Journal Article

Hemlock woolly adelgid (Adelges tsugae) infestation affects water and carbon relations of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana)

Rivera, Laura N, Hain, Fred, Domec, Jean-Christophe, Frampton, John, Smith, Benjamin, King, John S, Department of Forestry and Environmental Resources ; North Carolina State University [Raleigh] (NC State) ; University of North Carolina System (UNC)-University of North Carolina System (UNC), Transfert Sol-Plante et Cycle des Eléments Minéraux dans les Ecosystèmes Cultivés (TCEM) ; Institut National de la Recherche Agronomique (INRA)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB), North Carolina State University [Raleigh] (NC State) ; University of North Carolina System (UNC), Peszlen, Ilona

2013

Overview

Hemlock woolly adelgid (HWA) is an exotic insect pest causing severe decimation of native hemlock trees. Extensive research has been conducted on the ecological impacts of HWA, but the exact physiological mechanisms that cause mortality are not known. Water relations, anatomy and gas exchange measurements were assessed on healthy and infested eastern (Tsuga canadensis) and Carolina (Tsuga caroliniana) hemlock trees. These data were then used in a mechanistic model to test whether the physiological responses to HWA infestation were sufficiently significant to induce changes in whole-plant water use and carbon uptake. The results indicated coordinated responses of functional traits governing water relations in infested relative to healthy trees. In response to HWA, leaf water potential, carbon isotope ratios, plant hydraulic properties and stomatal conductance were affected, inducing a reduction in tree water use by >40% and gross primary productivity by 25%. Anatomical changes also appeared, including the activation of traumatic cells. HWA infestation had a direct effect on plant water relations. Despite some leaf compensatory mechanisms, such as an increase in leaf hydraulic conductance and nitrogen content, tree water use and carbon assimilation were diminished significantly in infested trees, which could contribute to tree mortality.

• Publisher: Wiley,HAL CCSD,New Phytologist Trust,Wiley Subscription Services, Inc
• Subject: Adelges tsugae / Animals / Branches / Carbon / Carbon - metabolism / carbon dioxide fixation / Carbon fixation / carbon isotope / Carbon Isotopes / Cell activation / Circadian Rhythm - physiology / Conductance / Ecological effects / Environmental Sciences / Gas exchange / gross primary productivity / Hemiptera - physiology / hydraulic conductivity / Hydraulic properties / Hydraulics / Infestation / insect pests / Insects / Isotope ratios / isotopes / Leaf area / leaf water potential / Leaves / Life Sciences / mechanistic models / Model testing / Models, Biological / Mortality / Nitrogen / Nitrogen - metabolism / nitrogen content / Physiological responses / Physiology / Plant Diseases - parasitology / Plant Leaves - anatomy & histology / Plant Leaves - physiology / Plant roots / Plant Stems - physiology / Plant Stomata - physiology / Plants / Primary production / Resistance / Seasons / soil–plant–atmosphere model / Stomata / Stomatal conductance / traumatic resin canals / tree mortality / Tree physiology / Trees / Tsuga - parasitology / Tsuga canadensis / Tsuga caroliniana / Uptake / Water - metabolism / Water potential / Water relations / Water use / Wood - anatomy & histology / wood anatomy / Xylem / Xylem - anatomy & histology
• ISBN: 0003206184000