Academic literature on the topic 'Eucalyptus grandis Propagation'

Effective rooting and survival of cuttings has become more important owing to increased global wood demands and climate change. This study assesses the survival of ten (10) clones each of Eucalyptus grandis x Eucalyptus urophylla (E. grandis x E. urophylla) and Eucalyptus pellita (E. pellita) clonal cuttings when treated with different Indole-3-butyric acid (IBA) auxin concentrations of 0 ppm (control), 2000 ppm, 3000 ppm and 4000 ppm respectively. Overall, the mean survival of cuttings with respect to both species (10 clones each) was low (i.e < 50%) for all concentrations of IBA used. E. grandis x E. urophylla cuttings had the highest mean survival (43.39%) when treated with 2000 ppm of IBA and lowest mean survival (37.86%) when treated with 0 ppm. E. pellita (P) cuttings had the highest mean survival (27.14%) when treated with 2000 ppm of IBA. Individual clones however showed higher survival with respect to IBA treatments. Eucalyptus grandis x Eucalyptus urophylla clone (GH11) achieved a mean survival rate of 75% with 2000ppm of IBA. E. pellita clone P2 achieved its highest survival (52.68%) in the control experiment (0 ppm). Although IBA application had significant effect on cutting survival, parent material (individual clones) also plays a vital role in cutting survival as some clones such P51 and P82 achieved survivals of less than 10% given all four levels of IBA used. Individual clones also respond to IBA concentration differently. GH3 and GH10 had their highest survivals (i.e 66.07% and 61.61% respectively) in the control (0ppm of IBA). Results from this study can be used in plus tree clonal selection regimes to identify the best economically rewarding clones in terms of cutting survival to be used in forest plantation establishments.

Interspecific hybrids of E. grandis × E. camaldulensis were generated to widen the plantation area. The aim of this study was to assess root capability and development for six different clones of eucalyptus grown in substrates made with three different composts derived from poultry manure. A factorial design was used to assess the effect of different composts on six growth variables. The analysis detected a greater effect from the genotype than the substrate. E. grandis × E. camaldulensis hybrid vegetative propagation was successful in alternative substrates formulated from composted poultry manure. GC8 was the genotype that showed the greatest differences for four the different variables among the substrates, being both the most sensitive and the one with the highest values for all parameters measured. The hybrids' vegetative propagation was determined in alternative substrates formulated from poultry manure compost. The physicochemical characteristics of substrates composed of pine bark and sawdust provided adequate conditions for the growth of eucalyptus. GC8 was the genotype most sensitive to the use of different substrates, showing significant differences in the ratio of roots/callus, radicular dry weight, and cutting dry weight. These clones might be a good option for evaluating compost-based substrates for forestry applications.

Imazapyr has been used in Brazilian eucalypt cultivation for the maintenance of clearings and coppicing control in areas undergoing stand reform. However, inquiries have been made as to the final fate of the molecule. Imazapyr root exudation in eucalypt plants was evaluated through a bioassay under greenhouse conditions, by applying different herbicide doses (0.000, 0.375, 0.750, 1.125, and 1.500 kg ha-1 a.i.) on Eucalyptus grandis seedlings derived from vegetative propagation, hydroponically cultivated in 2.500 ml vases. Forty-day-old seedlings of the same clone were used as bioindicators, transplanted to the vases two days after herbicide application. After a period of 13 days of coexistence, the sprayed plants were removed and discarded; ten days later, the visual symptoms of toxicity were evaluated and the total dry biomass (aerial part and roots) of the bioindicators were determined. The lowest herbicide dose (0.375 kg ha-1 a.i.) affected the total biomass and growth, being most evident in the aerial part, with larger I50 for root dry biomass. The E. grandis seedlings exuded imazapyr, and/or its metabolites, in concentrations capable of affecting the growth of plants of the same species.

We investigated the feasibility of visible–near-infrared (Vis–NIR) spectroscopy for estimation of wood qualities of fast-growing Eucalyptus grandis. Partial least squares regression (PLSR) models are applied to predict the diameter at the breast height (DBH), lateral growth rate (LGR) and propagation velocity of stress waves (PVSW). It was possible to estimate LGR and PVSW with appropriate accuracy. This suggested that perhaps information in terms of maturation is included in Vis–NIR spectra. The key factors in the validation of PVSW and LGR were the water and cellulose condition in wood.

Este trabalho teve como objetivo verificar os efeitos de diferentes concentrações de cálcio nas respostas de brotações de E. grandis submetido à deficiência hídrica. A hipótese deste trabalho foi a de que o cálcio atua como amenizador dos efeitos causados pela deficiência hídrica. Isto é, aumentando a tolerância (estabilidade) das plantas, retardando as alterações de alguns parâmetros bioquímicos que contribuem para o ajuste osmótico, evitando assim, perdas energéticas excessivas nas sínteses de osmólitos como: açúcares solúveis, aminoácidos solúveis entre outros. Brotações de E. grandis foram cultivadas em meio JADS líquido, suplementadas com 15% de PEG 6000 e diferentes concentrações de cálcio: 5,0 (controle); 7,5; 10,0; 12,5 e 15,0 mmol.L -1 . Foram realizadas 4 repetições por tratamento em blocos inteiramente casualizados. As respostas das plantas foram avaliadas de acordo com os seguintes parâmetros: taxa de crescimento relativo, conteúdo de aminoácidos solúveis totais; açúcares solúveis totais; prolina; proteínas totais; teores de clorofila a, b e total; anatomia foliar e potencial hídrico foliar (yf) As condições de de cultivo foram: PAR 50 ± 2 mmol. m -2 s -1 , 25 ± 2° C, e fotoperíodo de 16 horas. As análises foram realizadas aos 7 e 21 dias de cultivo. Então, todo o material vegetal restante foi repicado e transferido para meio JADS básico por 21 dias para a avaliação da recuperação das plantas. O tratamento com PEG, sem cálcio suplementar induziu respostas significativas (Tukey, p< 0,05) em todos os parâmetros bioquímicos em relação ao controle (JADS básico). As análises de componentes principais demonstraram que a dose de cálcio suplementar que mais contribuiu para a homeostase das plantas sob deficiência hídrica foi 7,5 mmol.L -1 de cálcio na forma de CaCl2.
The aim of this work was to verify the effects of diferent calcium concentrations in the response of E. grandis shoots to the water deficit. The hypotesis of this work was the calcium acts as a buffer to the effects induced by the water deficit. Thus, increasing the tolerance (estability) of the plants, slowing the changes in some biochemical parameters that contribute to the osmotic adjustment and avoiding excessive energetic losses in the synthesis of osmolites like: soluble sugar, soluble aminoacids amg others. Shoots of E. grandis were cultivated in liquid JADS medium supplemented with 15% of PEG 600 and different concentration of calcium: 5,0 (control) 7,5; 10,0; 12,5 e 15,0 mmol.L-1. Four replicates were made for treatment in a totally randomized blocks design. The plant responses were evalueted according to the folling variables: relative growth rate, total soluble aminoacid content; total soluble sugars; proline content, total sugars; proline content, total soluble proteins, chlorophyll a and b contents, leaf anatomy and leaf water potencial (yf). The growth conditions were: PAR 50 ± 2 mmol. m -2 s -1 , 25 ± 2° C ad 16 hour photoperiod. The analysis were made at the seventh and the 21 rts days of culture. Then, all the remainng shoots were transplanted in vitro JADS basic medium for shoots recovery after 21 days of culture. The tratment with PEG 6000 without calcium addition induced signifitive responses (Tukey, p<0,05) for all biochemical variables in the relation to the control (basic JADS medium). The PCA showed that the supplementar calcium concentration that contributed the most to the shoot homeostais under water deficit was that of 7.5 mmol.L-1 in the form of CaCl2.

Adventitious rooting in stem cuttings of Eucalyptus grandis Hill ex Maid. was thought to be influenced by a putative inhibitor. In previous studies it has been usual to infer the presence of putative rooting inhibitors and promoters from the mung bean bioassay, but the possibility was raised that treatment responses in this assay could be mediated more by the concentration of the treatment solution than by the chemical identity of the solute. This appeared to be so: several solutes, including hydrochloric acid and common salt, were found to promote the rooting of mung bean cuttings when present in the treatment solution at an apparently injurous concentration. The concept of promoters and inhibitors of adventitious rooting, as constituted at present, was considered to be an unfavourable approach for further studies. Stem cuttings must contain a morphogen, broadly defined, which operates the 'switch' from stem to adventitious root. The leaves and buds of E.grandis stem cuttings did not appear to be sole sources of a morphogen (as is often assumed), but nevertheless the activity of the leaves and buds was good for rooting. This activity was reflected in the pattern of root emergence. A slight preponderance emerged from the leaf trace sectors of the stem, suggesting that the leaves and buds cause a morphogen (of unknown origin) to circulate in the cutting. The existence of a vascular morphogen was confirmed and it proved to be very mobile in the stem, suggesting that it is well distributed circumferentially at the base of the cutting rather than confined to the leaf trace sectors. It appeared to be super-abundant at the base of easy-to-root cuttings, but it was not possible to tell to what extent the morphogen was rendered accessible to the sites where roots initiate. In general, the rate of efflux from the transporting tissues, the rate of attenuation of the morphogen after efflux, and the number of potential sites for root initiation must interact on a small scale to determine rooting ability. The relative prominence of these groups of factors would be expected to vary with circumstances, for example at different locations within a single stem cutting, so the traditional concept of a limiting morphogen ('rhizocaline') is unhelpful in its simplest form. Nevertheless, the rhizocaline concept provides a starting point towards a more comprehensive view of adventitious rooting, which is required in order to predict and improve rooting ability. This view remains a remote objective because many of the factors which could be important have recieved very little attention and will be difficult to elucidate.
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1988.

Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Biotechnology, Technikon Natal, 2001.
Biotechnology techniques such as micropropagation VIa somatic embryogenesis offer potential significant advances in the improvement of forest species, which could sustain forest production in South Africa, as well as globally, without increased use of land. In order to apply such techniques to commercial breeding and clonal programmes of E. grandis species, it is necessary to develop reliable and efficient protocols applicable to explants of proven superior genotypes. Most of the research on E. grandis somatic embryogenesis has used the genetically variable embryos or seedlings as explant sources, which results in the propagation of material of unproven genetic value. In order to exploit somatic embryogenesis maximally for cloning of superior trees, somatic embryos have to be induced from highly selected and, hence, mature trees. The aim of this investigation was to develop such a protocol for E. grandis and to test its applicability to various E. grandis hybrids. Somatic embryos were induced from buds, stems, leaves and petioles, with petioles and buds giving the best results. Thus, these were selected for further studies which involved testing the effect of medium composition on embryogenic callus induction. Media used for this purpose contained MS or B5 nutrients, 1 mg.l' 2,4-D, 0.5 g.r! glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 30 or 50 g.rl sucrose. All the media tested were able to support induction of embryogenic callus, although the number of explants producing embryogenic calli was affected significantly by the media composition (10-91 %). Callus induction media with B5 nutrients seemed to have a significant effect onn the developmental stage of embryos in the callus induction medium. Presence of 50 g.r! sucrose in the callus induction medium reduced the embryo yield, but the progress of embryo development was enhanced. The callus induction medium containing B5, 1 mg.l' 2,4-D, 0.5 g.rl glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 30 g.l' sucrose was chosen for subsequent studies. Of all the media tested for embryo development, the medium with B5, 2.5 mg.l' 2iP, 0.5 g.r! glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 50 g.r! sucrose was found to be the most suitable for embryo development to the cotyledonary stage. Experiments involving incorporation of both ABA and 2iP aiming at maturation of E. grandis somatic embryos led to an increase in size of the cotyledonary embryos formed but not to germination.
M

In clonal deployment programmes of plantation species, there is frequently the need to deploy Eucalyptus species and interspecific hybrids as rooted cuttings. However, the rooting ability of a particular species or hybrid is a major, and usually limiting, factor affecting the economics of commercial deployment. There is also significant between-species and between-family variation for this trait. Recently, Eucalyptus longirostrata was crossed with E. grandis in an effort to combine its desirable wood properties, drought tolerance and disease resistance with the latter's vigorous growth. Should progeny with these suitable characteristics be identified, there is the possibility of extending plantations to more marginal areas and increasing the quality and volume from existing plantations. An investigation was undertaken to study the rooting ability of E. grandis x E. longirostrata hybrid cuttings. The plant material was sourced from five families in seedling derived hedges at two nurseries, as well as five families coppiced from an unreplicated progeny trial planted in the midlands of KwaZulu-Natal. Their rooting ability was assessed by determining the percentage of cuttings that developed roots using two different rooting methods. The variation between and within families and clones is presented. The study shows that root strike is under moderate genetic control, with an estimate of broad-sense rooting heritability of 0.197 (S.E. = 0.070). The two nurseries used in this study used different rooting technologies, with cuttings rooted either in media (traditional method) or in air (aeroponically). The aeroponics technology was highly significantly (p<0.0001) superior, in terms of rooting success. Rooting was also highly significantly affected (p<0.0001) by the temperature at the time of cutting. Rooting success of cuttings from seedling-derived parental hedges was similar to cuttings from coppiced stumps. The consequences of the low repeatability of measurements of rooting ability, 0.187 (S.E. 0.067) by clone and 0.340 (S.E. 0.072) by ramet, which was influenced by the response to age of material and nursery conditions, is discussed. This study demonstrated that large improvements in rooting success can be made by the optimization of rooting protocols and selecting for superior genotypes, as long as the performances of genotypes are accurately assessed.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Clones of the Eucalyptus grandis x Eucayptus nitens (GN) hybrids were produced and selected through the CSIR‟s breeding programmes for colder plantation sites in South Africa. Some GN clones consistently exhibit high and superior pulp properties, which makes them valuable for commercial plantations in South Africa. In nurseries, stockplants are usually seven cm in length and maintained at high (100 x1.5 m-2) planting density. However, rooting frequency varies with season and little is known about the impact of position of cuttings on overall rooting frequency of a clone. The aim of this study was to investigate the effect of size and planting density of stockplants in mini-hedges, on the yield and subsequent rooting of cuttings from various positions of GN clones of known rooting potential (i.e. GN 018B: difficult-to-root and PP 2107: easy-to-root clones). Stockplants (10 cm vs. 20 cm) were established at high (100 x 1.5 m-2) and at low (25 x 1.5 m-2) densities for GN 018B and PP 2107 under commercial nursery conditions in a polyethylene tunnel. Cuttings were harvested every two to three weeks in September-October 2010 (spring), December 2010-January 2011 (summer), April-May 2011 (autumn) and June-July 2011 (winter). The harvested material was 5 – 7 cm in length and the light intensity received by individual stockplants at the two planting density levels was recorded. Harvested cuttings from the three positions (apical, middle and basal shoots) were used for: (i) rooting experiments under nursery conditions, (ii) bio-stimulant analysis using the mung bean bioassay, and (iii) analysis of soluble sugars. Between spring and summer 2010, the two GN clones established at low density yielded a similar number of cuttings, but differences in the rooting frequencies were significant in favour of PP 2107 clone. Similar observations were made at high density in terms of production of cuttings, but the significant differences in the rooting observations were reversed between the clones. The GN 018B clone had low rooting rates in summer under nursery conditions but its tissue extracts promoted higher rooting in the bioassay during that time, when compared to spring. Spring and summer had similar effects on rooting responses of PP 2107 cuttings in nursery and bioassay experiments. For both clones, short stockplants produced fewer cuttings but had a higher rooting frequency than cuttings from tall stockplants, with a high rooting frequency recorded from basal cuttings. Similar results were observed in the bioassay experiments which showed high rooting potential of mung bean hypocotyls cuttings using tissue extracts of PP 2107 cuttings maintained at high planting density. Although apical cutting tissues had high concentration of sugars (i.e. sucrose, glucose and fructose), their rooting rates were usually lower at high and low planting density compared to middle and basal cuttings. Sucrose concentration was the highest sugar present in stockplants grown under low planting density. A higher and lower rooting frequency was also observed in autumn although the two clones responded differently to Quambalaria eucalypti (Sporothrix eucalypti) disease infestations. Position, size and genotype had a significant impact on type and concentration of sugar (i.e. sucrose, glucose and fructose), particularly in PP 2107 clone, although rooting rates in the bioassay did not correlate with sugar contents of Eucalyptus cuttings. High carbohydrate (i.e. soluble sugar) content and auxin concentration increased production and subsequent rooting of cuttings across both clones, particularly in spring. Furthermore, rooting was enhanced by relatively higher light intensity intercepted by individual stockplants and in particular the GN 018B clone. Light intensity in the high and low planting densities caused variation in the rooting frequencies thereby increasing or decreasing soluble sugar and auxin concentrations of the two clones. Light intensity and fertiliser concentration received by tall and short stockplants impacted on endogenous hormone levels thereby increasing or decreasing rooting. High sugar concentration levels of PP 2107 clone increased its susceptibility to fungal infection thereby decreasing its rooting frequency in autumn, as its rooting rates increased in winter. Overall results of the investigation revealed that PP 2107 clone has higher rooting potential than GN 018B clone, in particular at high planting density and if stockplants are not infected by fungal diseases. Higher sugar levels were recorded in spring for PP 2107, although rooting rates of mung bean hypocotyl cuttings were higher in summer for GN 018B, suggesting that sugars have nothing to do with rooting of GN cuttings. Season, planting density and size of stockplants affect the rooting frequency of GN clone. Thus, short stockplants maintained at low and high planting densities are recommended for GN 018B and PP 2107 respectively, although the impacts of fertilisers and pathogen resistance on rooting rates still need to be investigated under similar conditions.
Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Hybrid clones of the fast-growing Eucalyptus grandis and cold-tolerant E. nitens (GN clones) have been identified by the South African Forestry Industry as being highly suitable for plantations in cold-dry marginal areas. However, one of the main problems regarding their propagation is the difficulty in rooting of cuttings, both in vitro and ex vitro. The aims of this investigation, therefore, were (1) to develop widely applicable and efficient in vitro rooting system(s) for these commercially important clones, and (2) to assess some physiological characteristics of the roots produced. Adventitious shoots (15-20 mm in length) were obtained (l0 shoots/explant) from axillary buds on Murashige and Skoog's (MS) medium containing 0.01 mg.l-1 NAA, 0.01 mg.l-1 IBA and 0.2 g.l-1 FAP. The effect of various medium components, as well as modification of culture environment on in vitro rooting, were investigated. The highest rooting frequencies in clones GN121 (75%) and GN107 (65%) were achieved on l/4 MS with additional 0.22 g.l-1 CaCl2..2H2O and 0.18 g.1-1 MgS04.7H2O, 0.1 mg.l-1 IBA, 0.1 mg.l-1 biotin, 0.1 mg.l-1 calcium pantothenate, 15 g.1-1 sucrose and 4 g.l-1 Gelrite. Best culture conditions were an initial 72-hours dark incubation followed by a 16-hours day/8-hours night photoperiod at a PPFD of 37 µmol.m-2.s-1 and 23°C day/21°C night for seven days, after which the PPFD was increased to 66 µmol.m-2.s-1 at 27°C day/21°C night for 18 days. Towards the development of a more widely applicable in vitro rooting protocol for GN clones, the use of Agrobacterium rhizogenes strains was investigated. Production of transgenic roots was observed on carrot discs and shoots from seedlings of Eucalyptus grandis and E. nitens, but not on shoots of GN clones. Therefore, a method needs to be established for the successful transfer and integration of the Ri plasmid of Agrobacterium into the hybrid plant genome for induction of transgenic roots. The quality of roots produced in vitro and from cuttings was assessed by examination of root anatomy and hydraulic characteristics. Adventitious roots were prepared for measurement of hydraulic conductivity by detopping explants, then filtered, acidified distilled water was drawn through undisturbed potted root systems under partial vacuum, causing no damage to the roots. Initial studies showed that tissue culture-derived roots exhibited a higher specific root mass hydraulic conductivity than those derived from cuttings (6.46 x 10-6 vs. 3.06 X 10-6 g.kPa-1.s-1.g-1 dry root), probably due to root architecture. Curves relating vulnerability to water potential were constructed and both types of roots showed vulnerability to cavitation at high water potentials. Differences were also observed in staining reactions (safranin and fastgreen) which might suggest differences in presence and level of secondary metabolites in these roots at the juvenile stage. Applications of the developed protocols and future research strategies are discussed.
Thesis (M.Sc.)-University of Natal, Durban, 1999.