Properties of Bark Particleboard Bonded with Demethylated Lignin Adhesives Derived from Leucaena leucocephala Bark

Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.

Experimental Analysis of Shear Strength of Undisturbed Soil in Leucaena Forest in Jiangjia Ravine,Yunnan,China

Five leucaena trees of similar age were chosen in Jiangjia Ravine of Dongchuan,Yunnan Province,China,near which the soil samples were collected by digging profiles 2m in depth and 1m in width.In each section,soil samples at different depths were taken for direct shear experiments to determine the root amount and mechanical composition.It is found that the cohesion and internal friction angle of the undisturbed soil are related to the root amount,depth,clay content and breccias content.Cohesion correlates negatively with root content,a finding that differs from that of other researchers.In addition,internal friction angle correlates positively with all these factors.

Antioxidant, antimicrobial and cytotoxic potential of condensed tannins from Leucaena leucocephala hybrid-Rendang

Condensed tannins(CTs)are one of the promising compounds due to their potentially health-promoting qualities.In this study,CTs were extracted from a Leucaena leucocephala hybrid-Rendang and subjected to various biological studies including antioxidant(using Ferric reducing antioxidant power(FRAP),DPPH and ABTS radical scavenging assay),anti-microbial(against different pathogens)and cytotoxic activities(toward human breast adenocarcinoma(MCF-7),human colon carcinoma(HT29),human cervical carcinoma(HeLa)and human liver carcinoma(HepG2)cell lines)in cancer cells through in vitro experiments.The structural characteristics and purity of CTs extract were determined using 13C NMR.The results showed that CTs exhibited higher in vitro antioxidant activities(2257.12±80.55 mg TEAC/g extract,605.3±1.82 mg TEAC/g extract and 1014.03±1.20 mg TEAC/g extract in FRAP,ABTS and DPPH assay,respectively)and demonstrated anti-microbial activities toward selected Gram’s positive and Gram’s negative bacteria tested with MIC and MBC value at 6.25–50 mg/mL.Furthermore,among other selected cancer cells,CTs also demonstrated cytotoxic activity toward human breast cancer cells(MCF-7)(IC50=38.33±2.08mg/mL).Characteristic of apoptosis such as cell shrinkage,nuclear condensation and apoptotic bodies were shown in MCF-7.These preliminary investigations have provided scientific rationale to use CTs as an alternative therapy for various oxidative and inflammatory associated diseases.©2016 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

In vitro activities of acetonic extracts from leaves of three forage legumes(Calliandra calotyrsus,Gliricidia sepium and Leucaena diversifolia) on Haemonchus contortus

Objective:To assess ovicidal activity of three acetonic extracts from the leaves of three forage legume,Calliandra calotyrsus(C.calotyrsus),Gliricidia sepium(G.sepium) and Leucaena diversifolia(L.diversifolia) in vitro on Haemonchus contortus(H.contortus).Methods:Eggs were exposed for 24 hours to five different concentrations(0.075,0.15,0.3,0.6 and 1.25 mg/mL) of acetonic extracts at room temperature(24℃).Distilled water and 0.4%Tween were used in the bioassay as negative controls.Results:The later did not affect embryonation and egg hatching of H.contortus.Conversively,significant effects were obtained with the acetonic extracts of leaves of all three plants and the maximum activity was observed with the highest concentration (1.25 mg/mL).The acetonic extract of G.sepium was found to be more active(2.9%and 0.0% for embryonation and egg hatching,respectively) than the other substances 16.5%and 33.5%, respectively for C.calothyrsus,33.7%and 33.3%,respectively for L diversifolia.Conclusions: These results suggest that the three forage legumes do possess ovicidal properties and further studies on larvae should be carried out.

Effects of sludge on germination and initial growth performance of Leucaena leucocephala seedlings in the nursery

A study was carried out to determine the influence of different types of sludges （municipal, industrial and residential） on field germination, growth and nodulation of L. leucocephala seedlings in the nursery. Before sowing of seeds, different combinations of sludges were incorporated with the nutrient deficient natural forest soils. Field germination, nodulation status and physical growth parameters of seedlings （shoot and root length, vigor index, collar diameter, leaf number, fresh and dry weight of shoot and root and total dry biomass increment） were recorded after three and six months of seed sowing. Field germination, nodulation status and growth parameters were varied significantly in the soil amended with sludges in comparison to control. The highest number of nodule was recorded from soil amended with residential sludge （ 1：1 ） and highest fresh and dry nodule weight was also found from the same combination in both three and six month old seedlings. In case of growth parameters, the highest growth was recorded from soil and residential sludge （ 1：1 ） combination compared to control. From the study, it can be recommended that soil amended with residential sludge （ 1：1 ） provide better field germination, growth and nodule formation of L. leucocephala in degraded soil.

Landscape Ecological Evaluation on the Artificial Forest of Leucaena leucocephala——Taking the Example of Xiaokua Hill of Yuanmou

Based on the theory of ecology, this article conducted a landscape ecological evaluation on Leucaena leucocephala artificial forest in the add-hot valley, Yuanmou Xiaokua hill, using a combination method of qualitative analysis and landscape comprehensive evaluation. The comprehensive evaluation indexes of landscape include forest coverage, biodiversity, stability, soil erosion, environmental quality, availability, scientific research characteristic, economic benefits. Using AHP （analytical hierarchy process）, determine the grade of ecological evaluation factors and the weight of evaluation index and calculate the CEI （comprehensive evaluation index） on ecological evaluation. Evaluation results showed that the area CEI was 0.714 225, a better quality of the ecological level, but biodiversity indicators was the lowest. To sum up, it was difficult to maintain ecological restoration effectiveness and process but also guarantee a good biodiversity in the add-hot valleys. We must reasonably arrange the alien species and the native species, in order to obtain a stable and sustainable eco-system.

Genetic analysis of growth and wood variations in Leucaena leucocephala (Lam.) de Wit.

We selected 28 populations of Leucaena leucocephala from different geographical locations in the states of Andhra Pradesh, Tamil Nadu and Orissa of India on the basis of height and girth at breast height （GBH）. We evaluated fiber length, optical density, wall thickness, vessel element length, vessel element diameter, specific gravity and lignin of these populations of L. leucocephala in different sites. Populations had significant variations for all growth, wood and paper parameters. Girth at breast height （GBH） and specific gravity were the most important pa- rameters for heritability and genetic gain, respectively. The minimum heritability was reported for vessel element length and genetic gain for fiber length. The populations were grouped into six clusters, cluster II had maximum number of populations （14） and clusters IV and VI had one population each. GBH contributed maximum of 34.39 % towards total divergence followed by specific gravity （14.02%）. An economic technique to produce quality seed by establishing seed orchards with genetically divergent parents was suggested. The hybridization among the populations selected from diverse clusters could produce greater heterosis needed for higher growth and suitable wood and paper manu- facturing parameters.

Optimization of South China 5 Cassava-Leucaena Protein Feed Production by Kombucha in Solid-State Fermentation

[Objective] To optimize solid-state fermentation of South China 5 （SC5） cassava-leucaena protein feed by kombucha. [Method] The SC5 cassava-leucaena protein feed was fermented by kombucha. The fermentation conditions were optimized. [ Result] The optimum conditions of solid-state fermentation were as follows： cassava and leucaena weight ratio, 7：3; fermentation time, 6 d; kombucha volume, 10 ml; fermentation temperature, 30 ℃; and water volume, 200 ml. The content of crude protein in feed was substantially increased and reached 23.64%. [ Conclusion] The optimized fermentation process greatly improves utilization of the SC5 cassava-leucaena protein feed.

Steroids from the Whole Plants of Leucaena Leucocephala

Four steroids, 5α,8α-epidioxy-(24ξ)-ergosta-6,22-dien-3β-ol (1), β-sitosterol (2), β-sitostenone (3), and stigmastenone (4), along with 10 known compounds were isolated from the whole plants of Leucaena leucocephala (Leguminosae). 1, Lupeol (5), 1,3-dipalmitoyl-2-oleoylglycerol (6), methylparabene (8) and isovanillic acid (9) were found for the first time from the species. The structure of these compounds were characterized and identified by spectra analyses.

Polyprenol from the Whole Plants of Leucaena leucocephala

Ficaprenol-11 (polyprenol) (1), squalene (2), lupeol (3), ?-sitostenone (4), trans-coumaric acid (5), cis-coumaric acid (6) pheophytin-a (7), pheophorbide a methyl ester (8), methyl-132-hydroxy-(132-S)- pheophorbide-b (9) and aristo-phyll-C (10) were isolated from the whole plants of Leucaena leucocephala (Leguminosae). Among them, 1 and 2 was found for the first time from this species. The structure of these compounds were characterized and identified by spectra analyses.

Yield-density effects on growth and biomass partitioning in Leucaena leucocephala seedlings

Experiments were conducted to study the effects of density on growth and biomass partitioning of Leucaena leucocephala seedlings.Four plantations with densities of 10,000,20,000,40,000,and 80,000 seedlings ha^-1 were evaluated only from 15 to 25 months after planting.At 15 months,crown height and width decreased with increasing density.Seedling height/dbh ratios increased with increasing density.Biomass increased with greater density according to the yield–density effect equation,which was evident for all densities.With increasing age,biomass division to branches and leaves increased,whereas partitioning to roots decreased in the 10,000 and 20,000 seedlings ha-1 plantings.Partitioning to branches and leaves remained relatively steady,while partitioning to roots increased in the 40,000 and 80,000 seedlings ha^-1 plantings.Biomass division into stem and bark components remained relatively steady in all densities.Yield–density and organ yield–density curves shifted upward with increasing seedling age on a log–log graph throughout the experimental period.

Fine Root Distribution Pattern of Different Aged Leucaena leucocephala Trees in Debris Flow Source Area in Jiangjia Gully, China

Fine root is critical to restrain soil erosion and its distribution pattern is of great influence on the restraining effects. This study studied the fine root biomass （Br） distribution of different aged Leucaena leucocephala （5, 10, 15 years） in debris flow source area in Jiangjia Gully by digging downward to the bottom at different distances to stem in three directions on slope. The results showed the Br increased dramatically by 143% from 5 years to lO years and then rose slowly by 38% from to years to 15 years. The Br of 5 years was significantly asymmetric between uphill and alonghill directions, but there was little difference among directions for other ages, and a concentration trend appeared to exist in downhill and alonghill directions. Moreover, fine root （D≤1 mm） was significantly heavier than that of fine root （1mm〈D〈2 ram）, playing a leading role in the vertical distribution of the whole fine root, with a logarithmic or an exponential function. The results presented may shed light on fine root distribution pattern and evaluation of its effect on slope stability in debris flow source area.

Molecular cloning and characterization of two differentially expressed Cellulose synthase gene isoforms in <i>Leucaena leucocephala</i>: A pulp yielding tree species

Leucaena leucocephala is fast growing leguminous tree species, acclimatized to variety of soil and climatic conditions. It is widely used for pulp production in India. Pulp mainly consists of cellulose, which is a simple polymer of unbranched β-1, 4-linked glucan chains. The polymerization of glucose residues into a β-1, 4-linked backbone is catalysed by the enzyme cellulose synthase (CesA). Here, cDNAs encoding CesA genes from Leucaena were isolated and characterized. The two complete cDNAs of 3.228 kb and 3.222 kb encoding CesA gene from L. leucocephala were designated as Ll-7CesA (FJ871987) and Ll-8CesA (GQ267555) respectively. In-silico studies showed that Ll-7CesA has 95.2% identities and Ll- 8CesA has 95.8% identities with Acacia mangium CesA2. Phylogenetic analysis revealed significant similarity with known dicot CesA genes. The deduced amino acid sequence of both CesA genes contained the conserved D, D, D, QxxRW motif, eight membrane spanning regions and a putative zinc binding domain, which are characteristic of glycosyltransferases. DNA blot analysis suggested, CesA gene to be in multiple copies in Leucaena genome. Semi quantitative and quantitative real-time PCR expression analysis of Ll-7CesA gene showed more expression in stem than leaf and not detected in root where as Ll-8CesA gene was expressed more in stem than leaf and root. Overall Ll-8CesA was expressed in all tested tissues and could be involved in active cellulose biosynthesis.

Productivity of Soil Fertilised with Fermented Calliandra, Gliricidia and Leucaena Browses and Maize Forage

Fermented Callliandra, Gliricidia and Leucaena browses and maize material （milk stage） were applied to the soil to determine their effect on soil productivity. Hopi Red Dye Amaranthus （Amaranthus cruentus） was used as the test crop. Its DM yield was determined. The browse materials had higher total N and narrower C：N ratio than the maize material. Calliandra material had higher levels of insoluble fiber （ADF）, fiber bound N （ADFN） and lignin. Application of the browse and maize materials raised C, N, and C：N ratio of the soil in which they were applied compared to the control soil. The treated soils maintained higher levels of C and N and a narrower C：N ratio up to the third crop. Amaranthus DM yield was highest （P 〈 0.05） with browse treatments. Treatment with maize material did not have DM yield advantage over the control soil. Treatments with browse materials could have given higher yields because the materials had more N and fermentation could not only have increased the proportion of soluble N, but also degradability of the materials, thus making the N and other nutrients in the fermented materials available for plant growth. DM yield was highest （P 〈_ 0.05） with the first and third crops but lowest （P 〈 0.05） with the second crop. Plant growth in the second crop could have coincided with high demand for the N by the soil micro-organisms decomposing the added materials. During the third crop, decomposition of the readily degradable components of the added materials could have been complete and the N became available for plant growth. DM yield dropped （P 〈 0.05） with the fourth crop as the available N could have been depleted from the soil for plant growth.

Effect of Leucaena leucocephala （Lam.） and Sodium Lauryl Sulfate in Meat Goat Diets on Nematode Eggs and Protozoa Interaction in the Rumen

The effeclt of condensed tannins from Leucaena leucocephala （Lam.） and sodium lauryl sulfate （SLS） addition to basal diets of corn silage on nematode eggs and protozoa interaction in the rumen within Thai native x Anglo-Nubian male goats was studied. Goats （n = 24 male; BW = 30 ＋ 2） were randomly considered toward treatment position into randomized complete block design （RCBD）. The treatments were： 1） Basal （B; 1.0-1.2 kg/head/day, corn silage）, 2） B ＋ SLS 8 g/head/day） 3） B ＋ 40g Leucaena/head/day （1.0% condensed tannins）, and 4） B ＋ 40g Leucaena/head/day （1.0% condensed tannins） with SLS 4 g/head/day）. These studies indicate that the action of 1.0% condensed tannins by Leucaena with 8 g SLS has the effect of increasing C3 （P 〈 0.05）. The opposite effect was observed for C2 which decreased （P 〈 0.05）. Both intestinal nematode eggs and protozoa in the rumen were reduced highly significantly （P 〈 0.01）. Bacteria population was raised （P 〈 0.01）. Nevertheless, all of these treatments did not affect intake, productive performances and blood urea nitrogen.

Leucaena leucocephala Meal as Replacement to Soybean Meal in Growing Goat Diets

Eight goats of 7-8 months old and an average body weight （BW） of 20 ± 5.0 kg were used in double 4 × 4 Latin square design. The treatments were the four levels of leucaena meal replacement for soybean meal in concentrates at 0%, 25%, 50% and 75% of crude protein. The results showed that roughage intake （% BW and g/kgBW^0.75） increased linearly （P 〈 0.01） with increasing levels of leucaena meal while total feed intake was not significantly different among dietary treatments. Similarly, dry matter, organic matter, neutral detergent fiber digestibility and ruminal ammonia nitrogen （NH3-N） were not significantly different among dietary treatments. However, crude protein digestibility, ruminal pH （6 hr after feeding）, nitrogen （N） intake, N absorption, N retention and total volatile fatty acids increased quadratically （P 〈 0.01） with the increasing levels of leucaena meals. It could be concluded that leucaena meal could replace up to 50% of soybean meal in the diet without any negative effect on feed intake, nutrient digestibility and rumen fermentation of meat goats.

金沙江干热河谷新银合欢(Leucaena leucocephala)的光合与荧光特征干湿季对比研究

为了研究引进树种对干热河谷环境的适应性,以生长于干热河谷野外环境中的新银合欢(Leucaena leucocephala)为研究对象,研究分析了其在湿季(7月)和干季(11月)的光合生理特征和叶绿素荧光特征。结果表明:(1)在Pn-Ci响应曲线中,当Ci<150μmol/mol,干季的净光合速率(Net photosynthetic rate,Pn)高于湿季,而当Ci>150μmol/mol,干季的Pn低于湿季;(2)相较于湿季,干季的初始羧化效率(Initial carboxylation efficiency,CE)、光合能力(Photosynthetic capacity,Amax)、CO2补偿点(CO2 compensation point,Γ)、光呼吸速率(Photorespiration rate,Rp)、最大羧化速率(Maximum carboxylation rate,Vcmax)、最大电子传递速率(Maximum electron transport rate,Jmax)、磷酸丙糖利用率(Triose phosphates utilization rate,TPU)、Jmax/Vcmax、气孔限制值(Stomatal limitation,Ls)和叶片饱和水汽压差(Vapor pressure deficit,VPD)均显著下降(P<0.05),而暗呼吸速率(Dark respiration rate,Rd)、胞间CO2浓度(Intercellular CO2 concentration,Ci)、气孔导度(Stomatal conductance,Gs)、蒸腾速率(Transpiration rate,Tr)、饱和光下最大净光合速率(Light-saturated net photosynthetic rate,Pnmax)和水分利用效率(Water use efficiency,WUE)则显著上升(P<0.05);(3)干季的PSII实际光化学效率(Actual photochemical efficiency of PSII,ФPSII),光化学猝灭系数(Photochemical fluorescence quenching,qP),电子传递效率(Electron transport rate,ETR)较湿季出现显著下降(P<0.05),非光化学猝灭系数(Non-photochemical fluorescence quenching,NPQ)显著增加(P<0.05);(4)叶绿素荧光参数的ФPSII、NPQ、ETR与各光合生理指标相关性较强。在干热河谷地区,气孔限制是影响新银合欢湿季光合速率的主要因素;而非气孔限制是影响其干季光合速率的主要因素。

银合欢种子萌发特性及其影响因素研究

为了解银合欢Leucaena leucocephala的种群扩散机制,并为其规模化繁殖育苗和生态修复上的合理利用提供技术支持,研究分析其3种成熟阶段果实和种子的形态特征、鲜重和含水量,种子在不同温度、光照中的萌发情况,以及播种基质和6-BA、GA_(3)溶液对种子萌发的影响。结果表明:幼嫩荚果的种子粒数最多,平均为19.30粒,含水量最高,为61.88%;中熟荚果的鲜重最大,为42.09 g。幼嫩种子的含水量最高,为73.10%;中熟种子的鲜重最重,百粒重为7.04 g。种子在25℃和常温(昼25~35℃/夜18~25℃)的萌发率和萌发指数最高,为萌发的较适温度,且光照下萌发率显著比黑暗高,种子为需光性种子。中熟种子萌发率和萌发指数最高,其次是幼嫩种子,完熟种子最小。将完熟种子播种于不同基质中,出苗率最高的为营养土,其次是园土,砂中最低。100 mg/L GA_(3)和10 mg/L 6-BA溶液浸泡24 h对完熟种子的萌发具有显著的促进作用(P<0.05),而300~700 mg/L的GA_(3)和30~70 mg/L浓度的6-BA溶液反而有抑制作用。

新银合欢林土壤理化性质–微生物生物量耦合协调关系研究

研究采用空间代替时间序列的方法,通过方差分析、相关性分析和偏最小二乘路径模型探究向家坝工程扰动区6种不同龄级新银合欢林土壤理化性质与微生物生物量的耦合协调关系。结果表明:①原生草地群落(A1,无新银合欢群落)土壤含水量、养分水平和微生物生物量均最高,新银合欢入侵后在草灌阶段土壤含水量、养分水平和微生物生物量显著下降。新银合欢成为灌丛时(A3,新银合欢2 a群落)土壤含水率、有机碳、全氮、全磷、微生物生物量碳氮含量分别下降为A1群落的51.2%、33.9%、31.6%、27.1%、72.8%和61.5%,pH上升至8.16,使得土壤更为碱化。②土壤微生物生物量碳与土壤含水率显著相关(P<0.05),土壤微生物生物量碳氮比与pH呈显著相关;土壤含水率、养分水平和微生物生物量三者之间相互影响且作用显著,高土壤含水率有利于土壤养分与微生物生物量的存在和转化。③原生样地结构稳定,协调度D较高(0.7162);新银合欢入侵后,协调度随着新银合欢林龄增大呈现波动下降,至A4群落(新银合欢3~4 a)时协调度降至最小值(0.5012);在乔木阶段土壤养分与微生物生物量缓慢增加且趋于稳定,协调度缓慢上升,最终在新银合欢纯林时稳定趋于勉强协调发展类型。因此,针对不同龄级新银合欢林,要根据不同恢复阶段的土壤生境条件采取不同调控措施,在植被恢复的物种搭配选择上应注重草灌结合,促进土壤以及整个生态系统的健康发展。

新银合欢篱对紫色土坡地土壤有机碳固持的作用

土壤有机碳的固持对保持土壤肥力以及缓解全球温室效应具有重要意义。通过田间定位试验,探讨了新银合欢(Leucaena leucocephala)篱对10°和15°的紫色土农耕地(玉米地)和经济林地(油桃地)表层(0—20cm)土壤有机碳积累的影响。结果表明:种植3a的新银合欢篱的10°和15°农耕地、10°经济林地土壤有机碳密度分别比相应的无植物篱的对照地提高41.53%、43.29%、32.15%。经济林处理土壤有机碳含量、有机碳密度、呼吸强度显著大于农耕地处理;10°比15°农耕地更有利于土壤有机碳、呼吸速率及微生物量碳提高;农耕地比经济林地更利于微生物生物量维持。各处理下坡比上坡更利于土壤有机碳蓄积,且土壤呼吸强度提高,但土壤微生物商基本相同。不同处理下,土壤有机碳与土壤理化性质相关性各不相同:定植新银合欢篱的10°和15°农耕地、10°经济林地土壤有机碳与有机质含量、土壤微生物碳有极显著的相关性,与全钾呈正相关,与pH负相关;定植新银合欢篱的10°和15°农耕地呼吸强度与有机碳相关关系均达到了极显著性,10°经济林地呼吸强度与有机碳显著相关;土壤微生物指标变化与有机碳的变化趋势一致,能反映土壤质量变化。阐明定植新银合欢篱利于土壤有机碳固持,且能增强土壤微生物活性,提高土壤质量。