No abstract

The present study investigated the influence of two Brazilian environments on the physico-chemical and physiological properties of Jatropha curcas L. (physic nut) – an oilseed plant of great potential in biodiesel production. Fruits and seeds of plants grown in the Brazilian Atlantic rainforest (AF) and in the semiarid climate of Caatinga (SA) were compared. Fruits from the SA were longer, wider and heavier than those from the AF. In contrast, the AF seeds were larger and heavier than the SA seeds. Soluble sugars, protein, relative water content and electrical conductivity of the SA seeds significantly exceeded that of the AF seeds by 28%, 23%, 32% and 94%, respectively. Seeds of the AF had a significantly greater percentage germination (17.5%) and needed less time to germinate (10%) than did the SA seeds. Shoot dry biomass of seedlings grown from the AF seeds significantly exceeded that of the SA by 18.5%. Results suggest this pattern may be due to the higher carbon storage (i.e. sugars, proteins and oil) in the AF than SA seeds. Further studies are warranted to verify whether the differences observed between the seed sources investigated in the present study could be due to varietal or biotype factors.

Resumo: Nos canaviais, espécies do gênero Euphorbia são relatadas como plantas daninhas capazes de reduzir a produtividade em até 85%. Para traçar estratégias corretas de controle dessas plantas é necessário o conhecimento tanto da sua biologia quanto do seu crescimento. Assim, objetivou-se com este trabalho avaliar o crescimento de três espécies daninhas do gênero Euphorbia ocorrentes nos canaviais. O estudo foi realizado em casa de vegetação, utilizando delineamento experimental inteiramente casualizado, em esquema de parcela subdividida, com cinco repetições. Os fatores foram três espécies de Euphorbia (E. heterophylla, E. hyssopifolia e E. hirta) e 13 períodos de avaliação: 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91 e 98 dias após a semeadura (DAS). Em cada avaliação foram mensuradas a altura da planta (AP), a área foliar (AF), o número de folhas (NF) e a matéria seca total (MST). Com valores médios de matéria seca da parte aérea (MSPA), MST e AF foram calculadas as taxas de crescimento absoluto (TCA) e relativo (TCR), a razão de área foliar (RAF) e a razão massa foliar (RMF). Os dados foram submetidos à análise de variância e à regressão não-linear. E. heterophylla foi maior em AP até os 63 DAS, a partir desse ponto, E. hyssopifolia ultrapassou obtendo maior altura dentre as espécies estudadas. E. heterophylla destacou-se por ter maior acúmulo de AF, MST e TCA dentre as espécies estudadas, seguida da E. hyssopifolia e E. hirta. O ponto máximo de crescimento das espécies avaliadas ocorreu aos 77 DAS. Dentre as espécies estudadas, E. heterophylla apresenta maior crescimento e desenvolvimento. Palavras-chave: Análise de crescimento. E. heterophylla. E. hyssopifolia. E. hirta. Massa seca.Abstract: In sugarcane plantations, species of the genus Euphorbia are reported as weeds able to reduce productivity by up to 85%. Planning the correct strategies for controlling these plants requires knowledge of their biology and growth. The aim of this work therefore, was to evaluate the growth of three weed species of the genus Euphorbia occurring in sugarcane plantations. The study was carried out in a greenhouse, using a completely randomised experimental design in a scheme of lots subdivided over time, with five replications. The factors were three species of Euphorbia (E. heterophylla, E. hyssopifolia and E. hirta) and 13 periods of evaluation 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91 and 98 days after sowing (DAS). Each evaluation measured plant height (PH), leaf area (LA), number of leaves (NL) and total dry matter (TDM). From the mean values for shoot dry matter (SDM), TDM and LA, the absolute growth rate (AGR) and relative growth rate (RGR), leaf area ratio (LAR), and leaf weight ratio (LWR) were calculated. Data were submitted to analysis of variance and non-linear regression. E. heterophylla displayed greater PH up to 63 DAS, from this point E. hyssopifolia obtained greater height among the species under study. E. heterophylla was noteworthy for having a greater accumulation of LA, TDM and AGR among the ...

Resumo: A mudança na colheita da cana-de-açúcar vem causando alterações no seu manejo devido à permanência da palhada sobre o solo, que impõe uma barreira física que pode alterar a qualidade e a quantidade de radiação solar que chega ao solo, modificando a fitossociologia das plantas daninhas. Assim, objetivou-se com este trabalho avaliar a qualidade de luz na germinação de sementes e níveis de palhada, sobre a emergência e desenvolvimento inicial de três espécies daninhas do gênero Euphorbia. Sementes de E. heterophylla, E. hyssopifolia e E. hirta foram submetidas à germinação sob luz branca, vermelha, vermelha extrema e escuro, à temperatura de 20-30 °C, em laboratório, e semeadas sob 0, 5, 10, 15, 20 e 25 t ha -1 de palhada, em casa de vegetação. No primeiro ensaio, foram avaliadas a porcentagem e o índice de velocidade de germinação (IVG) e a massa seca das plântulas, e no segundo, porcentagem de emergência, cobertura do solo, altura e massa seca de plantas. As sementes de todas as espécies germinaram em todas as condições luminosas, entretanto, E. heterophylla apresentou maior geminação e IVG sob luz vermelha, enquanto que E. hirta e E. hyssopifolia apresentaram sob luz branca. Sob palhada, E. heterophylla teve o melhor desempenho, suportando duas vezes mais palhada que E. hyssopifolia e quatro vezes mais que E. hirta, para haver redução de 50% de emergência e desenvolvimento das plantas. A presença da palhada não controla E. heterophylla, por outro lado suprime as espécies E. hyssopifolia e E. hirta. As três espécies estudadas são indiferentes à luz. Palavras-chave: Cobertura morta. Euphorbia heterophylla. Euphorbia hyssopifolia. Euphorbia hirta. Germinação.Abstract: Changes in the sugarcane harvest have resulted in changes in management due to straw remaining on the ground, which imposes a physical barrier that can alter the quality and quantity of solar radiation that reaches the soil, modifying the phytosociology of weeds. The aim of this study therefore, was to evaluate light quality on seed germination, and the levels of straw on emergence and early development, in three species of the genus Euphorbia. Seeds of E. heterophylla, E. hyssopifolia and E. hirta were subjected to germination under white, red, strong red and dark red light at a temperature of 20-30° C in the laboratory and planted under 0, 5, 10, 15, 20 and 25 t ha -1 straw in a greenhouse. In the first trial, the percentage emergence, germination speed index (IVG) and seedling dry weight were evaluated, and in the second, the percentage emergence, ground cover, plant height and dry weight. The seeds of each species reached germination under all light conditions; however, E. heterophylla displayed greater values for germination and IVG under red light, while E. hirta and E. hyssopifolia under white light. Under straw, E. heterophylla had the best performance, withstanding twice as much straw as E. hyssopifolia and four times more than E. hirta, for a 50% reduction in plant emergence and development. The presence of straw does not control E. ...

The conservation of seed quality during storage is important to perform the maintenance and conservation of germplasm banks. Several native species of Brazil are intolerant to desiccation to desirable levels for conservation during storage is necessary to develop specific technologies for their conservation. The objective of this research was to evaluate the physiological quality of Paquira aquatica seeds submitted to drying periods. The study was carried out using seeds of P. aquatica dried at a temperature of 35 ºC, the following exposure times: 0 (no drying), 24, 48, 72 and 96 hours. Before and after each period of drying samples for the evaluations, the data were submitted to analysis of variance and regressionat level of 5%. The seeds of P. aquatica were dispersed with very high water content and a small reduction in its physiological value agrees quality, allowing the seeds to characterize this as a recalcitrant species. The drying temperature is 35 ºC until the viable 24 hours after this period the water content of seed reduced from 55% to 43%, which was considered the critical level for desiccation of seeds of P. aquatica. Because it reduces the values of first count, germination, rate of germination and growth of seedlings.The drying temperature the 35 ºC until the viable 24 hours, whit small reduction in its physiological quality seed P. aquatica.

H. impetiginosus belongs to the Bignoniaceae family; it has a great potential for economic exploitation and can be used in landscaping of urban areas, reforestation, recovery of degraded areas, and folk medicine. The experiment was carried out to evaluate the effect of light and temperature regimes on the germination and vigor of Handroanthus impetiginosus seeds at the Seed Analysis Laboratory of UFRPE/UAG. The seeds were subjected to light regimes: white, far red, red, and no light at 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C, using a completely randomized experimental design in a factorial scheme (4 × 6), with four repetitions of 25 seeds. The different light regimes did not influence the seed germination of H. impetiginosus. The highest germination percentage (92%) and germination speed index (7.94) were obtained at temperatures 28.2°C and 29.2°C, respectively, both under red light. The longest seedling length was also obtained from the seeds subjected to red light regime at 25°C. The temperatures of 15°C and 40°C inhibited the germination of H. impetiginosus seeds. H. impetiginosus seeds are classified as neutral photoblastics, and constant temperatures of 28.2°C and 29.2°C provided maximum germination.

-The permanence of straw on the ground changes the phytosociology of weeds and affects control by the difficulty of transposing from straw to soil; thus, it is extremely important to transport it as quickly as possible. This research had the goal to know the effectiveness of two herbicides, applied on straw in different periods without rain, in controlling three weed species from the Euphorbia genus. The experiments were conducted in a greenhouse using a completely randomized design, arranged in split-plot in time (rainless periods: 0, 15, 30 and 45 days), with three replications. Seeds were distributed over the soil and covered by a 10 t ha -1 straw layer. The application of diuron + hexazinone + sulfometuron-methyl and tebuthiuron herbicides was performed during pre-emergence on the straw. Then, respecting the rainless period, planters received an irrigation of 20 mm water. At 43 days, the visual control and dry mass of the aerial parts were evaluated. Data were submitted to analysis of variance and adjusted to the linear or quadratic equation model. E. hirta was 100% controlled by the two herbicides in all periods without rain. Tebuthiuron was not effective in controlling E. heterophylla and E. hyssopifolia after 45 days without rain. Diuron + hexazinone + sulfometuron-methyl herbicide is effective in controlling the three Euphorbia species, even when applied on the straw and after the 45-day period to be leached. Diuron + hexazinone + sulfometuron applied over sugarcane straw was effective in controlling all Euphorbia species studied. fundamental importância o seu transporte o mais rápido possível. Este trabalho teve por objetivo conhecer a eficiência de dois herbicidas, aplicados sobre palhada, em diferentes períodos sem chuva, no controle de E. heterophylla, E. hyssopifolia e E. hirta. Os experimentos foram conduzidos em casa-de-vegetação sob delineamento inteiramente casualizado, disposto em parcelas subdivididas no tempo (períodos sem chuva: 0, 15, 30 e 45 dias), com três repetições. As sementes foram distribuídas sobre o solo e cobertas por uma camada de palhada de 10 t ha -1 . A aplicação dos herbicidas, diuron + hexazinone + sulfometurom-metílico e tebuthiuron, foi realizada em pré-emergência sobre a palhada. Em seguida, respeitando o período sem chuva, os vasos receberam uma lâmina de irrigação de 20 mm de água. Aos 43 dias, foram avaliados o controle visual e a massa seca da parte aérea. Os dados foram submetidos à análise de variância e ajustados ao modelo de equação linear ou quadrática. E. hirta foi 100% controlada pelos dois herbicidas em todos os períodos sem chuva. O tebuthiuron não foi eficiente no controle de E. heterophylla e E. hyssopifolia após 45 dias sem chuva. O diuron + hexazinone + sulfometurom é eficiente no controle das três espécies de Euphorbia mesmo sendo aplicado sobre a palhada e passando o período de 45 dias para ser lixiviado. Diuron + hexazinone + sulfometurom aplicado sobre a palhada da cana-deaçúcar foi eficiente no controle de todas as espécies de Euphorbia estu...

Peanuts (Arachis hipogaea L.) have a great potential for grain production for feed and forage production, being an alternative for producers, as it grows a double product. Grains have excellent quality and contain a greater amount of protein with which to feed the herd. The present study is a cutoff effect study with an application of Stimulate® phytostimulant to determine grain quality and peanut fodder genotype. In the first planting, the peanuts were cultivated under field conditions in a randomized block design in a 4 × 2 × 2 subplot scheme, with four cultivars and two cutting periods, with or without phytostimulant. The cultivars were IAC Tatu ST and Caiana (vertical growth), as well as non-flowering and harvesting seeds. For the second planting, a randomized block design was used with a subplot scheme of 3 × 2 × 2, with three cultivars and 2 cutting periods, with or without phytostimulant. The cultivars were IAC Tatu ST and Caiana (vertical growth) and IAC 503 (prostrate growth). All cultivars contained a high percentage of hay protein in the two plantings. The cultivar IAC 503 was efficient in the production of protein and fiber in the grains in both plantings, demonstrated the potential of protein for animal supplementation, and also presented high grain yield in the summer planting.