A general report on the use of the Allium test as cytotoxicological and genotoxicological assay is proposed, with particular emphasis about the standardization of the test in several common applications. The intraspecific variation in Allium cepa has been overlooked, as in most investigations no mention is made about origin and denomination of the onion cultivar used. A standardization of the used material would allow a better generalization of the results, since we cannot be sure that all cultivars would give the same response. A more frequent use of transmission electron microscopy (TEM) investigation is proposed. Even if relatively time consuming and not available in all laboratories, it may help to better understand the mechanism of cytotoxicity, since many morphological characters may appear similar but be arisen from different processes observable only with TEM. About statistical testing, tests other than chi-squared may be used in case of a lower amount of data. The most commonly used statistical tests are the parametric tests ANOVA and Student's t, and the nonparametric tests Kruskal-Wallis and Mann-Whitney U, for analysis of variance. Tests should be used also to assess the minimal sample dimension for obtaining significance, since data collection (microscope observation) appears to be one of the main bottle necks of the test. Also the use of the Allium test for testing liposomes and other nanovectors for drug delivery is proposed, in order to assess the cytotoxicity of these types of medium and the possible increase in cytotoxicity of the associated drug.

First developed for biomedical and industrial applications, nanovectors have recently been extended to agriculture. Therefore, innovative plant growing procedures making use of nanoparticles should be adapted to sustainable processes and materials. This work aims at proposing newly synthetized polymeric nanocapsules (NCs) to be used as biocompatible vectors for delivery of bioactive compounds to plants. Nanoparticles were fabricated from lignin, which is the main byproduct of wood processing and is currently a waste material. Lignin can thus find a virtuous fate and be reused in the context of circular economy. Specifically, we loaded lignin NCs with Gibberellic Acid (GA), assessing that stable and reproducible nanoparticles could be obtained in a range of GA content that is relevant for delivery purposes, i.e. 0.5-1.5 mg ml-1. Plain and GA-loaded NCs were characterized by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM). Assays of cytotoxicity and cargo release were carried out in two model plants, Eruca vesicaria and Solanum lycopersicum. These experiments, conducted both in vitro and in vivo, included the investigations of the percentage of germination, the stem and primary root lengths, as well as the fresh and dry weight of treated plants vs non-treated ones. Furthermore, NCs were loaded with Fluorol Yellow 088 to track their entrance and accumulation in seeds and seedlings.

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Callus cultures were initiated from micropropagated Artemisia absinthium plantlets on MS basal medium supplemented with different concentrations of BA, Kn, NAA, IAA and 2,4-D in combination or singly. Supplementing the medium with low doses of both BA in combination with NAA, and Kn in combination with NAA enhanced the growth rate of callus cultures. However, cultures grew slowly following the second subculture and the majority turned brown and died within the next month. Initiation of root and shoot primordia occured directly from leaf explants cultured on 1.81/~M 2,4-D, while adventitious shoot formation from callus was observed occasionally when BA was added to the medium in combination with IAA. Furthermore, medium containing 2.22 #M BA and 2.69 #M NAA stimulated both callus growth and organogenesis on some callus cultures derived from leaves and stems of young stock material. The best results were obtained with leaf explants. Cytological analysis of root meristems revealed that all regenerants were diploid (2n = 18), as expected.

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