus

Abstract The genetic and phytosanitary certification has to guarantee the quality of the propagation material also in Citrus. Traditional methods can be assisted by the techniques of in vitro culture, which are fundamental for the mass production of high quality plants. The encapsulation technology represents an innovative tool to combine the advantages of micropropagation with handling ease, storability, reduced size of the propagules, mechanization potentiality, transportability of the gamic seeds. In this work somatic embryos obtained from in vitro anther culture of the cultivar Mandarino Tardivo di Ciaculli (Citrus reticulata Blanco) were encapsulated in a sodium alginate matrix and synthetic seeds were obtained. The conversion ability in non sterile conditions of the synthetic seeds has been evaluated and the addition to the artificial endosperm of the fungicide Thiophanatemethyl did not limit the further development into plantlets of the encapsulated somatic embryos sown on paper (control) and on perlite. A high level of viability has been observed and conversion in ex vitro conditions on substrates similar to those used in the traditional nursery structures (perlite and paperfilter) has been obtained.

From Somatic Embryo to Synthetic Seed in Citrus spp. Through the Encapsulation Technology

In vitro propagation by somatic embryogenesis represents an efficient alternative method to produce high-quality and healthy plants in Citrus species. The regenerated somatic embryos need protection from mechanical damages during manipulation and transport, as well as nutritive support for their evolution in plantlets after sowing. The encapsulation technology allows to obtain synthetic seeds by covering somatic embryos with a gel of calcium alginate enriched by nutrients. This chapter describes the procedure for producing synthetic seeds containing somatic embryos from different Citrus genotypes.