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 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...

To evaluate the physiological potential of the seeds, the tetrazolium test would be an interesting alternative, as it is a quick test that provides a detailed analysis of viability and vigor. Therefore, it is necessary to define pre-conditioning conditions, such as temperature and duration of soaking, concentration of the tetrazolium solution, and method of exposing the seeds to staining. Moringa oleifera Lam., belonging to the family Moringaceae, is widely distributed in tropical countries and easily adapted to semi-arid conditions, possessing medicinal value, as forage, condiment, in the cosmetics industry, melliferous, fuel, and in water purification treatment through the coagulant solution made from seeds. Based on the above, the objectives of the present work were to establish the most appropriate procedure for conducting the tetrazolium test to evaluate the viability and vigor of M. oleifera seeds. Only the cotyledons containing the embryo were placed in 50 mL plastic cups and immersed in a solution of 2,3,5-triphenyl chloride tetrazolium salt at concentrations of 0.05; 0.075 and 0.1% for staining periods of 1, 2, and 3 hours in a Biochemical Oxygen Demand chamber at 30 ºC in the dark. The seeds were evaluated one by one for tissue condition (firm or flaccid) and seed color, and by the location and size of the lesions on the cotyledon and embryonic axis. For the standardization of the tetrazolium test, the Completely Randomized Design was used in a 3x3+1 factorial scheme (three concentrations of tetrazolium solution x three staining periods + control = germination test) with four repetitions of 25 seeds. M. oleifera seeds were found to have a high germination rate (100%), there was no significant difference between the control and the percentage of viable seeds (TZ) for the 2 and 3 hours staining periods, immersed in tetrazolium solution at concentrations of 0.075 (96%) and 0.05% (99%), respectively. The most appropriate procedure for conducting the tetrazolium test to assess the viability and vigor of M. oleifera seeds is to use a concentration of 0.05% for 3 hours of salt immersion

Phenology works as an indicator of the response of plants to local climatic and edaphic conditions, enabling a better understanding of the dynamics of the species. The seasonal climate also influences the occurrence of periodic rhythms of growth and reproduction (phenophases). Moringa oleifera Lam., belong to the Moringaceae family, is widely distributed in tropical countries and easily adapts to semiarid conditions, having medicinal value as a forage, flavoring, in the cosmetics, honey, fuel and in the treatment of water purification through the coagulant solution made from the seeds. The objectives of the present work were to study the phenological behavior of M. oleifera and to relate the variations in phenophases with climatic factors, precipitation and temperature. For collection of phenological data, ten trees were selected, and the records were carried out between the first half of August 2020 and the first half of July 2021. The observations were carried out at fortnightly intervals, recording the presence and absence of the flowering and fruiting phenophases including flowering – period in which the tree is in full flowering; fructification – which starts from the moment that small fruits are visible after the fertilization of the flowers and ends with the dispersal of seeds. The Fournier intensity index was determined using a semiquantitative interval scale of five categories (0 to 4), with an interval of 25% between each category. The phenological data of intensity of each phenophase (flowering and fruiting) were related to precipitation and average temperature fortnightly using Spearman's correlation. The flowering and fruiting phenophases of M. oleifera intensified in August, September and December 2020, showing Fournier intensity peaks of 47.5 and 77.5, 72.5 and 92.5, and 35 and 55 %, respectively, and April and June 2021, in the monthly intervals of greater rainfall, with percentage rates of 82.5 and 95, 77.5 and 80%, respectively. In general, we found that M. oleifera produced seeds between the first half of August and the first half of September, and the second half of December 2020, and the second half of April and the first half of June 2021. Thus, it can be stated that the production of fruits by M. oleifera is interrupted in the months with less rainfall (October to November 2020, and January to February 2021). The intensity and duration of the flowering and fruiting phenophases in M. oleifera are synchronized with the temporal distribution of the precipitation pulses in that habitat