Am J Bot. 1997 Sep;84(9):1198.
The halophytic genus Suaeda (Chenopodiaceae) includes species with the C3 and C4 photosynthetic pathways. North American species of this genus were investigated to determine whether C3 and C4 leaf anatomy are consistent within the two sections of Suaeda, Chenopodina and Limbogermen, present on this continent. All species from section Chenopodina were found to possess C3 anatomy, whereas all species from section Limbogermen were found to be C4 species. Characteristics of leaf anatomy and chloroplast ultrastructure are similar to those reported from C3 and C4 species, respectively, from the Eastern Hemisphere. All species from section Limbogermen have the suaedoid type of leaf anatomy, characterized by differentiation of the mesophyll into palisade parenchyma and a chlorenchymatous sheath surrounding central water-storage tissue, as well as leaf carbon isotope ratios (_13C) of above -20. All species from section Chenopodina have austrobassioid leaf anatomy without a chlorenchymatous sheath and _13C values of below -20. According to our literature review, the photosynthetic pathway has now been reported for about half (44) of the Suaeda species worldwide. The C3 and C4 photosynthetic syndromes are with few exceptions distributed along sectional or subsectional lines. These findings throw new light on the infrageneric taxonomy of this genus.
盐生植物属苏达（藜科）包括具有 C3 和 C4 光合作用途径的物种。对本大陆存在的两个节，Chenopodina 和 Limbogermen 中的北美物种进行了调查，以确定 C3 和 C4 叶片解剖结构是否在这两个节内一致。Chenopodina 节的所有物种都被发现具有 C3 解剖结构，而 Limbogermen 节的所有物种都被发现是 C4 物种。叶片解剖结构和叶绿体超微结构的特征与分别来自东半球的 C3 和 C4 物种的特征相似。Limbogermen 节的所有物种都具有苏达型叶片解剖结构，其特征是将叶肉分化为栅栏薄壁组织和围绕中央储水组织的绿色组织鞘，以及叶片的碳同位素比（_13C）高于-20。Chenopodina 节的所有物种都具有 austrobassioid 叶片解剖结构，没有绿色组织鞘，_13C 值低于-20。根据我们的文献综述，光合作用途径现在已在全球约一半（44）的苏达物种中得到报道。C3 和 C4 光合作用综合征除了少数例外，都沿着分类或亚分类的线分布。这些发现为该属的种下分类学提供了新的线索。
