As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and...As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds,primarily fl avonoids.Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level.During the early stages of development,non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics.At later developmental stages,and during secondary wall thickening,phenolics are transferred to the cell walls of the trichomes.Due to the diff use deposition of phenolics in the cell walls,trichomes provide protection against UV-B radiation by behaving as optical fi lters,screening out wavelengths that could damage sensitive tissues.Protection from strong visible radiation is also aff orded by increased surface light refl ectance.Moreover,the mixtures of trichome phenolics represent a superfi-cial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens.Although the cells of some trichomes die at maturity,they can modulate their quantitative and qualitative characteristics during development,depending on the prevailing conditions of the external biotic or abiotic environment.In fact,the structure and chemical constituents of trichomes may change due to the particular light regime,herbivore damage,wounding,water stress,salinity and the presence of heavy metals.Hence,trichomes represent dynamic protective structures that may greatly aff ect the outcome of many plant–environment interactions.展开更多
Between January 1985 and July 1987, 1,622 cancer patients were evaluated to outline the possible applications and limits of various investigative techniques for evaluating metastases. Seventy-three cases with superfic...Between January 1985 and July 1987, 1,622 cancer patients were evaluated to outline the possible applications and limits of various investigative techniques for evaluating metastases. Seventy-three cases with superficial metastases of the dermal-hypodermal (59) layers, of the muscles (11) and of other target organs (3) were included in the study.Although non-glandular superficial metastases are a relatively rare occurrence, diagnostic imaging techniques are indicated for evaluating their extent and anatomical connections. Secondary neoplasms were studied using the imaging techniques of sono-graphy, computed tomography and xeroradiography.The diagnostic reliability of these three techniques was evaluated, taking into account their ability to determine the extent of metastases and of assessing malignancy.Sonography is considered as a satisfactory screening technique, but CT is an even better tool for evaluating the extent and anatomical connections of such lesions. Xeroradiography has been made obsolete by the introduction of the other two techniques.展开更多
基金partially funded by the Greek General Secretariat of Research and Technologythe Greek Scholarship FoundationThe ’Empirikion’ Foundation
文摘As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds,primarily fl avonoids.Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level.During the early stages of development,non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics.At later developmental stages,and during secondary wall thickening,phenolics are transferred to the cell walls of the trichomes.Due to the diff use deposition of phenolics in the cell walls,trichomes provide protection against UV-B radiation by behaving as optical fi lters,screening out wavelengths that could damage sensitive tissues.Protection from strong visible radiation is also aff orded by increased surface light refl ectance.Moreover,the mixtures of trichome phenolics represent a superfi-cial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens.Although the cells of some trichomes die at maturity,they can modulate their quantitative and qualitative characteristics during development,depending on the prevailing conditions of the external biotic or abiotic environment.In fact,the structure and chemical constituents of trichomes may change due to the particular light regime,herbivore damage,wounding,water stress,salinity and the presence of heavy metals.Hence,trichomes represent dynamic protective structures that may greatly aff ect the outcome of many plant–environment interactions.
文摘Between January 1985 and July 1987, 1,622 cancer patients were evaluated to outline the possible applications and limits of various investigative techniques for evaluating metastases. Seventy-three cases with superficial metastases of the dermal-hypodermal (59) layers, of the muscles (11) and of other target organs (3) were included in the study.Although non-glandular superficial metastases are a relatively rare occurrence, diagnostic imaging techniques are indicated for evaluating their extent and anatomical connections. Secondary neoplasms were studied using the imaging techniques of sono-graphy, computed tomography and xeroradiography.The diagnostic reliability of these three techniques was evaluated, taking into account their ability to determine the extent of metastases and of assessing malignancy.Sonography is considered as a satisfactory screening technique, but CT is an even better tool for evaluating the extent and anatomical connections of such lesions. Xeroradiography has been made obsolete by the introduction of the other two techniques.
