International Journal of Horticulture, 2017, Vol.7, No.18, 146-153
152
Figure 5 Total polyphenol and flavonide contents in shoots of intact plant and
in vitro
micropropagated shoots of potato (
Solanum
tuberosum
L.) cv. PRI-Red
4 Discussion
Potato (
Solanum tuberosum
L.) is an economically important vegetable crop and is consumed by more than one
billion people around the globe (Venkatasalam et al., 2013). Therefore, for the production of disease free
seedlings of potato an expedite, efficient and genotype independent micropropagation system is required. In this
study, different micropropagation media with varying level and combination of NAA and BAP were studied.
Hence a micropropagation medium, MPm7 was selected as best medium for in vitro micropropagation because it
gave genotype independent response as well as excellent, expedite and proficient response for both genotypes
under study viz., PRI-Red and FD 69-1. Plant growth hormones are the most important factors for regulating
shoot development and multiplication. Thus, the inclusion of auxins and cytokinins in the micropropagation
medium greatly influences the shoot formation and development. The response and the quality of in vitro cultures
are highly influenced by different concentrations and the type of nutrients used in the culture media (Niedz and
Evens, 2007). The effect of different nutritive and hormonal constituents of tissue culture media on
micropropagation was reported by many researchers (Thirunavoukkarasu and Debata, 2002). Among cytokinins,
BAP is proved to be the best responsive for shoot induction (Badoni and Chauhan, 2009; Rahman et al., 2010).
Different scientist observed that BAP produces more shoots as compared to kinetin and IAA in micropropagation
systems (Carelli and Echaverigary, 2002; Moeinil et al., 2011). However, in this study medium containing BAP
lone at concentration of 2.75 mg/l also showed best response to micropropagation and maximum numbers of
shoots were achieved in both genotypes of potato from this medium. However, in vitro shoots achieved from
medium that was proved to be best, were assessed phytochemically and results of this study showed that total
polyphenolic contents were higher in shoots of intact plant than in vitro micropropagated shoots. Alkaloids were
not detected in both samples of plant. The variation in the content of the phytochemicals might be due to the
different growth conditions and phases of plant development (Nickolova et al., 2013). High contents of
polyphenols in shoots of intact plants may be due to increased synthesis of phenols in natural conditions as a
defensive reaction to environmental stress (Ramesh et al., 2009). In some other studies also reported that field
grown plant leaves contained higher total phenolic than in vitro cultured plants (Hegazai 2011; Sagwan et al.,
2011; Singh et al., 2011; Seth and Sarin 2012). Nikolova et al. (2013) also studied that the total content of
phenols and flavonoids in the extracts of in vitro cultures were lower than in the extracts of ex vitro and in vivo
grown plants.
Acknowledgement
We highly acknowledge Director Potato Research Institute Sahiwal, Pakistan for providing us potato germplasm for this research
work.
References
Anonymous, 2013, Pakistan Economic Survey, Economic Advissor’s Wing, Finance Division, Government of Pakistan, Islamabad
