Compensatory responses in plant-herbivore interactions: Impacts of insects on leaf water relations

PESCHIUTTA ML; BUCCI SJ; SCHOLZ FG; GOLDSTEIN G

ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY

GAUTHIER-VILLARS/EDITIONS ELSEVIER

Lugar: Paris; Año: 2016 vol. 73 p. 71 - 79

1146-609X

Herbivore damage to leaveshas been typically evaluated in terms of fractions of area removed; however morpho-physiologicalchanges in the remaining tissues can occur in response to removal. We assessedthe effects of partial removal of the leaf mesophyll by Caliroa cerasi (Hymenoptera) on leaf hydraulic conductance (Kleaf),vascular architecture, water relations and leaf size of three Prunus avium cultivars. The insect feedson the leaf mesophyll leaving the vein network intact (skeletonization). Withineach cultivar there were trees without infestations and trees chronicallyinfested, at least over the last three years. Leaf size of intact leaves tendedto be similar during leaf expansion before herbivore attack occurs across infestedand non-infested trees. However, after herbivore attack and when the leaves were fully expanded, damagedleaves were smaller than leaves from non-infested trees. Damaged area variedbetween 21 to 31% depending on cultivar. The non-disruption of the vascularsystem together with either vein density or capacitance increased in damagedleaves resulted in similar Kleaf and stomatal conductance ininfested and non-infested trees. Non-stomatal water loss from repeated leafdamage led to lower leaf water potentials in two of the infested cultivars.  Lower leaf osmotic potentials andvulnerability to loss of Kleaf were observed in infested plants. Ourresults show that skeletonization resulted in compensatory changes in terms of waterrelations and hydraulics traits and in cultivar-specific physiological changesin phylogenetic related P. avium. Ourfindings indicate that detrimental effects of herbivory on the photosyntheticsurface are counterbalanced by changes providing higher drought resistance,which has adaptive significance in ecosystems where water availability is lowand furthermore where global climate changes would decrease soil wateravailability in the future even further.