Fitotoxicidade e análise fitoquímica a partir de folhas de cinco espécies de Cerrado

Pós-graduação em Biociências - FCLAS

Viabilidade de sementes de Handroanthus heptaphyllus (Vell.) Mattos armazenadas nos frutos

Pós-graduação em Ciência Florestal - FCA

Evaluation of allelopathic potential of leaf extract of kielmeyera coriacea on lactuca sativa l

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Phytotoxicity of Solanum aculeatissimum Jacq: leaves extract

The objective of this study was to evaluate the phytotoxicity of Solanum aculeatissimum Jacq. leaves ethanolic extract in seeds germination, development and fixation of Lactuca sativa seedlings. The same study also aimed to assess the mitotic index of lettuce roots meristematic cells, quantification of phenols and total flavonoids and triage by mean of phytochemical testing of the main secondary metabolites classes. Bioassays of germination, development of root and hypocotyl were carried out in Petri dishes using achenes of Lactuca sativa L. cv. 'Grand Rapids' (lettuce). Concomitantly, were evaluated the physico-chemical characteristics (pH, osmotic potential and electrical conductivity), mitotic index, quantification of total phenols and flavonoids and determination of phytochemical profile of the treatments extract. The results obtained in the bioassays demonstrate that the ethanol extract of S. aculeatissimuma presents phytotoxic potential in the development of lettuce seedlings, given that the concentration of 20 mg/ml showed greater inhibition (41% of germination). The extract contains significant amounts of antioxidants, total flavonoid and phenols, where the concentration 1000µg/mL showed higher values (86.50%). Furthermore, it was possible to observe the presence of compounds with allelopathic activity in the phytochemical screening test as coumarins, tannins, terpenes, flavonoids and alkaloids. Given the above it is clear that the ethanolic extract of S. aculeatissimum presents allelopathic substances with phytotoxic activity that can affect the germination and development of other plant species in their natural environment.

Aspectos físicos e fisiológicos de sementes de Fimbristylis dicothoma relacionados à germinação e dormência

In the seeds of pioneer plants, the application of treatments for breaking dormancy, and selection by colour and size, are strategies for obtaining seeds of less dormancy and better germination performance. The aim of this study was to evaluate the effect of the physical and physiological aspects of seeds of the tall fringe-rush (Fimbristylis dichotoma) on germination and dormancy. To do this, the seeds were submitted to the following treatments in three studies: (i) control, immersion in H2SO4 (98%, 36N) for 1 minute, immersion in KNO3 (1, 2 and 3%) for 15 minutes, seeding on a substrate moistened with KNO3 (0.2%) and exposure for 5 and 10 hours in a forced air circulation oven at 40 and 70 degrees C; (ii) classification of the seeds by colour (light and dark) and application of the following treatments: control, immersion of the seeds in H2SO4 (98%, 36N) for 1 and 2 minutes, immersion in KNO3 (5% and 10%) for 15 and 30 minutes and seeding on a substrate moistened with KNO3 (0.2%); (iii) classification by size (0.60, 0.50 and 0.40 mm) and germination on a substrate moistened with KNO3 (0.2%) or distilled H2O. The seeds were evaluated by germination test, first count and germination speed index. Moistening the substrate with KNO3 (0.2%), and heat treatment at 40 degrees C for 10 hours improve performance in seeds of the tall fringe-rush. Light-coloured seeds do not display dormancy. Medium-sized seeds of the tall fringe-rush show better performance in terms of percentage and speed of germination.

Estresse térmico no acúmulo de prolina livre de plântulas de guandu oriundas de sementes tratadas com poliaminas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Seletividade do clomazone em sementes de algodão tratadas com dietholate e acetato de zinco

The objective of this study objective was to evaluate the selectivity of pre-emergence applications the herbicide clomazone cotton seeds treated with dietholate and zinc acetate. The 4 x 2 factorial arrangement was adopted (4 seed treatment methods and 2 clomazone dosages), distributed in a randomized block design with 4 repetitions. In treatments where dietholate and zinc acetate were applied, rates of 0.4 kg ha(-1) and 8 ml per kg of seeds were used respectively. The clomazone rates used refer to 0.8 and 1.0 kg ha(-1). The cotton cultivar used was the Fiber Max 966 LL. Independent of treatment, all seeds were treated with tiametoxam insecticide and fludioxonil + metalaxyl-M fungicide at rates of 2.24 and 0.08 + 0.03 g per kg of seed, respectively, to control pests early and limit losses caused by pathogens in germination and seedling emergence. Dietholate and zinc acetate treatment had greater initial effect on cotton plants at 21, 30 and 45 days after application. In phytointoxication symptoms were observed for treatment with dietholate and zinc acetate during the evaluation periods. Seeds treated with dietholate, dietholate and zinc acetate or zinc acetate alone provided a higher number of bolls and seed cotton production compared to the control.

Efeito de extratos de adubos verdes sobre Lactuca sativa e Digitaria horizontalis

Objetivou-se avaliar os efeitos de extratos de quatro espécies de adubos verdes (Canavalia ensiformis, Crotalaria spectabilis, Mucuna aterrimae Sorghum bicolor cv. AG 2005) sobre a germinação de sementes e o crescimento inicial de plântulas deLactuca sativa e de Digitaria horizontalis. Foram realizados dois experimentos: no primeiro, avaliou-se a aplicação das soluções diluídas a 1%, 2%, 3%, 4%, 5% e10% de extratos aquosos da parte aérea e das raízes das espécies de adubos verdes sobre a germinação, índice de velocidade de germinação e o comprimento radicular de L. sativa; no segundo, avaliou-se a incorporação ao solo de 0, 10, 20, 30, 40 e 50 g dm-3 da biomassa dos adubos verdes sobre o acúmulo de massa seca (parte aérea e raízes) e o desenvolvimento radicular de plântulas de L. sativa e de D. horizontalis. Concluiu-se que os extratos aquosos das espécies C. ensiformis, C. spectabilis, M. aterrima e S. bicolor cv. AG 2005 promoveram efeitos negativos sobre a germinação e o IVG das sementes de L. sativa. A incorporação ao solo da biomassa dessas espécies de adubos verdes influenciou negativamente no desenvolvimento inicial das plântulas de L. sativa. Entretanto, verificou-se efeito positivo sobre o desenvolvimento inicial de D. horizontalis com a incorporação ao solo da biomassa de C. spectabilis.

Anatomia de espécies brasileiras de Eriocaulaceae: Comanthera e Syngonanthus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Permeabilidade a água e germinação de sementes heteromórficas de Bowdichia virgilioides Kunth

Pós-graduação em Ciência Florestal - FCA

Strains of Coniothyrium minitans reduce the emission of apothecia of Sclerotinia sclerotiorum

Sclerotia of Sclerotinia sclerotiorum (Ss) can survive for long time in soil and are the main inoculum source of the white mold disease. An alternative for reducing this inoculum is the use of parasites, such as Coniothyrium minitans (Cm). We evaluated the potential of Cm isolates for the biological control of Ss in beans. The effect of the temperature on the growth of 15 isolated of Cm was evaluated in vitro. The hyperparasitism ability of Cm was evaluated in soil infested with sclerotia and conditioned in pots. The infested soil was treated with conidia suspension of the antagonists, fluazinan or sterile distilled water. After seven days at 20°C, the sclerotia were removed from soil and placed inside Petri dishes over bean leaves previously disinfested. The germination and parasitism of sclerotia were evaluated after 7 to 10 days. To evaluate the apothecia emission, soil infested with sclerotia of Ss and treated as described was maintained at 18°C and the number of emerged apothecia was counted up to 84 days after inoculation. The emergence of bean plants in soil infested with sclerotia and mycelium of the pathogen and treated as described was evaluated in greenhouse. The ideal temperature for growth of Cm isolates varied from 18 to 19°C and at 30-35°C they were complete inhibited. The isolates of Cm promoted less than 10% of reduction in viability of the sclerotia, but they significantly reduced the emission of apothecia. Two isolates increased the emergence of plants in relation to the inoculated check, but was significantly lower than the non-inoculated check. Field tests will be conduct to confirm the potential of the selected isolates to reduce the inoculum source of the pathogen.

Sementes de leguminosas forrageiras sob estresse salino tratadas com ácido salicílico e espermidina

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação de resíduos orgânicos para o manejo de Fusariose em diferentes patossistemas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pré-tratamentos com luz em sementes de tomateiro para indução de tolerância ao déficit hídrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Remoção de elementos potencialmente tóxicos em resíduo sólido da indústria canavieira para utilização como condicionador de solo na agricultura

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)