Nutrient uptake and assimilation in fragrant rosewood (Dalbergia odorifera T.C. Chen) seedlings in growing media with un-composted spent mushroom residue.

The purpose of this study was to detect nutrient uptake and assimilation in woody plants subjected to growing media with some peat replaced by spent mushroom residue (SMR). Fragrant rosewood (Dalbergia odorifera T.C. Chen) seedlings were cultured in five types of growing media with SMR and peat in volumetric proportions of 0% (control), 25%, 50%, 75%, and 100%. With the increase of SMR proportion, ammonium- and nitrate-nitrogen (N) concentrations declined but available phosphorus (P) concentration and electrical conductance both increased. Seedlings in the full SMR substrates showed obvious mortality. Seedlings in substrates with SMR in proportions higher than 25% showed symptoms of excessive N and P toxicities. The utilization efficiency for P was highest in the 25% SMR growing-media. Mineral N in substrates had a positive relationship with growth and biomass but not with glutamine synthetase activity. Available P was negatively related with acid phosphatase activity in both leaves and roots. Un-composted SMR can replace 25% of peat in growing media for fragrant rosewood seedlings, benefitting P uptake and assimilation.

Morphological and physiological responses of Dalbergia odorifera T. Chen seedlings to different culture substances.

Dalbergia odorifera T. Chen seedlings do not grow well in the typical red soils of tropical regions. Eighteen culture substances filled with different substrate combinations and proportions of red soil, coconut coir powder, deciduous leaf powder, and sand were used as to determine their effects on the growth, root system development, dry matter accumulation and allocation, leaf relative electrolyte leakage, chlorophyll content, root superoxide dismutase activity, root malondialdehyde content, and total soluble sugar content of D. odorifera. Results demonstrated that different substrate combinations and proportions had different effects on the performance of D. odorifera. All mixed substrates were better than any single substrate. The suitable substrate combinations and proportions of sand, coconut coir powder, and deciduous leaf powder mixed with red soil improved the growth, root architecture, and physiological characteristics of D. odorifera seedling. For example, groups C1-2 (coconut coir/red soil = 2/2, v/v, the same below) and C3-2 (red soil/sand = 2/2) exerted the best effects on plant growth and biomass accumulation. Groups C1-2, C2-2 (deciduous leaf powder/red soil = 2/2), and C3-2 remarkably enhanced root system development. Group C6 (coconut coir/red soil/sand = 1/1/1) substantially promoted root nodule development. Group C3-1 (red soil/sand = 3/1) exhibited the best effects on physiological characteristics. On the basis of the comprehensive evaluation of Euclid's multidimensional space mathematical model, we found that the suitable substrate combinations followed the order of C1-2 > C3-1 > C2-2. This research provides scientific guidance for the proper seedling culture of D. odorifera and the rational utilization of solid wastes such as coconut coir and deciduous leaves of Ficus elastica.

Molecular Mechanism Underlying Mechanical Wounding-Induced Flavonoid Accumulation in Dalbergia odorifera T. Chen, an Endangered Tree That Produces Chinese Rosewood.

Dalbergia odorifera, a critically endangered tree species, produces heartwood containing a vast variety of flavonoids. This heartwood, also known as Chinese rosewood, has high economic and medicinal value, but its formation takes several decades. In this study, we showed that discolored wood induced by pruning displays similar color, structure, and flavonoids content to those of natural heartwood, suggesting that wounding is an efficient method for inducing flavonoid production in D. odorifera. Transcriptome analysis was performed to investigate the mechanism underlying wounding-induced flavonoids production in D. odorifera heartwood. Wounding upregulated the expression of 90 unigenes, which covered 19 gene families of the phenylpropanoid and flavonoid pathways, including PAL, C4H, 4CL, CHS, CHI, 6DCS, F3'5'H, F3H, FMO, GT, PMAT, CHOMT, IFS, HI4'OMT, HID, IOMT, I2'H, IFR, and I3'H. Furthermore, 47 upregulated unigenes were mapped to the biosynthesis pathways for five signal molecules (ET, JA, ABA, ROS, and SA). Exogenous application of these signal molecules resulted in the accumulation of flavonoids in cell suspensions of D. odorifera, supporting their role in wounding-induced flavonoid production. Insights from this study will help develop new methods for rapidly inducing the formation of heartwood with enhanced medicinal value.

Metagenomic evidence of stronger effect of stylo (legume) than bahiagrass (grass) on taxonomic and functional profiles of the soil microbial community.

Plants are key determinants of soil microbial community (SMC). Legumes and grasses are distinct groups in various ecosystems; however, how they differentially shape SMC structure and functioning has yet to be explored. Here, we investigate SMC in soils grown with stylo (legume) or bahiagrass (grass). Soil metagenomic sequencing indicates that Archaea was more abundant in unplanted soils than in planted soils, and that stylo selected higher abundance of fungi than bahiagrass. When the stylo soils enriched Streptomyces, Frankia, Mycobacterium and Amycolatopsis, the bahiagrass soils enriched Sphingomonas and Sphingobium. NMDS reveals that the legume shaped SMC more greatly than the grass (P < 0.004). SMC functional profiles (KEGG and CAZy) were also greatly altered by plants with the legume being more effective (P < 0.000 and P < 0.000). The abundant microbial taxa contributed to the main community functions, with Conexibacter, Sphingomonas, and Burkholderia showing multifunctionality. Moreover, soil chemical property showed much higher direct effect on SMC structure and functional profiles than soil extracts, although the soil total nitrogen and some compounds (e.g. heptadecane, 1-pentadecyne and nonanoic acid) in soil extracts were best correlated with SMC structure and functional profiles. These findings are the first to suggest that legume species shape SMC more greatly than grass species.

The Use of DNA Barcoding in Identification and Conservation of Rosewood (Dalbergia spp.).

The genus Dalbergia contains many valuable timber species threatened by illegal logging and deforestation, but knowledge on distributions and threats is often limited and accurate species identification difficult. The aim of this study was to apply DNA barcoding methods to support conservation efforts of Dalbergia species in Indochina. We used the recommended rbcL, matK and ITS barcoding markers on 95 samples covering 31 species of Dalbergia, and tested their discrimination ability with both traditional distance-based as well as different model-based machine learning methods. We specifically tested whether the markers could be used to solve taxonomic confusion concerning the timber species Dalbergia oliveri, and to identify the CITES-listed Dalbergia cochinchinensis. We also applied the barcoding markers to 14 samples of unknown identity. In general, we found that the barcoding markers discriminated among Dalbergia species with high accuracy. We found that ITS yielded the single highest discrimination rate (100%), but due to difficulties in obtaining high-quality sequences from degraded material, the better overall choice for Dalbergia seems to be the standard rbcL+matK barcode, as this yielded discrimination rates close to 90% and amplified well. The distance-based method TaxonDNA showed the highest identification rates overall, although a more complete specimen sampling is needed to conclude on the best analytic method. We found strong support for a monophyletic Dalbergia oliveri and encourage that this name is used consistently in Indochina. The CITES-listed Dalbergia cochinchinensis was successfully identified, and a species-specific assay can be developed from the data generated in this study for the identification of illegally traded timber. We suggest that the use of DNA barcoding is integrated into the work flow during floristic studies and at national herbaria in the region, as this could significantly increase the number of identified specimens and improve knowledge about species distributions.

[Cryopreservation study on seeds and embryos in Dalbergia odorifera].

The mature seeds and excised embryos of Dalbergia odorifera were used as materials to study the effect of moisture content on their survival, as well as the effect of rapid freezing and vitrification freezing method on seeds and in vitro embryos cryopreservation. The results showed that the germination rate and vigor decreased from 82.67%, 85% to 18.35%, 25% respectively, when the seed moisture content decreased from 15.04% to 8.14%; and the germination rate decreased from 82.67% to 37.50%, 25.37% respectively by vitrification freezing method and rapid freezing method, when the seed moisture content decreased from 15.04% to 9.37%. Among all the moisture content gradient, 12.35% moisture reached the maximal germination rate, which were 63.58% and 50.45% respectively by vitrification freezing and rapid freezing; and when the embryo moisture content was 26.32%, the germination rate decreased from 95.67% to 58.31% and 33.82% respectively by vitrification freezing and rapid freezing. And when the moisture content was in the range of 14.17% -21.34%, the germination rate was a bit of decrease. The experiment results showed that the optimum conditions of seed cryopreservation were: moisture content 12.35%, vitrification freezing; and the optimum conditions of in vitro embryo cryopreservation were: moisture 15.04%, vitrification freezing. In conclusion, the effects of moisture content on germination rate after cryopreservation in D. odorifera seeds and embryo were significant, and vitrification freezing method is much better than rapid freezing method.

Micropropagation of Dalbergia sissoo Roxb. through tissue culture technique.

Multiple shoots of Dalbergia sissoo Roxb. (Sissoo) were incited from seeds through indirect somatic embryogenesis method. Seeds were inoculated in Murashige and Skoog's medium without any growth hormone. Than cotyledonary leaves were struck and used for callus induction on MS medium amplified with 2, 4-dichlorophenoxyacetic acid (0.5 to 4 mg mL(-1)). After 3 to 4 weeks the embryogenic callus clumps was transferred to medium supplemented with cytokinin (BAP 1 to 5 mg L(-1), kinetin 1-5.0 mg L(-1)) for embryo maturation and germination. The high-frequency shoot proliferation (82%) and maximum number of shoots per explants were recorded in MS medium containing NAA (0.5)+BAP (0.5). The findings of recent investigations have shown that, it is possible to induce indirect somatic embryogenesis in Dalbergia sissoo and plant regeneration from callus cultures derived from cotyledonary leaves as explants.

Two-way transfer of nitrogen between Dalbergia odorifera and its hemiparasite Santalum album is enhanced when the host is effectively nodulated and fixing nitrogen.

Nutrient translocation from a host plant is vital to the growth and survival of its root parasitic plant, but few studies have investigated whether a parasitic plant is also able to transfer nutrients to its host. The role of N2-fixation in nitrogen (N) transfer between 7-month-old Dalbergia odorifera T. Chen nodulated with Bradyrhizobium elkanii DG and its hemiparasite Santalum album Linn. was examined by external (15)N labeling in a pot study. Four paired treatments were used, with (15)N given to either host or hemiparasite and the host either nodulated or grown on combined N. N2-fixation supplied 41-44% of total N in D. odorifera. Biomass, N and (15)N contents were significantly greater in both nodulated D. odorifera and S. album grown with paired nodulated D. odorifera. Significantly higher total plant (15)N recovery was in N donor D. odorifera (68-72%) than in N donor S. album (42-44%), regardless of the nodulation status in D. odorifera. Nitrogen transfer to S. album was significantly greater (27.8-67.8 mg plant(-1)) than to D. odorifera (2.0-8.9 mg plant(-1)) and 2.4-4.5 times greater in the nodulated pair than in the non-nodulated pair. Irrespective of the nodulation status, S. album was always the N-sink plant. The amount of two-way N transfer was increased by the presence of effective nodules, resulting in a greater net N transfer (22.6 mg plant(-1)) from host D. odorifera to hemiparasite S. album. Our results may provide N management strategies for D. odorifera/S. album mixed plantations in the field.

Phenotypic plasticity to light of two congeneric trees from contrasting habitats: Brazilian Atlantic Forest versus cerrado (savanna).

The Brazilian Atlantic Forest is a typically multi-layer tropical forest, while cerrado (savanna) is a patchy habitat with different physiognomy. Despite these differences, both habitats have high light heterogeneity. Functional traits of Dalbergia nigra and D. miscolobium from the Atlantic Forest and cerrado, respectively, were evaluated under shade (25% of full sunlight) and full sunlight in a nursery experiment. We hypothesised that both species should benefit from high phenotypic plasticity in relation to light. Plasticity was estimated using the relative distance phenotypic index (RDPI). D. miscolobium had lower shoot growth under both light conditions, suggesting it has low competitive capacity in the forest environment, which could explain its limited ability to expand over areas of Atlantic Forest. The studied species exhibited photoprotection strategies under high light and improved light capture under low light. Stomatal conductance, ETR(max) (maximum electron transport rate), PPFD(sat) (saturating photosynthetically active photon flux density), chlorophyll and carotenoid content had higher RDPI than stem morphological traits. Although both species showed considerable phenotypic plasticity, D. miscolobium had higher RDPI for eight of 11 evaluated traits. This high plasticity could be one of the factors that explain the occurrence of this species in a wide range of environmental conditions, from open grassland to dense woodlands, and it could also reflect its adaptation to high light. D. nigra also had considerable plasticity and good growth performance in both shade and full sunlight, but its absence in areas of cerrado suggests that factors other than light limit its occurrence in these habitats.

Growth of Dalbergia sissoo in desert regions of western India using municipal effluent and the subsequent changes in soil and plant chemistry.

Increasing demand for fodder and fuelwood and the scarcity of a good quality water in arid areas has resulted in a search for an alternative source of water for biomass production. An experiment utilizing municipal effluent in growing Dalbergia sissoo was conducted. Five treatments included T1, municipal effluent at 1 PET (Potential evapo-transpiration) (without plant); T2, municipal effluent at 1/2 PET; T3, municipal effluent at 1PET; T4, municipal effluent at 2 PET; and T5, canal water at 1 PET. Observations included plant height, collar diameter at one-month intervals and plant mineral composition, mineral uptake and changes in soil properties at 24 months of plant age. Application of municipal effluent produced better growth in D. sissoo seedlings. Concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) were greater in seedlings irrigated with municipal effluent than those of the seedlings irrigated by the treatment T5, and positively related with the quantity of irrigation. The concentrations were greatest in foliage compared to the other parts of seedling, with the exception of Cu concentration. Application of municipal effluents resulted in a 2- to 3-fold increase in the concentrations of soil K, Cu, Fe, Mn and Zn, whereas NH4-N and PO4-P availability increased by 8.1- and 4.5-fold, respectively. The increase in soil organic carbon was only observed in treatments T3 and T4. The accumulations of soil NO3-N, Na, Cu, Fe, Mn and Zn were more in lower soil layers but the other soil parameters showed their greatest values in the upper soil layer. Irrigation using municipal effluent did not result in toxicity to the seedlings before the age of 24 months. The results suggest that municipal effluent could be utilized, as an important source of water and nutrients in growing D. sissoo to increase biomass production in the needs of suburban dwellers. However, a preliminary treatment to reduce excess NH4-N and PO4-P will be required before application to the plantation.

Biomonitoring of lead in atmospheric environment of an urban center of the Ganga Plain, India.

Monitoring of atmospheric lead from the Dalbergia sissoo tree was undertaken at Lucknow urban centre of the Ganga Plain, India. A total of 26 leaf samples were collected in spring, monsoon and winter seasons from 16 sampling sites and was analysed by Atomic Absorption Spectrophotometry method. Lead concentrations were low in spring season, increased in monsoon to winter seasons and range from 2.1 to 28.2 microg/g (dry wt.). This accumulative response of lead in the tree leaves is directly linked with the exposure time of automobile emission that is considered to be the predominant source for it. Highway localities show higher lead concentrations by a factor of 2 as compared to urban localities. Highest concentration was recorded at Sitapur Road (National Highway No. 24) in winter season. A linear quantitative relationship between urban air-lead levels and lead-in-the Dalbergia sissoo leaves is used to infer the qualitative assessment of present day atmospheric lead pollution. Reported results suggest a drastic reduction in mean lead concentration in Lucknow urban air from 1.32 microg/m3 in 1994 to 0.19 microg/m3 in 2002. Similarly, mean lead concentration in the tree leaves during winter season also dropped from 17.9 microg/g in 1994 to 8.1 microg/g in 2004. Despite of increasing urban population, urban area, vehicle population and traffic density, the introduction of unleaded-petrol (vehicular fuel) keeps lead level in the urban environment of Lucknow much lower than the past. Like Lucknow, other urban centres of the Ganga Plain are also on way to the exponential increase in pressure of urbanization. An appropriate urban public transport planning is required to provide healthy atmospheric environment for millions of people especially future young generation.

[In vitro organogenesis in Dalbergia retusa (Papilonaceae)]. / Organogénesis in vitro en Dalbergia retusa (Papilonaceae).

Plants were obtained via organogenesis from hypocotyl explants of Dalbergia retusa from in vitro germinated seedlings. Adventitious bud induction was achieved on Murashige and Skoog medium containing five BA (benzyladenine) concentrations. The best BA concentration for budding induction and budding development was 8.8 microM. Shoot rooting was obtained on half-strength modified MS basal medium, supplemented with 20 g x l(-1) of sucrose and five concentrations of indole-3-butyric acid (IBA). The highest number of shoot rooting was obtained with 19.7 microM IBA but the highest average number of roots for plantlet was achieved with 24.6 microM IBA. Plants were transferred to greenhouse conditions.

Mineral accumulation, growth, and physiological functions in Dalbergia sissoo seedlings irrigated with different effluents.

Present study aimed to observe the mineral accumulation added through effluent application and their influence on physiological functions and growth of Dalbergia sissoo and ultimately to find out suitable combination of industrial and municipal effluent for their utilization in raising tree plantation. Dalbergia sissoo seedlings were irrigated with: canal water (T1); municipal effluent (T2); textile effluent (T3); steel effluent (T4); textile + municipal effluent in 1:1 ratio (T5); steel + municipal effluent in 1:2 ratio (T6); steel + municipal + textile in 1:2:2 ratio (T7); and steel + textile in 1:2 ratio (T8). Mineral accumulation, water relations and gas exchange, growth and biomass production were the recorded observations. Mortality occurred within a day for the seedlings in T4, 45 days in T6, and 60 days in T7 and T8 treatments. This was probably the result of high (P<0.01) Mn, Fe, Cu, and Zn and low N, P, K, Ca, and Mg concentration in different parts of the seedlings in these treatments affecting physiology and growth. Reduction in rate of photosynthesis (Pn) and transpiration (T) to the level of 90%, leaf water potential (LWP) and increased stomatal resistance (R) at two months of age is the indicator of metal toxicity in these treatments. Pn and T were 20 and 17% high in T2 treatment, respectively. However, the reduction was only 21 and 10% in Pn and 18 and 26%, respectively in the seedlings of T3 and T5 than that in T1 treatment. During nine months of observation, the seedlings of T2 and T5 maintained high LWP and same rate of Pn and T but they reduced significantly (P<0.01) in the seedlings of T3 treatment affecting biomass production. This was believed to be due to increase in Na concentration leading to decrease in Mg, Ca, Mn, Fe, Cu and Zn concentration and ratio of Mg/Na and Mg/K and increased ratio of N/Mg and K/Ca + Mg. The enhanced physiological functions in T5 treatment were probably the result of ameliorative effect of municipal effluent through increased mineral status producing biomass equivalent to that in T1 treatment at 10 months of age. The seedlings of T2 attained greater (P<0.01) height and collar diameter and produced 120g seedling(-1) of dry biomass. The study suggests that addition of excess mineral elements leads to metal toxicity that adversely affects physiology and ultimately growth and productivity of tree seedlings. Mixing of effluents to ameliorate the toxic effects could be the better management practices for their use in tree irrigation.