Given the consistent release of zinc oxide(ZnO)nanoparticles into the environment,it is urgent to study their impact on plants in depth.In this study,grains of rice were treated with two different concentrations of Zn...Given the consistent release of zinc oxide(ZnO)nanoparticles into the environment,it is urgent to study their impact on plants in depth.In this study,grains of rice were treated with two different concentrations of ZnO nanoparticles(NP-ZnO,10 and 100 mg/L),and their bulk counterpart(B-ZnO)were used to evaluate whether ZnO action could depend on particle size.To test this hypothesis,root growth and development assessment,oxidative stress parameters,indole-3-acetic acid(IAA)content and molecules/enzymes involved in IAA metabolism were analyzed.In situ localization of Zn in control and treated roots was also performed.Though Zn was visible inside root cells only following nanoparticle treatment,both materials(NP-ZnO and B-ZnO)were able to affect seedling growth and root morphology,with alteration in the concentration/pattern of localization of oxidative stress markers and with a different action depending on particle size.In addition,only ZnO supplied as bulk material induced a significant increase in both IAA concentration and lateral root density,supporting our hypothesis that bulk particles might enhance lateral root development through the rise of IAA concentration.Apparently,IAA concentration was influenced more by the activity of the catabolic peroxidases than by the protective action of phenols.展开更多
Aims The plants of Mediterranean sea cliff ecosystems are resistant to several environmental challenges.In this study,six species typical of the coastal rocky cliffs have been analyzed in order to evaluate their diver...Aims The plants of Mediterranean sea cliff ecosystems are resistant to several environmental challenges.In this study,six species typical of the coastal rocky cliffs have been analyzed in order to evaluate their diverse morphological and physiological responses to their environment across the seasons,and to examine the strategy of the ecological group to which each species belongs.Since these species are widespread across the Mediterranean region,our aim was also to highlight their ecophysiological features in habitats where the direct influence of the sea is stronger.Methods The selected species are characteristic of the sea cliffs of Elba island(Tyrrhenian sea,Italy):the halophyte Crithmum maritimum,the semideciduous Helichrysum italicum and Lavandula stoechas and the sclerophylls Myrtus communis,Quercus ilex and Rhamnus alaternus.Four morphological traits-canopy height,leaf area,specific leaf area and leaf dry matter content-and two physiological traits-leaf water potential(LWP)and photosynthetic efficiency(PE),measured before the dawn and at midday-were analyzed.Water potential was measured by a pressure chamber and photosynthetic efficiency was determined by the analysis of chlorophyll fluorescence.Plant performance was also evaluated by calculating chronic(PIchr)and dynamic photoinhibition(PIdyn).Important Findings Crithmum maritimum showed high resistance to the recurrent dry periods,because of the high water storage capacity of its leaves and its PE declined markedly only in July,under the harshest climatic conditions.Semideciduous taxa utilize primarily an avoidance strategy,which aims at reducing the overall leaf surface,while sclerophylls mostly show a tolerance strategy towards the prevailing stressors,as demonstrated by LWP and PE,that are lower in the sclerophylls than in the semideciduous taxa during summer,due to osmoregulation and photoinhibition,respectively.Furthermore,variability of physiological parameters was higher in the sclerophylls than in the semideciduous taxa,because the former had to withstand wider oscillations of their LWP and PE.The sclerophyllous taxa underwent a slight loss of PE also in winter,likely owing to the combined action of low temperature and high irradiance.In Mediterranean sea cliff ecosystems,the stressful combination of high irradiance,high temperatures and low rainfall typical of the summer season may have been intensified by the shallow soil which displays a poor water storage capacity.On the other hand,winter stress,caused by high solar radiation and low temperatures,does not seem to seriously affect the performance of the studied species.展开更多
基金financed by local funding of the University of Pisa。
文摘Given the consistent release of zinc oxide(ZnO)nanoparticles into the environment,it is urgent to study their impact on plants in depth.In this study,grains of rice were treated with two different concentrations of ZnO nanoparticles(NP-ZnO,10 and 100 mg/L),and their bulk counterpart(B-ZnO)were used to evaluate whether ZnO action could depend on particle size.To test this hypothesis,root growth and development assessment,oxidative stress parameters,indole-3-acetic acid(IAA)content and molecules/enzymes involved in IAA metabolism were analyzed.In situ localization of Zn in control and treated roots was also performed.Though Zn was visible inside root cells only following nanoparticle treatment,both materials(NP-ZnO and B-ZnO)were able to affect seedling growth and root morphology,with alteration in the concentration/pattern of localization of oxidative stress markers and with a different action depending on particle size.In addition,only ZnO supplied as bulk material induced a significant increase in both IAA concentration and lateral root density,supporting our hypothesis that bulk particles might enhance lateral root development through the rise of IAA concentration.Apparently,IAA concentration was influenced more by the activity of the catabolic peroxidases than by the protective action of phenols.
基金European Community within INTERREG IIIA Italy/France‘Islands’Sardinia-Corse-Tuscany(2000-2006 Islands IT-FR).
文摘Aims The plants of Mediterranean sea cliff ecosystems are resistant to several environmental challenges.In this study,six species typical of the coastal rocky cliffs have been analyzed in order to evaluate their diverse morphological and physiological responses to their environment across the seasons,and to examine the strategy of the ecological group to which each species belongs.Since these species are widespread across the Mediterranean region,our aim was also to highlight their ecophysiological features in habitats where the direct influence of the sea is stronger.Methods The selected species are characteristic of the sea cliffs of Elba island(Tyrrhenian sea,Italy):the halophyte Crithmum maritimum,the semideciduous Helichrysum italicum and Lavandula stoechas and the sclerophylls Myrtus communis,Quercus ilex and Rhamnus alaternus.Four morphological traits-canopy height,leaf area,specific leaf area and leaf dry matter content-and two physiological traits-leaf water potential(LWP)and photosynthetic efficiency(PE),measured before the dawn and at midday-were analyzed.Water potential was measured by a pressure chamber and photosynthetic efficiency was determined by the analysis of chlorophyll fluorescence.Plant performance was also evaluated by calculating chronic(PIchr)and dynamic photoinhibition(PIdyn).Important Findings Crithmum maritimum showed high resistance to the recurrent dry periods,because of the high water storage capacity of its leaves and its PE declined markedly only in July,under the harshest climatic conditions.Semideciduous taxa utilize primarily an avoidance strategy,which aims at reducing the overall leaf surface,while sclerophylls mostly show a tolerance strategy towards the prevailing stressors,as demonstrated by LWP and PE,that are lower in the sclerophylls than in the semideciduous taxa during summer,due to osmoregulation and photoinhibition,respectively.Furthermore,variability of physiological parameters was higher in the sclerophylls than in the semideciduous taxa,because the former had to withstand wider oscillations of their LWP and PE.The sclerophyllous taxa underwent a slight loss of PE also in winter,likely owing to the combined action of low temperature and high irradiance.In Mediterranean sea cliff ecosystems,the stressful combination of high irradiance,high temperatures and low rainfall typical of the summer season may have been intensified by the shallow soil which displays a poor water storage capacity.On the other hand,winter stress,caused by high solar radiation and low temperatures,does not seem to seriously affect the performance of the studied species.
