Elimination and molecular identification of endophytic bacterial contaminants during in vitro propagation of Bambusa balcooa.

Bambusa balcooa is an economically important, multipurpose bamboo species, decidedly used in construction industry. Availability of natural bamboo is depleting very rapidly due to accelerated deforestation and its unrestrained use. The large number and timely supply of saplings are the need of the hour for the restoration of bamboo stands. Micropropagation, being the potent alternative for season independent rapid regeneration, is restricted in bamboo because of endophytic contamination. An in vitro attempt has been taken to overcome the endophytic contamination by using broad spectrum antibiotics as surface sterilant as well as a media component. Ampicillin sodium salt (5 mg/ml for 30 min) as a surface sterilant was found as the best treatment for high bud breaking (80%) coupled with high branching and low contamination (20%) but it was found ineffective to control the contamination during multiplication stage. Then, two endophytes were isolated and minimum inhibitory concentration was determined through antibiotic susceptibility test for successful eradication at multiplication stage. Finally, contamination free cultures were obtained when streptocycline (100 µg/ml) and gentamicin sulphate (75 µg/ml) were added into the medium. The two isolated endophytes, BB1 and BB2, were identified through 16S rDNA techniques and NCBI-BLAST algorithm with 99% sequence similarity with those of Janibacter sp. (KX423734) and Serratia marcescens strain (KX423735). To our knowledge, this is the first report for B. balcooa where antibiotics were used as surface sterilant as well as medium component, to control endophytic bacterial contaminants, followed by their identification.

In vitro flowering in Bambusa bambos (L.) Voss, an anatomical perspective.

Bamboo [Bambusa bambos (L.) Voss (Syn. Bambusa arundinacea Retz.)] is an important arborescent grass with immense socio economic implications. The plant exhibits unique biological and growth characteristics including a distinct monocarpic gregarious flowering behavior. Studies on in vitro flowering in bamboo are not uncommon. The present study focuses on effect of different growth regulators on in vitro flowering in B. bambos and analyzes the morphological and developmental changes accompanying the process. Multiple shoots were raised from B. bambos seeds on MS medium supplemented with 10 µM BAP. Anatomical sections showed intense mitotic activity in the apical meristem of the main shoot and formation of additional shoot buds along the margins. For multiplication, propagules of 7-9 shoots were transferred to maintenance medium containing 5 µM BAP. Longitudinal sections of propagules showed prolific cell divisions and formation of meristemoids, which continuously gave rise to new shoots upon subculture. In vitro induction of flowering in cultures was observed in multiple shoots after 8 weeks. Transfer of multiple shoots to MS basal medium containing 10 µM NAA resulted in rooting and proliferation of inflorescences. On medium supplemented with 10 µM 2,4-D callusing and development of shoot buds and somatic embryos was followed by development of inflorescences. The report outlines a protocol that can be used to raise and proliferate flowering cultures in B. bambos.

Estudios para el aprovechamiento potencial de hojas de Guadua angustifolia Kunth (Poaceae), para el sector cosmético / Studies for the potential utilization of Guadua angustifolia Kunth (Poaceae) leaves for the cosmetic sector

Introducción: el aprovechamiento de residuos agroindustriales es una práctica que se trata de implementar por el impacto ambiental que representa. Objetivo: realizar un análisis bromatológico y fitoquimico de las hojas de Guadua y evaluar el efecto de algunas variables implicadas en el proceso de obtención del materia vegetal que puedan afectar el rendimiento y la actividad antioxidante del extracto hidroalcohólico. Métodos: se identificó cualitativamente los metabolitos secundarios presentes en las hojas y se complementó con un estudio bromatológico según normas AOAC. Mediante diseños de comparación simple y diseño factorial 22, se determinó la influencia del proceso de secado (natural y controlado), el tamaño de partícula (120 µm y 64 µm), edad de los cultivos (3-4 años) y el tiempo de almacenamiento de las hojas secas y molidas (1 y 6 meses) sobre el rendimiento de extracción y la actividad antioxidante ( Folin Ciocalteu y DPPH) del extracto hidroalcohólico. Resultados: las hojas secas revelan presencia de compuestos con actividad antioxidante (flavonoides y fenoles) y un 2,4 por ciento de nitrógeno menor al reportado para otros bambús. A partir de las hojas se puede obtener un extracto hidroalcohólico con un rendimiento hasta del 10,6 por ciento y con actividad antioxidante hasta de 9,2 mg ácido gálico/100g y 14,5 mg Trolox /100g. Se observó que la propiedad antioxidante del extracto hidroalcohólico y el rendimiento de extracción no varían con la edad de los cultivos (3-4 años) de donde provienen las hojas, ni con el método de secado, ni con el tiempo de almacenamiento de las hojas, mientras que si cambian con el tamaño de partícula. Conclusión: las hojas de Guadua por su actividad antioxidante son una materia prima potencial para ser usada en la industria cosmética(AU)

Introduction: the use of agro-industrial wastes is a practice that has been implemented by the environmental impact it represents. Objective: to perform a bromatological and phytochemical analysis of Guadua leaves and to evaluate the effect of some variables involved in the process of obtaining plant material that may affect the yield and the antioxidant activity of hydroalcoholic extract. Methods: secondary metabolites in the leaves were qualitatively identified and then supplemented with bromatologic study according to AOAC standards. Through a simple comparison designs and factorial design 22, there was determined the influence of the drying process (natural and controlled), the particle size (120 and 64 µm), crop age (3-4 years) and storage time of the dried and ground leaves (1 and 6 months) on the extraction yield and antioxidant activity (DPPH Folin and Ciocalteu) of hydroalcoholic extract. Results: dried leaves revealed the presence of compounds with antioxidant activity (flavonoids and phenols) and 2,4 percent nitrogen less than reported for other bamboo trees. From the leaves, one can obtain a hydroalcoholic extract with yield up to 10,6 percent and antioxidant activity up to 9,2 mg gallic acid / 100g and Trolox 14,5 mg / 100g. It was observed that neither age of the cultures (3-4 years) from leaves, the drying method, nor the time storage of leaves affect antioxidant properties and the extraction yield of hydroalcoholic extract, whereas these properties did change with the particle size. Conclusions: Guadua leaves, for their antioxidant activity, are a potential raw material for use in the cosmetics industry(AU)

Large scale propagation of an exotic edible bamboo, Phyllostachys pubescens Mazel ex H. De Lehale (Moso Bamboo) using seeds.

For ex vitro propagation, seeds of P.pubescens were treated with different concentrations of gibberellic acid (GA3) and germination of seeds was tested both in plastic pots as well as by direct sowing in the nursery beds. Maximum seed germination was achieved when treated with 200 mgL(-1) (w/v) GA3. For in vitro propagation, an exposure of nodal explants from in vitro raised seedlings to 0.2 mgL(-1) 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea and 1 mgL(-1) kinetin supplemented medium for 30 days and thereafter to hormone free Murashige and Skoog basal medium resulted in axillary shoot proliferation. For rooting, in vitro raised shoots were exposed to MS medium containing 2 mgL(-1) indole-3-butyric acid for 15 days and then shifted to hormone free medium. On an average, 2.8 shoots were obtained in 75% of the cultures within 4 weeks. Such in vitro raised plants were successfully hardened and shifted to field conditions.

Effects of high nutrient supply on the growth of seven bamboo species.

Over the last decade, bamboo has emerged as an interesting plant for the treatment of various polluted waters using plant-based wastewater treatment systems. In these systems, nitrogen and phosphorous concentrations in wastewater can exceed plant requirements and potentially limit plant growth. The effects of two nutrient rates on the growth of seven bamboo species were assessed in a one-year experiment: Dendrocalamus strictus, Thyrsostachys siamensis, Bambusa tuldoides, Gigantochloa wrayi, Bambusa oldhamii, Bambusa multiplex and Bambusa vulgaris. Nutrient rates were applied with a 20:20:20 NPK fertilizer as 2.6 and 13.2 t.ha.yr(-1) NPK to three-year-old bamboo planted in 70 L containers. Morphological characters, photosynthetic responses, and NPK content in bamboo tissues were investigated. Under high-nutrient supply rate, the main trend observed was an increase of culm production but the culms' diameters were reduced. For the seven species, the above ground biomass yield tended to increase with high-nutrient rate. Increasing in nutrient rates also improved the photosynthetic activity which is consistent with the increase of nitrogen and phosphorus contents measured in plant tissues. All the bamboo species tested appears suitable for wastewater treatment purposes, but the species Bambusa oldhamii and Gigantochloa wrayi showed the higher biomass yield and nutrient removaL

Enhanced enzymatic hydrolysis of bamboo (Dendrocalamus giganteus Munro) culm by hydrothermal pretreatment.

Bamboo was non-isothermally pretreated with hot water at 140-200°C for different times (10-120 min). The effects of pretreatment conditions on the degradation of carbohydrates, cellulose crystallinity, partial removal/relocation of lignin, morphologic change of the feedstock, and glucose yield during the enzymatic hydrolysis were investigated. The effective removal of amorphous cellulose and hemicelluloses led to the increase of crystalline index of the residues. In comparison with the raw material, the surface of the pretreated samples was irregular and numerous lignin droplets appeared on the cellulose bundle surface under the intense pretreatment conditions. The glucose conversion increased with the raise of pretreatment temperature and the prolongation of time, and the maximum conversion of 75.7% was achieved for the sample pretreated at 200°C for 120 min, whereas the untreated sample was only 15.7%. The result illustrated that hydrothermal pretreatment affected the composition of bamboo, and remarkably enhanced the enzymatic hydrolysis efficiency.

Lignin removal and benzene-alcohol extraction effects on lignin measurements of the hydrothermal pretreated bamboo substrate.

Lignin content of hydrothermal pretreated bamboo chips was determined by the two methods: TAPPI standard method (222om-06) and TAPPI standard method without benzene-alcohol extraction (BAE). The results showed that including BAE resulted in lower Klason lignin (KL) and acid soluble lignin (ASL) measurements in the prehydrolyzed substrate, that is to say, BAE removed parts of KL and ASL. Therefore, the TAPPI standard method should be modified by omitting the BAE for lignin measurements of pretreated substrate. The following lignin removal analysis suggested that lignin was removed from the bamboo substrate during pretreatment by a combination of degradation reaction and deconstruction; thereafter the pseudo lignin generated in the hydrothermal pretreatment and condensation reaction between the lignin fragments accounted for the later KL increase.

Comparison of bamboo green, timber and yellow in sulfite, sulfuric acid and sodium hydroxide pretreatments for enzymatic saccharification.

The response and behavior of bamboo green, timber, and yellow of moso bamboo (Phyllostachys heterocycla) to three pretreatments, sulfite (SPORL), dilute acid (DA), and alkali (NaOH), were investigated and compared with varied chemical loadings at 180°C for 30 min with a 6.25:1 (v/w) liquor-to-bamboo ratio. All the pretreatments improved the enzymatic digestibility of bamboo substrates. Under the investigated conditions, the DA pretreatment achieved better enzymatic digestibility, but had lower sugar recovery yield, and formed more fermentation inhibitors. The results suggested that the SPORL pretreatment be able to generate more readily digestible bamboo substrate with higher sugar yield and fewer fermentation inhibitors than the corresponding DA pretreatment if hemicelluloses are sufficiently removed by adding more acid to bring down the pretreatment pH. Bamboo timber had higher sugar content and better enzymatic digestibility and therefore was a better feedstock for bioconversion than bamboo green and yellow.

Fractionation of bamboo culms by autohydrolysis, organosolv delignification and extended delignification: understanding the fundamental chemistry of the lignin during the integrated process.

Bamboo (Phyllostachys pubescens) was successfully fractionated using a three-step integrated process: (1) autohydrolysis pretreatment facilitating xylooligosaccharide (XOS) production (2) organosolv delignification with organic acids to obtain high-purity lignin, and (3) extended delignification with alkaline hydrogen peroxide (AHP) to produce purified pulp. The integrated process was comprehensively evaluated by component analysis, SEM, XRD, and CP-MAS NMR techniques. Emphatically, the fundamental chemistry of the lignin fragments obtained from the integrated process was thoroughly investigated by gel permeation chromatography and solution-state NMR techniques (quantitative (13)C, 2D-HSQC, and (31)P-NMR spectroscopies). It is believed that the integrated process facilitate the production of XOS, high-purity lignin, and purified pulp. Moreover, the enhanced understanding of structural features and chemical reactivity of lignin polymers will maximize their utilizations in a future biorefinery industry.

Hydrothermal pretreatment of bamboo and cellulose degradation.

A systematic hydrothermal pretreatment of bamboo chips had been conducted with an aim to trace the cellulose degradation. The results showed that cellulose chain cleavage basically occurred when the temperature exceeded 150°C. A slightly higher DP (degree of polymerization) than starting material had been observed at low temperature pretreatment. Treatment at higher temperature (≥ 170°C) caused severe cleavage of cellulose and therefore gave rise to low DP with more soluble species. DP of cellulose declined drastically without additional hemicelluloses dissolution when hemicelluloses removal reached to the limit level. Cellulose degradation under hydrothermal pretreatment generally followed the zero reaction kinetics with the activity energy of 121.0 kJ/mol. Besides, the increase of cellulose crystalline index and the conversion of Iα-Iß had also observed at the hydrothermal pretreatment.

Surface characterizations of bamboo substrates treated by hot water extraction.

Environment Scanning Electron Microscopy (ESEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology and chemical changes on both the interior and exterior surface of bamboo (Dendrocalamopsis oldhami) substrates treated by hot water extraction. ESEM results showed the visible changes between exterior and interior surface of the treated substrates, in where spherical droplets did not extensively appear on both the surfaces at start of the pretreatment; nevertheless the droplets formation on the exterior surface occurred more rapidly than that of the interior surface. Results from XPS examination that the increase of C1 (C-C, C-H) concentration and decrease of O/C ratio and O1 (C=O) concentration of the samples on the both surfaces further demonstrated that both surfaces consisted of increasing amount of lignin as the extraction continued, especially for exterior surface. The O/C ratios finally reached to a level-off value with exterior surface 0.34 and interior surface 0.37.

Purification of protein AP-toxin from Arthrinium phaeospermum causing blight in Bambusa pervariabilis × Dendrocalamopisis grandis and its metabolic effects on four bamboo varieties.

Bambusa pervariabilis × Dendrocalamopisis grandis blight is caused by a toxin produced by the fungus Arthrinium phaeospermum. In this study, a toxin fraction (P1-2-2) with an estimated molecular mass of 31 kDa was purified from a culture filtrate of this fungus by ammonium sulfate precipitation, Sephadex G-50 gel chromatography, Q Sepharose Fast Flow anion exchange resin, and Sephadex G-75 chromatography. The N-terminal amino acid sequence (i.e., H(2)N-Gln-Val-Arg-Asp-Arg-Leu-Glu-Ser-Thr) determined by Edman degradation showed homology to known serine alkaline proteases. The purified protein was named AP-toxin. Effects of the purified protein toxin on total phenol, flavonoid, total nucleic acid, DNA, RNA, soluble protein, and soluble sugar content, as well as DNase and RNase activities and disease index, were analyzed in different bamboo varieties by the impregnation method. The toxin had a significant effect on each parameter tested. In addition, a significant correlation was observed among the metabolic index, treatment time, bamboo resistance, and disease index. These data suggest that AP-toxin plays an important role in mediating the phytotoxic activities of A. phaeospermum. This study also indicates that metabolic indices could reflect the resistance indices of hybrid bamboo to blight.

Effects of elevated CO2 and temperature on photosynthesis and leaf traits of an understory dwarf bamboo in subalpine forest zone, China.

The dwarf bamboo (Fargesia rufa Yi), growing understory in subalpine dark coniferous forest, is one of the main foods for giant panda, and it influences the regeneration of subalpine coniferous forests in southwestern China. To investigate the effects of elevated CO2, temperature and their combination, the dwarf bamboo plantlets were exposed to two CO2 regimes (ambient and double ambient CO2 concentration) and two temperatures (ambient and +2.2°C) in growth chambers. Gas exchange, leaf traits and carbohydrates concentration were measured after the 150-day experiment. Elevated CO2 significantly increased the net photosynthetic rate (Anet ), intrinsic water-use efficiency (WUEi ) and carbon isotope composition (δ¹³C) and decreased stomatal conductance (g(s)) and total chlorophyll concentration based on mass (Chl(m)) and area (Chl(a)). On the other hand, elevated CO2 decreased specific leaf area (SLA), which was increased by elevated temperature. Elevated CO2 also increased foliar carbon concentration based on mass (C(m)) and area (C(a)), nitrogen concentration based on area (N(a)), carbohydrates concentration (i.e. sucrose, sugar, starch and non-structural carbohydrates) and the slope of the A(net)-N(a) relationship. However, elevated temperature decreased C(m), C(a) and N(a). The combination of elevated CO2 and temperature hardly affected SLA, C(m), C(a), N(m), N(a), Chl(m) and Chl(a). Variables Anet and Na had positive linear relationships in all treatments. Our results showed that photosynthetic acclimation did not occur in dwarf bamboo at elevated CO2 and it could adjust physiology and morphology to enable the capture of more light, to increase WUE and improve nutritional conditions.

Assessment of genetic diversity of landraces of Dendrocalamus hamiltonii using AFLP markers and association with biochemical traits.

Fermented bamboo shoots are popular traditional food items of various ethnic groups of the northeastern India, especially in Manipur State. Dendrocalamus hamiltonii is an economically important bamboo species used to produce fermented bamboo shoots. We studied genetic variability of this bamboo species in Chandel and Imphal-East (commercial production districts), using AFLP molecular markers. Each of the selected primers detected polymorphisms and 1614 (95.8%) were found to be polymorphic. Cluster analysis based on Dice similarity coefficients using UPGMA differentiated the populations into two major groups. Principal coordinate analysis based on the AFLP data clearly separated the populations according to their genetic diversity and antioxidant activity. Four primers were tested through multiple regression analysis to identify marker-trait association between AFLP data and biochemical attributes, i.e., antioxidant activity and total cyanide content. The 273 bp generated by EcoRI-AAG(Joe)/MseI-CTC showed high positive correlation with antioxidant activity (r = 0.729, P < 0.01). The 396 bp generated by EcoRI-AAC(Ned)/MseI-CTG were negatively correlated with cyanide content (r = -0.694, P < 0.01). Thus, we found association of DNA markers with antioxidant activities and total cyanide content. These results could be of use for the identification of superior genotypes with desirable traits.

Characterization of copper/zinc and manganese superoxide dismutase in green bamboo (Bambusa oldhamii): Cloning, expression and regulation.

Bamboo is distinguished by its rapid growth, for growth more than 100 cm per day. Because of the rapid growth, tissues have significant ATP requirements, which results in intense reduction of oxygen and thus oxidative stress. For this reason, bamboo may have a special and efficient scavenger system to release the stress during fast cell division and elongation. Here, we investigated superoxide dismutase (SOD, E.C.1.15.1.1), the first line of antioxidant enzymes, in green bamboo (Bambusa oldhamii). The SOD activity profile in this species was complex, with 5 genes and 7 isozymes of CuZnSOD and 4 genes and 1 isozyme of MnSOD. We isolated one of each of the green bamboo CuZnSOD and MnSOD genes, and their activities were stable under a broad range of pH and temperature treatments, even at room temperature for more than 3 days. Bamboo SODs showed developmental and tissue-specific regulation, and both transcript and protein levels were responsive to abscisic acid, UV-B and high-light treatments. The complexity of the cis-elements in promoter regions implied that the regulation mechanisms of SOD might help accomplish the unique fast-growth phenotype of green bamboo.

Adsorptive removal of chloramphenicol from wastewater by NaOH modified bamboo charcoal.

This study described the adsorption of chloramphenicol (CAP) in wastewater on the renewable bioresource of bamboo charcoal (BC). Results showed that CAP adsorption on BC (Ln q(e)=1.272 Ln C(e)+1.971) and H(2)SO(4) modified BC (Ln q(e)=1.851 Ln C(e)+0.659) were very slight, and on NaOH modified BC was significantly increased (Ln q(e)=0.344 Ln C(e)+6.490). The adsorbents were characterized by N(2) adsorption-desorption, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). It is revealed that BC and modified BC had very small surface areas of less than 1 m(2) g(-1), H(2)SO(4) treatment led to minimal variation in surface functional groups, and NaOH treatment increased the percentage of surface graphitic carbon and other oxygen-containing groups. The increased adsorption of CAP on NaOH modified BC was mainly ascribed to the enhancement of the pi-pi interaction between the adsorbent and adsorbate.

The 3'-terminal sequence of Bamboo mosaic virus minus-strand RNA interacts with RNA-dependent RNA polymerase and initiates plus-strand RNA synthesis.

A 3'-terminal, 77-nucleotide sequence of Bamboo mosaic virus (BaMV) minus-strand RNA (Ba-77), comprising a 5' stem-loop, a spacer and a 3'-CUUUU sequence, can be used to initiate plus-strand RNA synthesis in vitro. To understand the mechanism of plus-strand RNA synthesis, mutations were introduced in the 5' untranslated region of BaMV RNA, resulting in changes at the 3' end of minus-strand RNA. The results showed that at least three uridylate residues in 3'-CUUUU are required and the changes at the penultimate U are deleterious to viral accumulation in Nicotiana benthamiana protoplasts. Results from UV-crosslinking and in vitro RNA-dependent RNA polymerase competition assays suggested that the replicase preferentially interacts with the stem structure of Ba-77. Finally, CMV/83 + UUUUC, a heterologus RNA, which possesses about 80 nucleotides containing the 3'-CUUUU pentamer terminus, and which folds into a secondary structure similar to that of Ba-77, could be used as template for RNA production by the BaMV replicase complex in vitro.

Taking ecological function seriously: soil microbial communities can obviate allelopathic effects of released metabolites.

BACKGROUND: Allelopathy (negative, plant-plant chemical interactions) has been largely studied as an autecological process, often assuming simplistic associations between pairs of isolated species. The growth inhibition of a species in filter paper bioassay enriched with a single chemical is commonly interpreted as evidence of an allelopathic interaction, but for some of these putative examples of allelopathy, the results have not been verifiable in more natural settings with plants growing in soil. METHODOLOGY/PRINCIPAL FINDINGS: On the basis of filter paper bioassay, a recent study established allelopathic effects of m-tyrosine, a component of root exudates of Festuca rubra ssp. commutata. We re-examined the allelopathic effects of m-tyrosine to understand its dynamics in soil environment. Allelopathic potential of m-tyrosine with filter paper and soil (non-sterile or sterile) bioassays was studied using Lactuca sativa, Phalaris minor and Bambusa arundinacea as assay species. Experimental application of m-tyrosine to non-sterile and sterile soil revealed the impact of soil microbial communities in determining the soil concentration of m-tyrosine and growth responses. CONCLUSIONS/SIGNIFICANCE: Here, we show that the allelopathic effects of m-tyrosine, which could be seen in sterilized soil with particular plant species were significantly diminished when non-sterile soil was used, which points to an important role for rhizosphere-specific and bulk soil microbial activity in determining the outcome of this allelopathic interaction. Our data show that the amounts of m-tyrosine required for root growth inhibition were higher than what would normally be found in F. rubra ssp. commutata rhizosphere. We hope that our study will motivate researchers to integrate the role of soil microbial communities in bioassays in allelopathic research so that its importance in plant-plant competitive interactions can be thoroughly evaluated.

Phytotoxic effects of (+/-)-catechin in vitro, in soil, and in the field.

BACKGROUND: Exploring the residence time of allelochemicals released by plants into different soils, episodic exposure of plants to allelochemicals, and the effects of allelochemicals in the field has the potential to improve our understanding of interactions among plants. METHODOLOGY/PRINCIPAL FINDINGS: We conducted experiments in India and the USA to understand the dynamics of soil concentrations and phytotoxicity of (+/-)-catechin, an allelopathic compound exuded from the roots of Centaurea maculosa, to other plants in vitro and in soil. Experiments with single and pulsed applications into soil were conducted in the field. Experimental application of (+/-)-catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations. Pulses replenished (+/-)-catechin levels in soils, but consistently at concentrations much lower than were applied, and even pulsed concentrations declined rapidly. Different natural soils varied substantially in the retention of (+/-)-catechin after application but consistent rapid decreases in concentrations over time suggested that applied experimental concentrations may overestimate concentrations necessary for phytotoxicity by over an order of magnitude. (+/-)-Catechin was not phytotoxic to Bambusa arundinacea in natural Indian soil in a single pulse, but soil concentrations at the time of planting seeds were either undetectable or very low. However, a single dose of (+/-)-catechin suppressed the growth of bamboo in sand, in soil mixed with organic matter, and Koeleria macrantha in soils from Montana and Romania, and in field applications at 40 microg l(-1). Multiple pulses of (+/-)-catechin were inhibitory at very low concentrations in Indian soil. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that (+/-)-catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied at low concentrations in the field. However, there is substantial conditionality in the effects of the allelochemical.

Laboratory study on the effect of deltamethrin WG and WP formulations against Anopheles maculatus Theobald (Diptera:Culicidae) on rough and smooth surfaces of bamboo wall.

Adults of Anopheles maculatus were tested for their residual activity to wettable powders (WP) and water dispersible granule (WG) formulations of deltamethrin. The residual effectiveness and lifespan of deltamethrin WG and WP were also assessed against the mosquitoes using rough and smooth surfaces of bamboo. Tests were conducted once a month up to 14 months after spraying using WHO standard method for the bioassay of insecticidal deposits on wall surfaces. Mortality data revealed that both deltamethrin WG and WP were effective against An. maculatus up to 14 months post-spraying. Efficacy and residual activity of deltamethrin WG at 25mg/m2 had proved to be the longest on both rough and smooth surfaces of bamboo.