In vitro serial subculture to improve rooting of Eucalyptus urophylla

New Forests - The aim of this study was to improve the rooting efficiency of Eucalyptus urophylla clones by in vitro reinvigoration/rejuvenation in two clones (02 and 04) from the breeding program...     

Morphological and photosynthetic alterations in the Yellow-ipe, <Emphasis Type="Italic">Tabebuia chrysotricha</Emphasis> (Mart. Ex DC.) Standl., under nursery shading and gas exchange after being transferred to full sunlight

The objective of this study was to evaluate the effect of nursery shading on the Yellow-ipe seedling (Tabebuia chrysotricha) growth, photosynthesis, and photosynthetic acclimation after being transferred into direct sunlight. The Yellow-ipe seedlings were grown under 0, 50, 70 and 95% shade. At the 134th day of sowing, leaf gas exchange and chlorophyll were measured under current growth shading, after exposure to 15 min and two day full sunlight. With the increase of shading, the Yellow-ipe seedlings allocated more biomass to the stem and leaves and less to the roots, and there was an increase in the leaf area ratio and specific leaf area. In relation to 0% of shading there was a increase of 211% in stem, 116% in leaf, and a reduction of 200% in roots biomass when seedling were grown under 95% of shading. The total biomass accumulation had a high correlation with collar diameter (r = 0.96). More than 70% of the shading reduced the photosynthesis, and after transferring the seedlings into full sunlight, more than 50% of the shading induced a reduction in chlorophyll, stomatal conductance, photosynthesis and instantaneous carboxylation efficiency, suggesting the presence of a photoinhibition process. The Yellow-ipe seedling growth under nursery conditions should not be done under more than 50% shading, which may result in the lower seedling quality and poorer acclimation to transplantation, particularly to severe degraded areas with direct sunlight. The species can be used for recovering from totally devastated forest areas to initial recovery when full canopy are forming.     

Variability with xylem depth in sap flow in trunks and branches of mature olive trees

Knowledge of sap flow variability in tree trunks is important for up-scaling transpiration from the measuring point to the whole-tree and stand levels. Natural variability in sap flow, both radial and circumferential, was studied in the trunks and branches of mature olive trees (Olea europea L., cv Coratina) by the heat field deformation method using multi-point sensors. Sapwood depth ranged from 22 to 55 mm with greater variability in trunks than in branches. Two asymmetric types of sap flow radial patterns were observed: Type 1, rising to a maximum near the mid-point of the sapwood; and Type 2, falling continuously from a maximum just below cambium to zero at the inner boundary of the sapwood. The Type 1 pattern was recorded more often in branches and smaller trees. Both types of sap flow radial patterns were observed in trunks of the sample trees. Sap flow radial patterns were rather stable during the day, but varied with soil water changes. A decrease in sap flow in the outermost xylem was related to water depletion in the topsoil. We hypothesized that the variations in sap flow radial pattern in a tree trunk reflects a vertical distribution of water uptake that varies with water availability in different soil layers.     

Influence of climatic factors on carbon accumulation in the aerial biomass of native vegetation in the south of Piauí, in the Brazilian Northeast

An understanding of forest carbon budgets, such as the factors that influence different levels of carbon accumulation, is one of the first steps in protecting and restoring areas of plant cover. Univariate and multivariate regression analysis was applied to evaluate the influence of climate variables (Rainfall, and mean maximum and minimum temperatures) on intra-annual above-ground carbon accumulated in tree species of the Caatinga. Above-ground carbon accumulated in the trees was 0.06 Mg ha^?1 month^?1. Carbon allocation in the aerial parts of the trees increased significantly with rainfall. Maximum and minimum temperature had little influence on carbon storage; however, variations in carbon accumulation are best explained when minimum and maximum temperatures are added to the regression model for rainfall, thereby demonstrating the simultaneous effect of these variables, and better explaining the carbon increase.     

Growth,flowering and fruiting of Campomanesia adamantium (Cambess) O. Berg intercropped with green manure species in Agroforestry Systems

Agroforestry Systems - Besides enabling economic activity, the domestication of indigenous species in situ configures a strategy for the conservation of genetic resources in Agroforestry Systems...     

An overview of forest loss and restoration in the Brazilian Amazon

New Forests - Forest restoration is a strategy to reverse forest loss and degradation. We overviewed deforestation in the period 1975–2018 in the Brazilian Amazon and the projects,...     

Phytochemical and antiprotozoal activity of Ocotea lancifolia

Thirteen known isoquinoline alkaloids were isolated from Ocotea lancifolia, popularly known as < canela pilosa > in Brasil and < laurel né > by the Guarani people which means smell laurel. Their activities against the promastigote forms of three Leishmania strains and the bloodstream form of Trypanosoma cruzi were evaluated, as well as their hepatocytotoxicity. Among them, the noraporphine alkaloid (-) caaverine has shown the most interesting antiprotozoal activity against Leishmania and T. cruzi parasites.