Com o objetivo de verificar o efeito do estrangulamento do caule e do ácido indolbutírico no enraizamento de estacas de plantas jovens de seringueira, foi conduzido este ensaio. As estacas utilizadas foram retiradas da perte basal, mediana e apical, sendo que parte das estacas foram estranguladas com fio de arame abaixo de duas folhas, 30 dias antes do estaqueamento no campo. As estacas tiveram suas bases imersas por 12 horas em água ou em solução com 200 ppm de IBA. Os resultados mostraram que as estacas da posição basal da planta foram as que apresentaram maior porcentagem de enraizamento. 0 estrangulamento na base da estaca não influiu no enraizamento. Aplicação de IBA + KOH causou necrose na base das estacas. Ocorreu formação de calo em 77,7% das estacas aneladas, 66,6%, das medianas e 33,0% das basais.
In some leguminous plants, associations with nitrogen-fixing microorganisms allow their nutrition with nitrogen (N) from the atmosphere. This process is known as Biological Nitrogen Fixation (BNF), where through nitrogenase enzymes, N2 is converted to an available form. This process can replace in part, or in total, nitrogen fertilizers. Cowpea bean is a legume species that is recognized for its high capacity to carry out BNF. In the last decades, studies have encouraged small farmers from north and northeast Brazil to use inoculants with rhizobia species since the results of researches have demonstrated that inoculation is an interesting strategy to improve cowpea production. Considering the specific function of molybdenum (Mo) in the N assimilation, different doses of Mo were tested in this study in order to find doses that could improve and enhance BNF. Therefore, this study aimed to compare nitrogen fertilization and BNF in the N assimilation by plants with different Mo doses. Inoculation was performed with the strains UFLA 03-84 and INPA 03-11B. Doses of Mo were applied in seeds and each pot contained five seeds. Thirty-five days after germination, the plants were analyzed for shoot dry matter and fresh matter, N contents and accumulation, as well as the Soil-Plant Analysis Development (SPAD) Index and nodulation in inoculated plants. The different doses of Mo and also the nodulation treatments did not show significant differences in the contents of N. Plants with N fertilization had significant higher shoot dry matter and root dry matter production, in addition to higher N foliar contents and N accumulation. Therefore, BNF was not as efficient as nitrogen fertilization in the evaluated experimental conditions using cowpea beans.
It was intended to evaluate the influence of indolebutyric acid (IBA) and zinc upon the rooting and development of rootstock of ‘Cravo’ lemon tree transplants of bare root to the modified hydroponic system in the grafting stage. Plants of rootstocks were treated by immersion of their root system into the different solutions tested for 24 hours. The experiment was arranged in a completely randomized design with seven treatments composed of IBA doses of 50, 100 and 200 mg.L-1 and Enervig® which contains in its formulation 33.92 g.L-1 of Zn at 60, 90 and 120 ml.L-1, and distilled water as a control with three replications and nine plants per plot, amounting to 189 plants , 15 cm tall. The rootstocks were transplanted to the tubes and taken to the modified hydroponic system, being evaluated (1) the development of the plants and (2) the time needed for the rootstocks to reach the grafting stage, considered ideal between 5 and 6 mm in diameter. The treatment with a solution of 100 mg.L-1of IBA proved superior to the others in the development of height and biomass yield and tended to provide greater stem diameter development. The grafting point was obtained, on average at 70 days after transplanting and the production of Rangpur lime trees in a hydroponic system may be recommended. When the root system of the ‘Cravo’ lemon tree was treated with 100 mg.L-1 solution the IBA grafting point was obtained at 45 days after transplanting.
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