|
|
|
|
|
| Brito,Carla E; Bown,Horacio E; Fuentes,Juan-Pablo; Franck,Nicolás; Perez-Quezada,Jorge F. |
| BACKGROUND: Quillaja saponaria Mol., Cryptocarya alba Mol. Looser, and Lithraea caustica Molina Hook et Arn., are common sclerophyllous species in Mediterranean Central Chile. Mesophyll conductance, g m, may strongly limit photosynthesis in these semiarid environments. RESULTS: Simultaneous measurements of gas exchange and chlorophyll fluorescence were carried out in 45 nursery plants from these species to determine diffusional and biochemical limitations to photosynthesis. Values of stomatal conductance, g s, were greater than those of mesophyll conductance, g m, while their ratio (g m/g s) was not influenced by species being on average 0.47. Relative limitations posed by mesophyll conductance to photosynthesis, Lm, (0.40 ± 0.02) were high compared to... |
| Tipo: Journal article |
Palavras-chave: Chloroplastic CO2 concentration; Electron transport; Mesophyll conductance; Rubisco carboxylation; Sclerophyllous species. |
| Ano: 2014 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2014000100008 |
| |
|
|
| Bown,Horacio E; Watt,Michael S. |
| Stem CO2 efflux is a highly variable component of the carbon budget of forest ecosystems. It reflects the balance between the CO2 respired by the living stem tissues, less the CO2 dissolved in the xylem sap moving upward in the transpiration stream, plus the CO2 transported from the roots and released at the stem. Although knowledge about such fluxes at different spatial and temporal scales has markedly increased, knowledge of the effects of silviculture treatments, such as fertilization, on stem CO2 effluxes are still limited, particularly when connecting above- and belowground processes. Using measurements obtained from twin plots (one control, one fertilized) installed in five-, 12- and 23-year-old stands of Pinus radiata, the objective of this study... |
| Tipo: Journal article |
Palavras-chave: Aboveground; Age; Belowground; CO2 efflux; Fertilization; Forest plantation. |
| Ano: 2016 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202016000100009 |
| |
|
|
| Toral,Manuel; Bown,Horacio E; Mañon,Alejandro; Alvarez,José; Navarro-Cerrillo,Rafael. |
| The toppling of young trees considerably reduces the value of the first log in Pinus radiata plantations. Although wind is the main cause of toppling, the quality and type of plants, planting techniques, soil fertility and soil preparation may play an important role in the susceptibility of the species to toppling. This article analyzes the influence of ripping and soil type on the probability of P radiata toppling after severe windstorms in central south Chile. To this aim, pairs of similar trees with and without toppling were selected in 2001 in six soil types with and without soil ripping. Root system differences in toppled versus straight trees were compared to gain better insight into the causes of the phenomenon. Among all root measurements, the... |
| Tipo: Journal article |
Palavras-chave: Ripping; Soil fertility; Tap root; Toppling. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202011000300010 |
| |
|
|
| Bown,Horacio E; Fuentes,Juan-Pablo; Perez-Quezada,Jorge F; Franck,Nicolás. |
| Sclerophyllous shrubs and forests are predominant in semiarid Central Chile and have a long history of degradation by fire, cultivation, firewood extraction and grazing. The aim of this study was to compare the amount and environmental drivers of soil respiration across a disturbance gradient in sclerophyllous ecosystems in the National Reserve Roblería del Cobre de Loncha in Central Chile. In a north-facing toe slope, four disturbance conditions were identified: slightly (D1) and moderately disturbed (D2) sclerophyllous forest, (D3) strongly disturbed thorn scrub and (D4) most disturbed A. caven savanna. Twelve 25×25-m plots (625 m²) were distributed equally across D1, D2, D3 and D4. Soil respiration (Rs), soil temperature (Ts), volumetric water content... |
| Tipo: Journal article |
Palavras-chave: Acacia caven savanna; Disturbance gradient; Sclerophyllous forest; Soil respiration; Thorn scrub. |
| Ano: 2014 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202014000100009 |
| |
|
|
| Bown,Horacio E; Mason,Euan G; Clinton,Peter W; Watt,Michael S. |
| Chlorophyll fluorescence responses to a factorial combination of nitrogen (N) and phosphorus (P) supply were measured in five clones of Pinus radiata cultivated in a greenhouse over twenty-four months. Chlorophyll fluorescence measurements were taken at months six (5 clones, 182 plants), nine (2 clones, 68 plants) and eighteen (2 clones, 48 plants). Plant growth in stem diameter, height, leaf area, fascicle mass, length and diameter were found to significantly increase with N and, to a lesser extent, P additions; and these values were greatest when both N and P were combined. Plant growth and fascicle size also varied significantly across clones and were generally consistent with the genotypic growth responses that were observed in the field. Dark (Fv /... |
| Tipo: Journal article |
Palavras-chave: Chlorophyll fluorescence; Quantum efficiency of PSII; Electron transport; Genotype; Nutrient limitation. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202009000300012 |
| |
|
| |
|
|
| Bown,Horacio E; Watt,Michael S; Clinton,Peter W; Mason,Euan G. |
| Patterns of carbon flux and partitioning were examined in highly stocked (40,000 stems ha-1) control and fertilized mini-plots of Pinus radiata D. Don at five sites, which covered a wide climatic and edaphic gradient on the South Island of New Zealand. The gross-primary productivity (GPP) and the partitioning of the GPP to the above- and below-ground productivity and respiration were determined using a carbon budget approach. All of the components of the GPP, the above-ground net primary productivity (ANPP [r² = 0.67, P ≤ 0.01]), above-ground plant respiration (APR [r² = 0.66, P ≤ 0.01]), and total below-ground carbon flux (TBCF [r² = 0.41, P ≤ 0.01]) significantly increased with the GPP, but the ANPP:GPP, APR:GPP and TBCF:GPP... |
| Tipo: Journal article |
Palavras-chave: Gross- primary productivity; Net-primary productivity; Nitrogen; Pinus radiata D. Don; Phosphorus; Total below-ground carbon flux; Whole carbon budget. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202011000200013 |
| |
|
| |
|
|
|
