Establishment of in vitro Culture of Rubber (Hevea brasiliensis) from Field-derived Explants: Effective Role of Silver Nanoparticles in Reducing Contamination and Browning

Moradpour M,Aziz Ma

doi:10.4172/2157-7439.1000375

Abstract

The development of in vitro methods to produce high quality clonal planting materials of c for replanting and new planting is highly essential. The establishment of in vitro cultures of challenging woody plant species like H. brasiliensis has frequently been hampered by persistent microbial contamination, phenolic production, phase change and low response to media. Therefore, the overall goal of this study was to establish an efficient in vitro propagation method for H. brasiliensis through solving those persistent problems. In determining the most suitable method of reducing explant contamination, different concentrations of sodium hypochlorite, mercuric chloride and nano silver (NS) at different immersion times were assessed on explants derived from three physiological leaf stages (bronze, light green and stable green leaf stages) of preculture and non-preculture treated plants. The highest percentage of survival (94.44%) was from explants derived from the light green leaf stage of preculture treated plants immersed in 10 ppm NS for 20 min. Different types of adsorbents which were silver nitrate, activated charcoal and NS were assessed in controlling browning of in vitro cultures of H. brasiliensis. NS at 4 ppm significantly produced the highest percentage of explant survival (87.03%) with a low percentage of browning (10%). In determining the most suitable medium for in vitro culture of H. brasiliensis explants, Murashige and Skoog (MS) medium, Woody Plant medium (WPM) and Enjalric and Carron (MB) medium in combination with 3%, 6% and 9% sucrose concentrations were assessed. After 16 weeks of culture, the highest percentage of shoot formation (80%) was on MB medium supplemented with 6% sucrose.

Highlights

Hevea brasiliensis is commonly the rubber tree, is a tree belonging to the family Euphorbiaceae
It is obvious that explants derived from the three leaf developmental stages of preculture treated plants generally showed moderate to high percentage of explant survival
Explants from the bronze leaf stage of preculture treated plants showed up to 79.62% survival after sterilization in 20% NaOCl for 20 min, while explants from the bronze leaf stage of non-preculture treated plants exhibited a maximum of 57.40% survival after sterilization in 20% NaOCl for 20 min

Summary

Introduction

Hevea brasiliensis is commonly the rubber tree, is a tree belonging to the family Euphorbiaceae. Previous studies have shown that physiological aging negatively affects the micropropagation capacity of H. brasiliensis from microcuttings [4,5] This phase change phenomenon has been observed in many studies and is associated with a noticeable decline in the potential of micropropagation or somatic embryogenesis of most arborescent species [6,7,8,9]. The second difficulty in in vitro establishment of Hevea species is the rapid browning and/ or necrosis of the explants. To optimise an efficient tissue culture method for Hevea rubber, explant preparation is one of the important steps that need to be given attention in order to overcome the problem of microbial contamination and browning. Besides understanding the mother plant and its interaction with the environment it is important that new types of sterilants are introduced to combat the problems faced during in vitro culture establishment. Nano silver is a new and non-toxic material which shows high capability in eliminating microorganisms, e.g., fungus, bacteria and viruses through the release of tiny particles of silver that could destroy the microorganisms [13]

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Discussion

Conclusion