title: Salsola laricifolia, another C3-C 4 intermediate species in tribe Salsoleae s.l. (Chenopodiaceae).
abstract: This study identifies Salsola laricifolia as a C3-C4 intermediate in tribe Salsoleae s.l., Chenopodiaceae, and compares S. laricifolia with the previously described C3-C4 intermediates in Salsoleae. Photosynthetic pathway characteristics were studied in four species of this tribe including S. laricifolia, C3 Sympegma regelii, C3-C4 S. arbusculiformis, and C4 S. arbuscula, using the approaches of leaf anatomy and ultrastructure, activities of ribulose 1-5-bisphosphate carboxylase/oxygenase (Rubisco) and PEP carboxylase (PEPC), CO2 compensation point, and immunolocalization of Rubisco, PEPC, and the P-subunit of glycine decarboxylase (GDC). Salsola laricifolia has intermediate features, with near continuous and distinctive Kranz-like cells (KLCs) compared with the C3-Sympegmoid anatomical type and the C3-C4 intermediate S. arbusculiformis, a relatively low CO2 compensation point (30.4 μmol mol(-1)) and mesophyll (M)-to KLC tissue ratio, mitochondria in KLCs primarily occurring along the centripetal wall, and specific localization of P-protein GDC in the KLCs. The C3-type isotope value (-22.4 ‰), the absence of the clear labeling for PEPC in M cells, and the low activity of the PEPC enzyme (61.5 μmol mg(-1 )chlorophyll(-1) h(-1)) support the identification of S. laricifolia as a type I C3-C4 intermediate. Although these C3-C4 intermediate species have different structural features, one with discontinuous KL cells and the other with continuous, they have similar characteristics in physiology and biochemistry.
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, No. 818 South Beijing Road, Ürūmqi, 830011, Xinjiang, People's Republic of China, zhibinwen158@gmail.com.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Wen
authors.forename: Mingli
authors.initials: M
authors.lastname: Zhang
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide; D002247:Carbon Isotopes; D050841:Glycine Dehydrogenase (Decarboxylating) / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D031248:Salsola / Q000145:classification* / Q000502:physiology*; D013045:Species Specificity
chemical_list: D002247:Carbon Isotopes; D002245:Carbon Dioxide; D002244:Carbon; D050841:Glycine Dehydrogenase (Decarboxylating); C069767:phosphoenolpyruvate carboxylase kinase; D017346:Protein Serine-Threonine Kinases; D012273:Ribulose-Bisphosphate Carboxylase