title: Seasonal development of cambial activity in relation to xylem formation in Chinese fir.
abstract: The vascular cambium is a lateral meristem which can differentiate into secondary phloem and xylem. The secondary growth of woody plants resulting from vascular cambium activity has been a focus of considerable attention, but the quantitative relationships between cambial activity and secondary xylem formation have been little studied. Our analysis of cytological changes in the cambium of Chinese fir (Cunninghamia lanceolata), revealed a significant positive correlation between vascular cambium cell numbers and cambium zone width through the seasonal cycle. Cambium cell numbers and the cambium cell radial diameter were closely related to xylem formation. Immuno-labeling showed that de-esterified homogalacturonan and (1-4)-β-d-galactan epitopes were highly abundant in cell walls of dormant-stage cambium, whereas high methylesterified homogalacturonan was strongly labeled in the active stage. Raman spectroscopy detected significant changes in the chemical composition of cell walls during the active-dormant stage transition. More pectin and less monolignols occurred in radial cell walls than in tangential walls during the dormant stage, but no significant changes were found in other stages, indicating that pectin accumulation facilitates cell wall expansion, with cambium activity transition. Our quantitative analysis of the relationship between cambial activity and xylem formation, as well as the cell wall modification during the active stage provides useful information about cambial characteristics and xylogenesis.
authors.affiliation: Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants of Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, PR China.
authors.forename: Hongyang
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants of Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, PR China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Laboratory of Lignocellulosic Chemistry, College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, PR China.
authors.forename: Hanyin
authors.initials: H
authors.lastname: Li
authors.affiliation: School of Life Science, Taizhou University, Zhejiang 318000, PR China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wei
authors.affiliation: Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants of Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, PR China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Lin
authors.affiliation: Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants of Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, PR China. Electronic address: lixj@bjfu.edu.cn.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
mesh_terms: D058506:Cambium / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D032486:Cunninghamia / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D010368:Pectins / Q000378:metabolism; D052585:Phloem / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D012621:Seasons; D052584:Xylem / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism
chemical_list: D011134:Polysaccharides; C088556:mucoric acid; D010368:Pectins; C003181:polygalacturonic acid
keywords: Cambial activity; Cell wall; Confocal Raman microscopy; Cunninghamia lanceolata; Pectin immune-localization