Assessment of morphological and phytochemical attributes in triploid and hexaploid plants of the bioenergy crop Miscanthus x giganteus

Giant Miscanthus (Miscanthus x giganteus) is a perennial, warm-season C4 grass. It is a sterile triploid that grows rapidly, accumulates significant biomass, and has the potential to be a new bioenergy crop. Hexaploid Miscanthus x giganteus can be induced from triploid M x giganteus using colchicine. Here, we compared a range of parameters between triploid and hexaploid plants using phytochemical and histological analyses. Inductively coupled plasma-atomic energy spectrometry (ICP-AES) and high performance liquid chromatography (HPLC) showed significant differences in the amounts of 21 microelements and macroelements elements (Al, Ca, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb, Se, Ag, Ti, Zn, P, Si, S, Na, K, and Sr) between triploid and hexaploid plants. Additionally, phenolic compounds such as pyrogallol, catechin, veratric acid, o-coumaric acid, and myricetin were present at higher concentrations in leaf extracts of hexaploid plants compared to triploid plants. Pyrogallol, gentisic acid, chlorogenic acid, and catechin were also higher in the stem extracts of hexaploid plants. The cellulose content of leaf extracts of hexaploid plants was significantly higher than that of triploid plants, while total lignin content was higher in triploid plants. Significant differences were found between triploid and hexaploid plants for plant height, number of leaves, leaf length, leaf width, number of nodes, stem diameter, tiller number, fresh weight during both pre-flowering and post-flowering stages, and photosynthetic rate. Our analyses indicate that hexaploid M x giganteus exhibited superior agronomical traits and improved biomass yield compared to triploid plants and thus could be suitable for future large-scale biomass production. (C) 2016 Elsevier B.V. All rights reserved.