Enviromnental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of pla...Enviromnental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of plants is being hampered by these heavy metals. In the present studies, effect of heavy metal especially cadmium has been studied on stomatal diffusive resistance （SDR）, transpiration rate, leaf surface humidity and leaf temperature of soybean plants growing in hydroponic cultures. Cadmium treatment decelerates the rate of transpiration. The inhibition of transpiration associated with increased SDR leads to dehydration of leaf surface, thereby, increasing temperature of leaves in comparison to control plants. In the present study, temperature difference between stressed and non-stressed plant leaves was as high as 3℃ Moreover, any such rise in leaf temperature due to uptake and induced toxicity of heavy metals can possibly be a good bio-indicator having wide applications in thermal remote sensing and geospatial monitoring of metal polluted soils.展开更多
Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied...Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO2 concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research. However, for plants with originally thin and fragile cuticles, e.g., most deciduous plants, conventional techniques sometimes fail to obtain cuticular membranes with sufficient size, or sometimes unable to recover any. This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo- climatological research. Here, we describe a new method using clear nail polish as a medium to ＂strengthen＂ the originally thin and fragile cuticles prior to maceration procedures. We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature. Metasequoia, with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre- sentative, 114. glyptostroboides, as a comparative reference, bas been widely used as a model genus for the study of evolution of plants, palaeoclimatological reconstruction, and plant adaptation to climate changes. But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process. The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.展开更多
Stomatal characteristics and its plasticity were surveyed in leaves of four canopy species, Shoreachinensis, Pometia tomentosa, Anthocephalus chinensis, Calophyllun polyanthum and three middle-layerspecies, Barrington...Stomatal characteristics and its plasticity were surveyed in leaves of four canopy species, Shoreachinensis, Pometia tomentosa, Anthocephalus chinensis, Calophyllun polyanthum and three middle-layerspecies, Barringtonia pendula, Garcinia hanburyi, Horsfieldia tetratepala, acclimated to different lightconditions for more than one year. All plants stomata are distributed on the abaxial of leaves. Pometiatomentosa and Barringtonia pendula have higher stomatal density and the guard cell length of Anthocephaluschinensis and Calophyllun polyanthum were much greater than others. Stomatal density and stomatal index(ratio of stomatal numbers to epidermal cell number) were increased with growth irradiance increased, whilenumbers of stomata per leaf were higher in the low than the high relative PFD, and stomatal conductance ofleaves was the highest in the 50% of full light except for Anthocephalus chinensis. The relative PFD has littleeffects on the guard cell length of all seven plants. We have also found a significant negative correlationbetween stomatal density and leaf area, but the stomatal conductance was not significantly positive with thestomatal conductance. The analysis of phenotypic plasticity of stomatal characteristics showed: plasticityindex for stomatal index and numbers of stomatal per leaf were similar for canopy and middle-layer species,while the plasticity index of stomatal density and stomatal conductance were significantly greater for canopyspecies than middle-layer species. The high plasticity of canopy species was consistent with the hypothesisthat specialization in a more favorable environment increases plasticity.展开更多
文摘Enviromnental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of plants is being hampered by these heavy metals. In the present studies, effect of heavy metal especially cadmium has been studied on stomatal diffusive resistance （SDR）, transpiration rate, leaf surface humidity and leaf temperature of soybean plants growing in hydroponic cultures. Cadmium treatment decelerates the rate of transpiration. The inhibition of transpiration associated with increased SDR leads to dehydration of leaf surface, thereby, increasing temperature of leaves in comparison to control plants. In the present study, temperature difference between stressed and non-stressed plant leaves was as high as 3℃ Moreover, any such rise in leaf temperature due to uptake and induced toxicity of heavy metals can possibly be a good bio-indicator having wide applications in thermal remote sensing and geospatial monitoring of metal polluted soils.
基金supported by CAS/SAFEA International Partnership Program for Creative Research Teams,the Pilot Project of Knowledge Innovation of CAS (Grant No. KZCX2-YW-105)National Basic Research Program of China (Grant No. 2006CB806400)National Natural Science Foundation of China (Grant Nos. 40402002,40872011)
文摘Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO2 concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research. However, for plants with originally thin and fragile cuticles, e.g., most deciduous plants, conventional techniques sometimes fail to obtain cuticular membranes with sufficient size, or sometimes unable to recover any. This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo- climatological research. Here, we describe a new method using clear nail polish as a medium to ＂strengthen＂ the originally thin and fragile cuticles prior to maceration procedures. We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature. Metasequoia, with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre- sentative, 114. glyptostroboides, as a comparative reference, bas been widely used as a model genus for the study of evolution of plants, palaeoclimatological reconstruction, and plant adaptation to climate changes. But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process. The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.
文摘Stomatal characteristics and its plasticity were surveyed in leaves of four canopy species, Shoreachinensis, Pometia tomentosa, Anthocephalus chinensis, Calophyllun polyanthum and three middle-layerspecies, Barringtonia pendula, Garcinia hanburyi, Horsfieldia tetratepala, acclimated to different lightconditions for more than one year. All plants stomata are distributed on the abaxial of leaves. Pometiatomentosa and Barringtonia pendula have higher stomatal density and the guard cell length of Anthocephaluschinensis and Calophyllun polyanthum were much greater than others. Stomatal density and stomatal index(ratio of stomatal numbers to epidermal cell number) were increased with growth irradiance increased, whilenumbers of stomata per leaf were higher in the low than the high relative PFD, and stomatal conductance ofleaves was the highest in the 50% of full light except for Anthocephalus chinensis. The relative PFD has littleeffects on the guard cell length of all seven plants. We have also found a significant negative correlationbetween stomatal density and leaf area, but the stomatal conductance was not significantly positive with thestomatal conductance. The analysis of phenotypic plasticity of stomatal characteristics showed: plasticityindex for stomatal index and numbers of stomatal per leaf were similar for canopy and middle-layer species,while the plasticity index of stomatal density and stomatal conductance were significantly greater for canopyspecies than middle-layer species. The high plasticity of canopy species was consistent with the hypothesisthat specialization in a more favorable environment increases plasticity.
