Periodicity in phloem rings of Avicennia marina?

Nele Schmitz, Anouk Verheyden, Hans Beeckman, Nico Koedam

Research output: Chapter in Book/Report/Conference proceedingMeeting abstract (Book)


On sanded stem disks of the mangrove species Avicennia marina (Avicenniaceae) a clear alternation of light colored bands of phloem and darker xylem bands, which are created by successive cambia, can be observed. However, little is known about the factors responsible for the formation of a new cambium and whether these are formed at periodic intervals. Whereas Chapman (1947) considered the rings to be annual, Gill (1971) found them to be related to stem diameter and suggested an endogenous control. The objective of this study is to investigate whether the formation of the successive cambia of A. marina is influenced by environmental factors such as salinity and inundation frequency and whether they are formed at periodic intervals.

A combination of various methodologies was used. First, the annual character of ring formation was studied by counting rings from stem disks as well as branches from three plantation trees of known age. Besides, a preliminary set of three in 1999 cambially marked trees was analyzed. The results showed that the phloem rings in A. marina are not annual rings.
Second, if development of successive cambia is influenced by environmental conditions, it is expected that the outermost rings in all trees of a same site are at the same growth stage. The number of xylem and phloem cells of the last ring is counted from 65 trees, growing at seven sites in Gazi Bay (Kenya), differing in salinity and inundation class. Samples from the outermost wood were sectioned and slides stained with safranin and fast green.
Third, the cambium of another set of 65 A. marina trees of the same sites was marked to investigate if a well-defined number of rings is formed annually and if the number is influenced by the environmental conditions. A first marking was done in May 2005 during the rainy season and a second marking will be done in February 2006 (dry season). Cuttings will be performed after one year of growth.
Original languageEnglish
Title of host publicationOctober 2-5 San Vito di Cadore, Belluno, Italy
Publication statusPublished - 2005
EventFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet - Stockholm, Sweden
Duration: 21 Sep 200925 Sep 2009

Publication series

NameWorkshop “Intra-annual analysis of wood formation”, October 2-5, 2005


ConferenceFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet


  • wood formation
  • successive cambia
  • wood anatomy
  • avicennia marina


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