Effect of slope position on leaf and fine root C,N and P stoichiometry and rhizosphere soil properties in Tectona grandis plantations

Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.

Tectona grandis (Teak Tree) Young Leaf Extract as a Histological Stain

Stains are applied to impart contrast to the tissue and identify particular features of interest. However, the use of synthetic dyes as staining reagents has been associated with significant human health challenges and pollution of the ecosystem. These developments have necessitated a shift towards using natural dyes that are eco-friendlier and readily available. We investigated the staining reaction patterns of teak tree leaves (Tectona grandis) dye extracts and explored their suitability as a cytoplasmic stain in micromorphological assessments. Dye extracts were prepared using acetone, methanol, and ethanol as solvents from air-dried (under shade) teak tree young leaves. The dye extracts were applied as a counterstain and evaluated against eosin in formalin-fixed paraffin-embedded (FFPE) bovine tissue sections at varying concentrations and different staining times. Teak tree leaves (Tectona grandis) dye extracts produced relatively varying staining intensities of reddish-brown cytoplasmic coloration when used on bovine tissue at different concentrations and staining times comparable to eosin and with blue-purple hematoxylin nuclear stain. The present study showed that Tectona grandis leaf dye extracts provide an excellent cytoplasmic staining pattern and can be used as an alternative counterstain in routine H&E staining techniques.

An efficient method for clonal propagation and in vitro establishment of softwood shoots from epicormic buds of teak(Tectona grandis L.)

Softwood shoots were produced from 40 cm long stem segments placed horizontally in flat trays containing sterilized sand under natural light or shade conditions for subsequent rooting and micropropagation studies in teak （Tectona grand＆ L.）. Higher number of shoots （6.17） per log was produced under natural light as compared to shade conditions. Forcing was also better in natural light as compared to shade in terms of shoot length, number of nodes or leaves. For rooting, 2-4 cm long softwood shoots were excised and treated with either indole-3-butyric acid （IBA） or α-naphthyl acetic acid （NAA） at 0, 1000, 2000 or 3000 μmol.L^-1 each or with combinations （1000 ＋ 1000, 2000 ＋ 2000 or 3000 ＋ 3000 μmol.L^-1） and then placed in flat trays containing autoclaved sand at 25 ± 2℃ in 16 h photoperiod at 35 μmol.m^-2.s^-1. After 28 days, softwood cuttings treated with IBA ＋ NAA （3000 ＋ 3000 μmol.L^-1） had highest rooting percentage （89.3%） with 5.5 mean roots. Shoot apex and nodal explants of softwood cuttings were pretreated with 0.1% （w/v） ascorbic acid, boric acid, activated charcoal, citric acid, glutamine or polyvinylpolypyrollidone （PVP） for 24 h to remove phenolic compounds before surface disinfestation. Glutamine （G1） and PVP were equally effective resulting in 60% establishment of shoot apices on MS medium supplemented with 10 μmol.L^-1 6-benzylaminopurine （BAP） ＋ 5 μmol.L^-1 NAA. Using shoot apices, highest （42.80） number of multiple shoots with 54.33 mm shoot length were obtained on MS ＋ BAP （8.8 p.mol.L 1） ＋ IBA （2 μmol.L^-1） after 45 days. Shoots were successfully rooted and acclimatized to greenhouse conditions.

Genetic and morphological variation in natural teak(Tectona grandis) populations of the Western Ghats in Southern India

Teak （Tectona grandis L.f.） is a popular hardwood species native to South and South-East Asia. The possible association of ampli- fied fragment length polymorphism （AFLP） marker with morphological variables of eleven important characters viz. girth at breast height （GBH）, height of tree, bole height, branch knots, presence of fluting, spiral stem, leaf hair, leaf length/breadth ratio, branching pattern, bark colour and petiole shape for nine natural populations comprising 180 genotypes of teak （9 populations x 20 trees）. The phenogram constructed using Euclidean distances for the eleven morphological characters showed that the populations were not grouped according to their geographical origin. The Mantel＇s test for pairwise correlation between Euclidean distances of different morphological variables and genetic distances from AFLP data revealed that only petiole character （r =0.269; p =0.046） and height of tree （r =0,200; p =0.001） were significantly correlated with that of AFLP data matrix. The nine populations in this study covered a geographic area of about 1000 km stretch along the Western Ghat of South India. A test of correlation between genetic and geographic distance matrices revealed a significant positive correlation （r =0.475; p =0.009）. The lack of perfect congruence between morphological and molecular data except for geo-graphic distance, tree height and petiole character suggested that the morphological system might be useful for the morphotypes management but not appropriate to study the genetic structure of the teak populations.

Quantification by allometric equations of carbon sequestered by Tectona grandis in different agroforestry systems

Non destructive methods for quantification of carbon seques- tration in tropical trees are inadequately developed. We described a stan- dardized method for estimating carbon stock in teak （Tectona grandis Linn. F.）. We developed linear allometric equations using girth at breast height （GBH）, height and age to quantify above ground biomass （AGB）. We used AGB to estimate carbon stock for teak trees of different age groups （1.5, 3.5, 7.5, 13.5, 18.5 and 23.5 years）. The regression equation with GBH, y = 3.174x - 21.27, r2=0.898 （p 〈0.01）, was found precise and convenient due to the difficulty in determination of height and age in dense natural forests of teak. The equation was evaluated in teak agroforestry systems that included Triticum aestivum （wheat）, Cicer arietinum （gram）, Withania somnifera （ashwagandha）,

Color and chemical characterization of partially black-streaked heartwood in teak (Tectona grandis)

The heartwood of teak in certain areas of Java Island displays irregular black streaks along the annual rings. We investigated the color and chemical characteristics in a radial direction of partially black-streaked heartwood samples. Color properties （pH value, inorganic element, extractive content and extractive characterization） were measured in the color co-ordinates CIELAB system. The results show that the black streak part was 12-15 brightness （L^＊） value units less than the normal heartwood. Furthermore, the black streak part had more red （a^＊） but less yellow （b^＊）, hue （h） and chroma （C^＊） than the normal wood. The pH value, ash content and calcium contents of the black streak part were slightly higher than those obtained for the normal wood. The content of the low-polar extractive （n-hexane and ethyl acetate） of the black streak part was considerably higher than that for the normal wood. The blackening process was speculated to be a kind of defense mechanism indicated by remarkable amount ofbioactive compound called tectoquinone.

Antifungal Activity of Crude Extracts of Tectona grandis L.f. against Wood DecayFungi

Wood is mainly made up of cellulose, hemicelluloses, lignin polymers and other organic and inorganic substances, making it susceptible to deteriorate by various biological agents. Tectona grandis L.f. (Teak) is a timberspecies with high resistance to biological deterioration, valued for its durability, beauty, and mechanical resistance.The purpose of this work was to evaluate the antifungal activity of crude extracts from teak on various fungi thatcause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaininga flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporatorthrough solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extractsobtained were tested against fungal organisms collected in the field, and the LC50 was determined using teak crudeextracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtainedwith hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). Byusing nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compoundswere tested, inhibiting 25% of mycelial growth with tetrahydrofuran (T. versicolor), and 40.9% with dichloromethane(G. trabeum). Likewise, the biological model of A. salina showed an LC50 of 84.9 μg/mL with hexane, 43.3 μg/mLwith dichloromethane, 59.6 μg/mL with tetrahydrofuran, and 54.7 μg/mL with acetone. For this reason, it is concluded that Teak wood contains many extractable compounds in relation to its weight, besides having antimicrobialactivity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.

Simple Protocol for the Micropropagation of Teak(Tectona grandis Linn.)in Semi-Solid and Liquid Media in RITA^(█) Bioreactors and ex Vitro Rooting

In Latin America the forestry of exotic species such as teak has been increasing in recent decades, due to their advantages in wood quality, rapid growth;and the relative ease of producing clones and their multiplication with respect to native species. Therefore, there is great interest in developing larger-scale propagation strategies that reduce costs and intensive manual labor. Culture in liquid media with temporary immersion and the semi-automation of the system has raised expectations for large-scale micropropagation. We report a protocol for teak, which reuses the primary explants in several culture cycles in semi-solid medium to produce nodal explants for the multiplication phase in temporary immersion bioreactors (RITA®). The control of factors such as cytokinin concentration, explants density, immersion frequencies and culture duration was analyzed. The number of shoots increased with 0.5 mg·l-1 of BA (6-Benzyladenine), alone or in combination with 0.5 mg·l-1 of Kinetin, with 2 daily immersions of 1 minute each;however, these shoots showed a high degree of hyperhydricity. When 0.05 mg·l-1 of BA was used with 1 immersion of 1 minute every 2 days, the hyperhydricity decreased. Although the number of shoots was lower, they showed good length to be used during multiplication and rooting ex vitro. Our results suggest that teak micropropagation can be simplified in two phases in vitro, the establishment and multiplication;followed by rooting ex vitro and acclimatization. This would imply a reduction in production costs, since most of the multiplication would take place in RITA®containers.

Heavy metal concentrations in redeveloping soil of mine spoil under plantations of certain native woody species in dry tropical environment, India

Total concentration of heavy metals(Cd, Cr, Cu, Fe, Pb, Ni, Mn and Zn) was estimated in the redeveloping soil of mine spoil under 5 yr old plantations of four woody species namely: Albizia lebbeck, Albizia procera, Tectona grandis and Dendrocalamus strictus. The data recorded in the present study were compared with other unplanted coal mine spoil colliery, which was around to the study site and adjoining area of dry tropical forest. Among all the heavy metals, the maximum concentration was found for Fe and minimum for Cd. However, among all four species, total concentrations of these heavy metals were recorded maximally in the plantation plots of T. grandis except for Fe, while minimally in A. lebbeck except for Zn, whereas, the maximum concentration of Fe and Zn was in the plantation plots of D. strictus and A. procera. Statistical analysis revealed significant differences due to species for all the heavy metals except Cu. Among four species, A. lebbeck, A. procera and D. strictus showed more efficient for reducing heavy metal concentrations whereas T. grandis was not more effective to reduce heavy metal concentrations in redeveloping soil of mine spoil.

Temporal patterns of storage and flux of N and P in young Teak plantations of tropical moist deciduous forest,India

Teak （Tectona grandis Linn. f.） ranks among the top five tropical hardwood species and is being promoted for use in plantations in its non-native range due to its high economic value. However, there is a general lack of data on ecosystem functioning of teak plantations. We aimed at understanding storage and flux of nutrients related to young plantations of teak. Cycling of nitrogen （N） and phosphorus （P） in a chronosequence of plantations （1, 5, 11, 18, 24 and 30 years） was studied in the Moist Deciduous Forest Region of North India with the objective of investigating the nutrient cycling pattern at younger age since the current trend of harvesting age of the species in several tropical countries is being drastically reduced for quick return from this high value crop. Standing state, nutrient uptake, nutrient return and nutrient retransloca-tion in these plantations were estimated by tree harvesting and chemical analysis methods. The range of total standing nutrient across all these plantations was 20.3 to 586.6 kg？ha-1 for N and 5.3 to 208.8 kg？ha-1 for P. Net uptake of N ranged from 19.4 to 88.9 kg？ha-1？a-1 and P from 3.8 to 18.1 kg？ha-1？a-1. Retranslocation of N and P among all the stands ranged from 8.7 to 48.0 kg？ha-1？a-1 and 0.01 to 3.5 kg？ha-1？a-1, respectively. Range of total nutrient return was 25.8 to 91.3 kg？ha-1？a-1 for N and 2.7 to 10.1 kg？ha-1？a-1 for P. N and P use efficiency was between 107.4 and 192.5 g dry organic matter （OM） g-1N, and 551.9 and 841.1 g OM g-1P, respec-tively. The turnover time ranged from 2.04-13.17 years for N and be-tween 2.40-22.66 years for P. Quantity of N and P in the soil nutrient pool ranged from 2566.8 to 4426.8 kg？ha-1 and 372 to 520 kg？ha-1, re-spectively. Storage and flux of components in different plant parts of different aged plantations were assessed and depicted in compartment models. Percentage storage in soil, litter and vegetation ranged from 82% to 99%, 0.6% to 2.4% and 0.5% to 15% for N, respectively, and from 63% to 98%, 0.5% to 2% and 1% to 35% for P, respectively. This infor-mation could be useful in managing external nutrient manipulation to crops of different ages for optimum biomass production or carbon se-questration.

Site index for teak in Colombia

Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations. Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and clas- sify site quality ofteak （Tectona grandis） plantations by using data from 44 permanent sample plots established since 1990 in 3--22 years old teak plantations in the Colombian Caribbean region. We used Korf＇s and yon Bertalanffy＇s models to fit curves as non-linear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf＇s model was superior. The resulting curves were anamorphic and closely reflected high variability in site quality. Five site classes were clarified： at a base age of 12 years old, teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m in the worst sites, and in the averages sites, 15.8-18.8 m. Using this model, we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management.

Developing a dynamic growth model for teak plantations in India

Background： Tectono grandis （teak） is one of the most important tropical timber species occurring naturally in India. Appropriate growth models, based on advanced modeling techniques, are not available but are necessary for the successful management of teak stands in the country. Long-term forest planning requires mathematical models and the principles of Dynamical System Theory provide a solid foundation for these. Methods： The state-space approach makes it possible to accommodate disturbances and avarying environment. In this paper, an attempt has been made to develop a dynamic growth model based on the limited data, consisting of three annual measurements, collected from 22 teak sample plots in Karnataka, Southern India. Results： A biologically consistent whole-stand growth model has been presented which uses the state-space approach for modelling rates of change of three state-variables viz., dominant height, stems per hectare and stand basal area. Moreover, the model includes a stand volume equation as an output function to estimate this variable at any point in time. Transition functions were fitted separately and simultaneously. Moreover, a continuous autoregressive error structure is also included in the modelling process. For fitting volume equation, generalized method of moments was used to get efficient parameter estimates under heteroscedastic conditions. Conclusions： A simple model containing few free parameters performed well and is particularly well suited to situations where available data is scarce.

柚木与降香黄檀混交效果

采用1年生柚木(Tectona grandis)无性系和降香黄檀(Dalbergia odorifera)实生苗,按照随机区组试验方法,设置柚木纯林及柚木+降香黄檀混交林造林试验。10年生混交林树高、胸径单株材积均值比柚木纯林分别增加7.48%、13.71%、35.69%,2种林分树高、胸径、单株材积3个生长指标差异极显著。柚木混交林林下土壤密度和通气度均高于柚木纯林,而其他土壤物理指标均低于纯林,2种林分各土壤物理性质指标差异不显著。柚木+降香黄檀混交林林下土壤化学性质pH值、全K含量、交换性Ca2+量比柚木纯林均有所提高,交换性Al3+减少,4个指标差异显著。采用降香黄檀和柚木混交种植可显著提高土壤pH值、全K含量、交换性Ca2+量,减少交换性Al3+量,促进柚木的树高、胸径和单株材积生长。

基于高通量测序的柚木边材转录组分析

本研究利用Illumina HiseqTM4000测序平台对柚木(Tectona grandis L.F.)边材组织进行转录组测序,获得39.65 Gb的数据。拼接组装共得到90843个Unigene,平均长度、N50以及GC含量分别为1415 bp,2208 bp和41.28%。将获得的Unigene与七大功能数据库进行比对,分别有64416(NR:70.91%)、69281(NT:76.26%)、28777(COG:31.68%)、18630(GO:20.51%)、49594(KEGG:54.59%)、44707(Swissprot:49.21%)以及50938(Interpro:56.07%)个Unigene获得功能注释。经过GO数据库的比对分析,18630个Unigene被注释到生物过程、细胞组分和分子功能3大类别55个亚类。与COG数据库进行比对分析,28777个注释Unigene按功能被划分为25类。基于KEGG数据库,44595个Unigene序列注释到6大类,21个亚类代谢通路中。根据注释结果预测出2772个编码转录因子的Unigene,检测出26773个SSR位点,以及39856个SNP位点。本研究为柚木分子育种工作的开展提供数据和参考。

柚木格木混交林与纯林营造效果比较

为了解柚木(Tectona grandis)纯林与柚木与格木(Erythrophleum fordii)混交林2种林分的生长效果、林地养分差异及其生长影响因素,在10年生柚木纯林及柚木与格木混交林中设置代表性样地14块,调查林分的树高、胸径、活枝下高,混交林中格木比例,柚木间伐材心材率,林地土壤物理化学性质等。采用方差、相关性分析方法对调查数据进行统计分析。结果表明:1)混交林中柚木的树高、胸径、单株材积和林分蓄积量均大于纯林,但柚木间伐材心材率混交林小于纯林。2)混交林中对柚木树高生长有显著负相关影响的因子有:格木株数比例、格木蓄积量和土壤水解氮。3)混交林中柚木胸径生长与格木密度呈负相关。4)纯林土壤有效P与柚木心材率呈显著正相关;柚木纯林的土壤pH值和交换性Ca2+含量显著大于混交林。由此得出结论:1)采用格木营造柚木混交林可增加土壤的水解氮,但pH值和交换性Ca2+有所降低。2)混交林中格木的混交比例以1/3较适宜,柚木密度为600~750株/hm2,柚木的蓄积量最大。

幼龄林柚木人工林生物量及含水率分布规律

以龙陵勐糯11年生柚木(Tectonagrandis)人工林为研究对象,调查其胸径、树高等生长指标,采用树干解析的方法,测定各器官生物量,探究其生物量生长规律。结果表明,11年生柚木人工林各径阶林木呈正态分布,树干生物量随径阶增大呈线性递增,树干、枝和叶生物量占比分别为81.18%、16.39%和2.43%;单株间生物量差异极显著(P≈0.000<0.01),单株各区段生物量随树高的增加显著递减(P≈0.000<0.01),不同径阶树干生物量与单株分布规律相一致;各器官含水率相近,含水率随树高而增加,此林分正处于生长期。林分中林木分化较严重,林木尖削度大,应及时进行抚育。

10年生柚木胸径分布与生长

通过对幼龄柚木(Tectona grandis L.f)胸径调查和解析,研究其径级、生长量分布及生长变化规律,表明幼龄柚木胸径分布呈正态分布,径级分化程度较小。13 cm径级以下的占39.84%。胸径各生长量级百分比随生长量增高所占百分比下降,年生长量小于0.2 cm的占39.84%,优势木的胸径和胸径年平均生长量是被压木的1.75倍和1.99倍,生长差异极为明显。第5~10年进行1~2次间伐,间伐强度控制在40%以下,林分密度560株/hm2以上。