16 diploid and polyploid cultivars of loquat were used for studying the relationship between the number of chloroplast in stomata guard cell and the ploidy. The number of chloroplast in guard cell and the density of stomata were observed and compared. The result showed that the relationship between the density of stomata and the ploidy was unclear. The chloroplast numbers of diploid, triploid and tetraploid cultivars were 14.22,17.98 and 17.46 , and the polyploid cultivars had distinctly more chloroplasts t...