Neodiprion sertifer defoliation causes long-term systemic changes of oxidative enzyme activities in Scots pine needles

Abstract

The aim of the experiments reported here was to study possible long-term effects of Neodiprion sertifer Geoff. (Hymenoptera: Diprionidae) herbivory, or artificial defoliation, on oxidative enzyme activities in Scots pine (Pinus sylvestris L.) needles as a consequence of induced defense responses. During year 1 (the first season), defoliation by N. sertifer, which feeds on previous season's needles, did not result in statistically significant changes in polyphenol oxidase activity in the current year's needles. In contrast, defoliation did lead to increased peroxidase activity in those needles. In the second season (year 2) N. sertifer defoliation of pine seedlings, also defoliated in the previous season either by larvae or artificially, resulted in a decrease of peroxidase activity in the current year's needles. No significant differences between treatments carried out in year 1 were found in year 2 for peroxidase activity in the previous year's needles. However, defoliation in year 1 by N. sertifer resulted in decreased needle consumption, and higher mortality of larvae, in year two. These results indicate the existence of long-term changes in needle oxidative enzyme activities as a consequence of N. sertifer feeding.

Compensatory Growth and Physiological Protective Mechanisms of Populus talassica Kom. × Populus euphratica Oliv. in Response to Leaf Damage

“…During long-term growth and development, plants tend to form defense mechanisms for selfprotection to avoid or reduce insect feeding or other mechanical damage, and the synthesis of defense enzymes is an important expression of the defense system's formation [49]. The important defense enzymes CAT, SOD, POD, and PAL are closely related to plant-induced resistance and damage tolerance [13,14,50].…”

“…After the artificial defoliation of Pinus cumerosae, the POD activity significantly increased by 3 d; however, there was no significant change in the SOD activity [54]. The POD activity in the leaves of Pinus sylvestris L. increases briefly at 72 h after defoliation and then rapidly decreases [50]. In addition, mechanical damage can stimulate an increase in PAL activity, which induces resistance in plants [55].…”