Histogenic analysis of chemically induced mixoploids in Spathiphyllum wallisii

Tetraploids and mixoploids were induced in several Spathiphyllum wallisii genotypes through in vitro application of mitosis inhibitors. Flow cytometry of leaves enabled the identification of sectorial hybrids, whereas microscopic nuclei research combined with root flow cytometry was required to provide insights in the histogenic composition of the mixoploids and to identify periclinal chimeras. Microscopic observation of epidermal or parenchymatic cell areas or the average cell thickness did not allow unequivocal characterization. However, direct visualization of diploid and tetraploid cells was enabled by analysis of nuclear areas. Root analysis was performed by classical fluorescence of metaphase chromosome spreads. This study showed the necessity of microscopic techniques for a thorough characterization of mixoploids. It also demonstrated the potential of the combination of these techniques with flow cytometry to unravel the exact effect of mitosis inhibitors on monocot plants. Finally, it might help to optimize the tetraploidization efficiency.