Chloroplast structure and function in wild-type and aurea-type leaves of the Japanese spindle-tree over their life span

The evergreen leaves of the Japanese spindle-tree (Euonymus japonicus Thunb. \u27Aureomarginatus\u27) are adapted to endure repeated freezing and thawing during the winter. We investigated the physiological and morphological characteristics of the chloroplasts in young, overwintering, and overwintered wild-type and aurea-type leaves. When developing in the shade, both leaf types during their life span maintained a well-developed thylakoid system in their chloroplasts. The photosynthesis rates were also similar. When growing in intense sunlight, the aurea variety contained chloroplasts with a reduced thylakoid system, but photosynthesis was less reduced. In spring, overwintered leaves of both varieties clearly showed ultrastructural and physiological characteristics of senescence. The senescence in aurea leaves exposed to full sunlight was more pronounced

Structural changes of lamellar cells in leaves of the moss Polytrichum formosum Hedw. during winter freezing and thawing processes

The lamellar cells of winter leaves of Polytrichum formosum were studied by electron microscopy of thin sections, and the results were compared with those for spring and summer plants. Pigment content and photosynthetic activity were also analysed. The lamellar cells of winter plants, when grown at temperatures above zero, had a similar ultrastructure to those of spring and summer plants. Their pigment content and photosynthetic activity were also similar. On the other hand, the lamellar cells of frozen plants (examined at temperatures about –5 °C) were desiccated, i.e. deformed, the cytosol was shrunken, and the ribosomes and mitochondria were aggregated. The thylakoid system of their chloroplasts was irregularly arranged and the grana thylakoids were compressed. The desiccation of the cells was soon annulled when the ambient temperature rose above zero

Structural changes of lamellar cells in leaves of the moss Polytrichum formosum Hedw. during winter freezing and thawing processes

The lamellar cells of winter leaves of Polytrichum formosum were studied by electron microscopy of thin sections, and the results were compared with those for spring and summer plants. Pigment content and photosynthetic activity were also analysed. The lamellar cells of winter plants, when grown at temperatures above zero, had a similar ultrastructure to those of spring and summer plants. Their pigment content and photosynthetic activity were also similar. On the other hand, the lamellar cells of frozen plants (examined at temperatures about –5 °C) were desiccated, i.e. deformed, the cytosol was shrunken, and the ribosomes and mitochondria were aggregated. The thylakoid system of their chloroplasts was irregularly arranged and the grana thylakoids were compressed. The desiccation of the cells was soon annulled when the ambient temperature rose above zero

Exceptional dense water formation on the Adriatic shelf in the winter of 2012

In this paper we document dense water formation throughout the Adriatic shelf and coastal area in January/February 2012, resulting in record-breaking densities observed during and after the event. The unprecedented dense water generation was preconditioned by a dry and warm year which resulted in a significant reduction of coastal freshwaters, superimposed on a long-term basin-wide salinity increase. The final event that triggered the dense water formation was an extended period of cold weather with strong and severe winds. Record-breaking potential density anomalies (above 30 kg m⁻³) were measured at several formation sites. Accumulated surface net heat and water losses in some coastal regions exceeded 1.5 GJ m⁻² and 250 kg m⁻² over 21 days, respectively. Excessiveness, importance of shelf-type dense water formation and effects on the thermohaline circulation and deep aquatic systems are discussed

DNAqua-Net: Developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe

publisher: Pensoft Publishers articletitle: DNAqua-Net: Developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe journaltitle: Research Ideas and Outcomes copyright: http://creativecommons.org/licenses/by/4.0/ received: 2016-11-27 published: 2016-11-29publisher: Pensoft Publishers articletitle: DNAqua-Net: Developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe journaltitle: Research Ideas and Outcomes copyright: http://creativecommons.org/licenses/by/4.0/ received: 2016-11-27 published: 2016-11-29publisher: Pensoft Publishers articletitle: DNAqua-Net: Developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe journaltitle: Research Ideas and Outcomes copyright: http://creativecommons.org/licenses/by/4.0/ received: 2016-11-27 published: 2016-11-29publisher: Pensoft Publishers articletitle: DNAqua-Net: Developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe journaltitle: Research Ideas and Outcomes copyright: http://creativecommons.org/licenses/by/4.0/ received: 2016-11-27 published: 2016-11-2