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Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)

SIMPLE SUMMARY: Galls induced by insects are commonly found on oak leaves in temperate climates. Their induction and development are, however, still only partially known. Our aim was to present a detailed description of their anatomy and fine structure. Using scanning electron microscopy (SEM), we o...

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Autores principales: Jankiewicz, Leszek Stanisław, Guzicka, Marzenna, Marasek-Ciolakowska, Agnieszka
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8537352/
https://www.ncbi.nlm.nih.gov/pubmed/34680619
http://dx.doi.org/10.3390/insects12100850
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author Jankiewicz, Leszek Stanisław
Guzicka, Marzenna
Marasek-Ciolakowska, Agnieszka
author_facet Jankiewicz, Leszek Stanisław
Guzicka, Marzenna
Marasek-Ciolakowska, Agnieszka
author_sort Jankiewicz, Leszek Stanisław
collection PubMed
description SIMPLE SUMMARY: Galls induced by insects are commonly found on oak leaves in temperate climates. Their induction and development are, however, still only partially known. Our aim was to present a detailed description of their anatomy and fine structure. Using scanning electron microscopy (SEM), we observed the wax cover of a gall and two types of openings on its surface: one similar to degenerated stomata and the other one that we called “large openings on epidermal protuberance”. Nutritive tissue underwent marked changes with time: in a young gall, the cellular walls were not visible, and a distinct cellular structure appeared only later. In the mound of the gall, there was a distinct subepidermal layer of cells containing dense cytoplasm. Tannins occurred in vacuoles or in cell walls in granular form or in compact formations. The leaf subtending the gall showed additional cell divisions and strong lignification of cell walls in the tissue surrounding the peduncle of the gall. ABSTRACT: The structure and ultrastructure of two developmental stages of the spangle gall induced by Neuroterus quercusbaccarum (Hymenoptera, Cynipidae) were investigated using light microscopy (LM), fluorescence microscopy (FM), and transmission (TEM) and scanning (SEM) electron microscopy. The general design of the gall structure was typical of Cynipidae, but some structural features distinguished the spangle gall. Previously undescribed, characteristic multicellular epidermal protuberances with large openings were observed in autumn on the surface of galls. These may facilitate the gas exchange between the atmosphere and the inside of the gall, thus assisting larval respiration. The larval chamber is surrounded by both a sclerenchymatous capsule and numerous cells containing calcium oxalate crystals that may both serve as protective barriers. In young galls, the nutritive tissue is a wall-less protoplasmic mass, potentially easily accessible to young larvae with delicate mandibles. Cell walls only develop at a later stage. The nutritive tissue was found to be rich in proteins and lipids, but starch grains were not observed. Cellular topology suggests that spangle galls grow by anticlinal division of marginal epidermal cells and periclinal division of subepidermal cells. Cellular proliferation (hyperplasia) also occurs in the leaf tissue near the connection with the gall peduncle, which eventually lignifies.
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spelling pubmed-85373522021-10-24 Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur) Jankiewicz, Leszek Stanisław Guzicka, Marzenna Marasek-Ciolakowska, Agnieszka Insects Article SIMPLE SUMMARY: Galls induced by insects are commonly found on oak leaves in temperate climates. Their induction and development are, however, still only partially known. Our aim was to present a detailed description of their anatomy and fine structure. Using scanning electron microscopy (SEM), we observed the wax cover of a gall and two types of openings on its surface: one similar to degenerated stomata and the other one that we called “large openings on epidermal protuberance”. Nutritive tissue underwent marked changes with time: in a young gall, the cellular walls were not visible, and a distinct cellular structure appeared only later. In the mound of the gall, there was a distinct subepidermal layer of cells containing dense cytoplasm. Tannins occurred in vacuoles or in cell walls in granular form or in compact formations. The leaf subtending the gall showed additional cell divisions and strong lignification of cell walls in the tissue surrounding the peduncle of the gall. ABSTRACT: The structure and ultrastructure of two developmental stages of the spangle gall induced by Neuroterus quercusbaccarum (Hymenoptera, Cynipidae) were investigated using light microscopy (LM), fluorescence microscopy (FM), and transmission (TEM) and scanning (SEM) electron microscopy. The general design of the gall structure was typical of Cynipidae, but some structural features distinguished the spangle gall. Previously undescribed, characteristic multicellular epidermal protuberances with large openings were observed in autumn on the surface of galls. These may facilitate the gas exchange between the atmosphere and the inside of the gall, thus assisting larval respiration. The larval chamber is surrounded by both a sclerenchymatous capsule and numerous cells containing calcium oxalate crystals that may both serve as protective barriers. In young galls, the nutritive tissue is a wall-less protoplasmic mass, potentially easily accessible to young larvae with delicate mandibles. Cell walls only develop at a later stage. The nutritive tissue was found to be rich in proteins and lipids, but starch grains were not observed. Cellular topology suggests that spangle galls grow by anticlinal division of marginal epidermal cells and periclinal division of subepidermal cells. Cellular proliferation (hyperplasia) also occurs in the leaf tissue near the connection with the gall peduncle, which eventually lignifies. MDPI 2021-09-22 /pmc/articles/PMC8537352/ /pubmed/34680619 http://dx.doi.org/10.3390/insects12100850 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jankiewicz, Leszek Stanisław
Guzicka, Marzenna
Marasek-Ciolakowska, Agnieszka
Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)
title Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)
title_full Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)
title_fullStr Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)
title_full_unstemmed Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)
title_short Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)
title_sort anatomy and ultrastructure of galls induced by neuroterus quercusbaccarum (hymenoptera: cynipidae) on oak leaves (quercus robur)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8537352/
https://www.ncbi.nlm.nih.gov/pubmed/34680619
http://dx.doi.org/10.3390/insects12100850
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