898 resultados para Rooting of cutting
Resumo:
In Australia, macadamia trees are commonly propagated by germinating rootstock seed and grafting when seedlings reach a suitable size. The production of grafted trees is a protracted and complex process, however, propagation of macadamia via cuttings represents a simpler and faster method of multiplication. Macadamias have traditionally proven difficult to propagate from cuttings, and while recent developments in the process have improved success rates, substantial variation in rooting ability between cultivars and species has been reported. The cultivar 'Beaumont' (Macadamia integrifolia × M. tetraphylla) is commonly propagated by cutting for use as a rootstock, and is relatively easy to strike while other cultivars are more difficult. There is speculation that Hawaiian cultivars are more difficult to strike from cuttings than Australian cultivars due to species and genetic composition. In this experiment, cuttings of 32 genotypes were evaluated for rooting ability. Each genotype's species profile was estimated using historical data, and used to determine species effects on survival (percentage) and rooting ability (rating 0-2). M. jansenii (100%), M. tetraphylla (84%) and M. integrifolia/tetraphylla hybrids (79%) had the highest success rates while M. integrifolia (54%) and M. ternifolia (43%) had the lowest survival. Rooting ability of M. jansenii (1.75) was significantly higher than M. ternifolia (0.49) but not significantly higher than M. tetraphylla × M. integrifolia with (1.09), M. tetraphylla (1.03) or M. integrifolia (0.88).
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Rooted cutting propagation is widely used for maximising tree yield, quality and uniformity in conjunction with clonal selection. Some eucalypt species are deployed as rooted cuttings but many are considered to difficult to root. This study examined IBA effects on photoinhibition, root formation, mortality and root and shoot development in cuttings of Corymbia torelliana, C. citriodora and their hybrids. IBA had little or no effect on photoinhibition but it had strong, dose-dependent effects on root formation and mortality. IBA frequently increases primary root number of rooted cutting but it did not increase total root weight, length, surface area or volume, possibly because the highest doe (8g IBA/kg IBA/kg powder) caused leaf abscission and sometimes reduced leaf area (by 55-79%)or shoot dry weight (by 40-58%). An intermediate dose (3g IBA/kg powder) most consistnely improved root formation with little or no effect on mortality or shoot development. Across the F1 hybrid families this treatment increased the number of rooted cuttings by 72-121% and more than ddoubled the number of primary roots per rooted cutting (from 1.1-1.7 roots to 3.5-4.1 roots). This simple treatment will facilitate commercial multiplication of superior individuals or selected families of C. torelliana x C. citriodora through a vegetative propagation system.
Resumo:
The Japanese apricot (Prunus mume Sieb. et Zucc.) is a fruit tree of the Rosaceae family which produces very acid and bitter fruits, highly appreciated by Orientals. In Brazil, this species has been studied as a rootstock for peach and nectarine trees, its main advantage being the reduction in plant vigour, which can favour the production of compact trees and orchard cultural treatments. This study was conducted in the Vegetable Production Department of FCAV/UNESP, Jaboticabal Campus, São Paulo State, Brazil, and the objective was to examine the effect of wounding the herbaceous cutting bases on the rooting of four Japanese apricot clones. The clones were obtained from plants under cultivation in the Instituto Agronomico de Campinas, Brazil, and were identified as Clones 02, 05, 10 and 15. The stock plants, obtained through herbaceous cuttings, were maintained under lath house conditions (50% of natural light). Cuttings 12 cm long with 3 to 5 leaves were collected from these clones and prepared. The experiment was carried out in a completely randomised design with 4 repetitions of 20 cuttings per replication, in a factorial 4 x 2 design, the clone factor having 4 levels (Clones 02, 05, 10 and 15) and the wounding factor at 2 levels of incisions into the cutting base (with and without). All the cuttings were treated with 2000 mg.L-1 of IBA for five seconds. Differences between the clones were observed concerning the rooting percentage, dead cuttings, number and length of roots. The incision (wound) at the base of the herbaceous cuttings of the Japanese apricot increased the number of roots and improved the distribution of these in the damaged tissue but the results were not considered sufficiently beneficial to make the treatment worthwhile.
Resumo:
Chrysanthemums are commercially propagated through cuttings. Pre-rooting storage of cuttings in the dark is a common practice among growers and companies that work and trade with chrysanthemum cuttings. Therefore, the maximum storage period for cuttings and differences in tolerance among cultivars has been investigated. Adventitious roots of cuttings can originate in almost any tissue, including the epidermis, stem cortex and pericycle, ray parenchyma, immature xylem and phloem cells, and pith. The aims of this work were to determine the effect of time of cold storage of cuttings (0, 1, 2, 3, 4, 5 and 6 weeks) on the rooting of four cut chrysanthemum cultivars (Super White, Sheena, Dark Orange Reagan and Town Talk) for two seasons of the year (summer and winter), and also to determine the origin of root formation in chrysanthemum cuttings. The study was carried out as a randomized complete block design with 5 replications for each storage treatment. Each plot was comprised of three cuttings that were examined 14 days after the cutting procedure. During the winter, the roots were studied by scanning electron microscopy (SEM) at the Electron Microscope Laboratory. The following conclusions were made: in winter, cold storage affected the rooting of cuttings, mainly after two weeks of storage for all cultivars. The rooting percentage was lower in the winter and the cuttings could be preserved for a shorter period. The source and growth of roots in chrysanthemum cuttings was found to be endogenous. After three days, callus formed in the pericycle and the first emergence of adventitious roots occurred by the fourth day of rooting. During the summer, cold storage could be up to 4 weeks without any problems.
Resumo:
Propagation by hardwood cuttings is an important technique for producing plant of many species. The technique is usually easy and inexpensive and makes it possible to high plants. But it is not commonly used for peach propagation in Brazil. The objective of this study was to evaluate the effects of different substrates, container types and cutting diameters on rooting of peach hardwood cuttings. The cuttings (two size groups, diameters of 2-6 mm and 6-10 mm) were inserted in six substrates (carbonized rice husk, vermiculite, washed sand, carbonized rice husk + vermiculite, carbonized rice husk + washed sand and vermiculite + washed sand, each 1:1 v/v), each in three types of containers (plastic bag, plastic tray and polystyrene tray). The best rooting occurred with smaller cuttings (47%) and larger cuttings (38%) in plastic bag with vermiculite, and with smaller cuttings in plastic bag with washed sand + vermiculite (33%). While these rooting percentages were unsatisfactory for commercial propagation, the results are encouraging and suggest need for more investigation to improve rooting.
Resumo:
Aloysia triphylla (L'Hérit) Britton is a perennial and bushy plant, with simple, entire, lanceolate and whorl shaped leaves and originally from South America. It is used as medicinal plant in Brazil with stomatic and sedative properties. The employment of stem cuttings for propagation of pre-selected plants, acquired great importance, because it eliminates the juvenile phase of seedlings, which can be produced in a shorter period of time. The rooting of stem cuttings is stimulated by auxin and, boric acid supply is essential for growth and development of initial rootlets. This micronutrient is required 48 hours after plant segments have been placed into auxin solution and it can be supplied any time, including the seedling growth period. The experiment was carried out in the Department of Plant Production, UNESP-Botucatu-SP-Brazil, with stem-cuttings of Aloysia triphylla (L'Hérit) Britton, Verbenaceae obtained from the Medicinal and Aromatic Plant Garden. The aim of the work was to verify the influence of growth regulators and boric acid on stem cutting rooting of this species. The 15 cm-stem cuttings, without leaves, were submerged during 24 hs in the following solutions: water; 150 mg.L-1 of IBA; 150 mg.L-1 of IBA+ Boric acid; 250 mg.L-1 of IBA; 250 mg.L-1 of IBA + Boric acid. The statistical design was entirely randomized with 5 treatments and 3 replications, totalizing 15 plots with 10 stem cuttings each. They were planted on propylene trays with vermiculite and kept under spraying condition during twenty five days. The best results were observed in treatment 250 mg.L -1 of IBA+ Boric acid on number of roots, length of roots, rooting percentage, fresh and dry weight of leaves when compared with all other treatments. We can conclude that this treatment is the most suitable for stem cutting rooting of this species.
Resumo:
Two methods of pre-harvest inventory were designed and tested on three cutting sites containing a total of 197 500 m3 of wood. These sites were located on flat-ground boreal forests located in northwestern Quebec. Both methods studied involved scaling of trees harvested to clear the road path one year (or more) prior to harvest of adjacent cut-blocks. The first method (ROAD) considers the total road right-of-way volume divided by the total road area cleared. The resulting volume per hectare is then multiplied by the total cut-block area scheduled for harvest during the following year to obtain the total estimated cutting volume. The second method (STRATIFIED) also involves scaling of trees cleared from the road. However, in STRATIFIED, log scaling data are stratified by forest stand location. A volume per hectare is calculated for each stretch of road that crosses a single forest stand. This volume per hectare is then multiplied by the remaining area of the same forest stand scheduled for harvest one year later. The sum of all resulting estimated volumes per stand gives the total estimated cutting-volume for all cut-blocks adjacent to the studied road. A third method (MNR) was also used to estimate cut-volumes of the sites studied. This method represents the actual existing technique for estimating cutting volume in the province of Quebec. It involves summing the cut volume for all forest stands. The cut volume is estimated by multiplying the area of each stand by its estimated volume per hectare obtained from standard stock tables provided by the governement. The resulting total estimated volume per cut-block for all three methods was then compared with the actual measured cut-block volume (MEASURED). This analysis revealed a significant difference between MEASURED and MNR methods with the MNR volume estimate being 30 % higher than MEASURED. However, no significant difference from MEASURED was observed for volume estimates for the ROAD and STRATIFIED methods which respectively had estimated cutting volumes 19 % and 5 % lower than MEASURED. Thus the ROAD and STRATIFIED methods are good ways to estimate cut-block volumes after road right-of-way harvest for conditions similar to those examined in this study.
Resumo:
Slow flow in granular materials is characterized by high solid fraction and sustained inter-particle interaction. The kinematics of trawling or cutting is encountered in processes such as locomotion of organisms in sand; trawl gear movement on a soil deposit; plow movement; movement of rovers, earth moving equipment etc. Additionally, this configuration is very akin to shallow drilling configuration encountered in the mining and petroleum industries. An experimental study has been made in order to understand velocity and deformation fields in cutting of a model rounded sand. Under nominal plane strain conditions, sand is subjected to orthogonal cutting at different tool-rake angles. High-resolution optical images of the region of cutting were obtained during the flow of the granular ensemble around the tool. Interesting kinematics underlying the formation of a chip and the evolution of the deformation field is seen in these experiments. These images are also analyzed using a PIV algorithm and detailed information of the deformation parameters such as velocity, strain rate and volume change is obtained.
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Fiber-reinforced plastics (FRPs) are typically difficult to machine due to their highly heterogeneous and anisotropic nature and the presence of two phases (fiber and matrix) with vastly different strengths and stiffnesses. Typical machining damage mechanisms in FRPs include series of brittle fractures (especially for thermosets) due to shearing and cracking of matrix material, fiber pull-outs, burring, fuzzing, fiber-matrix debonding, etc. With the aim of understanding the influence of the pronounced heterogeneity and anisotropy observed in FRPs, ``Idealized'' Carbon FRP (I-CFRP) plates were prepared using epoxy resin with embedded equispaced tows of carbon fibers. Orthogonal cutting of these I-CFRPs was carried out, and the chip formation characteristics, cutting force signals and strain distributions obtained during machining were analyzed using the Digital Image Correlation (DIC) technique. In addition, the same procedure was repeated on Uni-Directional CFRPs (UD-CFRPs). Chip formation mechanisms in FRPs were found to depend on the depth of cut and fiber orientation with pure epoxy showing a pronounced ``size effect.'' Experimental results indicate that in-situ full field strain measurements from DIC coupled with force measurements using dynamometry provide an adequate measure of anisotropy and heterogeneity during orthogonal cutting.
Resumo:
Extending the season of production and improving the scheduling of ornamental crops are key commercial objectives for nurserymen. In some woody species, the period in which cuttings can be rooted successfully is transient, thus limiting the opportunities for scheduled production. Optimum rooting often occurs in early- to mid-summer coinciding with periods of active shoot growth. The relationship between this shoot activity and root initiation was investigated in Cotinus coggygria 'Royal Purple'. Shoot growth on stock plants was manipulated by altering the photoperiod or light quality. Results indicated there were seasonal effects on rooting, but the importance of shoot activity varied with harvest time. Cuttings harvested in August had high rooting percentages, irrespective of photoperiod, and despite shoot growth terminating in response to the short-day treatment. In contrast, by September, rooting percentage was highest in cuttings from plants under long-days, which had maintained greatest shoot growth activity. Cotinus shoots grown in vitro under 16 h days showed reduced shoot growth and increased rooting competence compared with shoots grown under 8 h days. Growing stock plants under polythene films, which altered the amount and quality of the incident light, influenced the rooting of cuttings harvested in August, but no consistent relationship with shoot activity was apparent. From a practical viewpoint, maintaining shoot activity late in the season may prolong the period for propagation by cuttings; but, from a scientific viewpoint, processes associated with an active shoot apex do not provide a complete explanation of seasonal variation in rooting.
Resumo:
Cutting force data for Nylon 66 has been examined in terms of various different models of cutting. Theory that includes significant work of separation at the tool tip was found to give the best correlation with experimental data over a wide range of rake angles for derived primary shear plane angle. A fracture toughness parameter was used as the measure of the specific work of separation. Variation in toughness with rake angle determined from cutting is postulated to be caused by mixed mode separation at the tool tip. A rule of mixtures using independently determined values of toughness in tension (mode 1) and shear (mode 11) is found to describe well the variation with rake angle. The ratio of modes varies with rake angle and, in turn, with the primary shear plane angle. Previous suggestions that cutting is a means of experimentally determining fracture toughness are now seen to be extended to identify the mode of fracture toughness as well.
Resumo:
Response surface methodology was used to study the effect of temperature, cutting time, and calcium chloride addition level on curd moisture content, whey fat losses, and curd yield. Coagulation and syneresis were continuously monitored using 2 optical sensors detecting light backscatter. The effect of the factors on the sensors’ response was also examined. Retention of fat during cheese making was found to be a function of cutting time and temperature, whereas curd yield was found to be a function of those 2 factors and the level of calcium chloride addition. The main effect of temperature on curd moisture was to increase the rate at which whey was expelled. Temperature and calcium chloride addition level were also found to affect the light backscatter profile during coagulation whereas the light backscatter profile during syneresis was a function of temperature and cutting time. The results of this study suggest that there is an optimum firmness at which the gel should be cut to achieve maximum retention of fat and an optimum curd moisture content to maximize product yield and quality. It was determined that to maximize curd yield and quality, it is necessary to maximize firmness while avoiding rapid coarsening of the gel network and microsyneresis. These results could contribute to the optimization of the cheese-making process.
Resumo:
The work reported here involved an investigation into the grinding process, one of the last finishing processes carried out on a production line. Although several input parameters are involved in this process, attention today focuses strongly on the form and amount of cutting fluid employed, since these substances may be seriously pernicious to human health and to the environment, and involve high purchasing and maintenance costs when utilized and stored incorrectly. The type and amount of cutting fluid used directly affect some of the main output variables of the grinding process which are analyzed here, such as tangential cutting force, specific grinding energy, acoustic emission, diametrical wear, roughness, residual stress and scanning electron microscopy. To analyze the influence of these variables, an optimised fluid application methodology was developed (involving rounded 5, 4 and 3 turn diameter nozzles and high fluid application pressures) to reduce the amount of fluid used in the grinding process and improve its performance in comparison with the conventional fluid application method (of diffuser nozzles and lower fluid application pressure). To this end, two types of cutting fluid (a 5% synthetic emulsion and neat oil) and two abrasive tools (an aluminium oxide and a superabrasive CBN grinding wheel) were used. The results revealed that, in every situation, the optimised application of cutting fluid significantly improved the efficiency of the process, particularly the combined use of neat oil and CBN grinding wheel. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)