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In the present study, the applicability of four wide-spectrum light-emitting diodes (LEDs) emitting warm light (AP67, AP673L, G2, and NS1) was determined for the micropropagation of five popular ornamental plant species: Chrysanthemum × grandiflorum, Gerbera jamesonii, Heuchera × hybrida, Ficus benjamina, and Lamprocapnos spectabilis. Plantlets were grown in a growth room with a 16-h photoperiod. The photosynthetic photon flux density was set at 62-65 μmol m −2 s −1. The composition of the media and subculture timing were adjusted to the needs of each species tested. The results were compared to the cool daylight-emitting fluorescent (FL) control (TLD 36W/54). In most of the species studied (except for F. benjamina), the highest propagation ratios, or ratios similar to the FL control, were observed under the red-and far-red-abundant G2 LEDs. NS1 spectrum (with the highest proportion of blue and green light) was also efficient for G. jamesonii and L. spectabilis, and it provided a similar propagation ratio as the FL control. Light quality affected shoot length, number of leaves, callus regeneration, and the biosynthesis of chlorophyll. This influence, however, was species-dependent. Lighting conditions did not affect the dry matter and rooting in most of the species tested, except for G. jamesonii. The substitution of FLs with G2 LEDs can result in a 50% reduction of annual electricity costs, while the application of NS1 lamps can generate savings of up to 75%. In conclusion, the G2 LED lighting system seemed to be the most suitable in terms of propagation efficiency, plantlet quality, and cost reduction.

No abstract

The in vitro propagation of chrysanthemum (Chrysanthemum × grandiflorum (Ramat.) Kitam.), one of the world's most important ornamentals, is a very well-studied topic and shows numerous strides each year. This mini-review condenses the knowledge that has been published on chrysanthemum biotechnology, especially in vitro culture in the wider plant science literature. In 2013 and 2014, important strides were made in molecular breeding, particularly anti-viral strategies, including through transgenics, and our understanding of flower genetics and flowering regulation.

The choice of explant and its preparation are most likely one of the most important biotic factors that determine the success of a tissue culture protocol when the explant is derived from ex vitro organs. This review assesses the disinfection protocols available for saffron (Crocus sativus L.; Iridaceae) explants in an attempt to ascertain the most suitable set of parameters that could ensure successful tissue culture in subsequent treatments. From a methodological perspective, two explant types are most commonly adopted in saffron biotechnology, namely the use of fresh field-grown shoots, or dormant corms. The latter is more recommended to minimize contamination and to allow the use of more aggressive disinfection treatments.

Despite the tremendous progress in breeding, novel and user-friendly techniques of plant improvement are desirable. The study aimed to analyze the usefulness of silver nanoparticles (AgNPs) in the breeding of chrysanthemum: one of the top ornamental plant species. In vitro regeneration of adventitious shoots from internodes of chrysanthemum ‘Lilac Wonder’ was induced on the modified Murashige and Skoog (MS) medium supplemented with 0.6 mg L−1 6-benzylaminopurine (BAP), 2 mg L−1 indole-3-acetic acid (IAA) and AgNPs at 0, 5, 10 and 20 ppm concentration. The efficiency of callogenesis and caulogenesis were analyzed after 10 weeks of culture. The concentration of chlorophylls, carotenoids, and phenolic compounds in shoots and calli were estimated. Plants obtained from 20 ppm AgNPs treatment were additionally analyzed on the genetic level using randomly amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers. In vitro rooted shoots were acclimatized in the glasshouse and subjected to biochemical and phenotype stability evaluation. AgNPs at the highest concentration (20 ppm) suppressed both callogenesis and caulogenesis in vitro. The concentration of metabolites in callus was stable, regardless of AgNPs treatment, except for carotenoids which production was enhanced by 20 ppm AgNPs. In contrast, the content of chlorophyll a and b in shoots varied depending on AgNPs treatment. Polymorphic loci were detected in 12 and 9 AgNPs-treated-plants by RAPD and ISSR markers, respectively (one of which was common to both marker systems). Rooting and acclimatization were fully successful in all experimental combinations. Phenotype alternations were detected in six plants; one from 10 ppm AgNPs treatment and five from 20 ppm treatment. They included variation in pigment content (anthocyanins and carotenoids) and/or inflorescence shape. Interestingly, only two plants revealed both genetic and phenotype polymorphisms. No genetic or phenotype variation was detected in the control plants. In conclusion, AgNPs can be used in chrysanthemum breeding.

Numerous environmental and endogenous factors affect the level of genetic diversity in natural populations. Genetic variability is the cornerstone of evolution and adaptation of species. However, currently, more and more plant species and local varieties (landraces) are on the brink of extinction due to anthropopression and climate change. Their preservation is imperative for the sake of future breeding programs. Gene banks have been created worldwide to conserve different plant species of cultural and economic importance. Many of them apply cryopreservation, a conservation method in which ultra-low temperatures (−135 °C to −196 °C) are used for long-term storage of tissue samples, with little risk of variation occurrence. Cells can be successfully cryopreserved in liquid nitrogen (LN) when the adverse effect of ice crystal formation and growth is mitigated by the removal of water and the formation of the so-called biological glass (vitrification). This state can be achieved in several ways. The involvement of key cold-regulated genes and proteins in the acquisition of cold tolerance in plant tissues may additionally improve the survival of LN-stored explants. The present review explains the importance of cryostorage in agronomy and presents an overview of the recent works accomplished with this strategy. The most widely used cryopreservation techniques, classic and modern cryoprotective agents, and some protocols applied in crops are considered to understand which parameters provide the establishment of high quality and broadly applicable cryopreservation. Attention is also focused on the issues of genetic integrity and functional genomics in plant cryobiology.

There is little information on the in vitro tissue culture systems in Lamprocapnos spectabilis (bleeding heart). The aim of this study was to analyze the influence of plant growth regulators (PGRs) on the development, quality, and physiological state of in vitro-grown bleeding heart “Gold Heart” and “White Gold”. Single-node explants were inoculated on the modified MS medium (Murashige and Skoog in Physiol Plant 15:473–497, 1962), fortified with different auxins, which included indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), and picloram (PIC), along with cytokinins, which included 6-benzyladenine (BA), kinetin (KIN), and thidiazuron (TDZ) at various concentrations. The morphogenetic response of the explants was cultivar-specific. KIN was preferable for the proliferation and development of shoots in “Gold Heart.” However, none of the auxins or cytokinins improved the development of “White Gold” explants, compared with the PGR-free control medium. NAA was the most effective for stimulating rhizogenesis in both cultivars, although IAA resulted in the regeneration of the longest roots. TDZ, NAA, and PIC suppressed the development of shoots in both cultivars tested and stimulated abundant callus formation. Indirect regeneration of somatic embryos occurred on the NAA- and PIC-fortified media. In particular, the latter media stimulated regeneration of the highest number of somatic embryos per nodal segment. Composition of the culture medium also affected the levels of primary and secondary metabolites in shoots and callus of L. spectabilis. IAA (at 1.0 mg L−1) stimulated the synthesis of chlorophyll a and carotenoids in the “Gold Heart,” while BA and KIN (at 0.5 mg L−1) had a negative impact on the concentration of chlorophyll b in the shoots of this cultivar. None of the PGRs increased the level of the pigments in the shoots of bleeding heart “White Gold.” The concentration of chlorophylls and carotenoids in the callus of both cultivars tested was significantly lower compared with the shoots; however, callus was abundant in flavanols.