Olive Oil for Dressing Plant Leaves so as to Avoid O3 Injury

Koike

2018

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A series of laboratory no-choice assays were performed to test changes in the feeding, growth, and nutrition of leaf beetle (Agelastica coerulea) larval instars on O-treated leaves of Japanese white birch (Betula platyphylla var. japonica). Larvae fed with O-treated leaves grew and developed significantly faster throughout their developmental cycle than the corresponding controls. The growth rate (GR) and consumption index (CI) were mostly decreased with age for both control and O-treated leaves. Efficiency of conversion of both ingested and digested food (ECI, ECD) showed an increase from the 2nd to the 4th instar, after which they decreased significantly and reached the lowest value in the last larval instars (7th). GR, CI, ECI, and ECD were greater and approximate digestibility (AD) was lower in larvae fed with O-treated leaves than those fed with control leaves. This indicated that the greater rate of growth on fumigated leaves was due primarily to a greater rate of consumption (i.e., O increased the "acceptability" of the host more than "suitability") and efficiency in converting food into body mass. Overall, larval performance seemed to have improved when fed with O-treated leaves in these assays. This study suggests that insects may be more injurious to O-treated plants and warrants further investigations on birch-beetle interactions under field conditions.

Section: Discussionmentioning

confidence: 99%

Growth and nutrition of Agelastica coerulea (Coleoptera: Chrysomelidae) larvae changed when fed with leaves obtained from an O3-enriched atmosphere

ElEla

Koike

2018

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“…For statistically significant linear contrasts, the effect magnitude of EOZ was calculated using a bias-corrected Cohen's δ (Hedges and Olkin 1985;Cohen 1988), as described previously (Agathokleous et al 2016c). The effects were converted into percentile gain, which appeared in the experimental condition using the Cohen's U 3 index (Cohen 1977); δ was converted to the overlapping coefficient (OVL) (Reiser and Faraggi 1999) [1.50-3.00)], or large (δ = 3.00+) (Cohen 1988;Agathokleous et al, 2016b).…”

Section: Discussionmentioning

confidence: 99%

Enzyme activity modification in adult beetles (Agelastica coerulea) inhabiting birch trees in an ozone-enriched atmosphere

ElEla

Ghazawy

et al. 2018

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Tropospheric ozone (O 3) is a naturally occurring gas in the atmosphere. However, the concentration of O 3 increased in the 20 th century. Although the effects of O 3 on vegetation have been extensively studied since the 1950s, limited information exists regarding the effects of O 3 on insect herbivores. In particular, evidence is lacking regarding the effects of O 3 on the biology of insect herbivores. Agelastica coerulea (Baly, 1874) is a coleopteran species that grazes on Betulaceae plants. In this study, to investigate the effects of O 3 on A. coerulea biology for the first time, female adult insects were collected from Japanese white birch trees grown in a Free Air Controlled Exposure System (FACE) in Sapporo, Japan. These beetles inhabited trees exposed either to ambient or to elevated O 3 for 23 days. After 2 collection, the enzyme activities in the beetles were measured. Elevated O 3 led to a greater total antioxidant activity and lower α-and β-esterase activities, a phenomenon that may suggest an increased resistance of the beetles to stress. Our results are further discussed with regard to biological and toxicological aspects. Collectively, our findings indicate that total antioxidants and α-and β-esterase activities can serve as effective O 3 biomarker systems in this beetle species. This adaptive response of the beetle, which was induced by moderate O 3 exposure, should be further tested across generations and for its protection against greater exposure.

“…The unbiased Cohen's δ was estimated based on balanced real replicates (Hedges and Olkin 1985) so as to quantify the magnitude of difference when the predictor was statistically significant. For covariate-adjusted response variables, δ was estimated by subtracting the baseline effect from the post-treatment effect (Agathokleous et al 2016c). Estimations of δ were calculated according to Agathokleous et al (2016bAgathokleous et al ( , 2016c…”

Section: Discussionmentioning

confidence: 99%

Stem and crown growth of Japanese larch and its hybrid F1 grown in two soils and exposed to two free-air O3 regimes

Amelie

Kita

et al. 2017

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Ozone (O) pollution and soil infertility may negatively affect boreal forests across the Northern Hemisphere. Impacts to economically and ecologically important larches (Larix sp., Pinacaeae) are particularly concerning. Using a free air O enrichment (FACE) system, we investigated the effect of 2-year elevated O exposure (≈66 nmol mol) on Japanese larch (L. kaempferi) and its hybrid larch F (L. gmelinii var. japonica × L. kaempferi) planted directly into either fertile brown forest soil (BF) or BF mixed with infertile volcanic ash soil (VA). Overall, photosynthetic pigmentation and the growth performance of the stem and crown were reduced in both taxa exposed to elevated O. Furthermore, hybrid larch, in both O treatments, performed better than Japanese larch. This finding contradicts findings of prior experiments with potential experimental artifacts of O exposure facilities and root restrictions. Elevated O also disproportionately inhibited stem diameter growth and caused an imbalance in chlorophylls a/b and chlorophyll/carotenoid ratios. Hybrid and Japanese larches grown in BF and VA had a significantly lower drop of stem diameter over the run of stem height (from base to top) when exposed to elevated O, compared to ambient O. This finding indicates altered stem shape under elevated O. Among 11 response variables, there were no significant interactions between O treatment and taxa. There was also no significant interaction of soil condition and taxa, suggesting that the two larches shared a similar response to O and soil type. Understanding the performance of hybrid larch in relation to its parent species has ramifications for breeding success in a soil-degraded and O-polluted environment.