Storm density的用法和样例：
例句
- The stomatal density and stomatal index had little taxonomical significance among the six genera.However, the two characters might be useful for species identification.
气孔密度和气孔指数在属间的分类意义不明显，但在属内种间的分类上具有一定价值。 - The results showed that the ploidy level had a significantly positive correlation with the stoma diameter, but a negtive correlation with the stoma density.
结果表明，红掌倍性与气孔长度呈显著正相关，而与气孔密度呈显著负相关。
