Timber Tree Species Research Articles

Two chemical mutagens modulate the seed germination, growth, and phenotypic characteristics of Chinese fir (Cunninghamia lanceolata)

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook), a fast-growing and economically important timber tree species in China, is widely used in construction, furniture, and paper manufacture but has a long breeding cycle. Chemical mutagens, such as ethyl methane sulfonate (EMS) and sodium azide (SA), are widely used in crops such as rice, wheat, cotton, soybean and sugarcane but their utility for tree breeding is unknown. In this study we examined the effects of EMS and SA on Chinese fir seed germination and growth. Chinese fir seeds were treated with the two chemical mutagens; were planted in Jiangle County, Fujian Province, China; and their heights were measured from 2011 to 2017. The concentrations and durations of treatment with the two chemical mutagens were significantly associated with the Chinese fir seedling and mortality rates, as well as with the heights of trees from the seedling stage to 3 years old. We also generated 127 mutants with abnormal branches and reproductive growth. We report here the effects of two chemical mutagens on Chinese fir breeding; our data will contribute to knowledge of the utility of EMS and SA in forestry.

Population assessment of the endangered and valuable timber tree Torem (Manilkara kanosiensis) in Customary Forest of Lorulun, Yamdena Island, Indonesia

Torem (Manilkara kanosiensis) is a timber tree species endemic to Yamdena Island in Indonesia and the Bismarck Archipelago in Papua New Guinea. Due to its high-quality timber, the trees are harvested from its natural populations. These logging activities have put the species into the endangered category according to IUCN Red List since more than 20 years ago. In the present study, the population assessment of Torem will be conducted in the customary forest of Lorulun, Yamdena Island, Indonesia. Distance sampling using line-transect was used to assess the distribution of Torem, identify population size and structure, estimate population density, and update the conservation status of the species. The results showed Torem trees were mostly located at relatively flat areas (4.5±0.2°), with the elevation range of 81-134 m above sea level. A total of 228 individuals of Torem was located during the survey, with more than half of them (56.68%) were within 0-10 cm dbh class. The density estimate of the species was 14.8±4.4 individuals/ha. The assessment of conservation status against IUCN Red List Category and Criteria revealed that Torem was qualified for the status of Endangered A2cd, B2ab (i, ii, iv, v), C2a(i), D.

Preliminary Evidence for Domestication Effects on the Genetic Diversity of Guazuma crinita in the Peruvian Amazon

Guazuma crinita, a fast-growing timber tree species, was chosen for domestication in the Peruvian Amazon because it can be harvested at an early age and it contributes to the livelihood of local farmers. Although it is in an early stage of domestication, we do not know the impact of the domestication process on its genetic resources. Amplified fragment length polymorphic (AFLP) fingerprints were used to estimate the genetic diversity of G. crinita populations in different stages of domestication. Our objectives were (i) to estimate the level of genetic diversity in G. crinita using AFLP markers, (ii) to describe how the genetic diversity is distributed within and among populations and provenances, and (iii) to assess the genetic diversity in naturally regenerated, cultivated and semi-domesticated populations. We generated fingerprints for 58 leaf samples representing eight provenances and the three population types. We used seven selective primer combinations. A total of 171 fragments were amplified with 99.4% polymorphism at the species level. Nei’s genetic diversity and Shannon information index were slightly higher in the naturally regenerated population than in the cultivated and semi-domesticated populations (He = 0.10, 0.09 and 0.09; I = 0.19, 0.15 and 0.16, respectively). The analysis of molecular variation showed higher genetic diversity within rather than among provenances (84% and 4%, respectively). Cluster analysis (unweighted pair group method with arithmetic mean) and principal coordinate analysis did not show correspondence between genetic and geographic distance. There was significant genetic differentiation among population types (Fst = 0.12 at p ˂ 0.001). The sample size was small, so the results are considered as preliminary, pending further research with larger sample sizes. Nevertheless, these results suggest that domestication has a slight but significant effect on the diversity levels of G. crinita and this should be considered when planning a domestication program.

Evaluation of biochemical changes during different stages of somatic embryogenesis in a vulnerable timber tree Dalbergia latifolia (Indian rosewood)

In Dalbergia latifolia Roxb. (Indian rosewood), a premium-quality vulnerable timber tree species belonging to Family Fabaceae, direct somatic embryogenesis was achieved. Immature cotyledons from green pods were collected from trees at 90 d after flowering and somatic embryo formation was achieved on Murashige and Skoog’s medium supplemented with 0.5 mg L−1 2,4-dichlorophenoxyacetic acid and 0.1 mg L−1 kinetin. Different developmental stages, ranging from globular, heart-shaped, torpedo, and cotyledonary stage, were recorded during the complete formation of somatic embryos. Globular somatic embryos gradually converted into heart shape after 35 to 40 d, torpedo shape after 50 to 55 d, and dicotyledonary-shaped embryos after 60 d of culture. The individual isolated somatic embryos with well-developed cotyledons were transferred on medium containing 0.5 mg L−1 benzyl adenine and 0.1 mg L−1 abscisic acid to promote development into plantlets. Biochemical changes in soluble sugars, total carbohydrates, phenols, and nitrate reductase activity were monitored at 5-d intervals from 0 to 60 d. Soluble sugar content (%) increased from 5.26% to 28.05% during the culture period. Minimum sugar content was noted in the globular stage, followed by heart-shaped and torpedo stage and maximum sugar content was observed in cotyledonary somatic embryo stage. A similar trend was observed in total carbohydrate content also (12.83% to 41.23%). A significant variation in the phenol content and nitrate reductase activity of the somatic embryos was observed and the peak values were achieved at 35 d in phenol content (4.25%) and 30 d in nitrate reductase activity (0.79 μmol NO2 h−1 g−1). Therefore, it was concluded that increasing levels of endogenous soluble sugar and carbohydrate play an important role during the formation of somatic embryos. These findings can be utilized to study the underlying carbohydrate and nitrogen metabolic pathways during somatic embryogenesis.

Performance of Dalbergia palo-escrito Rzed. & Guridi-Gómez, a valuable timber tree, in a coffee plantation in Hidalgo, Mexico

As a contribution to ex-situ conservation and production recovery of the valuable timber tree species Dalbergia palo-escrito Rzed. & Guridi-Gómez, enrichment planting was undertaken in a coffee plantation at 830 m above sea level in the east of the State of Hidalgo, Mexico. The purpose of this study was to assess the growth and health status of this species in order to put forward forest management recommendations. Average growth at 11 years of age (n = 56) was as follows: normal diameter, 13.2 ± 2.9 cm; total height, 10.9 ± 1.9 m. These values represent a mean annual increase of 1.2 cm/year in diameter and 1.0 m/year in height. Significant statistical differences in diameter growth (P = 0.0001) and height growth (P = 0.003) were observed as a function of crown position; growth, both in diameter and height, was highest in trees with emergent crowns in comparison with poorly lit trees. An association was also found concerning infestation by Struthanthus sp. mistletoe: differences in diameter growth (P = 0.002) were found between trees with mild infestation in comparison with healthy trees, which showed more growth. On the other hand, no height growth differences were detected (P = 0.102). Diameter and height growth were comparable to other commercially valuable species of fine Dalbergia timber on the international market, such as Dalbergia sissoo in India and Dalbergia retusa in mixed plantations in Costa Rica. The study suggests pruning out the mistletoe as a control strategy is a recommended forest management practice, as well as releasing poorly illuminated trees from competition and preserving the shade canopy of other native species.

Complete plastome sequence of endangered timber species Dipterocarpus tempehes Slooten

Dipterocarpus tempehes is an endangered tropical timber tree species endemic to Borneo. In this study, the plastome of D. tempehes was assembled. The whole chloroplast genome was 145,323 bp in length, with a large single-copy (LSC) region of 80,375 bp and small single-copy (SSC) region of 20,394 bp, separated by two inverted repeats (IRs) regions of 22,277 bp. It contained 145 genes, including 102 coding genes, 35 tRNA genes, and 8 rRNA genes. A phylogenomic analysis confirmed that Malvaceae s.l., Thymelaeaceae, and Dipterocarpaceae formed its respective monophyletic clade, with D. tempehes forming a sister clade with species from the Shoraeae tribe within the family.

How long does the Amazon rainforest take to grow commercially sized trees? An estimation methodology for Manilkara elata (Allemão ex Miq.) Monach

It is important to know the growth rate of the species to be managed to establish sustainable forest management plans because from this information, it is possible to know which species have reached the minimum commercial size to be collected in future harvests. Manilkara elata (Allemão ex Miq.) Monach is considered one of the most commercialized timber tree species, both inside and outside of Brazil. Thus, the objective of this study was to model the growth rate and the time required for the trees of this species to reach the minimum cutting diameter defined by the current Brazilian legislation; the analysis was based on the adapted Weibull function with data from 31 years of monitoring in the National Forest of Brazil in Tapajós, Pará, Amazon, Brazil. Three models were proposed to estimate (i) the annual periodic increase in diameter (API), (ii) the future diameter (df) and (iii) the time period in years (t) that each tree would need to reach a future diameter according to the average growth rate of the target species and its forest community. Taken together, the data from the managed and unmanaged areas showed no statistically significant differences between the values observed and estimated by the proposed model when assessed with the Graybill F test. The adapted Weibull model performed well when estimating the annual periodic increment and future tree diameter of the M. elata population. Based on the diameter growth rate, the 5 cm diameter M. elata trees would require 601–781 years to reach the minimum commercial diameter of 50 cm, but the 40–49.9 cm diameter trees that are considered stock for the next harvest would take an average of 20 years to reach this commercial diameter. As the estimated average growth time is shorter than the cutting cycle prescribed by the legislation (25–35 years), it is recommended that forestry treatments that favor longer survival of M. elata individuals be adopted to achieve greater continuous production by primarily considering the long period that young individuals need to reach the cutting diameter.

The long-term effects of active management and landscape characteristics on carbon accumulation and diversity within a seasonal dry tropical ecosystem

Reforestation is the largest natural climate solution, while potentially reversing the biodiversity crisis, especially in tropical countries. Dry tropical forests are of particular interest because they experienced greater historic loss, and offer large reforestation opportunities. This study addressed the potential of secondary forests in dry tropical systems regenerating after 60 + years in cattle pasture to accumulate carbon while increasing floristic diversity. Total carbon and woody species diversity were quantified within experimental treatments established 15 years ago. Initial active management practices included removing exotic grass with herbicide, excluding cattle by constructing live fences, and monitoring succession relative to proximity to forested riparian zones and slope position. Overall, carbon accumulated relatively slowly in this landscape (1.30 MgC Ha-1 Yr-1). Differences were seen between management practices and landscape characteristics. Lower slope plots, adjacent to forested zones, had significantly more carbon than upper slope plots, isolated from riparian zones. The initial application of herbicide decreased total carbon. However, natural regeneration of two valuable timber species with small seeds, Astronium graveolens and Cedrela odorata, benefited from this initial treatment. Live fences that were initially planted to exclude cattle significantly increased carbon of regenerating woody species. Lianas were abundant at this successional stage. Almost half of all inventoried trees (44%) had at least one liana climbing through them, with the most common species being Bauhinia glabra and Macherium microfolium. Some valuable timber tree species found within older, protected riparian forests were not yet regenerating in any treatment, such as the wind-dispersed species, Cieba pentandra, and the animal dispersed species, Hymenaea coubaril. These species may need to be actively planted at the mid-successional stage (~15–20 years) to restore biodiversity. A trade-off between timber value, diversity, and carbon sequestration must be considered in reforestation programs and this depends on landscape characteristics and management. Passive management, even with invasive grass species, is a practical option when sites are located near forested riparian zones due to low cost and high timber value of a suite of native species that naturally regenerate. No intervention is needed other than continual protection from fire and grazing. However, low-cost management, such cutting lianas and enrichment planting at the mid-successional stage, is likely to increase carbon accumulation and diversity. More active management, such as planting drought-tolerant, higher timber value tree species, is recommended at sites isolated from forested riparian zones on upper slopes where carbon accumulation is lower. Tropical forest regeneration mechanisms in proximity to forest fragments can be surprisingly resilient if chronic human impacts are removed.

Agrobiodiversity, Composition and Functional Characteristics of Homegardens in Bhimtal Block of Nainital District, Uttarakhand, India

Present investigation was carried out to access the agrobiodiversity, composition and functional characteristics of homegardens in bhimtal block of Nainital district, Uttarakhand during 2011-12. The study was carried out in three villages diversified in respect to elevation and agroecological situations viz., Amritpur (520 mts) at low hill, Jeolikote (1219 mts) at mid hill and Ghorakhal (2000 mts) at high hill in Bhimtal block of district Nainital. In these villages a total of 22 respondents of different economic status in each village with a total of 66 respondents were selected and interrogated for the information related to the study. It was found that 80.30 per cent household practicing homegardening and the tree species, fruit tree species (Malus domestica, Citrus sinensis, Psidium guajava), sacred groves species (Ficus roxburghii, Tamarindus indica, Aegle marmelos), timber, fuel wood and fodder tree species (Grevia optiva, Toona ciliata, Mangifera indica, Citrus aurentifolia) were contributed as 33.33, 38.09, 11.90 and 40.74 per cent respectively.

Gendered Species Preferences Link Tree Diversity and Carbon Stocks in Cacao Agroforest in Southeast Sulawesi, Indonesia

The degree to which the maintenance of carbon (C) stocks and tree diversity can be jointly achieved in production landscapes is debated. C stocks in forests are decreased by logging before tree diversity is affected, while C stocks in monoculture tree plantations increase, but diversity does not. Agroforestry can break this hysteresis pattern, relevant for policies in search of synergy. We compared total C stocks and tree diversity among degraded forest, complex cacao/fruit tree agroforests, simple shade-tree cacao agroforestry, monoculture cacao, and annual crops in the Konawe District, Southeast Sulawesi, Indonesia. We evaluated farmer tree preferences and the utility value of the system for 40 farmers (male and female). The highest tree diversity (Shannon–Wiener H index 2.36) and C stocks (282 Mg C ha−1) were found in degraded forest, followed by cacao-based agroforestry systems (H index ranged from 0.58–0.93 with C stocks of 75–89 Mg ha−1). Male farmers selected timber and fruit tree species with economic benefits as shade trees, while female farmers preferred production for household needs (fruit trees and vegetables). Carbon stocks and tree diversity were positively related (R2 = 0.72). Adding data from across Indonesia (n = 102), agroforestry systems had an intermediate position between forest decline and reforestation responses. Maintaining agroforestry in the landscape allows aboveground C stocks up to 50 Mg ha−1 and reduces biodiversity loss. Agroforestry facilitates climate change mitigation and biodiversity goals to be addressed simultaneously in sustainable production landscapes.

Potential of Genome-Wide Association Studies and Genomic Selection to Improve Productivity and Quality of Commercial Timber Species in Tropical Rainforest, a Case Study of Shorea platyclados

Shorea platyclados (Dark Red Meranti) is a commercially important timber tree species in Southeast Asia. However, its stocks have dramatically declined due, inter alia, to excessive logging, insufficient natural regeneration and a slow recovery rate. Thus, there is a need to promote enrichment planting and develop effective technique to support its rehabilitation and improve timber production through implementation of Genome-Wide Association Studies (GWAS) and Genomic Selection (GS). To assist such efforts, plant materials were collected from a half-sib progeny population in Sari Bumi Kusuma forest concession, Kalimantan, Indonesia. Using 5900 markers in sequences obtained from 356 individuals, we detected high linkage disequilibrium (LD) extending up to >145 kb, suggesting that associations between phenotypic traits and markers in LD can be more easily and feasibly detected with GWAS than with analysis of quantitative trait loci (QTLs). However, the detection power of GWAS seems low, since few single nucleotide polymorphisms linked to any focal traits were detected with a stringent false discovery rate, indicating that the species’ phenotypic traits are mostly under polygenic quantitative control. Furthermore, Machine Learning provided higher prediction accuracies than Bayesian methods. We also found that stem diameter, branch diameter ratio and wood density were more predictable than height, clear bole, branch angle and wood stiffness traits. Our study suggests that GS has potential for improving the productivity and quality of S. platyclados, and our genomic heritability estimates may improve the selection of traits to target in future breeding of this species.

Geographic Distribution of Global Economic Important Mahogany Complex: A Review

Mahogany is the collective international trade name for the high-value tropical and subtropical timber tree species of the family Meliaceae. Mahogany species are noted for their deep red-brown heartwood and are widely used in the construction, boat building, interior decoration (particularly paneling and floor tiles), and in the manufacture of furniture. Across their natural geographical distribution range, many rural communities depend for their livelihoods on the genetic resources of the species as they provide natural products and services. However, mahogany populations across their native range are threatened by deforestation, habitat fragmentation, excessive logging and genetic erosion. In addition, climate change may bring about a shift in the distributional range of the native species. To safeguard the rich diversity of mahogany requires a conscientious effort in policy formulation and the enforcement of existing laws in regard to the management and conservation of the species. In addition, it is imperative that mahogany is used as an integral component in agroforestry systems and in reforestation efforts, as well as in the restoration of degraded forest ecosystems in order to protect the genetic resources of the species. The aim of this review was to highlight the threats to the sustainability of the species. We conducted literature review to examine the geographic distributional range of a mahogany complex (Khaya spp, Entandrophragma spp, Cedrela spp, Toona spp, Swietenia spp) at global, regional and ecosystem scales. We used maps as annotated diagrams to show the probable geographic global distribution range of the mahogany complex. The Khaya spp. and Entandrophragma spp. are native to Africa, Cedrela spp. and Swietenia spp. are native to Central and South America, whereas, Toona spp. are found primarily in southeast Asia.

Preliminary assessment on above ground carbon stock of agroforestry and monoculture crop systems in peatlands

Peatlands can be used for crop cultivation with various combination patterns both agroforestry and monoculture systems. Utilization of these lands not only produces high economic value products, but also contributes in providing environmental services, including carbon sequestration. This study aims to measure aboveground carbon stock of agroforestry and agricultural monoculture systems in Rasau Jaya, Kubu Raya Regency, West Kalimantan Province. The agroforestry system observed is divided based on the level of peat depth, which are 0-2 m and 3-4 m. The pattern of agroforestry at a depth of 0-2 m is a combination of timber and non timber tree species and agricultural crops, while the pattern of agroforestry at a depth of 3-4 m is a combination of timber and non-timber tree species and plantation crops. Timber tree species are Pulai (Alstonia pneumatohara) and Gerunggang (Cratoxylon arborescens Bl); the non-timber tree species is jelutung (Dyera costulata); and plantation crop species are Jengkol (Archidendron pauciflorum) and Pinang (Areca catechu); and the agricultural crops are peanuts, cayenne pepper, tomatoes, bitter melon and eggplant. Observations were also conductedon the agricultural monoculture pattern, including the eggplant, chili, bitter melon and tomato. The components of measured carbon stocks are plant biomass (trees and lower plants), wooden necromasses, non-woody necromasses, and wild plant biomass. The measurement results show a shallow peat agroforestry system (0-2 m) with a combination of one year old trees and agricultural crops contributing to carbon stock of 0.8 tons/ha. Deep peat agroforestry systems (3-4m) with a combination of timber trees, non-timber trees and plantation crops contribute to carbon stocks of 3 tons/ha. While the monoculture system of agricultural crops produce an average carbon stock of 1.1 tons/ha. Contribution of tree component in the agroforestry system are still relatively small, which is 2.6% of total carbon stock. However, it is estimated that the carbon stocks will continue to increase with increasing age.

Characterization of Genomic Microsatellite Markers and Analysis of Pollen Donors Number for Single Cone of Chinese fir

Chinese fir [ Cunninghamia lanceolate (Lamb.) Hook] is one of the most important indigenous timber tree species in China. The aim of the present work is to characterize simple sequence repeat (SSR) loci derived from the specific length amplified fragment sequencing (SLAF) data of the genome and to investigate the number of pollen donors for per cone was with novel SSR markers of low-frequency null alleles. A total of 58855 SLAF-SSR with frequency of 42.04 SSR/Mbp were identified in about 1.40 Gb Chinese fir genome. Dinucleotide repeat SSR contributed to 66.4% of the total SSR from SLAF data. The AT/AT and ATG/CAT motifs were predominant in the category of din- and trinucleotide repeat SSR. Low frequencies of null alleles (<5%) were detected at the nine novel SSR markers with average expected heterozygosity of 0.513 and polymorphism information content score of 0.508. The number of tested progeny of a cone was from 4 to 13. It could be 67 pollinizers for 15 cones and the average number of pollen donors per cone was 4.5. The study points out, for the first time, that there are multiple pollen donors for single cone in gymnosperm.

First report of Paradecatoma bannensis Masi (Hymenoptera, Eurytomidae) as seed parasite of Cordia africana in Ethiopia

Cordia africana is a highly-valued timber tree species that is quite dominant in riparian habitat, native to several countries in Africa and the Arabian Peninsula. It is mainly propagated by pyrene, which is found to be attacked by an unidentified seed borer insect. The main objective of this study was to investigate the cause of pyrene deterioration of C. africana in Ethiopia. Drupes were collected from nine study locations. Paradecatoma bannensis has emerged from de-pulped drupes. The larval and adult stages of this wasp were also found inside crushed drupes. Of the pyrenes having no exit hole, 20.8% were noticed with the presence of dead and alive larvae and adults of the insect when examined after crushing. Percentages of infestation varied between the sites (nil to 17.5%). The float-and-sink test method that used to sort out infested against sound pyrenes were found not applicable in our trial for the reason that both pyrenes were found sunk. This wasp was reported for the first time on the pyrenes/drupes of C. africana in Ethiopia. Therefore, future studies need to address the biology and distribution of P. bannensis on C. africana in order to provide management options.

Rapid in vitro Propagation and Efficient Acclimatisation Protocols of Neolamarckia cadamba

Background and Objective: Neolamarckia cadamba is a fast-growing commercial timber tree species with considerable economic returns to the growers on a rotation period of 4-10 years. The present study was aimed to establish an efficient micropropagation protocol for N. cadamba through direct organogenesis by using nodal explants. Materials and Methods: The nodal explants from in vitro-germinated seedlings were cultured on B5 medium supplemented with various BAP concentrations. The in vitro shoots were then rooted in 1/2 B5 medium added with growth regulators such as IBA, NAA and PBZ. Three types of potting media were tested for transplantation efficiency. Results: The B5 medium supplemented with 1.0 mg LG1 BAP provided the most suitable medium for shoot induction from nodal explants with a mean of 5.4 shoots per explant. The subculture interval could be shortened by proliferating the regenerated axillary shoots on B5 medium supplemented with 0.8 mg LG1 BAP. Half-strength B5 medium enriched with 0.1 mg LG1 PBZ was able to induce root growth with 100% of root formation and resulted in more than 95% survival during acclimatisation stage. Conclusion: This micropropagation protocol could pave the way for mass production of quality N. cadamba seedlings for industrial tree plantation development in order to assure the local timber industries to meet the global demand for wood. Therefore, this could reduce the reliance on natural forests for wood production.

Economic viability of agri-silvi-horticultural system

An experiment was conducted from 2006-2016 to study the economic viability of sapota timber based agroforestry system at University of Agricultural Sciences, Dharwad on medium black soils under rainfed conditions. The experiment consisted of sapota as major fruit tree species and five timber tree species, viz. Pterocarpus marsupium, Tectona grandis, Terminalia paniculata, Lagerstroemia lanceolata and Terminalia alata which were planted in between two sapota trees. Field crops, viz. soybean and safflower were sown ever year in alleys of sapota + timber trees in kharif and rabi seasons respectively. Recommended package of practices were followed for field crops and sapota trees and all the silviculture practices were followed for better growth of the timber trees. Height, diameter, marketable timber were higher in Tectona grandis with sapota and Lagerstroemia lanceolata with sapota as compared to other tree species. Both net returns, B:C ratio and IRR were higher in the field crops + Sapota + Tectona grandis (` 67129/, 3.84, 123% respectively) followed by field crops + sapota + Pterocarpus marsupium (` 64688, 3.74, 120% respectively) as compared to other tree species.

Morphological characterization and transcriptome analysis of pistillate flowering in pecan (Carya illinoinensis)

Pecan [Carya illinoinensis (Wangenh.) K. Koch] is a famous high grade dry fruit, oil tree species and excellent tree species for both timber and fruit. Pecan is a monoecious plant, and the formation and number of female flowers directly determine the pecan yield. In this work, to illuminate the molecular mechanism of floral formation in pecan, scanning electron microscopy was employed to distinguish the developmental stages of female flower. Three flower buds and two flowering stages were collected for high throughput RNA sequencing. 65,680 unigenes were generated with 41, 806 differentially expressed genes annotated. Genes involved in hormone signaling, carbon and nitrogen metabolism showed significant differential expression during the floral developmental process. The MADS-box gene family was analyzed in depth, the six type-I genes were not expressed in the FL2 stage, while most type-II genes were highly expressed in the late flower stages. In order to explore the regulation mechanism of pecan flowering, we selected 299 floral-related genes to construct gene co-expression network. The photoperiod pathway genes LHY, PHYA, ELF3 and the gibberellin metabolic pathway gene DELLA proteins function as key roles in floral pathways. We also identified four hormone metabolic pathway genes correlated (SAUR15, IPT1, IAA29, and ARF2) with CiMADS5, CiMADS8, CiMADS9, CiMADS20, and CiMADS39. Furthermore, the expression patterns of 16 unigenes involved in flower development were validated using quantitative real time PCR. These findings are of great significance for further understanding of the molecular basis for reproductive development in Carya Nutt species.

Biomass Production and Carbon Sequestration by Cultivation of Trees under Hyperarid Conditions using Desalinated Seawater (Sewage Water)

As growing economies – in particular in the Gulf region – use extreme and growing amounts of desalinated seawater for municipal purposes the use of produced waste waters is in the focus of science. The fixation of atmospheric carbon-dioxide by a safe cultivation of trees using this slightly salty water sources is of increased importance in times of ongoing climate change. Unfortunately, existing research relies on irrigation of trees in arid lands using ground water, any kind of precipitation, seasonal events like river flooding or a mix of them. To date no data support the biomass or tree production in total absence of natural precipitation and complete lack of ground water. In this study, seven timber and fuelwood tree species, namely, Eucalyptus occidentalis En., Eucalyptus tereticornis Smith, Eucalyptus camaldulensis Dehnh., Eucalyptus gomphocephala DC., Eucalyptus grandis Hybr. Hill ex Maid, Tamarix aphylla (L.) Karst., Tamarix nilotica (Ehrenb.) Bunge were tested for carbon sequestration and biomass-production. Above-soil and sub-soil parts were determined under two levels of drip-irrigation water supply: 25% and 50% of Evapotranspiration (ETo) over a period of two years and four months from planting to harvest. The trees were cultivated under hyper-arid climatic conditions using brackish irrigation water (3.5 dS m-1) on a research and development station in Arava, Israel. Purified waste water from a seawater desalination plant (reverse osmosis) was applied after municipal use. Eucalyptus gomphocephala DC. delivered the highest yields and had the highest water use efficiency, producing 70 t of Dry Matter (DM) /ha/a under the higher irrigation level. Compared with the other species, E. gomphocephala DC. showed a 32% to 65% superior performance . Whereas, lower amounts of saline irrigation water were favoured by E. camaldulensis and T. aphylla – both producing more than 50 t of DM/ha/a. Nevertheless, Tamarix, as a halophyte specialist plant, needed 30 % less water for this growth. Both Eucalyptus varieties mentioned before form a closed tree stand and reached a height of almost 10 m, two years after planting. Regardless of the particular use of the produced timber, about 15 – 25% of the trees’ total DM, approximately equal to the carbon-content, remains in the soil as long-term carbon-storage after harvesting the above ground biomass. Fast growing fuelwood tree species ensure a safe long-term biological fixation of carbon Irrigated with small amounts of saline waste water.

Genome-wide analysis of the Catalpa bungei caffeic acid O-methyltransferase (COMT) gene family: identification and expression profiles in normal, tension, and opposite wood.

Caffeic acid O-methyltransferase (COMT) is an important protein that participates in lignin synthesis and is associated with the ratio of G-/S-type lignin in plants. COMTs are associated with the wood properties of forest trees; however, little known about the COMT family in Catalpa bungei, a valuable timber tree species in China . We performed a comprehensive analysis of COMT genes in the C. bungei genome by describing the gene structure and phylogenetic relationships of each family member using bioinformatics-based methods. A total of 23 putative COMT genes were identified using the conserved domain sequences and amino acid sequences of COMTs from Arabidopsis thaliana and Populus trichocarpa as probes. Phylogenetic analysis showed that 23 CbuCOMTs can be divided into three groups based on their structural characteristics; five conserved domains were found in the COMT family. Promoter analysis indicated that the CbuCOMT promoters included various cis-acting elements related to growth and development. Real-time quantitative polymerase chain reaction (PCR) analysis showed differential expression among CbuCOMTs. CbuCOMT2, 7, 8, 9, 10, 12, 13, 14, 21, and 23 were mainly expressed in xylem. Only CbuCOMT23 was significantly downregulated in tension wood and upregulated in opposite wood compared to normal wood. Our study provides new information about the CbuCOMT gene family and will facilitate functional characterisation in further research.