Induced polyploidization increases 20-hydroxyecdysone content, in vitro photoautotrophic growth, and ex vitro biomass accumulation in Pfaffia glomerata (Spreng.) Pedersen

Abstract

The present study aimed to verify the effects of induced polyploidization on Pfaffia glomerata regarding its 20-hydroxyecdysone (20E) production both in vitro and under greenhouse conditions, its in vitro photoautotrophic potential, and its ex vitro biomass accumulation and photosynthetic performance. Synthetic polyploidization efficiently produced individuals with increased in vitro photoautotrophic potential and ex vitro biomass accumulation, although photosynthetic rates per leaf area did not vary between diploids and tetraploids. Among the five tetraploids tested (P28, P60, P68, P74, and P75), P28 showed significantly increased biomass both in vitro and ex vitro when compared with diploid plants, whereas the other tetraploids did not differ significantly from the diploids in terms of biomass accumulation. Although photosynthetic rates per unit leaf area remained constant among all the plants tested, P28 showed a significantly greater total leaf area, which may have resulted in an increase in net photosynthesis on a whole-plant basis. Under greenhouse conditions, the 20E content in the tetraploid P28 was 31% higher than that in diploid plants, and the final 20E mass per plant produced by P28 ex vitro was approximately twice that produced by diploid plants. Accumulation of 20E in vitro did not follow the same pattern observed among the plants ex vitro; instead, greater accumulation was observed in diploid plants. The induction of polyploidy in P. glomerata appears to be a promising strategy for producing plants with higher biomass accumulation and 20E production ex vitro, in addition to its higher in vitro photoautotrophic potential.