Study on the Relationship Between the Ploidy Level of Microspore-Derived Plants and the Number of Chloroplast in Stomatal Guard Cells in Brassica oleracea

The relationship between the ploidy level of microspore-derived plants and chloroplast number in stomatal guard cells was studied in cabbage, broccoli, and Chinese kale. In the experiment, distribution statistics analysis and t-test were used to perform statistical analysis on chloroplast number of different ploidy level in those stomata! guard cells mentioned above, and morphology identifying and chromosome counting were used to test accuracy of counting chloroplast number in stomata! guard cells. The chloroplast average number in stomata! guard cells was very similar among the different leaf positions on the same plant and among the different locations in the same leaf, while the chloroplast number varied significantly among the different ploidy stoma in the same variety. All the distributions of the chloroplast number in different ploidy stoma were normal distribution fitted. A correlation has been established between ploidy and chloroplast number in the stomatal guard cells. In every single stoma of microspore-derived plants, the chloroplast number for a haploid should not be more than 10, diploids 11 to 15, and polyploids more than 15. The accuracy of this method for identification of different ploidy plants was 93.93%. Furthermore, the accuracy of this method was reliable and did not vary with the plants growth conditions. Therefore, the chromosome ploidy of plants derived from microspore culture in cabbage, broccoli, and Chinese kale can be identified by simply counting the chloroplast number in stomatal guard cells.