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Olive trees are one of the most important oil crops in the world due to the sensorial and nutritional characteristics of olive oil, such as lipid composition and antioxidant content, and the medicinal properties of its leaves. In this paper, callus formation was induced using nodal segments of olive tree (Olea europaea cv. cornicabra) as explants. Fatty acid profile, total phenolic compounds and total flavonoid compounds were determined in callus culture after 15 weeks and compared with leaf and nodal segments tissues. There was no statistical difference in phenolic compounds among leaf, nodal segments and callus culture, whereas flavonoid compounds were higher in leaf. Fatty acid profile was similar in leaf, nodal segments and callus culture and was constituted by hexadecanoic acid, octadecanoic acid, cis-9-octadecenoic acid, cis-9,12-octadecadienoic acid, cis-9,12,15-octadecatrienoic acid. Hexadecanoic acid was the main fatty acid in callus, leaf and nodal segments with 35.0, 39.0 and 40.0% (w/w), of the lipid composition, respectively. With this paper, it is being reported for the first time the capacity of callus culture to accumulate fatty acids. Our results could serve to continue studying the production of fatty acids in callus cultivation as a biotechnological tool to improve different olive cultivars.

The effect of metals on the photosynthetic activities and epidermal polyphenol content of Prosopis glandulosa and Prosopis juliflora leaves was investigated by the tissue tolerance test. Foliar tissues of Prosopis glandulosa and Prosopis juliflora were incubated with Cd2+ (0.001 M) or Cu2+ (0.52 M) concentrations for 96 h. The results showed that significant reductions (p < 0.05) of photochemical efficiency in P. juliflora leaves were found after 96 h of exposure to 0.52 M Cu2+ compared with Cd-treatments and controls. In contrast, P. glandulosa leaves showed a progressive increase on photochemical efficiency at 72 h after Cu-treatment. The results also showed a significant decrease (p < 0.05) of epidermal polyphenols in P. juliflora leaves after 24 h of exposure to 0.52 M Cu2+ compared with Cd-treatments and control leaves. On the other hand, the values of leaf epidermal polyphenols observed in P. glandulosa exposed to copper and cadmium did not show any difference with respect to control. These findings are very important and suggest that these compounds could be considered as a protection mechanism of P. glandulosa when is treated with these heavy metals. Finally, the results of bioaccumulation showed that the copper concentration in P. glandulosa was higher than the values detected in P. juliflora Nevertheless, the cadmium concentration in foliar tissues of P. juliflora was significantly higher than P. glandulosa after 96 h of exposure to Cu2+ or Cd2+. Therefore, future studies are necessary to elucidate the effects of heavy metals on the biosynthesis of flavonoids and participation of these compounds in the reduction of metal toxicity in Prosopis species.

Potato (Solanum tuberosum L.) is the fourth major crop worldwide after cereals. Some producers use irrigation water with high salinity, which consequently decreases the agronomic yield and potato q...

In vitro antiviral effect of a crude methanol extract and six fractions isolated from Rhoeo discolor against pandemic influenza A (H1N1) evaluated herein. The phytochemical analysis to identify the main classes of secondary metabolites was performed by thin layer chromatography (TLC). The cytotoxic effect and cell viability was determined in MDCK cells, and the antiviral activity was evaluated by qRT-PCR to detect influenza virus nucleoprotein (NP) gene. Finally a metabolomic analysis was performed using UPLC-MS. The phytochemical analysis revealed the presence of coumarins, tannins, saponins and flavonoids in the methanol extracts. Cytotoxicity related to 50% cell viability indicated concentrations of 1μg/mL for the crude extracts. Fraction MF1 inhibited synthesis of viral NP at co-treatment level at a concentration of 0.02 + 0.07 g/mL with a selectivity index (SI) of 32. The metabolomic analysis identified the presence of five flavonoids kaempferol, quercetin, isoquercetin luteolin-5-glucoside and rutin. Antiviral activity of flavonoids from R. discolor against the influenza AH1N1 virus are reported for the first time.

Factors such as slow growth, low rates of sexual and asexual reproduction, and viability of seeds among others limit the massive propagation of Agave americana L. by conventional methods. In this study, callus induction and shoot proliferation was determined in A. americana using Murashige and Skoog (MS) medium supplemented with dicholorophenoxyacetic acid (2,4-D) and 6-benzyl adenine (BA). Meristematic tissue was used as the explants, and were placed on MS medium supplemented with 30.0 g·L−1 sucrose with 0.11, 0.18, or 0.45 μm 2,4-D and 11.0, 22.0, 38.2, 44.0, 58.7, or 73.3 μm BA. Treatments were implemented according to factorial experimental design 3 × 6. After 1 month, the number of explants with callus was determined, whereas the numbers of shoots per explant were monitored after 4, 16, 20, and 36 weeks. The maximum percent of explants with callus was obtained with 0.11 μm 2,4-D and 58.7 and 73.3 μm BA, whereas the maximum numbers of shoots per explant (71) were obtained with 0.11 μm 2,4-D and 73.3 μm BA. The effect of different concentrations of indolebutyric acid (IBA) in the rooting of shoots was evaluated. There were no significant effects of IBA on the number of roots, root length, and axillary roots. Plantlets were acclimatized in the glasshouse and they did not show any phenotypic alteration. This is a highly efficient protocol for the in vitro propagation of A. americana via indirect organogenesis.

In the present study the characterization and properties of silver nanoparticles from Prosopis glandulosa leaf extract (AgNPs) were investigated using UV–Vis spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The UV–Vis spectroscopic analysis showed the absorbance peaked at 487 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 421 nm with higher stability (−200 mV). The EDS analysis also exhibited presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 mg/mL) showed antibacterial activity against Acinetobacter calcoaceticus and Bacillus cereus. Finally, AgNPs from leaf extracts of P. glandulosa may be used as an agent of biocontrol of microorganism of importance medical. However, further studies will be needed to fully understand the antimicrobial activity of silver nanoparticles obtain from P. gland...

The green iguana appears to be a reservoir for bacteria causing gastrointestinal infections in humans. The presence of diarrheogenicE. coli(DEC) pathotypes, however, has not been studied in this reptile. The aim of the current work was to investigate the prevalence of DEC in the intestines of 240 captive green iguanas, their phylogenetic groups, and the antibiotic susceptibility profile.E. colistrains were isolated from 41.7% of the intestinal content of green iguanas. DEC strains was identified in 25.9% of the screened population and were detected in the majority (62%, p=0.009] of those reptiles carryingE. colistrains. Among DEC strains, STEC strains carrying thestx1gene were the most prevalent pathotype isolated (38.7%), followed by EAEC and ETEC (27.4% each). Genetic markers of DEC strains belonging to the EHEC pathotype were not detected. More than a half of DEC strains were classified into the Clade I-II phylogroup (64.5%), followed by the phylogroup A (14.5%). The antibiotic susceptibility method demonstrated that a high proportion of DEC strains were resistance, or non-susceptible, to carbenicillin, amikacin, and ampicillin (85, 74, and 66%, respectively). We conclude that the green iguana kept in captivity is a reservoir of DEC strains bearing resistance to first-line antibiotics, including penicillins. Given the increase presence of the green iguana in Latin American households, these reptiles represent a potential source of transmission to susceptible humans and therefore a potential source of gastrointestinal disease.ImportanceLatin-American countries present a high burden of diarrheal disease. In this part of the world, besides common pathogens, diarrheal diseases are also caused by pathogenic types ofE. colireferred as “diarrheagenicE. coli” (DEC). While inhabitants of Latin American countries suffer of self-limiting diarrhea when infected with DEC, a main target of these strains are tourists from developed countries who are not exposed to DEC strains. Efforts are in place to decrease the burden of DEC-associated diarrheal disease. As such, this study investigated a potential reservoir of DEC strains that had been underestimated, the green iguana. These reptiles are very common in Latin American households and are found virtually everywhere in Mexico, Central and South America. We found that 25% of green iguanas carried DEC strains in their intestines. We also demonstrated a high prevalence of antibiotic resistance in these strains, posing a potential risk to humans.

Endosulfan lactone is a metabolite obtained from the biological oxidation of the insecticide endosulfan by action of the microorganisms present in the soil. This metabolite is more toxic and persistent than the parent compound. Therefore, it is extremely important to be able to determine the presence of this metabolite in the soil. However, accessible methods for extraction of endosulfan lactone in soil were not found in published literature. For this reason, the aim of this study was to evaluate two conventional methods of liquid–solid extraction for the determination of endosulfan lactone in solid substrate using two solvents (ethyl acetate and acetonitrile) and HPLC UV-VIS. The acetonitrile and rotary agitation extraction method was the one with the highest efficiency (97%), optimized using a factorial 32 response surface design, and validated in terms of linearity and precision. The linearity shown was r &gt, 0.999 in a wide spike level (0.15–100 mg kg−1), with the detection limit (DL) of 0.045 mg kg−1 and quantification limit (QL) of 0.15 mg kg−1. The extraction of endosulfan lactone in solid substrate using acetonitrile was more efficient than that used with ethyl acetate, so this method could be used to extract and quantify endosulfan lactone in agricultural soil.

Cotton production in the Mexicali valley is adversely affected by wilt and root rot disease associated with Fusarium species. Therefore, the aim of this study was to identify the antifungal activity and presence of lipopeptides genes in Bacillus subtilis strain Bs-Cach isolated from the rhizosphere of the cachanilla (Pluchea sericea). The dual culture technique was conducted to test antifungal effect of the Bs-Cach on the growth of Fusarium solani strains (ICA-3 and ICA-4, respectively), and the presence of iturin (ItuA), surfactin (SrfC), and fengycin (FenD) (lipopeptides genes), was evaluated by PCR analysis. The results obtained revealed that Bs-Cach inhibited the growth of F. solani ICA-3 and ICA-4, with a range of percentage inhibition from 50 and 52 after 120 h, respectively. On the other hand, our result of the PCR amplification of the lipopeptide genes from DNA of Bs-Cach showed solely the presence of iturin but not surfactin and fengycin genes. The analysis of sequence ituA present in Bs-Cach showed 84 % identity with iturin A synthetase of different B. subtilis strains. This study showed that B. subtilis Bs-Cach strain has the ability of inhibiting F. solani strains by at least one mechanism, the lipopeptide synthesis. This result turns Bs-Cach into a potential alternative for the biological control of F. solani. Nevertheless, this study was conducted under in vitro conditions, and further studies are required to investigate whether these results hold true under field conditions.

The aim of this investigation was to determine the effect of vermicompost, vermiwash, and phosphate rock on plant, total phenols, flavonoids, and anti-oxidant activity in Piper auritum Kunth leaves. P. auritum plants were obtained from cuttings and were planted according to the Box-Behnken experimental design with three repetitions at the central point. The factors and levels were vermicompost (10, 20, and 30 g plant−1), vermiwash (5, 10, and 15 mL plant−1), and phosphate rock (1, 2, and 3 g plant−1). Plant growth parameters (plant height, stem diameter, leaves number) and chlorophyll content were measured 1 month after treatment applications. Total phenols, total flavonoids, and 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity was measured after 4 months. Vermicompost, vermiwash, and phosphate rock had no statistically significant effect on plant growth. Plant height, stem diameter, leaves number, chlorophyll, innermost number, fresh weight stem, fresh weight leaves, fresh weight root, ...

The effect of plant growth-promoting bacteria inoculation on plant growth and the sugar content in Agave americana was assessed. The bacterial strains ACO-34A, ACO-40, and ACO-140, isolated from the A. americana rhizosphere, were selected for this study to evaluate their phenotypic and genotypic characteristics. The three bacterial strains were evaluated via plant inoculation assays, and Azospirillum brasilense Cd served as a control strain. Phylogenetic analysis based on the 16S rRNA gene showed that strains ACO-34A, ACO-40 and ACO-140 were Rhizobium daejeonense, Acinetobacter calcoaceticus and Pseudomonas mosselii, respectively. All of the strains were able to synthesize indole-3-acetic acid (IAA), solubilize phosphate, and had nitrogenase activity. Inoculation using the plant growth-promoting bacteria strains had a significant effect (p < 0.05) on plant growth and the sugar content of A. americana, showing that these native plant growth-promoting bacteria are a practical, simple, and efficient alternative to promote the growth of agave plants with proper biological characteristics for agroindustrial and biotechnological use and to increase the sugar content in this agave species.

In vermicomposting, the main product is the worm casts, but a leachate is generated that contains large amounts of plant nutrients. This leachate is normally diluted to avoid plant damage. We investigated how dilution of vermicompost leachate combined with different concentrations of nitrogen (N) - phosphorus (P) - potassium (K) triple 17 fertilizer, and polyoxyethylene tridecyl alcohol as dispersant and polyethylene nonylphenol as adherent to increase efficiency of fertilizer uptake, affected sugarcane plant development. The vermicomposting leachate with pH 7.8 and electrolytic conductivity 2.6 dS m−1, contained 834 mg potassium (K) l−1, 247 mg nitrate (NO3−) l−1 and 168 mg phosphate (PO43−) l−1, was free of pathogens and resulted in a 65% germination index. Vermicompost leachate did not inhibit sugarcane growth and mixed with 170 g l−1 NPK triple 17 fertilizer resulted in the best plant development. No dispersant or adherent was required to improve plant height and stem development.

Los protocolos actuales para la micropropagacion de Agave americana L. tienen limitaciones para su aplicacion comercial debido al bajo numero de plantas producidas por cada explante. La organogenesis indirecta podria ser una alternativa, sin embargo, es necesario optimizar los reguladores de crecimiento vegetal para maximizar el numero de plantas. El objetivo del trabajo fue optimizar la concentracion de acido 2,4-diclorofenoxiacetico (2,4-D) y de 6-bencil adenina (BA) sobre la induccion de callos embriogenicos en A. americana usando meristemos apicales como explante para maximizar el numero de brotes por callo, utilizando un diseno experimental de superficie de respuesta. Se utilizo el medio Murashige Skoog (MS) adicionado con 30 g l-1 de sacarosa, y con 0,11;0,18; 0,45 o 2,26 μM de 2,4-D, y 11,0; 22,0; 38,2 o 44,0 μM de BA. Se implementaron 9 tratamientos con 3 repeticiones y el numero de brotes por callo fue evaluado despues de 4, 16, 20 y 36 semanas. Se indujo el enraizamiento in vitro usando medio MS adicionado con acido indolbutirico (AIB). Se obtuvo un maximo de 74 plantulas por callo, usando 2,26 μM de 2,4-D y 38,2 μM de BA. En conclusion, la organogenesis indirecta podria ser una alternativa para la micropropagacion de A. americana L con fines comerciales.

In the present study the production of phenolic acids and flavonoid compounds by E. gracilis exposed to two cadmium concentrations (0.02 and 0.14 mM) was evaluated using high-performance liquid chromatography (HPLC). The results showed that E. gracilis exposed to 0.02 mM Cd+2 increased significantly the total content of phenolic compounds (798.46 ± 12.61 μg GA/g) and total flavonoids (241.34 ± 47.63 μg QE/g) with respect to the control (137.34 ± 19.80 μg QE/g DW and 549.00 ± 8.57 μg GA/g DW, respectively). However, no significant increase in the total content of phenolic compounds (568.54 ± 17.42 μg GA/g DW) and total flavonoids (141.11 ± 9.36 μg QE/g DW) were observed in E. gracilis exposed to 0.14 mM Cd+2. Further research is necessary to determine the specific role of flavonoids in E. gracilis exposed to high concentrations of Cd+2.

The objective of this study was to investigate the effect of vermicompost, rock phosphate, Glomus fasciculatum (arbuscular mycorrhizal fungi), and Penicillium sp. (phosphate solubilizing fungi) on growth; mycorrhization percent; fructan, sucrose, glucose, and fructose contents in leaves and stem of Agave americana L. Experiments were done according to an orthogonal experimental design L8 with four variables at two levels: vermicompost (0 or 10 g per plant), rock phosphate (0 or 1 g per plant), G. fasciculatum (0 or 1 × 106 spores per plant), and Penicillium sp. (0 or 1 × 109 spores per plant). Vermicompost affected stem dry weight; the fructan, glucose, and fructose in stem; and mycorrhization percent in roots. Rock phosphate and Penicillium sp. increased the mycorrhization percent. Co-inoculation of Penicillium sp. and G. fasciculatum increased A. americana plant growth. The results obtained suggested a synergistic interaction between the arbuscular mycorrhizic fungi and the phosphate solubilizin...

A diazotrophic bacterial strain denominated 11B isolated from the rhizosphere of a banana plant (Musa spp.) was characterized morphologically, biochemically, and phylogenetically, whereas the symbiotic potential of the strain was assessed through tests of host range, interstrain nodulation competitiveness, and capacity to synthesize indole-3-acetic acid (IAA) and solubilize phosphate. Based on morphological and physiological–biochemical properties, as well as 16S ribosomal deoxyribonucleic acid (rDNA) sequence and phylogenetic analysis, the strain 11B belonged to the genus Rhizobium with 100.0% sequence similarity with Rhizobium tropici CAF440. The optimum growth temperature and pH for strain 11B are 28°C and 7.2, respectively. This strain was able to produce IAA, solubilize phosphate, and fix large amounts of nitrogen (N2) and form effective nodules on the legumes Acaciella angustissima, Gliricidia sepium, Leucaena leucocephala, Lysiloma acapulcensis, and Phaseolus vulgaris. The rhizobial strain ...

The aim of this study was analyze the effect of jasmonic acid (JA) and abscisic acid (ABA) as elicitors on fatty acids profile (FAP), phenolic compounds (PC) and antioxidant capacity (AC) in callus of Thevetia peruviana. Schenk & Hildebrandt (SH) medium, supplemented with 2 mg/L 2, 4-dichlorophenoxyacetic (2, 4-D) and 0.5 mg/L kinetin (KIN) was used for callus induction. The effect of JA (50, 75 and 100 μM) and ABA (10, 55 and 100 μM) on FAP, PC and AC were analyzed using a response surface design. A maximum of 2.8 mg/g of TPC was obtained with 100 plus 10 µM JA and ABA, respectively, whereas AC maximum (2.17 μg/mL) was obtained with 75 plus 100 µM JA and ABA, respectively. The FAP was affected for JA but not for ABA. JA increased cis-9, cis-12-octadecadienoic acid and decreased dodecanoic acid. Eight fatty acids were identified by GC-MS analysis and cis-9-octadecenoic acid (18:1) was the principal fatty acid reaching 76 % in treatment with 50 μM JA plus 55 μM ABA. In conclusion, JA may be used in T. peruviana callus culture for obtain oil with different fatty acids profile.

The objective of this study was to evaluate the changes of green metallic nanoparticles on biochemical and physiological effects in Annona muricata L., plants. Changes in proline, phenolic compounds, antioxidants enzyme, phenylalanine ammonia lyase (PAL) activity and phytohormones in A. muricata leaves exposed to Ag, Cu and Cu/Ag phytonanoparticles were evaluated up to 120 h. The results showed that the foliar application of green metallic nanoparticles at 250, 500, 750 and 1000 ppm caused changes significantly in flavonoids, anthocyanins, phenylalanine ammonia lyase and peroxidase activities in A. muricata leaves after 120 h exposure. The foliar application of green nanoparticles stimulates the enhancement of the antioxidant protection system that protect at A. muricata against oxidative stress caused by reactive oxygen species (ROS). Our results showed that values of gibberelins, auxins and proline depended of nanoparticle concentration and composition.

The present study was conducted to evaluate the impact of monometallic and bimetallic nanoparticles (NPs) of copper (Cu) and silver (Ag) from Justicia spicigera on the photochemical efficiency and phenol pattern of Prosopis glandulosa. In this study, the existence of localized surface plasmon resonance absorption associated with the nano-sized nature of Ag, Cu and Cu/Ag particles was confirmed by the presence of a single peak around 487, 585, and 487/580 nm respectively. Zeta potential and electrophoretic mobility were found to be 0.2 mV and 0.02 μmcm/(Vs) for synthesized NPs indicating less stability and thus tendency to agglomerate, and broad distribution of particles. Cu-NPs and Cu/Ag-NPs demonstrate that the dispersed phase is stable and has a minimum particle size at zeta potentials above –30 mV. Changes in phenolic compounds, total chlorophyll, and photochemical efficiency in leaves exposed to Ag, Cu and Cu/Ag phyto-nanoparticles were evaluated up to 72 hours. The results revealed that Ag-NP and Cu-NP from J. spicigera at 100 mg/L showed significant reduction in chlorophyll, epidermal polyphenol content and photochemical efficiency of P. glandulosa. In contrast, the application of bimetallic Cu/Ag-NP from J. spicigera showed a positive impact on physiological parameters of P. glandulosa after 72 h of exposure.

Olive trees are one of the most important oil crops in the world due to the sensorial and nutritional characteristics of olive oil, such as lipid composition and antioxidant content, and the medicinal properties of its leaves. In this paper, callus formation was induced using nodal segments of olive tree (Olea europaea cv. cornicabra) as explants. Fatty acid profile, total phenolic compounds and total flavonoid compounds were determined in callus culture after 15 weeks and compared with leaf and nodal segments tissues. There was no statistical difference in phenolic compounds among leaf, nodal segments and callus culture, whereas flavonoid compounds were higher in leaf. Fatty acid profile was similar in leaf, nodal segments and callus culture and was constituted by hexadecanoic acid, octadecanoic acid, cis-9-octadecenoic acid, cis-9,12-octadecadienoic acid, cis-9,12,15-octadecatrienoic acid. Hexadecanoic acid was the main fatty acid in callus, leaf and nodal segments with 35.0, 39.0 and 40.0% (w/w), of the lipid composition, respectively. With this paper, it is being reported for the first time the capacity of callus culture to accumulate fatty acids. Our results could serve to continue studying the production of fatty acids in callus cultivation as a biotechnological tool to improve different olive cultivars.

International audience; This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance), a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the inputs are the reflectance and transmittance of the leaf. Performance of the proposed method for chlorophyll content estimation was compared with a spectrophotometer and a Soil Plant Analysis Development (SPAD) meter. Chlorophyll content estimation was realized for Lactuca sativa L., Azadirachta indica, Canavalia ensiforme, and Lycopersicon esculentum. Experimental results showed that-in terms of accuracy and processing speed-the proposed algorithm outperformed many of the previous vision-based approach methods that have used SPAD as a reference device. On the other hand, the accuracy reached is 91% for crops such as Azadirachta indica, where the chlorophyll value was obtained using the spectrophotometer. Additionally, it was possible to achieve an estimation of the chlorophyll content in the leaf every 200 ms with a low-cost camera and a simple optical arrangement. This non-destructive method increased accuracy in the chlorophyll content estimation by using an optical arrangement that yielded both the reflectance and transmittance information, while the required hardware is cheap.

We report here the complete genome sequence of Rhizobium sp. strain ACO-34A, isolated from Agave americana L. rhizosphere. No common nod genes were found, but there were nif genes for nitrogen fixing. A low average nucleotide identity to reported species supports its designation as a novel Rhizobium species that has a complete ribosomal operon in a plasmid.

We report here the complete genome sequence of Rhizobium sp. strain ACO-34A, isolated from Agave americana L. rhizosphere. No common nod genes were found, but there were nif genes for nitrogen fixing. A low average nucleotide identity to reported species supports its designation as a novel Rhizobium species that has a complete ribosomal operon in a plasmid.

The aim of this investigation was to determine the effect of vermicompost and phosphate rock on plant growth, total phenols, flavonoids, flavanones, and antioxidant activity in Annona purpurea Moc & Sesse ex Dunal leaves. Annona purpurea seedlings were planted according to factorial 32 experimental design with nine repetitions. The factors were vermicompost (0, 50, and 100 g plant−1) and phosphate rock (0 and 10 g plant−1). Plant height, stem diameter, number of leaves, and chorophyll content were determined one month after application of the different treatments and total phenols, flavonols, flavanones, total flavonoids, and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity in dry leaves after 4 months. Plant height and stem diameter increased by phosphate rock, but not by vermicompost. Total phenols in leaves decreased by vermicompost. Flavonol content decreased by rock phosphate, whereas flavanones increased by vermicompost. Antioxidant activity decreased by vermicompost addition.

The influence of Naphtaleneacetic acid (NAA) and 6-Benzylaminopurine (BAP) on callus formation, its morphology and fatty acids profile were examined from Jatropha curcas L. Embryo from seeds of J. curcas L. were sown in Murashige and skoog (MS) medium with NAA and BAP. All treatments induced callus formation, however callus morphology was different in most of the treatments. Higher callus biomass was presented with 1.0 NAA + 0.5 BAP mg/L. Plant growth regulators modifies the fatty acids profile in callus of J. curcas L. BAP was induced linoleic and linolenic acids.

In the present study, the hexane, acetone and methanol extracts of stem, branches and roots from Crotalaria longirostrata were evaluated for their antifungal activity against Fusarium sp., Fusarium verticillioides and Aspergillus flavus. The variables analyzed were inhibition halos, mycelial growth inhibition, sporulation and minimum inhibitory concentration. Phytochemical analysis revealed the presence of saponins, coumarins, anthrones, anthraquinones, flavonoids and alkaloids on different organic extracts. The hexane extract showed zones of inhibition between 6.3 and 10.5 mm. The mycelia growth and sporulation of A. flavus were reduced to 90% with methanol extract. The minimum inhibitory concentration values obtained with hexane extracts were 6.75 mg mL-1 and with methanol extracts were 50 and 25 mg mL-1 for Fusarium strains. This is the first study reporting of phytochemical composition and biological activity of C. longirostrata that could be used as a natural alternative to control in vitro of certain important pathogenic fungi.

The objective of this study was to investigate the growth of coffee (Coffea arabica L. cv. ‘Bourbon’) in soil amended with compost, vermicompost, and bokashi at 25%, 50%, and 66% while mycorrhizal colonization and activity of acid and alkaline phosphatases and urease in soil were monitored. Treatments with 25% compost as well as higher application rates of compost and bokashi (50% or 66%) increased coffee growth. Shoot fresh weight increased 5 times when 25% bokashi or compost was applied, 8 times when 50% was applied and 10 times when 66% was applied compared to the control plants without organic fertilizer. Acid and alkaline phosphatase and urease activity increased when organic fertilizer was applied to soil. Application of organic fertilizers increased the growth and fresh weight of root and shoot of coffee plants and improved the root mycorrizal colonization and enzymatic activity of the soil.

Worm-bed leachate is a nutrient-rich by-product of composting organic wastes with earthworms. Worm-bed leachate was stored and characterized while its possible antifungal activity towards the pathogenic fungus Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. was investigated in vitro. The pH decreased from 9.6 at the onset of the storage to 8.9 after 28 days, while the total N and C nearly halved. The surfactin concentration in the worm-bed leachate reached 10.8 μg L−1 at day 10, while that of iturin A and iturin A homologues increased towards the end of the storage. Sterilized worm-bed leachate had little effect on the growth of C. gloeosporioides, but unsterilized worm-bed leachate inhibited growth 100%. It was found that unsterilized worm-bed leachate inhibited growth of C. gloeosporioides, but sterilizing the worm-bed leachate strongly reduced the inhibitory effect indicating that the microorganisms in the worm-bed leachate out-competed the fungus for nutrients or were antagonistic towa...

Extraction of oils from castor bean (Ricinus communis L.) and Jatropha curcas L. to produce biofuel is set to increase. The produced seed cake could be applied to soil as it is nutrient rich, but might affect soil functioning. Seven soils from Chiapas, Mexico, were amended with seed cake of both plants while CO 2 , CH 4 and N 2 O emissions and mineral N concentrations were monitored in an aerobic incubation. The concentration of phorbol esters in the J. curcas seed cake (JSC) was 0.993 mg/g while no ricin was detected in the R. communis seed cake (RSC). Application of JSC increased CO 2 emission 2.5-times, N 2 O 12.6-times and CH 4 18.4-times compared to the unamended soil, while RSC CO 2 emission 2.1-times, N 2 O 21.3-times and CH 4 2.3-times. On average, 66% of the 88 mg organic N added with JSC was mineralized and 83% of the 101 mg organic N of the RSC within 56 days. It was found that J. curcas and castor bean seed cake increased CO 2 , CH 4 and N 2 O emission and mineral N in soil, without inhibiting soil microbial activity.

The aim of this study was analyze the effect of jasmonic acid (JA) and abscisic acid (ABA) as elicitors on fatty acids profile (FAP), phenolic compounds (PC) and antioxidant capacity (AC) in callus of Thevetia peruviana. SchenkHildebrandt (SH) medium, supplemented with 2 mg/L 2, 4-dichlorophenoxyacetic (2, 4-D) and 0.5 mg/L kinetin (KIN) was used for callus induction. The effect of JA (50, 75 and 100 μM) and ABA (10, 55 and 100 μM) on FAP, PC and AC were analyzed using a response surface design. A maximum of 2.8 mg/g of TPC was obtained with 100 plus 10 µM JA and ABA, respectively, whereas AC maximum (2.17 μg/mL) was obtained with 75 plus 100 µM JA and ABA, respectively. The FAP was affected for JA but not for ABA. JA increased cis-9, cis-12-octadecadienoic acid and decreased dodecanoic acid. Eight fatty acids were identified by GC-MS analysis and cis-9-octadecenoic acid (18:1) was the principal fatty acid reaching 76 % in treatment with 50 μM JA plus 55 μM ABA. In conclusion, JA may be used in T. peruviana callus culture for obtain oil with different fatty acids profile.

In 1991, the 'International Maize and Wheat Improvement Center' (CIMMYT) started a field experiment in the rain fed Mexican highlands to investigate conservation agriculture (CA) as a sustainable alternative for conventional maize production practices (CT). CT techniques, characterized by deep tillage, monoculture and crop residue removal, have deteriorated soil fertility and reduced yields. CA, which combines minimum tillage, crop rotations and residue retention, restores soil fertility and increases yields. Soil organic matter increases in CA compared to CT, but increases in greenhouse gas emissions (GHG) in CA might offset the gains obtained to mitigate global warming. Therefore, CO(2), CH(4) and N(2)O emissions, soil temperature, C and water content were monitored in CA and CT treatments in 2010-2011. The cumulative GHG emitted were similar for CA and CT in both years, but the C content in the 0-60 cm layer was higher in CA (117.7 Mg C ha(-1)) than in CT (69.7 Mg C ha(-1)). The net global warming potential (GWP) of CA (considering soil C sequestration, GHG emissions, fuel use, and fertilizer and seeds production) was -7729 kg CO(2) ha(-1) y(-1) in 2008-2009 and -7892 kg CO(2) ha(-1) y(-1) in 2010-2011, whereas that of CT was 1327 and 1156 kg CO(2) ha(-1) y(-1). It was found that the contribution of CA to GWP was small compared to that of CT.

Vermicompost and worm-bed leachate (WBL) are two products obtained from vermicomposting. The objective of this study was to evaluate the effect of different combinations of vermicompost and WBL on cultivating radish (Raphanus sativus L.). A multilevel factorial design with 25 treatments was used to investigate the effect of vermicompost at 0, 10, 20, 30, or 40% and WBL at 0, 10, 20, 30, or 40% on germination and growth parameters. A maximum seed germination of 54%, number of leaves (2.8), and plant height (8.6 cm) were obtained with 10% vermicompost and 10% WBL. A maximum shoot (7.0 g) and root (7.3 g) dry weight was obtained with 10% vermicompost and 15% WBL. Vermicompost and worm-bed leachate have an inhibitory effect at higher concentrations on seed germination and plant growth. These inhibitory effects might be due to increased salt concentrations, pH or auxin-like effects of humic and fulvic acids.

This paper presents the assessment of coconut fibre thermal characteristics and its use to modulate temperatures in concrete slabs in the construction industry. Fibre is abundantly available in tropical regions, extracted from the husk of coconut fruits and manufactured at 115.54 MPa to obtain specimens. A first thermal conductivity of k = 0.048 (W/m K) is obtained by solving the heat diffusion equation with experimental temperatures as boundary conditions. A second value k = 0.0499 (W/m K) is obtained by solving the Fourier's law by using a known heat flux and temperature histories in the specimen. The maximum error between the first and second k values was 3.8%. However, the k = 0.048 (W/m K) was used for numerical analysis. Experimental work was done to find density and heat capacity, 174 kg/m 3 and 2600 J/kg K, respectively. Further numerical work was carried out to modulate temperature in concrete slabs. This showed that fibre put on the concrete external surface allows room temperatures to fall within the comfort range. Density, thermal conductivity and heat capacity of coconut fibre were varied in a wide range to investigate the sensitivity of temperature to such changes. This showed that temperature can be considered sensible only to thermal conductivity variations.

La leguminosa tropical Acaciella angustissima inoculada con o sin la cepa Sinorhizobium mexicanum ITTG R7T fue cultivada en un suelo tratado con (Al) para estudiar la tolerancia a este metal. Las plantas de A. angustissima fueron crecidas en el suelo con 0, 2, 4 y 6 mg de Al kg-1. Se hizo un seguimiento del efecto de Al e inoculacion en el crecimiento, la nodulacion, el contenido de nitrogeno y el contenido de taninos en las plantas. La altura, el peso seco total y el peso seco de la raiz de las plantas decremento significativamente cuando el suelo fue tratado con Al, pero incremento cuando fue inoculado. El Al disminuyo el numero de nodulos. El inoculo incremento el N total y el contenido de taninos de las plantas. En este experimento fue encontrado que el Al reduce el crecimiento de la leguminosa arbustiva tropical fijadora de N2 A. angustissima, mientras la inoculacion con S. mexicanum ITTG R7T estimula el crecimiento e incrementa el contenido de taninos y nitrogeno.

Aims: To characterize the bacterial community of taberna, an alcoholic traditional beverage from the Southern part of Mexico produced by the fermentation of the coyol palm sap (Acrocomia aculeate). Methods and Results: Bacterial 16S rDNA libraries were constructed from metagenomic DNA extracted during the fermentation process at 0, 60 and 108 h. A total of 154 clones were sequenced, and 13, 10 and nine unique sequences were found at each sampling time. At the onset of the fermentation, Zymomonas mobilis, Fructobacillus spp., Pantoea agglomerans and other Gammaproteobacteria were detected. After 60 h, lactic acid bacteria were found and 30% of clones in the library were related to Lactobacillus nagelii, L. sucicola and L. sp. By the end of the experiment, i.e. after 108 h, the bacterial community included Z. mobilis, Lact. nagelii and Acetobacter pasteurianus. Conclusions: Our results suggest that Z. mobilis population represented an important proportion of the bacterial community (60–80%), as well as the lactobacilli during the fermentation process. The bacterial diversity was low and decreased as the fermentation progressed. Significance and Impact of the Study: This culture-independent study suggests that Z. mobilis and lactobacilli play an important role in the alcoholic fermentation of the taberna beverage.

Jatropha curcas L. will be cultivated in large parts of the central highlands of Chiapas (Mexico) so that its seeds can be extracted for biofuel. Little is known how the cultivation of J. curcas, which contains phorbolesters, might affect soil processes. Soil was sampled at five locations and amended with leaves of J. curcas while dynamics of ammonium (NH4+), nitrite (NO2−) and nitrate (NO3−) and emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), well known greenhouse gasses, were monitored. If we considered no priming effect, then between 12 and 31% of the C added with Jatropha leaves mineralized within 56 days. However, the concentration of mineral N (sum of NH4+, NO2− and NO3−) did not increase in the Jatropha-amended soils compared to the unamended soils. The mean CO2 emission rate increased significantly 3.7 times when Jatropha leaves were added to the different soils. The N2O emission was low in the unamended soil and remained

This paper reports on the optimum concentrations of naphthalene acetic acid (NAA) and 6-benzyladenine (BA) to stimulate callus growth and NAA; kinetin and silver nitrate (AgNO3) for callus redifferentiation in Dianthus caryophyllus L. Meristems were excised and placed in MS medium with 30 g l−1 sucrose and 9.0 μM 2,4-d. Callus clusters were transferred to MS medium containing NAA (0, 1.7, 3.3, and 5.0 μM) and BA (0, 1.7, 3.3, and 5.0 μM) for proliferation and to MS medium with 30 g l−1 sucrose, 2.5 g l−1 phytagel, kinetin (0, 33, and 66 μM); NAA (0, 7.95, and 15.9 μM) and AgNO3 (0, 23.54 and 47.08 μM) for shoot and root induction. Treatments were applied according to a Box–Behnken design. After callus growth and redifferentiation, plants were incubated in the greenhouse at 18 ± 2°C for 4 wk and at 20–26°C for 4 wk. Finally, plants were changed to near-commercial greenhouse conditions with different day (30–35°C) and night (16–24°C) temperatures. Results showed better callus growth at higher NAA concentrations. A maximum callus weight was found with 5.0 μM NAA but without BA. A maximum of 78% calluses with shoots was obtained with 15.9 μM NAA, 47.08 μM AgNO3, and 0.74 μM kinetin and 58% with roots with 15.7 μM NAA and 47.08 μM AgNO3, but without kinetin. The shoots obtained showed little hyperhydricity. Vigorous plants were obtained after gradual acclimatization with an 80% survival rate under nursery conditions.

Extracts of neem (Azadirachta indica A. Juss.) and Gliricidia sepium Jacquin, locally known as 'mata-raton', are used to control pests of maize. Their application, however, is known to affect soil microorganisms. We investigated if these extracts affected emissions of methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O), important greenhouse gases, and dynamics of soil inorganic N. Soil was treated with extracts of neem, mata-raton or lambda-cyhalothrin, used as chemical control. The soil was amended with or without urea and incubated at 40% and 100% water holding capacity (WHC). Concentrations of ammonium (NH4+), nitrite (NO2(-)) and nitrate (NO3(-)) and emissions of CH4, CO2 and N2O were monitored for 7d. Treating urea-amended soil with extracts of neem, mata-raton or lambda-cyhalothrin reduced the emission of CO2 significantly compared to the untreated soil with the largest decrease found in the latter. Oxidation of CH4 was inhibited by extracts of neem in the unamended soil, and by neem, mata-raton and lambda-cyhalothrin in the urea-amended soil compared to the untreated soil. Neem, mata-raton and lambda-cyhalothrin reduced the N2O emission from the unamended soil incubated at 40%WHC compared to the untreated soil. Extracts of neem, mata-raton and lambda-cyhalothrin had no significant effect on dynamics of NH4(+), NO2(-) and NO(3)(-). It was found that emission of CO2 and oxidation of CH4 was inhibited in the urea-amended soil treated with extracts of neem, mata-raton and lambda-cyhalothrin, but ammonification, N2O emission and nitrification were not affected.

The effects of earthworm-processed sheep manure (vermicompost) on growth, productivity, and characteristics of bell pepper fruits (Capsicum annum) (cv ‘Ancho supremo’) were investigated in a greenhouse experiment. Six treatments were applied combining vermicompost and soil in 0:1, 1:1, 1:2, 1:3, 1:4, and 1:5 (v/v) ratios. Plant characteristics were measured 21 and 90 days after transplanting. Addition of vermicompost increased plant size significantly with 8 cm in the 1:3 vermicompost: soil treatment compared to the unamended soil after 21 days, but no significant differences were found after 90 days. Seven more flowers were found in the 1:2 vermicompost: soil treatment and four in the 1:3 vermicompost: soil treatment compared to the unamended soil after 90 days. The number of marketable fruits per plant was significantly 1.5 and 1.9 times greater in the 1:2 and 1:3 vermicompost: soil treatments compared to plants cultivated in unamended soil after 90 days. The addition of vermicompost to soil in...

Extracts of plants have been used to control pests, but little information exists about how effective they are to limit crop damage, or how they affect plant growth, crop yield and insects. Extracts from Azadirachta indica A. Juss. (L.) leaves (NEEM treatment), a plant originating from India known for its bio-insecticide characteristics, and Gliricidia sepium (Jacquin kunth ex Walp.) (GLIRICIDIA treatment), a plant originating from Mexico and Central America known to repel insects, were compared to a standard insecticide, lambda-cyalothrin or Karate ® (CHEMICAL treatment) for insect pest efficacy in cultivated maize in Chiapas, Mexico. Untreated maize plants served as control (CONTROL treatment). Plant damage, crop growth, yield and fauna were monitored during four growing seasons from 2003 to 2006. Mean maize yield was significantly higher in the NEEM and CHEMICAL treatments, i.e. 9784 and 9916 kg ha −1 , respectively, compared to the CONTROL treatment (7206 kg ha −1 ). The GLIRICIDIA treatment yielded 8747 kg ha −1 . Of the 26 insect species found during the growing season, only the number of Spodoptera frugiperda (Lepidoptera: Noctuidae), Macrodactylus spp. (Coleoptera: Melolonthidae) and Frankliniella spp. (Thysanoptera: Thripidae) was significantly different between the treatments, with the lowest values found in the chemical treated plots. The amount of beneficial insects was not affected by treatment, while the amount of insects that cause damage was significantly lower (ca. 2-fold) in the CHEMICAL treatment than in the other treatments. Mean damage to the newly formed leaves was 18% in the NEEM treatment and 23% in the GLIRICIDIA treatment and significantly lower than that of the CONTROL treatment (37%), but significantly higher than that of the CHEMICAL treatment (11%). It was found that leaf extracts of G. sepium and A. indica reduced damage to the newly formed leaves and increased yields compared to untreated maize plants, with neem being more effective. However, neem was not as effective as chemical control with lambda-cyalothrin, for overall maize protection.

An orthogonal experimental design L9 (34) in triplicate was used to optimize the osmotic drying process of jicama or Yam bean (Pachyrhizus erosus). The effect of sucrose content, temperature, time of submerging and thickness of the fruit, on the osmotic drying process of Yam bean were tested. Maximal water loss was obtained when 10 mm fruit slices were submerged in a sucrose concentration of 60° Brix maintained at 60 °C for 2 h, while maximum impregnation was obtained when 5-mm slices were submerged in a 50° Brix solution maintained at 60 °C for 6 h.

The effects of earthworm-processed sheep-manure (vermicompost) on the growth, productivity and chemical characteristics of tomatoes (Lycopersicum esculentum) (c.v. Rio Grande) were investigated in a greenhouse experiment. Five treatments were applied combining vermicompost and soil in proportions of 0:1, 1:1, 1:2, 1:3, 1:4 and 1:5 (v/v). Growth and yield parameters were measured 85 days and 100 days after transplanting. Addition of vermicompost increased plant heights significantly, but had no significant effect on the numbers of leaves or yields 85 days after transplanting. Yields of tomatoes were significantly greater when the relationship vermicompost:soil was 1:1, 1:2 or 1:3, 100 days after transplanting. Addition of sheep-manure vermicompost decreased soil pH, titratable acidity and increased soluble and insoluble solids, in tomato fruits compared to those harvested from plants cultivated in unamended soil. Sheep-manure vermicompost as a soil supplement increased tomato yields and soluble, insoluble solids and carbohydrate concentrations.

Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N2 fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7T and Rhizobium calliandrae LBP2-1T and of the reference strain Rhizobium etli CFN42T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1T, 167% for strain CFN42T and 219% for strain ITTG R7T) than for the other carriers after 240 days, except for CFN42T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7T was kept on PSB. The nitrogenase activity was the highest for ITTG R7T kept on PEAT (4911 μmol C2H4 per fresh weight nodule h−1); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them.

This study aimed to evaluate the removal of polychlorinated biphenyls, with a vermicomposting system, using the following as components: the earthworm Eisenia fetida, peat moss and rabbit excrement and a compound called decachlorobiphenyl, for a period of 91 days under non-sterile conditions. The results obtained were a removal of decachlorobiphenyl 79.6 % with an initial concentration of 100 mg L−1, 89.7 % with 150 mg L−1 and 95.38 % with 200 mg L−1; the earthworms bioaccumulated less than 5 mg L−1 in all concentrations of decachlorobiphenyl analysed without apparent toxic effect. Weight gain was observed in earthworms that assimilated contaminant during vermicomposting, as the number of cocoons produced in contrast to the control in which both the weight and the number of cocoons were lower. To our knowledge, this is the first study which suggests that vermicomposting may be a suitable mechanism for removal of decachlorobiphenyl with high recalcitrance from contaminated sediment or soils.

© 2015 The Netherlands Entomological Society. Social bee colonies can allocate their foraging resources over a large spatial scale, but how they allocate foraging on a small scale near the colony is unclear and can have implications for understanding colony decision-making and the pollination services provided. Using a mass-foraging stingless bee, Scaptotrigona pectoralis (Dalla Torre) (Hymenoptera: Apidae: Meliponini), we show that colonies will forage near their nests and allocate their foraging labor on a very fine spatial scale at an array of food sources placed close to the colony. We counted the foragers that a colony allocated to each of nine feeders containing 1.0, 1.5, or 2.0 M sucrose solution [31, 43, and 55% sucrose (wt/wt), respectively] at distances of 10, 15, and 20 m from the nest. A significantly greater number of foragers (2.6-5.3 fold greater) visited feeders placed 10 vs. 20 m away from the colony. Foraging allocation also corresponded to food quality. At the 10-m feeders, 4.9-fold more foragers visited 2.0 M as compared to 1.0 M sucrose feeders. Colony forager allocation thus responded to both differences in food distance and quality even when the travel cost was negligible compared to normal colony foraging distances (10 m vs. an estimated 800-1 710 m). For a nearby floral patch, this could result in unequal floral visitation and pollination.

The concentration of nitrous oxide (N 2 O) and carbon dioxide (CO 2 ) in the atmosphere has increased considerably over the last century, but few studies are available showing their production from soils in semi-arid areas. Soils from the tropical semi-arid Central Depression of Chiapas were sampled from fields cultivated with maize (MAI treatment), under canopy of Acacia angustissima (TIMBRE) or outside the canopy of the trees (OUT), adjusted to 40%, 60%, 80% or 100% of water-holding capacity (WHC) and amended with 0, 15 or 50 mg (NH 4 NO 3 )-N kg −1 dry soil. The production of N 2 O, CO 2 and concentrations of NH 4 + , and NO 3 − were monitored in the laboratory under aerobic conditions. Production of N 2 O in the first 3 days was significantly larger from the MAI and OUT soils, compared to the TIMBRE soil, while the addition of 50 mg inorganic N doubled the production of N 2 O. In all treatments, soil at 100% WHC had the largest production of N 2 O. The emission of CO 2 was significantly larger from soils at 60% and 80% WHC compared to the soil at 40% and 100% WHC, although the addition of inorganic N had no significant effect on CO 2 emission. The application of inorganic N and the absence of vegetation increased the production of N 2 O.

An efficient and reproducible protocol for regeneration of plantlets at a high frequency was developed by using sugar cane buds. Disinfected buds were firstly submerged in ethanol sodium hypochlorite solution with 0.1 % polyvinylpyrrolidone, 1.5 % ascorbic acid and 1.75 % citric acid as antioxidants and subsequently treated with solution of agrimicin:captan (1:1). The upper stalk segment was better to obtain bud in vitro culture compared to lower segments. The medium for induction of multiple shoots consisted of Murashige and Skoog basal medium (MS) supplemented with 2 mg dm−3 thidiazuron and 1 mg dm−3 naphthalene acetic acid. An average of 24 shoots per bud was obtained for cv. Mex 68-P23 within four weeks and 29 shoots for cv. MY 55-14 within six weeks. Indole-3-butyric acid induced more roots in both cultivars compared to the untreated plantlets. Plantlets transferred to soil showed normal growth with up to four axilliary buds in each node. It was concluded that the germplasm obtained through the above mentioned technique generated stalks with more buds in each node which would give farmers more vegetative material for plantations in field with 100 % germination.

The activities of sucrose phosphate synthase (SPS), sucrose synthase (SUSY), neutral invertase (NI) and soluble acid invertase (SAI) were measured in callus cultures of four Mexican sugarcane cultivars (Saccharum spp.) with a different capacity to accumulate sucrose in stem parenchyma cells. The results indicated that sucrose accumulation in callus was positively correlated to the activity of SPS and SUSY and negatively to the activity of SAI and NI while SPS explained most of the variation found for sucrose accumulation and NI least.

Mechanical defoliation of sugar cane plants (Saccharum spp.) will provide leaves that can be used as fodder. The effect of partial mechanical defoliation on sucrose content, enzyme activities and agronomic parameters of sugar cane is still unknown. We investigated how sucrose accumulation, activities of sucrose phosphate synthase, soluble acid invertase, sucrose synthase, neutral invertase, brix grades, purity grade, moisture content, fibre content, maturity index and reduced sugars of two commercial sugar cane plants (Mex 69-290 and Mex 57-473) were affected in a field experiment. The concentration of sucrose in stems of partial defoliated plants was not significantly different from that found in intact plants. Agronomic parameters and enzyme activities were not different in defoliated plants compared with intact plants except for the moisture content which was higher in defoliated plants than in intact ones. These results indicated that sugar cane plants could be partially defoliated without changing sucrose production and agronomic parameters while providing leaves that could be used as fodder.