In Vitro Regeneration of Miscanthus x giganteus through Indirect Organogenesis: Effect of Explant Type and Growth Regulators

Miscanthus x giganteus is a spontaneous sterile hybrid therefore the creation of useful genetic diversity by conventional breeding methods is restricted. Plant regeneration through indirect organogenesis may be a useful approach to create genetic variability of this important agricultural crop. The present study aimed to evaluate the effect of the explant type and growth regulators on indirect organogenesis of Miscanthus x giganteus and to determine the ploidy level of plant regenerants by flow cytometry. On average, the highest percentage of morphogenic callus tested explants formed in the medium supplemented with 2.5 mg L–1 IBA + 0.1 mg L–1 BAP + 4.0 mg L–1 l-proline. The most intensive secondary differentiation of callus cells was observed in the medium supplemented with 4.0 mg L–1 ZEA + 1.0 mg L–1 NAA. The highest root formation frequency with the highest number of roots was determined in the MS nutrient medium supplemented with 0.4 mg L–1 IBA, where more than 95% of plant regenerants survived and were growing normally.

Extraction, Identification And Determination of Antiviral And Anticancer Flavonoids By HPLC-DAD In Cell Suspension Culture of Melia Azedarach L.

Melia azedarach L. from the Meliaceae, contains a wide range of secondary metabolites used as antibacterial, antiviral, antioxidant and anticancer in traditional medicinal. In the present study, the effect of PGRs and explant type on callus induction and cell suspension culture establishment and growth were investigated. We investigated the biochemical properties, and production and accumulation of secondary metabolites such as rutin, quercetin and kaempferol in M. azedarach L. cell cultures. The results showed that the inflorescence and petiole explants had a high percentage of callus induction compared to the leaf explants, but the highest callus growth were observed in leaf explants in MS+3 mg/L NAA+5 mg/L BAP/3 mg/L Kin and 5 mg/L 2,4-D+5 mg/L Kin (6.307, 5.152 and 3.977 g/explant, respectively). The establishment and growth of cell cultures were significantly influenced by PGRs combination and explant type. The highest cell growth were obtained from the leaf and inflorescence callus transferred into the liquid MS medium supplemented with 1 mg/L 2,4-D+1 mg/L Kin (8.489 g/50 mL suspension) and 1 mg/L 2,4-D+1 mg/L BAP (6.852 g/50 mL suspension), respectively. HPLC analysis showed that the cell cultures derived from inflorescence callus in MS+3 mg/L NAA+1 mg/L BAP showed the highest of rutin (47.536 mg/g FW). However, the highest amount of quercetin (8.570 mg/g FW) and kaempferol (5.420 mg/g FW) were obtained from the petiole cell cultures in the MS+1 mg/L 2,4-D+1 mg/L Kin.

Induction of Callogenesis, Organogenesis, and Embryogenesis in Non-Meristematic Explants of Bleeding Heart and Evaluation of Chemical Diversity of Key Metabolites from Callus

Lamprocapnos spectabilis (L.) Fukuhara is a perennial plant species valued in the horticultural, cosmetic, and pharmaceutical markets. To date, however, there were no studies on tissue culture systems in this species when adjusted from non-meristematic explants. The aim of this study is to induce callogenesis, organogenesis, and somatic embryogenesis in non-meristematic explants of Lamprocapnos spectabilis ‘Alba’ cultured in various media and to analyze the chemical diversity of the produced callus. Leaf, petiole, and internode explants were cultured on the modified Murashige and Skoog (MS) medium fortified with various combinations and concentrations of 6-benzyladenine (BA), indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), 2,4-dichlorphenoxyacetic acid (2,4-D), and picloram (PIC). After 10 weeks of culturing, the morphogenetic response of explants was evaluated and the concentration of chlorophylls, carotenoids, anthocyanins, and polyphenols in callus was analyzed. There was no influence of explant type on the callogenesis efficiency (62.1–65.3%). The highest fresh weight of callus was produced on leaf explants in the presence of 2,4-D or PIC. In contrast, the highest share of dry weight was found in internode-derived calli and cultured on IAA-supplemented medium (up to 30.8%). Only 2.5% of all explants regenerated adventitious shoots, while rhizogenesis was reported in 4.5% of explants. Somatic embryos were produced indirectly by 0% to 100% of explants, depending on the culture medium and explant type. The highest mean number of embryos (11.4 per explant) was found on petioles cultured in the MS medium with 0.5 mg·L−1 BA and 1.0 mg·L−1 PIC. Calli cultured in media with NAA usually contained a higher content of primary and secondary metabolites. There was also a significant impact of explant type on the content of anthocyanins, polyphenols, and carotenoids in callus. Further studies should focus on the elicitation of metabolites production in callus culture systems of the bleeding heart.

Micropropagation of Livingstone Potato (Plectranthus esculentus N.E.Br)

Livingstone potato (Plectranthus esculentus N.E.Br) is an underutilised indigenous root vegetable grown by communal farmers in the eastern provinces of Zimbabwe. It is vegetatively propagated using unimproved retained tubers from the previous season. The risk of disease carryover is therefore high, leading to poor yields. The objective of the study was to exploit the tissue culture technique of micropropagation to produce a mass supply of healthy planting material for improved productivity. Two experiments were conducted: firstly, to determine the best explant type and secondly, to determine the best landrace and plant growth regulators for the growth of plantlets. The landraces, namely, Ndurwe, Musande, Chibanda, and Chizambezi, were sourced from communal farmers in the stated production areas. Naphthalene acetic acid (NAA) and benzyl amino purine (BAP) were the auxin and cytokinin used, respectively. The first experiment was laid out as a randomized complete block design (RCBD) with two factors: landrace and explant type (shoot tips, nodes, and leaves). After culturing the explants on a plain Murashige Skoog (MS) medium for ten weeks, the best explant was the node with regards to the number of nodes, shoots, and roots of the plantlets which were significant (P<0.05). The second experiment was laid out as a RCBD with two factors: landraces and the plant growth regulator combinations. The nodes were subcultured on an MS medium supplemented with the 16 combinations of plant growth regulators (0 mg/l, 0.5 mg/l, 1 mg/l, and 2 mg/l BAP concentrations: 0 mg/l, 0.2 mg/l, 0.5 mg/l, and 1 mg/l NAA concentrations), respectively. Chizambezi performed best and is, therefore, highly recommended for the rapid multiplication of Livingstone potato. Results from this study have clearly demonstrated that the addition of NAA: BAP at varying concentrations was significant and is essential for optimizing the growth media for micropropagation of Livingstone potato in Zimbabwe. Commercial production of plantlets can, therefore, be carried out to provide healthy planting material for the communal farmers for improved productivity while preserving the germplasm of the underutilised crop at the same time.

PRIMARY AND SECONDARY SOMATIC EMBRYOGENESIS OF CACAO: THE EFFECT OF EXPLANT TYPES AND PLANT GROWTH REGULATORS

<p class="abstrakinggris">The success of cacao somatic embryogenesis is affected by many factors, including the basal salt medium, the genotype, the explant type, and the concentration and composition of plant growth regulators (PGRs). The study aimed to evaluate the effects of PGRs composition on the primary somatic embryo (PSE) response and the effect of explant type and PGRs composition used in inducing PSE on the secondary somatic embryogenesis (SSE) response. PSEs were induced from basal petal and staminoid explants of MCC 01 and MCC 02 clones on DKW medium containing 2,4-D 2 mg l^-1+ kinetin 0.5 mg l^-1 or 2,4-D 2 mg l^-1 + kinetin 0.125 – 0.250 mg l^-1 + thidiazuron (TDZ) 2.5 – 5 µg l^-1 or 2,4-D 2 mg l^-1 + TDZ 10 µg l^-1. Genotype, explant type, and PGR composition dependently affected PSE response. The best PSE response was obtained from staminoid explant of MCC 02 clone on medium containing 2,4-D 2 mg l^-1 + kinetin 0.5 mg l^-1 (20%, 9 embryos). The explant type and PGR composition used in inducing PSEs affect the SSE response. The highest SSE response of MCC 01 clone was obtained from petal explant with medium containing 2,4-D 2 mg l^-1 + kinetin 0.5 mg l^-1. The formation of SSEs could increase the multiplication rate of MCC 01 clone by 7 times.</p>

The influence of the nutrient medium composition on the induction of calluso- and morphogenesis of Melissa officinalis L.

The features of the calluso- and morphogenesis induction during the cultivation of tissues and organs of Melissa officinalis depending on endogenous and exogenous factors were revealed. The maximum frequency of callus induction (59.5–92.9 %) was noted on the MS medium with 1.0 mg/l 2.4-D and 0.5 mg/l BAP. The induction of morphogenesis from callus was influenced by the composition of the culture medium, the explant type and cultivar. The maximum frequency of morphogenesis induction (20.0–28.0 % depending on the cultivar) from callus was noted on MS culture medium supplemented with 1.0 mg/L NAA and 0.5 mg/L BAP or 1.0 mg/L NAA and 0.5 mg L TDZ.