Open Access
Issue
BIO Web Conf.
Volume 11, 2018
IV(VI)th All-Russia Scientific-Practical Conference “Prospects of Development and Challenges of Modern Botany”
Article Number 00049
Number of page(s) 4
DOI https://doi.org/10.1051/bioconf/20181100049
Published online 21 August 2018

© The Authors, published by EDP Sciences, 2018

Licence Creative Commons
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1 Introduction

Mint is a well-known perennial herbaceous medicinal, essential oil and spicy aromatic plant in the family Lamiaceae. Different species of the genus Mentha are used in pharmacology, cosmetic and food industries, as well as in medicine. Preparations from mint plants have antiseptic, sedative, spasmolytic, and choleretic effect. Great interest to this valuable plant causes active development of breeding work, including creation of new essential oil cultivars. It is reasonable to involve biotechnological methods for the rapid propagation of the initial breeding material and cultivars, as well as for the development of techniques for their preservation in vitro.

The literature sources contain data regarding the studies related to the development of micropropagation methods for various mint species - Mentha piperita [1-3], M. viridis [4], M. canadensis, M. suaveolens, M. longiflora, M. aquatica, M. arvensis, M. x gracilis, M. gracilis, M. spicata [5]. According to these sources, scientists used meristems, buds [1, 3, 4] and stem segments with a node [2, 5] as explants in their experiments, as well as used different modifications of culture medium composition at the stages of propagation. However, many important issues of clonal micropropagation were not risen in these works, especially for cultivars and breeding samples of essential oil mint grown in the Crimea. The aim of our research was to study the influence of the genotype and the number of subcultures on the development of mint explants at the second stage of micropropagation in vitro.

2 Materials and Methods

Tissues and organs of mint cultivars and breeding samples – cultivar Diana (interline hybrid Mentha cadadensis L.), cultivar Krasnodarskaya 2 (obtained by selecting in the seed progeny of allopolyploid sample Mentha x piperita L.), sample K 37 (M. rotundifolia L. Huds), sample No. 2.8.14 (line S1 of M. spicata K65 sample) and sample A2 (allopolyploid sample M. x piperita L.) [6] were used as the material for the study. Meristems with one pair of leaf primordia isolated from axillary buds were introduced in culture in vitro. At the 2nd stage of micropropagation, segments of the stem with a node isolated from shoots, which were developed from meristems, were used as explants. Explants were cultivated on Murashige and Skoog culture medium (MS) supplemented with growth regulator such as BAP, Kinetin, IAA, GA3 (Sigma, USA). Explants in test tubes were kept at 26°C, 70% of relative air humidity, under 16-h photoperiod with illumination 2-3 klx.

Microcuttings were conducted every 40-45 days, before which the length and number of shoots, the number of nodes (pairs of leaves) on shoot, the frequency of rhizogenesis were determined. The multiplication index was calculated as the number of microcuttings that can be obtained during one subculture. For this the number of formed on the explant shoots was multiplied on the number of nodes on the shoot. Experiments on in vitro culture were carried out in three replications; at each variant 20 explants were analyzed. The data are processed using the Microsoft Office software package (Excel 2007). The tables show average values and their standard errors.

3 Results and Discussion

The studies revealed that active adventitious shoot formation and development of shoots which are long enough (up to 20-40 mm) were observed for almost all genotypes (excluding A2) when introducing meristems in culture in vitro. For the further micropropagation at the 2nd stage, microcutting of shoots was carried out. Microcuttings (segments of a stem with one node and a pair of leaves) were cultivated on the modification of MS culture medium with 1.0 mg/l mg L-1 BAP and 0.5 mg L-1 IAA, which we used for the propagation of other cultivars of peppermint [7]. It was identified that this medium was effective for four genotypes, whereas explants of sample A2 did not develop on it. Therefore, modification of MS medium with 0.5 mg L-1 Kinetin and 0.5 mg L-1 GA3 was chosen for this sample in a separate experiment.

During microcuttings cultivation, on average developed 2.7-15.2 shoots per explant, depending on the number of subcultures and genotype (Table 1.). At the same time, active growth of axillary and adventitious shoots was observed. They reached a length of 15.249.7 mm after 40-45 days of cultivation. Rhizogenesis with a frequency of 7.1 to 100% was observed for all studied genotypes at the second stage of propagation, during which an average of 1.0-5.7 roots per explants were formed. It was revealed that it is expedient to combine two methods for mint micropropagation in vitro – the induction of adventitious shoots and microcutting of main and additional shoots.

When analyzing the development of explants during six passages, the peculiarities of the influence of genotype and number of subcultures on the morphometric parameters of microshoots and multiplication index were identified (Table 1.). Gradual increase in the number and length of shoots and in the number of nodes during the 2-5th passages was observed for cultivars Krasnodarskaya 2 and Diana. Rhizogenesis with a frequency of 95.0 to 100% was observed for these passages. The main parameter at the second stage of micropropagation – multiplication index was significantly increased; it reached a maximum (23.0-48.7) for these cultivars in 4-5th passages. The decline of almost all the studied parameters occurred then in the 6th passage.

Similar tendencies of development were observed in other mint genotypes, however, there were no significant differences in many parameters during the 2-5th passages. However, the maximum multiplication index was identified for samples No. 2.8.14 (20.1) and K37 (23.3) in the fifth passage. After that, a slight decrease in the morphometric parameters was observed in the sixth passage. The maximum number of shoots, rooting frequency and multiplication index (12.0-12.1) were noted in the 3-4th subcultures for sample A2. Then, there was a significant decrease in parameters, and in the fifth passage the multiplication index was only 6.2 for this genotype.

Gomes et al. [5] when studying nine mint species during five passages also showed an increase in the multiplication index after the first passage. It reached the highest values in 3-5th subcultures, depending on the species. The same situation of increasing the multiplication index to a certain passage during prolonged micropropagation was revealed for some other essential oil plants. Thus, at the 2nd stage of micropropagation in vitro an increase in the multiplication index, which reached maximum in the third passage, was observed for the cultivars of essential oil rose [8] and lavender [9]. At the same time, this parameter for geranium was stable for two years, but for sage and fennel did not change significantly during the first three subcultures, and then it gradually decreased [9].

Comparing different mint genotypes, it was shown that ‘Krasnodarskaya 2’ had the best micropropagation ability. This cultivar showed the most active adventitious shoot formation, and as a result the number of shoots reached maximum value (15.2 per explant) in the 4th passage. The largest average length of shoots and the number of nodes were in the 5th passage. As a result, multiplication index for this cultivar reached the highest value - 48.7. The parameters of explants development for sample A2 were the lowest. Its multiplication index varied from 6.2 to 12.1, depending on the passage. Thus conducting mint propagation during six subcultures, it was established that the multiplication index was increased in the 4-5th passages for cultivars Krasnodarskaya 2, Diana and samples K37 and No. 2.8.14. But for micropropagation sample A2 it was neccesary to use culture medium of another composition, on which this index reached a maximum in 3-4th passages.

Table 1.

Influence of subculture number and genotype on the development of mint explants on the second stage of micropropagation in vitro

References

  • G.J. Minas, Acta Hort. 853, 77-82 (2010) [CrossRef] [Google Scholar]
  • J. Mehta, R. Naruka, M. Sain, A. Dwivedi, D. Sharma, J. Mirza, Asian J. Plant Sci. Res. 2, 518-523 (2012) [Google Scholar]
  • I.A. Bugara, Scientific Notes of Taurida V.I. Vernadsky National University, Ser. Biology, chemistry 26, 10-15 (2013) [Google Scholar]
  • H.D. Raja, D.I. Arockiasamy, Plant Tissue Cult. & Biotech. 18, 1-6 (2008) [Google Scholar]
  • H.T. Gomes, P.M. Bartos, A.E. Marins, S.O.D. de Oliveira, J.E. Scherwinski-Pereira, Acta Scientiarum. Biol. Sci. 37, 405-410 (2015) [CrossRef] [Google Scholar]
  • L.A. Bugaenko, N.P. Shilo, Polyploidy and interspecies hybridization in mint (Simferopol, Business-Inform, 2012) [Google Scholar]
  • M.S. Zagorskaya, N.A. Yegorova, Proceed. Int. Conf. dedicated to 85th anniversary of the Central Bot. Gar. of the Nat. Academy of Sci. of Belarus 2, 205-208 (Medisont, Minsk, 2017) [Google Scholar]
  • N.A. Yegorova, I.V. Stavtzeva, Bull. of the State Nikit. Botan. Gard. 120, 36-43 (2016) [Google Scholar]
  • N.A. Yegorova, A.G. Krivokhatko, I.V. Stavtzeva, L.I. Kamenek, Taurida Herald of the Agrarian Sciences 1, 9-14 (2013) [Google Scholar]

All Tables

Table 1.

Influence of subculture number and genotype on the development of mint explants on the second stage of micropropagation in vitro

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.