Ramos P.,University of Talca |
Valenzuela C.,University of Talca |
le Provost G.,French National Institute for Agricultural Research |
Plomion C.,French National Institute for Agricultural Research |
And 4 more authors.
Journal of Plant Growth Regulation | Year: 2012
Loss of verticality in conifers affects the normal wood development by inducing changes and chemical modifications in tree stems called compression wood. It is known that ethylene influences the response during this abnormal wood-forming process. The expression pattern of genes involved in the ethylene biosynthesis pathway during gravitropic response in gymnosperms has been identified in adult trees. Young seedlings of radiata pine were inclined to reveal the expression pattern of these genes by the quantitative real-time PCR (qRT-PCR) technique. The seedlings were exposed to gravitropic stimuli and harvested after 2.5 and 10 h (early responses) of inclination, and after 24 h (late response). Sampling includes transverse cuts at three heights of the whole stem of inclined seedlings. Our data revealed that genes encoding for 1-aminocyclopropane-1-carboxylate oxidase (ACO) and 1-aminocyclopropane-1-carboxylate synthase (ACS) were differentially expressed during the time of leaning, and, interestingly, at the basal portion of radiata pine stems. Additionally, transcriptional analysis in maritime pine showed a conserved profile of gene activation in conifers, and in mature compression wood, ACO gene transcription was strongly upregulated. These results indicate that the concerted activation of genes involved in ethylene biosynthesis could be responding to leaning signals in young radiata and maritime pine seedlings. © 2011 Springer Science+Business Media, LLC.
Pasicott P.,Forestal Mininco |
Murphy G.E.,The New School
New Zealand Journal of Forestry Science | Year: 2013
Background: To improve production efficiency and harvesting economics some forest companies are looking at extended hours of use for forest machinery, which may include longer shift lengths, multiple shifts per day, and more harvesting days per week. A review of the literature provides mixed signals on the costs and benefits of extending work hours. Methods: A long-term data base, which contained over 30 000 machine day records and was maintained by a Chilean forest company, was used to evaluate the effects of three types of extended work schedules (beyond a 9 hour work day) on the productivity of two types of harvesting operations; mechanised processing of Pinus radiata D. Don (radiata pine) stems into logs and mechanised harvesting of eucalypt (Eucalyptus globulus Labill and E. nitens H. Deane and Maiden) trees. Results: Production increased as working hours increased. However, average hourly productivity fell by 9 to 30% as the working day length for equipment was extended from 9 to 18 hours. A range of factors, some interacting, were found to affect the level of decrease. These factors included type of work schedule, type of operation, season, tree species, and tree size. Conclusions: Extending working hours beyond 9 hours per day did not result in equivalent increases in production for mechanized harvesting operations in Chile. Further research is needed on the overall economics of working extended hours. © 2013 Pasicott and Murphy; licensee Springer.
Angulo V.C.,University of Concepcion |
Sanfuentes E.A.,University of Concepcion |
Rodriguez F.,Forestal Mininco |
Sossa K.E.,University of Concepcion
Revista Argentina de Microbiologia | Year: 2014
Rhizospheric and endophytic bacteria were isolated from the rizosphere and root tissue of Eucalyptus nitens. The objective of this work was to evaluate their capacity to promote growth in seedlings of the same species under greenhouse conditions. The isolates that improved seedling growth were identified and characterized by their capacity to produce indoleacetic acid (IAA), solubilize phosphates and increase 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. One hundred and five morphologically different strains were isolated, 15 of which promoted E. nitens seedling growth, significantly increasing the height (50%), root length (45%) as well as the aerial and root dry weight (142% and 135% respectively) of the plants. Bacteria belonged to the genus Arthrobacter, Lysinibacillus, Rahnella and Bacillus. Isolates A. phenanthrenivorans 21 and B. cereus 113 improved 3.15 times the emergence of E. nitens after 12 days, compared to control samples. Among isolated R. aquatilis, 78 showed the highest production of IAA (97.5±2.87 μg/ml) in the presence of tryptophan and the highest solubilizer index (2.4) for phosphorus, while B. amyloliquefaciens 60 isolate was positive for ACC deaminase activity. Our results reveal the potential of the studied rhizobacteria as promoters of emergence and seedling growth of E. nitens, and their possible use as PGPR inoculants, since they have more than one mechanism associated with plant growth promotion. © 2013 Asociación Argentina de Microbiología.
Albaugh T.J.,Virginia Polytechnic Institute and State University |
Alvarez J.,Weyerhaeuser Company |
Rubilar R.A.,University of Concepcion |
Fox T.R.,Virginia Polytechnic Institute and State University |
And 2 more authors.
Forest Science | Year: 2015
The effects of tillage, vegetation control, and fertilizer treatments applied at stand establishment of Pinus radiata D. Don. at three sites (Sand, Clay, and Ash) in Chile were examined 10 years after planting. Selected sites were typical of sites that routinely received tillage as a normal part of site preparation operations in Chile. At each site, we used four blocks of a split plot design with whole plots testing tillage effects (none or subsoiling + bedding) and subplots testing a factorial combination of vegetation control (none or 2-year banded) and fertilization (boron at establishment or nitrogen, phosphorus, and boron at establishment + nitrogen, phosphorus, potassium, and boron after 2 years). We estimated the main effect growth responses, determined response types (Type A, B, C, D), and calculated main effect volume growth age shifts for each site. Vegetation control increased volume growth 7–99% through 10 years (Type A, B, or C responses), which resulted in volume age shifts of 3.4, 1.3, and 1.0 years for the Sand, Clay, and Ash sites, respectively. Fertilization increased volume growth at the Clay site (14%, Type A) and decreased volume growth at the Ash site (6%, Type D), with volume age shifts of 1.0 and 1.0 years for the Sand and Clay sites, respectively. Tillage increased survival at the Sand site and decreased height growth at the Ash site (4%, Type D) with volume age shifts of 0.9 and 0.1 years for the Sand and Ash sites, respectively. Vegetation control likely ameliorated water (Sand and Clay sites) and light (Ash site) limitations that were critical for improved growth. Fertilization addressed secondary nutrient limitations, especially on the Clay site. Tillage provided little benefit, likely because the sites were well drained and soil bulk density was not at a level where limitations to root growth would be found. When determining which treatments to apply, managers should have an understanding of what resources may be limiting and select the appropriate treatment to ameliorate those limitations in the most cost-effective manner. For sites similar to those in this study, vegetation control would likely ameliorate resource limitations in a cost-effective manner. © 2015 Society of American Foresters. All rights reserved.
Ramos P.,University of Talca |
Le Provost G.,French National Institute for Agricultural Research |
Gantz C.,Forestal Mininco |
Plomion C.,French National Institute for Agricultural Research |
Herrera R.,University of Talca
Plant Biology | Year: 2012
The gravitropic response in trees is a widely studied phenomenon, however understanding of the molecular mechanism involved remains unclear. The purpose of this work was to identify differentially expressed genes in response to inclination using a comparative approach for two conifer species. Young seedlings were subjected to inclination and samples were collected at four different times points. First, suppression subtractive hybridisation (SSH) was used to identify differentially regulated genes in radiata pine (Pinus radiata D. Don). cDNA libraries were constructed from the upper and lower part of inclined stems in a time course experiment, ranging from 2.5h to 1month. From a total of 3092 sequences obtained, 2203 elements were assembled, displaying homology to a public database. A total of 942 unigene elements were identified using bioinformatic tools after redundancy analysis. Of these, 614 corresponded to known function genes and 328 to unknown function genes, including hypothetical proteins. Comparative analysis between radiata pine and maritime pine (Pinus pinaster Ait.) was performed to validate the differential expression of relevant candidate genes using qPCR. Selected genes were involved in several functional categories: hormone regulation, phenylpropanoid pathway and signal transduction. This comparative approach for the two conifer species helped determine the molecular gene pattern generated by inclination, providing a set of Pinus gene signatures that may be involved in the gravitropic stress response. These genes may also represent relevant candidate genes involved in the gravitropic response and potentially in wood formation. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.