Single somatic cell development and differentiation in the gametiphytic blades of Pyropia suborbiculata (Bangiales, Rhodophyta)

Conchospores released from a wild-type strain of Pyropia suborbiculata were cultured in the laboratory for 20-80 days.Mother blades of different ages were enzymatically isolated to obtain single cells,which then developed into different types of regenerative plants within a liquid medium.These regenerative plant types includes:normal blades,abnormal blades,cell-masses,and sexual cell-masses.The age of mother blades distinctly affected the number and proportion of each type of regenerative plants.When the age of mother blades increased from 20 to 80 days,the proportion of normal blades in the isolated cells sharply decreased,the percentage of abnormal blades increased,and the proportion of cell-masses was relatively unchanged.After 40 days of cultivation,sexual cell-masses appeared in regenerated plants derived from the single blade cells of the PS-WT strain,and gradually increased with mother cell age.In addition,the proportion of normal blades decreased in regenerated plants sourced from the basal to apical parts of the same alga,while the proportion of abnormal blades and cell-masses increased.In summary,the isolated cells of the gametophytic blade of P.suborbiculata developed into different types of regenerated plantlets in vivo due to the different stages of cell differentiation.We preliminarily concluded that the differentiation from conchospores to the sexual cells could be divided into at least seven different groups.