Emergence of corn according to the sowing depth of the seed and loads on press wheels

The seeding process was the operation that suffered the most changes in no-tillage system due the cover crop soil and new particle soil arrangement. The objective of this study was to verify the effects of loads applied to the wheels and adjustments of sowing depth on seedling emergence of corn in no-tillage system. The experimental design was completely randomized with a factorial arrangement 5x4, with five loads applied to the wheels and four theoretical sowing depth adjustments. The real sowing depth increased in the lower theoretical depth and decreased in the higher theoretical depth, due to the compaction loads. Regarding the time of emergence, loads applied had not influence at the greater depths. Emergence time decreased with the load increase in the lower depths. Thus, the adjustment of the compactor wheels can influence in the corn seeding process.

Seedlings of Acrocomia aculeata in diferent substrates and protected environments

The seedling production stage is the key to achieve uniformity in tree breeding stage. This study evaluated "bocaiúva" (Acrocomia aculeata) seedling formation, with pre-germinated seeds in different substrates and protected environments, in the University of Mato Grosso do Sul State, Aquidauana, MS. As substrates, we used 100% cattle manure (M), 100% cassava branches (CB), 100% vermiculite (V), 50% cattle manure + 50% cassava branches, 50 % cattle manure + 50% vermiculite, 50% cassava branches + 50% vermiculite and ⅓ cattle manure + ⅓ cassava branches + ⅓ vermiculite. These substrates were tested in a greenhouse covered with 150 µm low density polyethylene (LDPE) film under thermo-reflective screen with 50% shading under film; black screen with 50% shading on the sides; black monofilament screen with 50% shading set on roof and sides; and aluminized thermo- reflective screen with 50% shading set on roof and sides. The completely randomized experimental design with 5 replications of 5 plants each was adopted. Initially, data were submitted to analysis of substrate individual variance in each growing environment, then performing the waste mean square evaluation and their environment joint analysis for comparison. The best growing environment is the thermo-reflective screen compared to LDPE greenhouse and black screen set. All substrates containing manure are recommended for bocaiúva seedlings formation. The pure cassava branch is not indicated for seedling, even using chemical fertilizer.

Soursop seedlings: emergence and development under different cultivation environments and substrates – Part I

ABSTRACT Seedling quality is crucial to obtain vigorous plants in the field. This study aims to evaluate the emergence and development of soursop seedlings in different substrates in protected environments. The experiment was conducted at the Mato Grosso do Sul State University and carried out using five protected environments: greenhouse, greenhouse with thermo-reflective screen, nursery with monofilament screen, nursery with thermo-reflective screen, and nursery with palm thatch. The substrates (S) consisted of cattle manure (M), humus (H), cassava branches (C), and vermiculite (V) as in the following ratios: S1 = H + V (1:3), S2 = H + V (1:1), S3 = H + V (3:1), S4 = H + C (1:3), S5 = H + C (1:1), S6 = H + C (3:1), S7 = M + V (1:3), S8 = M + V (1:1), S9 = M + V (3:1), S10 = M + C (1:3), S11 = M + C (1:1), S12 = M + C (3:1), S13 = H + M + V (1:1:1), S14 = H + M + C (1:1:1), and S15 = H + M + V + C (1:1:1:1). For the statistical analysis, each of those environments was considered as an experiment in which was used the completely randomized design; subsequently, it was performed a combined analysis of them. In summary, the greenhouse with thermo-reflective screen and combined substrates with “M + V” promote greater development of the seedlings. High concentrations of “V” or “C” cause no beneficial effect on soursop seedlings.

Soursop seedlings: biomasses and biometric relations in different farming environments and substrates – Part II

ABSTRACT The quality of seedling is critical to obtain vigorous plants in the field. The present study aimed to assess biomasses and biometric relations of soursop seedlings. We used different substrates in protected environments. The experiment was performed at the Universidade Estadual do Mato Grosso do Sul (UFMS) (State University of Mato Grosso do Sul). Five farming environments were developed in greenhouses: one covered with low-density polyethylene film (LDPE), another with with polyethylene and heat-reflective cloth under film under 50% shading in aluminized color, monofilament cloth under 50% shading in black, thermo-reflective cloth under 50% shading in aluminized color, and an environment covered with bacuri coconut straw. Substrates were made of manure, humus, cassava branches and vermiculite at different proportions. Each of them varying from 25%, 33.3%, 50% and 75% in mixture combination. Each environment was considered an experiment. A completely randomized design was adopted and later a joint analysis of them. Agricultural greenhouse covered with LDPE and thermo-reflective cloths under 50% of shading, proportionated seedlings with greater biomass. Substrates containing manure are the most suitable for soursop seedlings. High percentages of earthworm humus produce low quality soursop seedlings. Soursop seedlings had a Dickson’s quality index around 0.335. The greenhouse covered only with LDPE film did not produce high quality seedlings.

Toxoplasma gondii in semen of experimentally infected swine

Eight reproductive boars were divided into three groups and inoculated with Toxoplasma gondii [GI (n=3) 1.5x10(4) oocysts strain P; GII (n=3) 1.0x10(6) tachyzoites strain RH; and GIII (n=2) non-inoculated control]. Clinical, hematological, parasitemia and serological tests and studies of the parasite in the semen through bioassay and PCR, and in reproductive organs (Bioassay and immunohistochemical analyses) were conducted to evaluate the toxoplasmic infection. Blood and semen were collected on day -2, -1, 1, 3, 5, 7, 9, 11, 14 and weekly up to 84 days post-inoculation (DPI). No clinical or hematimetric alteration was observed in the boars. Parasitemia was detected in one boar inoculated with oocysts at the 7th DPI and in another boar infected with tachyzoites (GII) at the 3rd and 49th DPI. Serological tests revealed antibodies against T. gondii in animals inoculated with oocysts or tachyzoites at the 7th DPI with dilutions of 1:256 and 1:64, which reached peaks of 1:4096 at day 11 and 9, respectively. The bioassays revealed the presence of the parasite in semen samples of a boar inoculated with oocysts (GI) at 3, 49 and 56 DPI and from two boars infected with tachyzoites (GII), one animal at 5 and two animals at 49 days DPI. Mice inoculated with semen from the control group (GIII) remained serologically negative. PCR analysis showed T. gondii DNA in the semen of Boar 1 and Boar 3 inoculated with tachyzoites and oocysts, respectively. The immuno-histochemical tests showed T. gondii in the reproductive organs of Boar 1 and Boar 2, inoculated with tachyzoites and oocysts, respectively. These findings suggest the possible occurrence of venereal transmission of T. gondii in swine.

Toxoplasma gondii in experimentally infected Bos taurus and Bos indicus semen and tissues

Eighteen young steers were inoculated with Toxoplasma gondii and randomly distributed into three groups of six animals each: GI, 2.5x10(5) "P" strain oocysts, GII, 5.0x10(6) "RH" strain tachyzoites, and GIII (Control). Clinical, serological and parasitemia exams were realized. Parasite investigation by bioassay and PCR was realized on semen and fragments of skeletal musculature, lymph nodes, brain, retina, spleen, liver, lung, testicle, epididymis and seminal vesicle. Blood and semen samples were collected on days -2, -1, 1, 3, 5, 7, 14 and weekly thereafter, up to postinfection day (PID) 84. The inoculated steers (GI and GII) presented hyperthermia from PID 3 to 16. Antibodies against T. gondii were detected through the indirect fluorescence antibody test (IFAT) on PID 5 (1:16) in both inoculated groups (oocysts and tachyzoites), reaching peaks of 1:4096 on PID 7. Parasitemia outbursts occurred in all infected bovines, principally from PID 7 to 28, independent of the strain and inoculate used. Bioassays revealed the presence of parasites in semen samples of animals infected with oocysts (GI) and tachyzoites (GII) on several experimental days between PID 7 and 84. Tissue parasitism by T. gondii was diagnosed by bioassay and the PCR technique in several organ and tissue fragments. These findings suggest the possibility of sexual transmission of T. gondii in the bovine species.

Type C botulism in swine fed on restaurant waste

The paper addresses the epidemiologic data of the death of pigs during the period of 2002 to 2009 following the ingestion of botulinum neurotoxin type C. This neurotoxin was present in food residues originating from restaurant and hotel kitchens, stored in barrels without shelter from the sun and administered in a collective trough without prior thermal treatment. Animals which died at different ages showed clinical signs of botulism characterized by flaccid paralysis, weight loss, anorexia, weakness, lack of coordination, locomotion difficulties with the evolution of lateral recumbency with involuntary urination and defecation. No alterations were observed at postmortem and histological examination. The bioassay with serum neutralization in mice was carried out on samples of intestinal contents from pigs affected and revealed the presence of large quantities of botulinum toxin type C.

Persistence of the biocide activity of atrazine in soils of the southeast of Buenos Aires Province

Atrazine persistence in soils of the southeast of Buenos Aires Province, was studied by an oat bioassay. Atrazine doses of 0.58, 1.16, and 2.32 mg.g-1 dry soil weight (DSW) were applied to pots containing soils from Balcaree, A. Gonzáles Chaves and San Cayetano sites, whose organic matter (OM) content of soils were 5.70, 5.15, and 3,84%, respectively. Avena sativa cv. Millauquén plants were grownth in the pots under greenhouse conditions at different times after atrazine application. Shoots were evenly cut above the soil and dry weight determined as a measure of plant growth. Plants grown in non-sprayed soil were used as controls. Relative dry weight (RDW) of shoots was calculated as percentage of control. Atrazine phytotoxicity was expressed in terms of 50 % plant growth reduction (GR50) in the soils under study. Herbicide persistence was expressed in terms of days after treatment (DAT) needed for the plant to achieve 80% of RDW. Atrazine GR50 values of 0.30, 0.64, and 0.90 mg.g-1 DSW in soils from San Cayetano, Balcare and A.G. Chaves, were respectively obtained at 42 DAT. Herbicide persistences at the recommended dose (1.16 mg.g-1) were 100, 143, and 221 DAT for A.G. Chaves, Balcarce and San Cayetano soils, respectively. San Cayetano soil had both the lowest OM content and cation exchange capacity (CEC), as well as the highest pH, of all the soil studied here. These results were consistent with both the lowest GR50 and the highest persistence abtained for atrazine in this soil.

Effects of weed species competition on the growth of young coffee plants

The effects of competition of seven weed species on the growth of coffee plants were evaluated under greenhouse conditions. Thirty days after coffee seedling transplantation into 12 L pots with soil level area of 6.5 dm², weeds were transplanted into or sown in those pots, at densities of 0, 1, 2, 3, 4 and 5 plants per pot. Competition or weedy periods from weed transplantation or emergence to plant harvesting, at weed pre-flowering stage, were: 77 days - Bidens pilosa, 98 days - Brachiaria decumbens, 180 days - Commelina diffusa, 82 days - Leonurus sibiricus, 68 days - Nicandra physaloides, 148 days - Richardia brasiliensis and 133 days - Sida rhombifolia. Coffee plant height, stem diameter, leaf number and shoot dry matter were determined. Effects of competition by N. physaloides and S. rhombifolia against coffee plants were among the lowest, since only a slight decrease in all the characteristics evaluated in coffee plants was observed. The other weed species caused severe decrease in growth, mainly with increasing weed plant densities. Competition degree was found to depend on weed species and density.

Growth and nutrient concentration in coffee root system under weed species competition

The effects of competition of six weed species on growth, nutrient concentration and nutrient content of coffee plant root system under greenhouse conditions were evaluated. Thirty days after coffee seedling transplantation into 12 L pots with soil level area of 6.5 dm². Weeds were transplanted or sowed in these pots, at densities of 0, 1, 2, 3, 4 and 5 plants per pot. The duration of competition (or weedy periods) from weed transplantation or emergence until plant harvesting, at the weed preflowering stage, were (in days): 77 (Bidens pilosa), 180 (Commelina diffusa), 82 (Leonurus sibiricus), 68 (Nicandra physaloides), 148 (Richardia brasiliensis) and 133 (Sida rhombifolia). Dry matter of coffee plants was linearly reduced with increasing B. pilosa and S. rhombifolia density, with pronounced effect of B. pilosa. C. diffusa was the only weed species whose increasing density in the pots did not diminish crop root dry matter. L. sibiricus, N. physaloides and R. brasiliensis reduced root dry matter of coffee plants by 75, 52 and 47%, respectively, as compared to the weed-free treatment, regardless of weed density. Under competition, even though weed species showed lower macronutrient concentration in the roots (except for P), they accumulated 4.2 (N), 12.3 (P), 4.3 (K), 5.5 (Ca), 7.6 (Mg) and 4.4 (S) times more nutrients in the roots than the coffee plants. Crop and weed nutrient concentration, as well as competition degrees greatly varied depending on both weed species and densities.

Seed bank from soil of coffee plantations associated with grevillea trees

This study aimed to study the composition and dynamics of seed bank from soil of coffee plantations associated with grevilea trees in the experimental fields of the Southwest Bahia State University, on Vitória da Conquista campus. The experiments were carried out from September 2006 to May 2007. The coffee trees (Coffea arabica) were sown at three x one m spacing, associated with grevillea trees (Grevillea robusta) and maintained at densities of 277, 139, 123, 69, 62 and 31 plants ha-1, under direct sunlight. One hundred grams of soil were taken from each treatment with four repetitions and later identified and counted with a 10x magnifying glass. To determine seedling emergence, four soil samples of 1000 g were collected from each experimental field and transported to the greenhouse. Seedling emergence was observed by counts after 15, 30 and 45 days. The experimental design was randomized blocks of seven treatments (soil from different tree densities) and four replicates; the experimental unit consisted of a plastic tray (0, 30 x 0.22 x 0.06 m) containing 1.000 g of soil. The variables utilized to characterize the bank and its dynamics were: relative frequency, relative density, relative abundance, importance index and species diversity (Shannon-Weaver index).Increased number of monocotyledon seeds and sprouts were verified in the treatments maintained under full sunlight.

Weed control via intercropping with gliricidia: I. cotton crop

The majority of cotton grown commercially in the world has white lint, but recently, there has been a growing interest in colored lint cotton in several countries, including Brazil. The use of naturally-colored fiber reduces chemical pollution. The objective of this paper was to evaluate cotton cultivar fiber yield in response to weed control via intercropping with gliricídia. Cultivars BRS-Verde (greenish fibers), BRS-Rubi (reddish brown fibers), BRS-Safira (brown fibers), and BRS-187 8H (white fibers) were submitted to the following treatments: no hoeing, two hoeings (at 20 and 40 days after transplanting), and cotton intercropped with gliricídia. In the intercropped treatment, gliricídia was planted between rows of cotton plants, using one seedling pit-1, in pits spaced 50.0 cm apart. Twelve weed species predominated in the experiment, many of them belonging to the Poaceae family. Weeds occurred at different frequencies and in a non-uniform manner in the experimental area. Cultivars did not influence weed dry matter. Intercropping with gliricídia reduced weed dry matter but did not prevent reductions in cotton fiber and seed cotton yield, which were higher in hoed plots. Cultivar BRS Safira had the highest fiber yield, but no differences were observed between cultivars regarding to seed cotton yield.

Physiological response of vicia faba to prohexadione-calcium under saline conditions

Changes in the activities of oxidative enzymes (indole acetic acid oxidase, peroxidase and catalase), endogenous hormones (gibberellic acid (GA3), indole acetic acid (IAA), abscisic acid (ABA) and cytokinins (AsZeatin), photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), total carbohydrates, total soluble sugars, amino acid proline and vegetative growth parameters were used as indicators to explain the physiological role of the growth retardant prohexadione-calcium on Vicia faba seedlings 40 days after sowing under salinity stress for 30 days. The obtained results show that soaking faba bean seeds prior to sowing at different concentrations of prohexadione-calcium (0, 10, 20 and 30 ppm) significantly increased the activities of indole acetic acid oxidase (IAA-oxidase) and peroxidase enzymes, but decreased the catalase enzyme activity as compared with their respective control. Application of prohexadione-Ca caused markedly decreases in the endogenous contents of gibberellins and indole acetic acid (IAA) but increased the levels of natural growth inhibitor abscisic acid (ABA) and cytokinins in the shoots of faba bean seedlings. All the prohexadione-Ca concentrations increased the contents of amino acid proline, photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), total carbohydrates and total soluble sugars in faba bean seedlings grown under salt stress. Application of prohexadione-Ca decreased significantly seedling height and shoot fresh weight but significantly increased shoot dry weight.

Allelopathic effects of Eucalyptus citriodora on amaryllis and associated grassy weed

A Petri dish assay was carried out for screening different concentrations of aqueous extracts of fresh and dry leaves of Eucalyptus citriodora on germination and seedling growth of wild oat weed (Avena fatua). Seed germination, root and shoot length of wild oat exhibited different degrees of inhibition according to the concentration of the aqueous extract. Maximum inhibitions of germination percentage, root and shoot length were recorded when using 25% fresh leaf extract. Based on this preliminary work (Petri dish assay), studies were conducted under greenhouse conditions at the National Research Center, Egypt, in the two winter seasons of 2006/2007 and 2007/2008 to evaluate the effects of foliar and soil treatments of aqueous extracts of Eucalyptus citriodora fresh and dry leaves on wild oat weed as well as on the growth and flowering of amaryllis (Hippeastrum hybridum), compared with the recommended dose of the herbicide tralkoxydim. Amaryllis fresh and dry weights as well as flowering increased significantly when treated with the previous extracts, especially the fresh leaf extract. However, the fresh and dry weights of wild oat were significantly reduced by the aqueous extracts, either fresh or dry, indicating phytotoxic effects. Tralkoxydim caused complete inhibition of wild oat as compared with the control. The studies involved estimation of the endogenous contents of total phenols in weed. With all the treatments, the inhibitory effects on weeds were correlated with accumulation of the internal contents of total phenols, compared to their respective controls. The amount of phenols correlated well with the weed's growth performance. This study establishes the effect of the aqueous extracts on the weed wild oat, associated with amaryllis, which may serve as a tool in establishing their herbicidal potential.

Effects of Corynespora cassiicola on Lantana camara

The present study combines the examination of toxins produced by C. cassiicola and the effects of the fungus colonization on L. camara. C. cassiicola was cultivated on solid media and the crude extracts CAE and CE were produced. Both extracts were submitted to a seed germination and growth assay utilizing Physalis ixocarpa, Trifolium alexandrinum, Lolium multiflorum and Amaranthus hypochodriacus. The effect of the extracts on the ATP-synthesis in isolated spinach chloroplasts was also tested. Bioassay guided chromatographic fractionation identified the most active extract (CAE). From this extract ergosta-4,6,8(14),22-tetraen-3-one (C1) and fatty acids were isolated. The C1 compound reduce ATP synthesis in isolated spinach chloroplasts. The interference of fatty acids with ATP synthesis and also with weed growth provides one explanation of the phytogrowth-inhibitory properties of such fungal extracts. Histological observations involving fungus-plant interaction were made on L. camara plants inoculated with C. cassiicola conidia suspension. After inoculations, fragments of the leaf blades were prepared for observation by light and scanning electron microscopy. Fungal colonization of Lantana camara was typical of a necrotroph and penetration initiated a hypersensitive response. L. camara reacted to the pathogen penetration through thickening of the epidermis walls, cytoplasm granulation and a cicatrisation tissue.