title: [Seasonal changes in foliar micro-and ultra structure of two Sabina species and their relationships with cold tolerance].
abstract: In this paper, the foliar micro-and ultra structure of Sabina przewalskii and S. chinensis during growth and dormancy seasons was observed under microscope and transmission electron microscope, and the foliar soluble sugar content was measured, aimed to probe into their relationships with cold tolerance. The results showed that the foliar surface cells of these two Sabina species were covered with thick cuticular membrane, and the well-developed arenchyma appeared in the mesophyll. In growth season, starch grains accumulated in chloroplasts, but in dormancy season, the accumulated starch grains disappeared or diminished, while soluble sugar content had a larger increase. In wintertime, the chloroplasts of S. chinensis were injured, with some abnormal chloroplasts, increased plastoglobuli and some lipid drops, while those of S. przewalskii were not obviously injured. It was suggested that the cold tolerance of the two Sabina species was related to their well-developed arenchyma, accumulation of starch grains in growth season, and increase of soluble sugar content in dormancy season. S. przewalskii had more marked increase of soluble sugar content, and its chloroplasts were more stable than S. chinensis.
authors.affiliation: Cold and Arid Region Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China. zyfgau@163.com
authors.forename: Youfu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yinping
authors.initials: Y
authors.lastname: Chen
authors.forename: Manxiao
authors.initials: M
authors.lastname: Zhang
authors.forename: Tuo
authors.initials: T
authors.lastname: Chen
authors.forename: Lizhe
authors.initials: L
authors.lastname: An
mesh_terms: D000222:Adaptation, Physiological; D003081:Cold Climate; D003080:Cold Temperature; D018515:Plant Leaves / Q000648:ultrastructure*; D012621:Seasons; D014197:Trees / Q000145:classification / Q000502:physiology* / Q000648:ultrastructure*