Evaluating the spore genome sizes of ferns and lycophytes: a flow cytometry approach.
Ferns and lycophytes produce spores to initiate the gametophyte stage for sexual reproduction. Approximately 10% of these seedless vascular plants are apomictic, and produce genomic unreduced spores. Genome size comparisons between spores and leaves are a reliable, and potentially easier way to determine their reproductive mode compared to traditional approaches. However, estimation of the spore genome sizes of these plants has not been attempted. We attempted to evaluate the spore genome sizes of ferns and lycophytes using flow cytometry, collected spores from selected species representing different spore physical properties and taxonomic groups, and sought to optimize bead-vortexing conditions. By evaluating the spore and sporophyte genome sizes, we examined whether reproductive modes could be ascertained from these flow cytometry results. We proposed two separate sets of optimized bead-vortexing conditions for the nuclear extraction of green and nongreen spores. We further successfully extracted spore nuclei of 19 families covering most orders, and the qualities and quantities of these extractions satisfied the C-value criteria. These evaluated genome sizes further supported the reproductive modes reported previously. In the current study, flow cytometry was used for the first time to evaluate the spore genome sizes of ferns and lycophytes. This use of spore flow cytometry provides a new, efficient approach to ascertaining the reproductive modes of these plants.
Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, 10617, Taiwan.
Li-Yaung
LY
Kuo
Department of Forensic Science, Central Police University, Taoyuan City, 33304, Taiwan.|Division of Silviculture, Taiwan Forestry Research Institute, Taipei, 10066, Taiwan.
Yi-Jia
YJ
Huang
Chiayi Agricultural Experiment Branch, Taiwan Agricultural Research Institute, Chiayi City, 60044, Taiwan.
JenYu
J
Chang
Division of Botanical Garden, Taiwan Forestry Research Institute, Taipei, 10066, Taiwan.|Dr. Cecilia Koo Botanic Conservation and Environmental Protection Foundation/Conservation Center, Pingtung County, 90646, Taiwan.
Wen-Liang
WL
Chiou
Division of Silviculture, Taiwan Forestry Research Institute, Taipei, 10066, Taiwan.
Yao-Moan
YM
Huang
D002467:Cell Nucleus / Q000378:metabolism; D032461:Chromosomes, Plant / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D029624:Ferns / Q000235:genetics*; D005434:Flow Cytometry / Q000379:methods*; D059646:Genome Size; D055993:Germ Cells, Plant / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics; D013170:Spores / Q000235:genetics*
D018744:DNA, Plant
C-value; bead-vortexing; fern; flow cytometry; genome size; lycophyte; reproduction; spore