Tissue culture tools for selenium hyperaccumulator Neptunia amplexicaulis for development in phytoextraction

Area of Science:

• Plant biotechnology
• Environmental science
• Phytoremediation

Background:

• Neptunia amplexicaulis, an Australian legume, is a potent selenium hyperaccumulator with potential for phytoextraction.
• Efficiently propagating this species is crucial for its application in selenium remediation.
• Existing propagation methods may not be optimized for large-scale clonal production.

Purpose of the Study:

• To establish an efficient in vitro micropropagation protocol for the selenium hyperaccumulator Neptunia amplexicaulis.
• To optimize shoot multiplication and root induction for clonal plant generation.
• To confirm the selenium hyperaccumulation capacity of micropropagated plants.

Main Methods:

• Micropropagation using nodal segments from in vitro-germinated seedlings.
• Optimization of shoot multiplication using Murashige and Skoog (MS) media with varying concentrations of 6-Benzylaminopurine (BA) and Naphthaleneacetic acid (NAA).
• In vitro rooting of elongated shoots using NAA and subsequent acclimatization.
• Assessment of selenium (Se) tissue concentrations using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) after dosing with selenate/selenite.

Main Results:

• The most effective shoot multiplication was achieved with 2.0 mg/L BA + 0.2 mg/L NAA.
• The highest root induction rate of 30% was observed at 0.2 mg/L NAA, with 95% of rooted shoots surviving acclimatization.
• Clonally propagated plants retained their selenium hyperaccumulation ability, confirmed by ICP-AES analysis.

Conclusions:

• A robust in vitro micropropagation protocol for Neptunia amplexicaulis has been successfully developed.
• The protocol facilitates the generation of a large number of genetically identical plants for research.
• This method supports the potential optimization for industrial-scale selenium phytoextraction applications.