Considering the scarce information on nutrient extraction by plants for seed production within vegetable crops, as well as the effect of fertilization over extraction, studying nutrient accumulation in different plant parts under varied fertilization rates is necessary. This study aimed to evaluate the influence of phosphate rates on macronutrient accumulation in cauliflower plants during seed production. Five phosphate rates were studied (0, 300, 600, 900 and 1200 kg/ha P 2 O 5 ), in a randomized complete block design, with four replications. Accumulation of nutrients in the different plant parts was evaluated at the end of the cycle (vegetative and reproductive, the latter divided in seeds and inflorescence). Data were submitted to analysis of variance and regression. Considering only the seeds, a quadratic effect was obtained for the accumulation of all macronutrients, with maximum estimated for rates between 858 and 952 kg/ha P 2 O 5 . Considering the whole plant (total accumulation), a linear increase for P, Ca and S was obtained the higher the P 2 O 5 rates, while the effect was quadratic for N, K and Mg accumulation. The total nutrient accumulation descending order was: K>N>Ca>S>P>Mg, and considering only the seeds was: N>S>K>P>Ca>Mg, S being highlighted as the second most accumulated nutrient in the seeds.

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Nutrient need in each development stage of plant is showed by nutrient accumulation curve; this is an important tool for fertilization recommendation. However, researches on vegetables with the objective to estimate these curves are scarce, mainly in the modern hybrids that show higher productivity potential and, probably, higher nutrient demand. In this study, the authors aimed to determine macronutrient accumulation of beetroot plants, hybrid Boro. The experiment was carried out in São Manuel, São Paulo State, Brazil. Five treatments [seasons of plant collection: 0, 14, 28, 43 and 60 days after transplanting (DAT)], considering that in each season 16 plants were collected (four replications of four plants each, in a randomized block design). We evaluated dry matter accumulation, and nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S) in plant shoot and root. The period of the highest demand for most of macronutrients was from 29 to 43 DAT. The decreasing order of macronutrients exported by the roots of the beetroot was K>N>P>Mg>S>Ca (376, 232, 45, 29, 21 and 13 mg/plant, respectively), and accumulated by the whole plant (shoot + root) was K>N>Mg>Ca>P>S (709, 404, 126, 113, 69 and 50 mg/ plant, respectively).Keywords: Beta vulgaris, fertilization, nutrients absorption, nutritional demand. RESUMO Acúmulo de macronutrientes pela beterrabaA necessidade de nutrientes em cada etapa de desenvolvimento da planta é mostrada pela curva de acúmulo de nutrientes, sendo importante ferramenta para a recomendação de adubação. No entanto, são raras as pesquisas com hortaliças com o objetivo de se obter estas curvas, principalmente nos modernos híbridos que apresentam maior potencial produtivo e, provavelmente, maior necessidade de nutrientes. Objetivou-se com este trabalho determinar o acúmulo de macronutrientes pela planta de beterraba, híbrido Boro. O experimento foi conduzido em São Manuel-SP. Foram cinco tratamentos [épocas de coleta das plantas: 0, 14, 28, 43 e 60 dias após o transplante (DAT)], sendo em cada época coletadas 16 plantas (quatro repetições de quatro plantas cada, no delineamento em blocos ao acaso). Foram avaliados o acúmulo da massa seca e de nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg) e enxofre (S) na parte aérea e nas raízes das plantas. O período de maior demanda para a maioria dos macronutrientes foi dos 29 aos 43 DAT. A ordem decrescente dos macronutrientes exportados pelas raízes de beterraba foi K>N>P>Mg>S>Ca, com 376, 232, 45, 29, 21 e 13 mg/planta, respectivamente, e acumulados pela planta (parte aérea + raiz) foi K>N>Mg>Ca>P>S, com 709, 404, 126, 113, 69 e 50 mg/ planta, respectivamente. Palavras-chave:Beta vulgaris, adubação, marcha de absorção de nutrientes, demanda nutricional.

Most recent studies have focused to the nutrition and fertilizer recommendations of commercial broccoli production. There are a few studies on effect of fertilization on seed production. Although Brazil is a major producer of vegetables, research on seed production of broccoli is scarce. Therefore, it is necessary to develop research lines that increase the information regarding the nutritional requirements for seed production, since in broccoli; there is a 60 days cycle for production, which leads to the understanding of a greater nutritional need of the crop. It is known that sulphur is the second most accumulated nutrient in broccoli seeds. This study aimed to evaluate the effect of doses of sulphur topdressing; and organic compost fertilization on the production and quality of broccoli seeds at planting. The experimental design was a randomized complete block, with ten treatments (5x2 factorial design) and four repetitions. Treatments consisted of five doses of S topdressing (0, 58, 115, 173 and 230 kg S.ha-1) in the presence or absence of organic compost (100 t ha-1) at planting stage. Seed production (mass and number per plant), mass of thousands of seeds, seed quality (germination, first germination count, germination speed index, seedling length, and seedlings fresh weight); and macronutrients accumulation in the seeds were evaluated. The amount of seeds per plant was 9836 and 8005 seeds per plant in the presence or absence of organic compost, respectively. The seeds fresh mass of 45.7 and 33.1 g of seeds per plant was produced with and without organic compost, respectively. However, the other characteristics, such as total germination (G), first count (FC), germination index rate (GIR), and seedling fresh mass (SFM) did not reach any significant differences. Regarding to the doses of sulphur, a linear increase was detected to the equation for all macronutrients extracted in the absence of organic compost at planting. However, in the presence of organic compost (100 t ha-1) at planting, a linear equation was obtained for P, Mg and S. For the other macronutrients, a quadratic function occurred, with average values of 2329.2, 431.4 and 326, 5 mg plant-1 at the maximum doses estimated in 165.56, 146.50 and 171.42 for N, K and Ca, respectively.