Journal Article

Mineral nutrition, resin flow and phloem phytochemistry in loblolly pine

Jeffrey M. Warren, H. Lee Allen and Fitzgerald L. Booker

in Tree Physiology

Volume 19, issue 10, pages 655-663
Published in print August 1999 | ISSN: 0829-318X
Published online August 1999 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/19.10.655
Mineral nutrition, resin flow and phloem phytochemistry in loblolly pine

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Southern pine beetles and associated pathogenic fungi represent the largest biotic threat to pine forests in the southeastern USA. The two primary defensive mechanisms of the tree to the beetle–fungal complex are the primary oleoresin flow and the concentrations of preformed and induced secondary compounds. We compared oleoresin flow and concentrations of phloem nutrients, soluble sugars, starch, total phenolics and proanthocyanidins in Pinus taeda L. trees in fertilized and control plots in the Sandhills region of North Carolina. Four blocks of 10 trees per treatment were sampled on five dates from May to November 1995. Phloem nitrogen and potassium concentrations were elevated in trees on fertilized plots, whereas phloem calcium concentrations were decreased. Fertilization significantly enhanced (10–20%) concentrations of phloem phenolics and proanthocyanidins. In contrast, phloem soluble sugars and starch concentrations were up to 30% lower in fertilized trees than in control trees. Increased phenolic concentrations and lower nonstructural carbohydrates should correlate with reduced tissue palatability and decreased pathogen susceptibility in fertilized trees; however, resin flows were significantly lower (30–100%) in fertilized trees compared with control trees, which may facilitate pine bark beetle establishment. Furthermore, fertilization-induced increases in phloem nitrogen concentration may be more important than tissue carbohydrate or phenolic content in determining tissue palatability.

Keywords: carbohydrates; defense; Dendroctonus frontalis; nitrogen; nutrition; Ophiostoma minus; phenolics; Pinus taeda; proanthocyanidins; secondary compounds; southern pine beetle

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

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