Differential responses between mature and young leaves of sunflower plants to oxidative stress caused by water deficit

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

Kinetics of zinc uptake and anatomy of roots and leaves of coffee trees as affected by zinc nutrition

Zinc (Zn) uptake kinetics and root and leaf anatomy were studied in coffee trees grown in nutrient solutions with or without Zn. Leaves and roots were sampled and cuts were made in the medium part of the leaves and in root tips and observed under an optical microscope. Plants grown without Zn showed an increase in root and in root stele diameter. There was also an increase in epidermis thickness and in the cross-sectional area of the cortex and stele due to Zn deficiency, but the diameter of xylem vessels was decreased. An increase in root cortex and stele diameter provided for an increased surface for nutrient uptake. Accordingly, C(min) was decreased from 13.8 to 3.4 mu mol L(-1) and V(max) increased from 0.50 to 2.1 mu mol cm(-2) h(-1) .

In Vitro Evaluation of the Genotoxic Activity and Apoptosis Induction of the Extracts of Roots and Leaves from the Medicinal Plant Coccoloba mollis (Polygonaceae)

Coccoloba mollis (Family Polygonaceae) is a medicinal plant popularly used in cases of memory loss, stress, insomnia, anemia, impaired vision, and sexual impotence, but the scientific literature, to date, lacks studies on the biological effects of this species, particularly with regard to cytotoxicity and induction of DNA damage. The aim of the present study was to assess in vitro (in hepatic HTC cells) ethanolic extracts of the roots and leaves of C. mollis for cytotoxicity, genotoxicity, and induction of apoptosis. For these evaluations the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay, comet assay, micronucleus test with cytokinesis block, and an in situ test for detection of apoptotic cells with acridine orange staining were used. The results showed that the extract obtained from the roots of C. mollis is more cytotoxic than that obtained from the leaves and that the reduction in cell viability observed in the MTT assay was a result, at least in part, from the induction of apoptosis. Both extracts induced DNA damage at a concentration of 20 mu g/mL in the comet assay, but no genotoxicity was detected with any of the treatments carried out in the micronucleus test.

Anatomy of scapes, bracts, and leaves of Paepalanthus sect. Diphyomene (Eriocaulaceae, Poales) and its taxonomic implications

Paepalanthus sect. Diphyomene comprises 18 species with a convoluted taxonomic history. Aiming to correlate anatomical structures with the systematics of this group and its relatives, we studied the anatomy of scapes, reproductive axis bracts, and leaves of 20 Paepalanthus species. Bracts and leaves show differences in epidermal cell thickening; mesophyll width; vascular bundle arrangement; presence or absence of a hypodermis; types of cells in the vascular bundle sheath extensions; margin shape and composition; and presence or absence of aquiferous parenchyma. Scapes differ in contour, rib number, and pith size. Some diagnostic characters found are presence of aquiferous parenchyma and absence of vascular bundle sheath extensions in leaves of P. urbanianus; vascular bundles decreasing in size towards the margin of leaves and bracts, and scapes with a triangular contour in P. flaccidus; scapes with nine ribs in P. acanthophyllus and ten in P. macer. All anatomical features are summarized in tables. These results aid in the identification and characterization of the species of P. sect. Diphyomene. They also support the current section circumscription, reinforcing the relevance of the anatomical characters in order to define natural groups. © 2012 The New York Botanical Garden.

Accumulation of six metals in the mangrove crab Ucides cordatus (Crustacea: Ucididae) and its food source, the red mangrove Rhizophora mangle (Angiosperma: Rhizophoraceae)

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

Biochemical dissection of diageotropica and Never ripe tomato mutants to Cd-stressful conditions

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

Vertical growth of mini watermelon according to the training height and plant density

A melancia é uma espécie tradicionalmente conduzida em campo no sistema rasteiro. As cultivares de frutos pequenos (1 a 3 kg), que adquirem melhores preços de mercado, vêm sendo cultivadas também em ambiente protegido, onde são conduzidas no sistema vertical, com poda de ramos e raleio de frutos. Essas práticas possibilitam aumentar o adensamento das plantas, a qualidade e a produtividade de frutos em comparação ao sistema rasteiro. Objetivou-se com este trabalho avaliar a influência de três alturas de condução (1,7; 2,2 e 2,7 m) e duas densidades de plantas (3,17 e 4,76 plantas m-2) sobre as características produtivas e qualitativas da mini melancia Smile cultivada em ambiente protegido. A poda da haste principal foi realizada aos 43, 55 e 66 dias após o transplante (DAT) para as alturas de condução de 1,7; 2,2 e 2,7 m, respectivamente. A massa seca dos ramos, dos pecíolos, das folhas e total foram afetados pela altura de condução, cujos maiores valores foram obtidos para as plantas conduzidas a 2,2 e 2,7 m de altura. A área foliar, a área foliar específica e o índice de área foliar não foram influenciados pela altura de condução das plantas. A altura de condução de 2,7 m elevou a produtividade total. Entretanto, a produtividade comercial, a massa média dos frutos e todas as características qualitativas não foram significativamente diferentes das obtidos pela altura de poda de 2,2 m. em relação à densidade de plantas, a melhor opção foi a de 4,76 plantas m-2, pois elevou a produtividade comercial em 37,4% sem reduzir a massa média dos frutos.

Lepidopterans and their parasitoids on okra plants in Riberao Preto (SP, Brazil)

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

Pathogenicity, colony morphology and diversity of isolates of Guignardia citricarpa and G-mangiferae isolated from Citrus spp.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Detached leaf culture: Viability to evaluate 2,4-D toxicity symptoms in cotton apex leaves

To study the viability of detached leaf culture technique, studies were carried out with detached leaves from cotton apex (true trilobed leaves). The prepared leaves were sprayed with 2,4-D amine and ester, at rates of 10, 30, 70, and 100% of the recommended doses. Detached leaves without herbicide spray were used as controls. Simultaneously, a greenhouse experiment was conducted with the same treatments as used for the detached leaves experiment. Toxicity was measured through a 0-to-5 grading according to the percentage of affected leaf area in the detached leaves experiment or examining the affected rate of whole plant as indicated in the greenhouse. Results showed that the ester form of the herbicide induced earlier and more severe toxicity symptoms in detached leaves and greenhouse grown plants. Positive and significant correlations (p < 0.001) were found between toxicity results obtained at 7 and 14 days after application in detached leaves and greenhouse plants (r = 0.97 and 0.92, respectively). Negative, significant correlations (p < 0.005) were found between the toxicity levels found at 7 and 14 days after application in detached leaves and dry matter of cotton plants grown in the greenhouse (r = -0.92 and -0.92, respectively).

Liming and postharvest quality of carambola fruits

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

Nitrogen and silicon fertilization of upland rice

O silício não é considerado um elemento essencial para o crescimento e desenvolvimento das plantas, entretanto, sua absorção traz inúmeros benefícios, principalmente ao arroz, como aumento da espessura da parede celular, conferindo resistência mecânica a penetração de fungos, melhora o ângulo de abertura das folhas tornando-as mais eretas, diminuindo o auto-sombreamento e aumentando a resistência ao acamamento, especialmente sob altas doses de nitrogênio. O presente trabalho teve por objetivo avaliar os efeitos da adubação nitrogenada e silicatada nos componentes vegetativos, nos componentes da produção, na altura da planta e na produtividade da cultivar de arroz IAC 202. O experimento foi constituído da combinação de três doses de nitrogênio (5, 75 e 150 mg de N kg-1 de solo) aplicado na forma de uréia e quatro doses de silício (0, 200, 400 e 600 mg de SiO2 kg-1 de solo), aplicado na forma de silicato de cálcio. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 3 ´ 4 (N = 5). A adubação nitrogenada aumentou o número de colmos e panículas por metro quadrado e o número total de espiguetas, refletindo na produtividade de grãos. O perfilhamento excessivo causado pela adubação nitrogenada inadequada causou redução na porcentagem de colmos férteis, na fertilidade das espiguetas e da massa de grãos. A adubação silicatada reduziu o número de espiguetas chochas por panícula e aumentou a massa de grãos sem, contudo, refletir na produtividade de grãos.

Interaction between resistant tomato genotypes and plant extracts on Bemisia tabaci (Genn.) biotype B

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

Dolomite and phosphogypsum surface application effects on annual crops nutrition and yield

Brazil has extensive area with acid soils. Using phosphogypsum and soil acidity tolerant cultivars are alternatives to crop establishment in no-till system without previous limestone incorporation in many agricultural soils of Brazil. However, it remains unknown how phosphogypsum and limestone surface application affects rice (Oryza sativa L.) and common bean (Phaseolus vulgaris L.) nutrition and yield under a no-till system. A field experiment was conducted in a sandy clay loam, kaolinitic, thermic Typic Haplorthox, previously cultivated under conventional tillage, in Botucatu, Sao, Paulo State, Brazil. Treatments included four dolomitic limestone rates (0, 1100, 2700, and 4300 kg ha(-1)), two phosphogypsum rates (0 and 2100 kg ha(-1)), and two upland rice cultivars (Caiapo and IAC 202). in 2002-2003, and two bean cultivars (Perola and Carioca), in 2003-2004. Both amendments were applied on the surface, without soil incorporation. The content of Ca, Mg, and Mn in flag leaves and rice yield increased with limestone surface application. Liming increased the shoot dry matter of IAC 202 rice. Phosphogypsum increased S contents in leaves of both rice cultivars, and resulted in higher grain yield in the Caiapo rice. Liming increased K contents in leaves of both bean cultivars. In the absence of phosphogypsum, liming increased S contents and grain yield of bean. Content of Mg in leaves was reduced by phosphogypsum in lower limestone rates. In phosphogypsum presence, liming reduced Zn contents in leaves and increased bean shoot dry matter. Phosphogypsum increased Ca and S, and reduced Mg contents in bean leaves. Using soil acidity tolerant cultivars promoted higher crop yields in no-till systems establishment, even when the effective soil amelioration had not yet been achieved.

Composition and acaricidal activity of the essential oil of Lychnophora ericoides Mart. to Tetranychus urticae Koch (Acari: Tetranychidae).

The essential oil of the leaves and branches obtained by hydrodistillation of Lychnophora ericoides, collected in the Reserve of Furnas - MG, Brazil, was analyzed by CG/EM (Shimadzu QP2010). The major parts of the volatile components identified in the essential oil of leaves were monoterpenes (44.02%) and the sesquiterpene [alpha]-bisabolol (2.05%). The major acaricidal activity of the essential oil from L. ericoides was observed at 48 (14.55 [mu]L/L of air) and 72 h (8.01 [mu]L/L of air) of exposition. The oviposition of T. urticae oviposition was influenced by the essential oil, but the eclosion of eggs was not affected.