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EFFECTS OF TREE AGE ON SECONDARY XYLEM AND PHLOEM ANATOMY IN STEMS OF GREAT BASIN BRISTLECONE PINE (PINUS LONGAEVA)
Author(s) -
Connor Kristina F.,
Lanner Ronald M.
Publication year - 1990
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1990.tb13602.x
Subject(s) - xylem , phloem , tracheid , biology , vascular cambium , botany , pinus <genus> , cambium , woody plant
Xylem and phloem tissue samples were collected from various‐aged Great Basin bristlecone pine ( Pinus longaeva D. K. Bailey) stems in southern Utah and southeastern California to determine whether the vascular cambia of older trees produce fewer xylem rays, shorter‐lived xylem and phloem ray cells, fewer phloem sieve cells, and a thinner phloem. Increment cores were examined to determine whether ‘aged’ cambia produced narrower tracheids that might reduce water translocation. Sapwood thickness was measured and sapwood growth layers were counted on these cores. Regression and Classification and Regression Tree (CART) analyses of sample data found no age‐related changes in cambial products. Phloem and xylem production appeared normal at all ages, with no evidence of cambial malfunction.