Pinus Caribaea Morelet Research Articles

Micronutrientes no sistema solo-Pinus caribaea Morelet em plantios apresentando amarelecimento das acículas e morte de plantas

Com o objetivo de contribuir no diagnóstico de causas que têm levado à morte precoce de pinheiros, verificada após amarelecimento e necrose progressiva das acículas, foi desenvolvido este estudo em áreas de cerrado, no oeste de Minas Gerais. Foram comparadas árvores de Pinus caribaea Morelet das variedades caribaea e hondurensis, plantadas entre 1977-82. Em cada local de amostragem coletou-se material de 20 árvores, sendo 10 com acículas amarelecidas e 10 normais. Foram coletados acículas e tecidos do xilema e floema de raízes, nos quais foram analisados os teores de Fe, Mn, Zn, Cu e B. A classe de solo dos sítios de estudo é Latossolo Amarelo ácrico típico. As amostras foram coletadas nas profundidades: 0-5, 5-10, 10-20, 20-40, 40-60, 60-80, 80-100, 100-150, 150-200, 200-250 e 250-300 cm, nas quais foram analisados os teores trocáveis de Fe, Mn, Zn, Cu e B. Os teores de Fe, Zn, Cu e B não diferiram significativamente entre acículas verdes e amarelecidas, enquanto os teores de Mn foram significativamente inferiores nestas. Observou-se também que os teores de Mn foram maiores no xilema e menores nas acículas das plantas anormais, ocorrendo o inverso nas plantas normais. Os sintomas visuais, confirmados pelos resultados analíticos, revelam haver deficiência de manganês no sistema solo-planta estudado.

Cloning of a pine germin-like protein (GLP) gene promoter and analysis of its activity in transgenic tobacco Bright Yellow 2 cells.

Germins and germin-like proteins (GLPs) constitute a large and highly diverse family of ubiquitous plant cell wall proteins. These proteins seem to be involved in many developmental stages and stress-related processes, but their exact participation in these processes generally remains obscure. In Pinus caribaea Morelet, the PcGER1 gene is expressed uniquely in embryo tissues, and encodes a GLP ionically bound to the walls of pine embryo cells maintained in 2,4-D-containing medium. We have cloned a genomic fragment including the 1520 bp 5'-upstream promoter region of PcGER1. This sequence contains, in its 1200 bp distal part, several cis elements (e.g. SEF4, 60 kDa protein, ABA RE and Dof recognition sites) present in genes responding to hormones and/or expressed in embryo or seed tissues, or during germination. The PcGER1 promoter sequence was cloned upstream of the GUS (beta-glucuronidase) reporter gene and transferred to tobacco Bright Yellow 2 (BY-2) cells via Agrobacterium tumefaciens-mediated transformation. Promoter activity and growth performances of transgenic asynchronous cell suspensions were analysed in the presence or absence of 2,4-D and/or BA. Optimal growth, maximum cell-wall yield and PcGER1 promoter activity were observed in the presence of 2,4-D and BA at day 4, the end of the exponential growth phase where 70-75% cells have a 2C DNA content. Analysis of promoter activity during the cell cycle in an aphidicoline-synchronized culture suggested that the expression is maximum in G1 cells. We also showed that under optimal growth conditions, 5' promoter deletions decreased the activity of the reporter gene. We discuss the function of this gene with regards to cell growth. Accession number: The PcGER1 promoter sequence was submitted to the genbank database under the accession number AY077704.

Element storage in native, agri-, and silvicultural ecosystems of the Brazilian savanna

The expanding agriculture in the Brazilian savanna, the Cerrado, changes C and nutrient storages of the savanna ecosystems thereby affecting the global C budget and the sustainability of the local land use. We examined the biomass and the C, N, P, and S storages in above- and belowground biomass, in the organic layer, and in the top 2 m of the mineral soil (Anionic Acrustoxes) of three replicate plots of each of native Cerrado, Pinus caribaea Morelet plantations, productive and degraded Bracchiaria decumbens Stapf. pastures, and of conventional and no-tillage soybean cultivation. Aboveground biomass – in the cropping systems shortly before harvest – decreased in the order, Pinus (15 kg m−2) > Cerrado (2.3) > conventional tillage (1.9) > no tillage (1.5) > productive pasture (0.64) > degraded pasture (0.37) and belowground biomass in the order, Pinus (9.1) > Cerrado (3.0) > productive pasture (2.2) > degraded pasture (1.5) > conventional tillage (0.60) > no tillage (0.41). The aboveground biomass contained 1.1 (degraded pasture) to 19% (Pinus) of the total C storage, 0.3 (productive pasture, degraded pasture) to 3.5% of the total N storage, 0.3 (degraded pasture) to 2.1% (no tillage, conventional tillage) of the total P storage, and 0.3 (degraded pasture) to 3.7% (Pinus) of the total S storage of the ecosystems. Total C storage in the ecosystems was significantly larger in the Pinus stands (36 kg m−2) than in all other systems; differences among Cerrado (20), degraded pasture (19), productive pasture (20), no tillage (19), and conventional tillage (19) were small and not significant. All land-use systems had larger N (Pinus, 1.5; degraded pasture, 1.3; productive pasture, 1.4; no tillage, 1.4; conventional tillage, 1.4 kg m−2) and S storage (PI, 28; degraded pasture, 33; productive pasture, 34; no tillage, 36; conventional tillage, 38 g m−2) than the Cerrado (N, 1.2 kg; S, 26 g m−2). The P storages varied between 17 and 29 g m−2 and were not significantly different among the studied ecosystems. The N and S accumulations in the 12–20-year-old land-use systems were larger than the cumulative known fertilizer inputs indicating that there were unknown inputs possibly including the exploration of the deeper subsoil by deep-reaching roots and transfer of nutrients to the topsoil. Our results indicate that afforestation with Pinus trees has the potential to sequester large amounts of C while pasture degradation, no tillage, and conventional tillage tended to result in small C losses. Land use resulted in a marked accumulation of N and S relative to the Cerrado.

First Report of Arceuthobium hawksworthii in Honduras.

The dwarf mistletoe Arceuthobium hawksworthii D. Wiens & C. G. Shaw (Viscaceae) has only been reported from the Mountain Pine Ridge area of Belize (1). We observed this dwarf mistletoe parasitizing its principal host, Caribbean pine (Pinus caribaea Morelet var. hondurensis (Senecl.) Barrett & Golf.) (1), 10 km east of Gualaco, Department Olancho, Honduras (elevation 800 m). Several trees were severely infected, and some dwarf mistletoe-associated mortality was observed at this location. The identification of A. hawksworthii was confirmed by comparing specimens collected from Honduras with specimens from Belize, which are deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. The mistletoes Psittacanthus angustifolius Kuijt and P. pinicola Kuijt (Loranthaceae) were also observed at this location parasitizing Caribbean pine. However, infection by both of these mistletoes was not severe, and no mistletoe-associated mortality was observed. Specimens of these mistletoes from Caribbean pine have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras. To our knowledge, this is the first report of A. hawksworthii from Honduras and extends its range approximately 350 km to the east-southeast of the Mountain Pine Ridge in Belize. This is also the first report P. angustifolius on Caribbean pine, but P. pinicola commonly infects this host in northern Honduras and Belize (2).

Biogeochemical consequences of the transformation of native Cerrado into Pinus caribaea plantations in Brazil

Under the same climatic and edaphic conditions, native savanna vegetation in Brazil, the Cerrado, shows a lower stature and canopy cover than planted Pinus caribaea Morelet forests. To assess the differences in biogeochemical element cycling we compared the nutrient economy of Cerrado and Pinus on three replicate plots of each forest type. The mean nutrient storage in the soil organic layer under Pinus (N: 2630; P: 141; K: 103; Ca: 131; Mg: 20 kg ha−1) was substantially higher than under Cerrado (N: 23; P: 1.2; K: 0.83; Ca: 5.8; Mg: 1.0 kg ha−1) probably because the Pinus roots explored a larger soil volume. The Pinus trees had a higher nutrient-use efficiency as indicated by higher mean litter mass per unit nutrient in litter (N: 108; P: 2290; K: 729; Ca: 1360; Mg: 5420; S: 1190; Fe: 2960; Mn: 9990, Zn: 145000) than the Cerrado trees (N: 94; P: 1810; K: 619; Ca: 302; Mg: 938, S: 746; Fe: 1800; Mn: 7880; Zn: 63700). Mean annual small litterfall collected in 0.25-m2 samplers between May 1997 and April 1999 was 2.1 Mg ha−1 in Cerrado and 7.8 in Pinus. The litterfall rates of the 1–3 week collection intervals correlated negatively with the soil matric potential indicating that litterfall was partly related to water stress. The fluxes of N (73 kg ha−1 year−1), P (3.7), K (11), S (7.0), and Mn (0.83) to the soil with litterfall under Pinus were greater than the litterfall+turnover of the grass/herbs layer under Cerrado (N: 39, P: 2.8, K: 8.6, S: 5.4, Mn: 0.79 kg ha−1 year−1), those of Zn (0.06–0.07) were similar, and those of Ca (Pinus: 5.9/Cerrado: 10), Mg (1.5/4.4), and Fe (2.9/4.0) were smaller. Mean residence times of the organic matter and of all elements were longer in the soil organic layer under Pinus (3.7–26 years in the Oi horizon, 8.1–907 years in the whole organic layer) than under Cerrado (0.22–3.6 years in the Oi horizon, the only organic horizon under Cerrado). Our results demonstrate that the main differences in biogeochemical element cycling between the Pinus forest and the Cerrado consisted of a larger nutrient storage in the organic layer, a higher nutrient-use efficiency, and slower nutrient release rates from the organic layer in the Pinus forest than in the Cerrado. Nutrient cycling as assessed by the nutrient fluxes with litterfall was only partly faster in the Pinus forest than in the Cerrado.

Effects of Pinus caribaea forests on the C, N, P, and S status of Brazilian savanna Oxisols

Abstract The accumulation of humus in soils under Pinus caribaea Morelet forests may increase the availability of organically bound N, P, and S to plants and thus improve soil fertility. To test this hypothesis, we compared C, N, P, and S concentrations and forms in soil solid phase and soil solution under Pinus (PI) and natural savanna vegetation ( Cerrado , CE). We sampled the 0–0.15, 0.15–0.3, 0.3–0.8, 0.8–1.2, and 1.2–2 m soil depth layers of Oxisols from three spatially separated plots under CE and PI; at each plot, soil solution at 0.15, 0.3, 0.8, 1.2, and 2 m soil depth and under PI additionally below the organic layer was collected during two rainy seasons (21 October–28 April 1997/1998 and 1998/1999). Under PI, the organic layer stored more C (24.5 t ha −1 ), N (2.6 t ha −1 ), P (140 kg ha −1 ), and S (261 kg ha −1 ) than under CE (1.2 t C ha −1 , 23 kg N ha −1 , 1.2 kg P ha −1 , 2.3 kg S ha −1 ). No significant difference in C, N, P, and S concentrations between CE and PI in the surface horizons of the mineral soil (C: 20.7–23.4 g kg −1 , N: 1.2–1.5 g kg −1 , P: 0.16–0.26 g kg −1 , S: 0.18–0.21 g kg −1 ) was observed. However, at 1.2–2 m soil depth C and organic N (N org ) concentrations were significantly higher under PI (C: 6.9 g kg −1 , N org : 0.54 g kg −1 ) than under CE (C: 6.4 g kg −1 , N org : 0.41 g kg −1 ). C/P and C/S ratios in soil solid phase decreased with increasing soil depth under CE and PI, those of C/N org only under PI, leading to narrower C/N org ratios under PI (12.9) than under CE (15.6) at 1.2–2 m soil depth. The result indicated enhanced N transport to the subsoil under PI. Total organic C concentrations (TOC) in the soil solution were similar under CE and PI and throughout the mineral soil. Under PI, TOC concentrations decreased sharply between the litter leachate (30 mg C l −1 ) and 0.15 m soil depth (5 mg C l −1 ) indicating strong TOC sorption onto the surface mineral soil. Total N concentrations in the soil solution were 11–23 times higher under PI than under CE. Organic N concentrations also decreased between the litter leachate and 0.15 m soil depth under PI but NO 3 − concentrations increased from the litter leachate to 1.2 m soil depth and decreased between 1.2 and 2 soil depth, probably due to enhanced anion sorption at 2 m soil depth. No S and P was detectable in any solution sample. Higher C, N, and S storages and higher N availability under PI indicated that PI forests improve C, N, P, and S supply for plants in subsequent cultures and may therefore be considered sustainable with respect to organically bound nutrients.

Soil acidification in Pinus caribaea forests on Brazilian savanna Oxisols

The transformation of large areas in the Brazilian savanna into Pinus plantations may have resulted in soil acidification. The objective of this study was to determine if afforestation with Pinus caribaea Morelet (PI) influenced soil acidification by comparing the metal status of the soil solid phase and the course of metal concentrations in soil solution during one rainy season with those under natural savanna vegetation ( Cerrado, CE). Surface soil samples (0–0.15 m) from three spatially disconnected plots in CE and PI were sequentially extracted. At each plot, soil solution at 0.15, 0.3, 0.8, 1.2, and 2 m depth and in PI additionally litter leachate were collected between October 1997 and April 1998. Extracts and soil solution were analyzed for Al, Ca, Cu, Fe, K, Mg, Mn, Na, Si, and Zn concentrations, soil solution also for pH and electrical conductivity (EC). Total concentrations in soil solid phase ranged between 94 000 and 155 000 mg kg −1 (Al), 29 and 39 (Ca), 21 and 31 (Cu), 44 000 and 61 000 (Fe), 91 and 141 (K), 21 and 29 (Mg), 28 and 57 (Mn), 73 and 94 (Na), and 13 and 21 (Zn). Whereas 27–83% of total K, Ca, Mg, and Na concentrations were exchangeable, >83% of total Cu, Fe, Mn, Zn, and Al were bound in hardly plant-available forms. There were no significant differences in concentrations and partitioning between CE and PI. At the beginning of the rainy season (October to December), metal concentrations in soil solution were 2–5 times larger and more variable than between December and April because of the mineralization of organic matter which accumulated during the dry season. Metal concentrations in CE soil solution between December and April were extremely small at all depths (Al: not detected (n.d.)–3.26 μmol l −1, Ca: 2.8–11.7, K: 0.9–6.7, Mg: 0.7–8.3, Mn: n.d. −0.14, Na: 5.5–40.1, Zn: 0.13–1.02). Up to 1.2 m soil depth, soil solution pH was significantly lower in PI than in CE. Concentrations of Ca, K, Mg, and Na were up to two times larger than in CE, those of Mn and Al 9 and 60 times, respectively. Whereas the soil solid phase did not show significant differences in metal concentrations and partitioning, the soil solution composition clearly indicated enhanced acidification in PI. This resulted in increased leaching of plant nutrients from the topsoil.

Genetic variability and structure of natural and domesticated populations of Caribbean pine (Pinus caribaea Morelet)

Isozyme analysis of seed samples derived from natural and managed populations of the tropical pine Pinus caribaea vars ‘bahamensis’ and ‘caribaea’ was used to assess population genetic structure in its native range and to detect changes occurring during early domestication of the species. Baseline data from natural populations of the two varieties showed that populations sampled as seed are characterized by high gene diversity (mean He=0.26) and a low level of inbreeding ( mean Fis=0.15). A UPGMA tree of genetic relatedness among populations indicates that the two varieties represent distinct evolutionary units. Within each variety there is significant differentiation among populations, and this is greater for the more fragmented populations of var ‘bahamensis’ (Fst=0.08) than for var ‘caribaea’ (Fst=0.02). Seed from a seed orchard population of var ‘caribaea’ established within its natural range showed no change in genetic diversity but did show a reduced inbreeding coefficient (Fis=0.09) compared with its progenitor populations, suggesting a decrease in selfing and/or biparental inbreeding. A bulked seed sample from an exotic plantation of var ‘bahamensis’ in Australia displayed a large increase in the inbreeding coefficient (Fis=0.324) compared with that found in natural populations, possibly due to elevated self-fertilization. Finally, a bulked seed sample from an exotic plantation population of var ‘caribaea’ from China showed enhanced genetic diversity, an increase in the inbreeding coefficient and more linkage disequilibrium than its presumed progenitor populations. It was also genetically divergent from them. RFLP analysis of chloroplast DNA variation in the Chinese sample suggested that seeds of the related taxa P. elliottii and P. taeda, or seeds derived from hybridization with these taxa growing in the seed production area, had been included in the seed crop during harvesting. We conclude that monitoring of appropriate genetic markers may be an effective means of identifying potentially deleterious genetic changes occurring during forest tree domestication.

Characterization of a germin-like protein gene expressed in somatic and zygotic embryos of pine (Pinus caribaea Morelet).

Germin-like proteins (GLPs) ionically bound to the walls of preglobular somatic embryos of Pinus caribaea Morelet are markers of this early developmental stage. In order to reveal the physiological implications of such markers during early embryo development, we isolated a cDNA clone from somatic embryos predicted to encode a protein with sequence similarity to GLPs. PcGER1 has an open reading frame corresponding to a 220 amino acid polypeptide with a putative N-glycosylation site on Asn-69. The presence of a 24 amino acid putative signal peptide supports the hypothesis of an apoplastic location. The N-terminal 20 amino acid sequence of the predicted mature protein is identical to the amino terminal sequence of GP111, one of the extracellular pine GLPs previously identified. Southern blot hybridizations indicate that PcGER1 is probably unique in the pine genome. Transcripts homologous to PcGER1 are abundant in all embryogenic lines, absent from nonembryogenic lines, and present in quiescent zygotic embryos but not in the female gametophyte, the haploid storage tissue of conifers. Their abundance sharply decreases during germination. Isolation of gf-0.8, a genomic fragment identical to PcGER1 cDNA sequence, confirms that no introns disrupt the coding region as it has been already described for wheat gf-2.8 and gf-3.8 genomic clones. Recombinant PcGER1, produced in Escherichia coli, is recognized by antibodies raised against the GP111 N-terminal nonapeptide and the unglycosylated wheat germin monomer. The implications of GLPs in pine embryogenesis are discussed.

First-year freeze hardiness of pure species and hybrid taxa of Pinus elliottii (Engelman) and Pinus caribaea (Morelet)

Six pine taxa were compared for freeze hardiness following 2 whole plant freeze tests carried out in early and late winter 1993–94. Pure species included slash pine (Pinus elliottii var. elliottii Engelman) (PEE), Caribbean pine (Pinus caribaea Morelet) var. bahamensis (PCB), and var. hondurensis (PCH). The same six slash pine parents served as the female parents of the pure slash pine taxon and were control pollinated to create the F1 hybrids of slash pine × Caribbean pine var. bahamensis (F1B), the F1 of slash pine × Caribbean pine var. hondurensis (F1H), and the backcross of slash pine × (slash pine × var. hondurensis (B1H). Four traits related to adaptation (bud set, foliage/stem damage, survival) were compared. Significant differences existing among the three species at all temperatures for both freeze tests. The 3 hybrid taxa were intermediate to parental taxa for all measured traits and only at extreme temperatures was there an indication of hybrid vigor. However, inspection of foliage damage curves to estimate temperatures at which 50 percent damage occurs indicated that the hybrids deviated from the mid parent value toward the more freeze susceptible parent. Discriminant functions which included foliage damage and survival traits provided the best segregation of taxa groupings and the combining of canonical variable 1 for these discriminant functions placed hybrids intermediate to parental taxa. Parent × taxa interaction was significant, suggesting that within these taxa, family to family variation occurred, but different maternal parents were associated with the freeze hardly families in different taxa.

The Improvement of Bond Strength Properties and Surface Characteristics of Resinous Woods

Abstract Apitong (Dipterocarpus spp.) and Caribbean pine (Pinus caribaea Morelet) contain high amounts of extractives that contribute to poor bonding. To reduce, if not to eliminate, the effects of these extraneous substances, surfaces of small wood blocks were Soxhlet-extracted for 8 hours by different solvents. Wettability of the wood surfaces was then measured by droplet and dynamic methods using water and dilute NaOH as liquids. Tensile shear strengths of extracted wood bonded with aqueous vinyl polymer isocyanate (API), resorcinol formaldehyde (RF) and polyvinyl acetate (PVAc) resin adhesives were also measured. Results revealed that although Caribbean pine had much higher resin content than Apitong, the former had better wettability than the latter. Solvent extraction of the adherend with either hexane or ethanol-benzene (1:2) for 8 hours was not enough to improve its wettability but enough to improve its gluability. However, successive extraction with hexane, methanol and ethanol benzene rendered t...

Trends in variances and heritabilities with stand development of tropical pines

Phenotypic and additive genetic variances as well as narrow-sense heritability for cumulative height were determined from assessments of tropical pine (Pinuscaribaea Morelet, Pinuschiapensis (Mart.) Andresen, and Pinustecunumanii (Schw.) Eguiluz et Perry) trials established in South America and South Africa by the Central America and Mexico Coniferous Resources (CAMCORE) Cooperative. Cumulative stem height was analyzed from 1-, 3-, 5-, and 8-year data collected on open-pollinated families to determine additive genetic and phenotypic variances. Variances based on arithmetic as well as log-transformed values are presented. Phenotypic and genetic variances of log-transformed values decreased over time, probably reflecting the onset of intergenotypic competition. Absolute variances increased over time as the trials became older, but the rate of increase for phenotypic variance was greater than that for additive variance. Individual narrow-sense heritabiiities changed over time but without showing any definite trend by species. It appeared that variance trends reflected the varying ontogenetic changes during the development of the stands, which could be indicated by size of the trees rather than by their age. Breeding strategies in tropical pines should consider the increasing intensity of environmental effects as a stand matures, since they cause a decline of genetic variances at a higher rate than phenotypic variances. Furthermore, it is hypothesized that a phenotypic trait at a given ontogenetic stage of the individual is under temporal control of a set of genes that changes as the temporal environmental conditions change.

Three Glycosylated Polypeptides Secreted by Several Embryogenic Cell Cultures of Pine Show Highly Specific Serological Affinity to Antibodies Directed against the Wheat Germin Apoprotein Monomer

Embryogenic tissues of Pinus caribaea Morelet var hondurensis produce extracellular proteins; among them germins have been identified. Two-dimensional electrophoresis followed by electroblotting onto a polyvinylidene difluoride membrane allowed isolation and N-terminal amino acid sequencing of extracellular GP111, which is present within the five embryogenic cell lines studied. The amino acid sequence showed strong homologies with the sequences of germins deduced from cDNA sequencing, starting at the same amino acid position but one, compared with other sequences of mature germins deduced from protein sequencing. Immunoblots of embryogenic and nonembryogenic extracellular proteins indicated that the polypeptide GP111 plus two others with similar relative molecular mass values are present in embryogenic cell lines but not in nonembryogenic ones. They were recognized by an antiserum raised against the nonglycosylated monomer of wheat germin. The cross-reaction between pine and wheat apoproteins was highly specific. An antiserum against the glycosylated pentameric germin-like protein (an oxalate oxidase) of barley cross-reacted with all three, as well as with several other glycosylated polypeptides.

Average relative stem profile comparisons for three size classes of Caribbean pine

A method for determining and comparing average relative stem profiles is described. Under-bark diameters at several points along the stem and the total heights were measured on 572 sample trees of Caribbean pine (Pinuscaribaea Morelet var. hondurensis Barrett & Golfari). For each tree, the total volume and the diameters under bark at several consistent relative positions along the stem (viz. 0.10–0.50 in increments of 0.05) were interpolated. The trees were categorised into three size classes depending on volume. For each tree, a true form factor corresponding to each interpolated relative position was calculated. These form factors were regressed on volume for each size class to determine the most appropriate position along the stem for use in calculating the relative diameters. A polynomial model was fitted to each size class, using relative diameter as the dependent variable and powers of relative height as the independent variables. Differences between the three equations describing the mean relative profiles were statistically significant. Mean errors for the relative diameters are also presented to indicate the accuracy of the three equations.

Long shoot terminal bud development and the differentiation of pollen- and seed-cone buds in Pinuscaribaea var. hondurensis

Bud type differentiation and development were investigated in early and late flowering grafted clones of Pinuscaribaea Morelet var. hondurensis Barr. & Golf. (Caribbean pine) growing at two sites in the tropical north of Australia. Regardless of the early and late flowering tendencies, pollen- and seed-cone buds began to differentiate in middle and late March, respectively. Unlike the cone buds of temperate pines, there was no apparent pause in development between pollination and differentiation. The long shoot terminal bud organogenic sequence resembled that described in temperate pines and led to an episodic, monocyclic shoot growth pattern. The formation of up to several long shoot terminal buds between the onset of seed-cone-bud differentiation and flowering frequently resulted in multiple sets of seed cones.

Mineral nutrition of Pinus caribaea and Eucalyptus camaldulensis seedlings inoculated with Pisolithus tinctorius and Thelephora terrestris

Abstract Seedlings of Eucalyptus camaldulensis Dehnh. and Pinus caribaea Morelet var. hondurensis Loock. were inoculated witH mycelium of Pisolithus tinctorius (Pers.) Coker & Couch and Thelephora terrestris Ehrl. per Fr. After four months in glasshouse culture, the roots of Pisolithus inoculated seedlings had significantly more ectomycorrhizae than Thelephora inoculated seedlings. The Pisolithus inoculated Eucalyptus seedlings were significantly larger in size than plants colonized with T. terrestris. Shoot dry weight and needle surface area of P. caribaea seedlings were significantly increased by Pisolithus inoculation. Inoculation with Pisolithus significantly increased N, P, K, Ca, Mg, Cu, Fe, Mn, Zn, and B content in E. camaldulensis seedlings compared to Thelephora inoculated plants. In contrast, only N, Mg, Cu, Fe, Zn, and B content was significantly increased by Pisolithus colonization of P. caribaea, compared to Thelephora inoculated seedlings. These data suggest ectomycorrhizal fungi differs in their ability to provide nutrients to host symbiont.

Influence of taxonomic relatedness and medium composition on meristematic nodule and adventitious shoot formation in nine pine species

Embryos of Pinusechinata Mill., Pinustaeda L., Pinusserotina Michx., Pinuseldarica Medwed., Pinuscaribaea Morelet, Pinusoocarpa Scheide, Pinustecunumanii (Schwd.) Equiluz & Perry, Pinusstrobus L., and Pinusradiata D. Don were cultured following the protocol for Pinusradiata to determine if a perpetual meristem culture could be produced. Two subsequent experiments were done that included modifications to the medium's mineral composition, strength (modified LePoivre and Murashige and Skoog at half-strength and full strength), cytokinin concentration (1.0, 2.5, and 5.0 mg/L benzyladenine), and auxin concentration (0 and 0.1 mg/L indolebutyric acid). Pines in subsection Australes performed poorly in culture relative to those species in subsection Oocarpae. Pinusradiata and Pinuseldarica were the only species to produce long-term subculturable meristematic tissue, although shoots were obtained with seven of the species. Half-strength modified LePoivre medium containing 2.5 mg/L benzyladenine but no auxin gave the best results with most species. Significant differences in shoot production were found among Pinusoocarpa provenances.

Selection indices for the genetic improvement of Caribbean pine to increase sawn timber production

Summary Four selection indices were developed for Pinus caribaea Morelet var. hondurensis Barrett and Golfari grown in Queensland, in order to maximise the rate of genetic improvement in the volume of sawn timber recovered from 20-year-old trees. The first index placed no restriction on correlated genetic changes in density or spiral grain while the other three restricted changes in either or both of these wood properties to zero. Measurements of diameter at breast height, height and stem straightness made at 11 years were used as the controlling characters. For all indices, genetic responses in sawn-timber production were predicted using both mass selection and combined selection. Genetic gains of up to 18% were predicted, with an associated reduction of 13% in density. Gains in sawn-timber production of 8% were predicted with no decreases in density or spiral grain. Thus, substantial gains in sawn-timber production may only be possible at the expense of density. Other approaches for the development of a...

Plasticity of phenotypic expression in cultured shoot explants of Pinus caribaea morelet

The phenomenon of phenotypic plasticity, whereby genetically identical plants when grown in variable environments exhibit alterations in growth rates or patterns of growth, has been observed as morphogenic expression of plants or plant parts cultured in vitro. Plastic responses to sub- and supra-optimum temperatures for survival, growth and induction of rooting in vitro were observed in shoot explants of Pinus carribaea derived from ecologically diverse sources. The ability to form roots did not correspond with their ability to survive and grow under a range of temperatures. As both these characters are important for field performance, the plastic responses of characters and interactions between them are important considerations for selecting plants. In vitro procedures provide rapid and efficient means for early detection of these differences.

Variation among Pinus oocarpa provenances tested in the Savanna region of Nigeria

Variation in height, diameter at breast height (dbh), stem form, branch thickness and branch angle of 12-year-old provenances of Pinus oocarpa Schiede tested at three different locations (Afaka, Nimbia and Miango) in the Savanna region of Nigeria was studied. The five provenances tested were San Fernando (Nicaragua), Sebaco (Nicaragua), El Zapotillo (Honduras), San Marcos (Honduras) and Gualan (Guatemala). Significant provenance differences existed in all the characteristics except branch angle. The San Fernando, Nicaragua, provenance had the fastest growth and best stem form among the provenances. Its other characteristics compared well with those of the other provenances. This provenance is therefore the most suitable among the P. oocarpa provenances tested for plantation development in the Savanna region of Nigeria. Growth rate of P. oocarpa in the test locations was observed to be higher than that of Pinus caribaea Morelet at these locations. The former species was also observed to exhibit better stem form than the latter.