Use of nanotechnology to improve plant performance in boreal forest ecosystem

Ali, Md. Hossen (2019) Use of nanotechnology to improve plant performance in boreal forest ecosystem. Masters thesis, Memorial University of Newfoundland.

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Abstract

Nano-priming has been shown to significantly improve the total germination percentage and seedling vigor of different plant seeds including agricultural crops. In these applications, seeds primed with Carbon nanotubes (CNTs) exhibited dramatic improvements in germination rate and seedling vigor (root and stem lengths). Herein, we applied this technique to non-agriculture crop species in an attempt to resolve several different seeds dormancies hindering their propagation and field establishment. Specifically, the seeds of boreal forest plant species with embryo and seed coat dormancy were nano-primed with several carbon-based nanoparticles, as part of a strategy to overcome seed dormancy. Carboxylic acid functionalized multi-walled carbon nanoparticle (-COOH biomolecule coated) was the most effective in breaking physical (seed coat) and morphological dormancy (embryo), as well as increase the germination rate in combination with stratification in green alder (Alnus viridis L.), bog birch (Betula pumila), and labrador tea (Rhododendron groenlandicum). Conversely, a combination of carbon nanoparticles (CNPs), especially the multiwall carbon nanoparticles functionalized with carboxylic acid (MWCNT-COOH), cold stratification, mechanical scarification and hormonal priming (gibberellic acid) was effective in overcoming embryo and hard seed coat dormancy present in buffalo berry seeds (Shepherdia canadensis L.). A concomitant increase in the seedling vigor index and the number of normal seedlings was observed in the nano-primed germinated seedlings, indicating its superior ability to be established across a range of environmental sites. The improvement in germination rate and resolution of both embryo and seed coat dormancy appears to be associated with the remodeling of several membrane lipids as indicated by the segregation of these molecular species in the same quadrant of the biplot as germination rate (GR) and seedling vigor index (SVI), following redundancy analysis. Phosphatidylcholine (PC) (18:1/18:3), phosphatidylglycerol (PG) (16:1/18:3), phosphatidylethanolamine (PE) (18:3/18:2), and digalactosyldiacylglycerol (DGDG) (18:3/18:3) lipids classes were observed to be highly correlated with increased seed germination percentages and the enhanced seedling vigor observed in this study for the evaluated species. Mechanistically, it appears that carbon nano-primed seeds following stratification is effective in mediating seed dormancy by remodeling the seed membrane lipids {Phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidic acid (PA) and digalactosylglycerol (DG)} in both peatland and upland boreal forest species. These findings suggest that nanopriming (20 μgmL⁻¹ or 40 μgmL⁻¹) may be a useful approach to resolve seed dormancy issues and improve seed germination in non-resource boreal forest species ideally suited for forest reclamation following resource mining.

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