Regulation of reactive oxygen species on production, release, and early germination of archeospores in Pyropia yezoensis

Abstract

In plant, reactive oxygen species (ROS) play important regulatory roles in cell differentiation and development. The archeospores released from the blades of Pyropia yezoensis have important application value as secondary seedling sources in cultivation. However, whether ROS are involved in the production and early germination of archeospores of P. yezoensis is unclear. In this study, in situ ROS fluorescence detection was developed to observe the regulation of ROS on the processes of formation, release and germination of archeospores of P. yezoensis. The results are as follows, there was no ROS fluorescence in the marginal bladed cells of P. yezoensis with no formed archeospores, but strong ROS fluorescence in the marginal cells while releasing archeospores. Next, intensive ROS fluorescence was emerged in released archeospores which carried on amoeboid movement with irregular cell shape. Then, after the archeospores adhered to the glass substrate, the ROS fluorescence faded rapidly, accompanied with round cell shape, and formed cell wall. When the cells elongated for the first germination and division, ROS fluorescence disappeared eventually, and there was no ROS fluorescence in the germlings with two and more cells. On the other hand, by culturing the somatic cells isolated from the blades, ROS fluorescence could be continuously detected from stage of single cells to cell-masses composed of multiple cells, the intensity of which was raised with the increasing numbers of cells in the cell-mass. When the cells in cell-masses differentiated into archeospores, the ROS fluorescent intensity reached the peak. As the addition of diphenyleneiodonium (DPI) could inhibit the production of ROS, the speed of cell division was significantly affected and the ROS fluorescent intensity was decreased during treatment. The above results confirmed that ROS play roles in the regulation on the formation, release and early germination of archeospores of P. yezoensis.