Transient Effects of Snow Cover Duration on Primary Growth and Leaf Traits in a Tundra Shrub

With the recent climate warming, tundra ecotones are facing a progressive acceleration of spring snowpack melting and extension of the growing season, with evident consequences to vegetation. Along with summer temperature, winter precipitation has been recently recognised as a crucial factor for tundra shrub growth and physiology. However, gaps of knowledge still exist on long-living plant responses to different snowpack duration, especially on how intra-specific and year-to-year variability together with multiple functional trait adjustments could influence the long-term responses. To fill this gap, we conducted a 3 years snow manipulation experiment above the Alpine treeline on the typical tundra species Juniperus communis, the conifer with the widest distributional range in the north emisphere. We tested shoot elongation, leaf area, stomatal density, leaf dry weight and leaf non-structural carbohydrate content of plants subjected to anticipated, natural and postponed snowpack duration. Anticipated snowpack melting enhanced new shoot elongation and increased stomatal density. However, plants under prolonged snow cover seemed to compensate for the shorter growing period, likely increasing carbon allocation to growth. In fact, these latter showed larger needles and low starch content at the beginning of the growing season. Variability between treatments slightly decreased over time, suggesting a progressive acclimation of juniper to new conditions. In the context of future warming scenarios, our results support the hypothesis of shrub biomass increase within the tundra biome. Yet, the picture is still far from being complete and further research should focus on transient and fading effects of changing conditions in the long term

Widening of xylem conduits in a conifer tree depends on the longer time of cell expansion downwards along the stem

The diameter of vascular conduits increases towards the stem base. It has been suggested that this profile is an efficient anatomical feature for reducing the hydraulic resistance when trees grow taller. However, the mechanism that controls the cell diameter along the plant is not fully understood. The timing of cell differentiation along the stem was investigated. Cambial activity and cell differentiation were investigated in a Picea abies tree (11.5 m in height) collecting microsamples at nine different heights (from 1 to 9 m) along the stem with a 4 d time interval. Wood sections (8-12 μm thick) were stained and observed under a light microscope with polarized light to differentiate the developing xylem cells. Cell wall lignification was detected using cresyl violet acetate. The first enlarging cells appeared almost simultaneously along the tree axis indicating that cambium activation is not height-dependent. A significant increase in the duration of the cell expansion phase was observed towards the tree base: at 9 m from the ground, xylem cells expanded for 7 d, at 6 m for 14 d, and at 3 m for 19 d. The duration of the expansion phase is positively correlated with the lumen area of the tracheids (r2=0.68, P < 0.01) at the same height. By contrast, thickness of the cell wall of the earlywood did not show any trend with height. The lumen area of the conduits down the stem appeared linearly dependent on time during which differentiating cells remained in the expansion phase. However, the inductive signal of such long-distance patterned differentiation remains to be identified

Administração de azul de metileno no choque anafilático induzido por composto 48/80: estudo hemodinâmico em suínos

PURPOSE: To verify if the methylene blue (MB) administration prevents and/or reverses the compound 48/80 (C48/80)-induced anaphylactic shock in pigs. METHODS: Female Dalland pigs were anesthetized and had the hemodynamic parameters recorded during the necessary time to administer some drugs and observe their effect. The animals were randomly assigned to one of the five groups: 1) control; 2) MB: the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 3) C48/80: the animals received a bolus injection of C48/80 (4 mg/kg); 4) C48/80+MB: the animals received a bolus injection of C48/80 (4 mg/kg) and 10 minutes after the C48/80 administration the animals received a bolus injection of MB (2 mg/kg) followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump); 5) MB+C48/80: the animals received a bolus injection of MB (2 mg/kg) and 3 minutes later they received a bolus injection of C48/80 (4 mg/kg). RESULTS: The intravenous infusion of MB alone caused no changes in the mean arterial pressure (MAP) showing that the administered MB dose was safe in this experimental model. The C48/80 was effective in producing experimental anaphylactic shock since it was observed a decrease in both MAP and cardiac output (CO) after its administration. The MB did not prevent or reverse the C48/80-induced anaphylactic shock in this model. In fact, the MAP of the animals with anaphylactic shock treated with MB decreased even more than the MAP of the animals from the C48/80 group. On the other hand, the C48/80-induced epidermal alterations disappeared after the MB infusion. CONCLUSION: Despite our data, the clinical manifestations improvement brings some optimism and does not allow excluding the MB as a possible therapeutic option in the anaphylactic shock.OBJETIVO: Verificar se a administração de azul de metileno (AM) previne e/ou reverte o choque anafilático induzido por composto 48/80 (C48/80) em suínos. MÉTODOS: Porcos fêmeas Dalland foram anestesiados e tiveram os parâmetros hemodinâmicos registados durante o tempo necessário para administrar algumas drogas e observar seu efeito. Os animais foram aleatoriamente destribuídos em um dos cinco grupos: 1) controle, 2) AM: os animais receberam uma injeção em bolus de AM (2mg/kg), seguido de infusão contínua de AM (2,66mg/Kg /h por bomba de infusão de seringa); 3) C48/80: os animais receberam uma injeção em bolus de C48/80 (4mg/kg); 4) C48/80 + AM: os animais receberam uma injeção em bolus de C48/80 (4mg/kg) e 10 minutos após a administração de C48/80 os animais receberam uma injeção em bolus de AM (2mg/kg), seguido de infusão contínua de AM (2,66mg/kg/h por bomba de infusão de seringa); 5) AM+C48/80: os animais receberam uma injeção em bolus de AM (2mg/kg) e três minutos depois, receberam uma injeção em bolus de C48/80 (4mg/kg). RESULTADOS: A infusão intravenosa de AM não causou mudanças na pressão arterial média (PAM), mostrando que a dose de AM administrada foi segura neste modelo experimental. O C48/80 foi eficaz na indução do choque anafilático experimental, uma vez que foi observada redução na PAM e débito cardíaco (DC), após a sua administração. O AM não preveniu ou reverte o choque anafilático induzido por C48/80 neste modelo. Na verdade, a PAM dos animais com choque anafilático tratados com AM diminuiu mais do que o PAM dos animais do grupo C48/80. Por outro lado, as alterações epidérmicas induzidas pelo C48/80 desapareceu após a infusão do AM. CONCLUSÃO: Apesar dos resultados a melhora clínica das manifestações anafiláticas permite considerar a possibilidade do azul de metileno como opção terapêutica no tratamento do choque anafilático.(FAEPA) Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (USP) - Fundação de Apoio ao Ensino, Pesquisa e Assistência do Hospital das Clínica

Non toccate quei rami: le basi funzionali del "no pruning"

In urban areas trees are very often severely pruned and this would suggest that this management practice might be necessary or even \u201chealthy" for trees. Our main aim is to demonstrate how wrong this belief is. Repeated pruning alters plant functionality and also promotes the colonization of trees by pathogens. We present some empirical evidence as well as a conceptual framework that should raise awareness that plants grow following strict allometric trajectories, so their parts (leaves, stem, branches and roots) are strictly interconnected and related. Pruning deviates trees from these trajectories, leading to stressful conditions that worsen the general tree health

Calibration of Granier-Type (TDP) Sap Flow Probes by a High Precision Electronic Potometer

Thermal dissipation probe (TDP) method (Granier, 1985) is widely used to estimate tree transpiration (i.e., the water evaporated from the leaves) because it is simple to build, easy to install, and relatively inexpensive. However, the universality of the original calibration has been questioned and, in many cases, proved to be inaccurate. Thus, when the TDP is used in a new species, specific tests should be carried out. Our aim was to propose a new method for improving the accuracy of TDP on trees in the field. Small hazelnut trees (diameter at breast height 5 cm) were used for the experiment. The response of TDP sensors was compared with a reference water uptake measured with an electronic potometer system provided with a high precision liquid flow meter. We equipped three stems where we measured the sap flow density, the sapwood area (by using fuchsine), the total tree water uptake (reference), and the main meteorological parameters during summer 2018. Results confirmed that the original Granier&#8217;s calibration underestimated the effective tree transpiration (relative error about &#8722;60%). We proposed a new equation for improving the measurement accuracy within an error of about 4%. The system proposed appeared an easier solution compared to potted trees and particularly suitable for orchards, thus contributing to improve the irrigation management worldwide

I suoli del Parco Nazionale Dolomiti Bellunesi. Parte prima (profili 1-10).

Descrizione dei principali suoli delle formazioni forestali del Parco Dolomiti Bellunesi. Profili del suolo, analisi chimiche e fisiche degli orizzonti del suolo, classificazione di suoli e forme di humus; rilevamenti floristici e classificazione fitosociologica dei tipi forestali. I profili del suolo sono stati ricostruiti in scala reale e fissati in una cassettina in modo da ottenere dei quadri da esposizione. - - - - - (ABSTRACT: 10 common soils and humus forms of the forest ecosystems of the Parco Dolomiti Bellunesi. Tables of chemical and physical analysis of the soil horizons and plant species were completed for each site. Samples of each horizon of the soil profiles are fixed in a box and glassed for an exposition use

I suoli del Parco Nazionale Dolomiti Bellunesi. Parte seconda (profili 11-20).

Descrizione dei principali suoli delle formazioni forestali del Parco Dolomiti Bellunesi. Profili del suolo, analisi chimiche e fisiche degli orizzonti del suolo, classificazione di suoli e forme di humus; rilevamenti floristici e classificazione fitosociologica dei tipi forestali. I profili del suolo sono stati ricostruiti in scala reale e fissati in una cassettina in modo da ottenere dei quadri da esposizione. - - - - - (ABSTRACT: 10 common soils and humus forms of the forest ecosystems of the Parco Dolomiti Bellunesi. Tables of chemical and physical analysis of the soil horizons and plant species were completed for each site. Samples of each horizon of the soil profiles are fixed in a box and glassed for an exposition use

Reflections on the 24 years durability of an isolate tricuspid bovine pericardium IMC/Braile bioprosthesis Reflexões sobre a durabilidade de 24 anos de uma bioprótese IMC/Braile de pericárdio bovino em posição tricúspide isolada

We were challenged by the experience of one patient reoperation for a bioprosthetic bovine pericardium degenerative stenosis, 24 years after implantation. This bioprosthesis was implanted due to tricuspid valve bacterial staphylococcal endocarditis after septic abortion.<br>Vivenciamos a experiência de reoperar uma paciente por estenose degenerativa de uma prótese biológica de pericárdio bovino, após 24 anos de implante. Essa prótese degenerada havia sido implantada devido à destruição da valva tricúspide por endocardite bacteriana estafilocócica após aborto séptico

Bovine Pericardial Patch Augmentation of One Insufficient Aortic Valve Cusp with Twenty-three-year Positive Clinical Follow-up Independent of the Patch Degeneration

Abstract Scientific progress shall ultimately boost the current acceptance level for conservative aortic valve surgery. The present text aimed to report the 23-year long-term follow-up of one patient operated with bovine pericardium cusp extension. Growing confidence in the efficacy of the operation will allow a more expeditious indication for surgical treatment, as is already the case in mitral valve repair. This change of attitude will certainly make it possible for patients to be sent for operation in mild aortic valve regurgitation. The present report reinforces the concept and highlights the impression that the aortic valvoplasty, independent of the progressive bovine pericardium degeneration, may positively change the natural history of the aortic valve insufficiency