897 resultados para 300302 Plant Growth and Development


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A better understanding of the differential growth of upland rice (Oryza sativa L.) cultivars with increasing soil S availability could help improve rice yield under upland conditions. The objective of this study was to evaluate root and shoot growth and nutrition of upland traditional and modern rice cultivars as affected by S availability. The experimental design was completely randomized in a 3 (rates of S) × 3 (cultivars) factorial with four replications. Low availability of S in the soil reduces root and shoot development and the efficiency of N, P, and S uptake, as well as the concentration and content of these nutrients in rice cultivars. At 0 mg dm-3 of S, rice cultivars prioritize root growth over shoots, and the traditional cultivar does so with greater intensity. Our results suggested that more development of traditional cultivars under low S availability facilitates its adaptation in soils under this condition. On the other hand, the intermediate and modern cultivars are more responsive to S fertilization. Moreover, S fertilization allows significant increases in upland rice growth and must be considered in cropping systems aiming for high yields. © Soil Science Society of America.

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Summary Summarizes discussions and presentations on the following: review of activities at the subregional level in support of the International Conference on Population and Development; mechanisms to incorporate population issues into the development process; population policies; the effects of demographic trends on economic growth and poverty; the environmental effects; gender equality, equity and the empowerment of women; male responsibility and participation; reproductive health and the economic impact of the HIV/AIDS epidemic; and the partnership with civil society.

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This paper will contend that the post-2015 development agenda presents a major opportunity for Caribbean countries to reverse decades of lagging economic performance and make the transition to balanced, holistic, and people-centred growth and development. The MDGs, while valuable in promoting gains in poverty reduction, health, education, nutrition, and maternal well-being were not tailored to the growth and development needs of the region. This can now be changed by a post-2015 development agenda which goes beyond improving the welfare of citizens by meeting basic needs and enhancing access to primary services. The necessary scaling-up of the MDG framework will require that the sustainable development goals, which will anchor the post- 2015 development agenda, are capable of promoting structural change, competitiveness and output gains while advancing social development and meeting environmental concerns. They must also address the unfinished business of the millennium development goals, primarily in the area of human development.

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Latin America’s fiscal accounts deteriorated slightly during 2015, registering an average deficit of 3.0% of GDP and average gross public debt of 34.7% of GDP. Of the 19 countries considered, the fiscal deficit and public debt as a share of GDP both increased in 11. The region started to build up public debt, most of it domestic, after the 2008 international financial crisis to meet the growing financing needs resulting from the worsening growth situation.

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Em estudos anteriores descrevemos o isolamento de nove substâncias, a partir das folhas de Derris urucu, uma espécie encontrada amplamente na floresta Amazônica, as quais foram identificadas como cinco estilbenos e quatro diidroflavonóis. Neste trabalho, três desses diidroflavonóis [urucuol A (1), urucuol B (2) e isotirumalina (3)] foram avaliados para identificar seus potenciais como aleloquímicos. Estamos relatando também, o isolamento e a determinação estrutural de um novo flavonóide [5,3′-diidroxi-4′-metoxi-(7,6:5″,6″)-2″,2″-dimetilpiranoflavanona (4)]. Investigamos os efeitos dos diidroflavonóis 1-3 sobre a germinação de sementes e desenvolvimento da radícula e do hipocótilo da planta daninha Mimosa pudica, usando soluções a 150 mg.L–1. Urucuol B, isoladamente, foi quem apresentou o maior potencial para inibir a germinação de sementes (26%), por sua vez, isotirulamina exibiu maior capacidade para reduzir o desenvolvimento do hipocótilo (25%), porém nenhuma das três substâncias mostrou potencial para inibir o desenvolvimento da radícula. Quando combinadas aos pares, as substâncias mostraram sinergismo ao desenvolvimento da radícula e do hipocótilo e efeitos, na germinação de sementes, que poderiam ser atribuídos a antagonismo. Quando testadas separadamente, as substâncias apresentaram maior tendência para inibir a germinação de sementes, enquanto que, quando testadas aos pares, observou-se aumento no efeito de inibição do desenvolvimento da planta daninha.

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Mentha piperita L. is an aromatic and medicinal species of the family Lamiaceae, known as mint or peppermint, and its leaves and branches produce essential oil rich in menthol. This study aimed to evaluate physiological indexes, macro- and micronutrients inthe shootsand essential oil of Mentha piperita L. grown in nutrient solution number 2 of Hoagland and Arnon (1950) with different N, P, K and Mg levels. Shoot length, dry mass of the different organs, total dry mass, leaf area, essential oil yield and composition, and macronutrient (N, P, K, Mg, Ca, S) and micronutrient (Mn, Cu, Fe, Zn) contents in the shoot were evaluated. Plants treated with 65%N/50%P/25%K/100%Mg had a tendency towards longer shoot, greaterroot and leaf blade dry masses, higher essential oil yield, higher menthol levels and lower menthone levels. The results showed that Mentha can be grown in nutrient solution by reducing 65% N, 50% P, 25% K and 100% Mg. This solution had better development compared to the other tested treatments. Therefore,we recommendMentha piperita L. to be grown with such nutrient levels.

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The aim of the present study was to determine the size at sexual maturity in the freshwater crab Dilocarcinus pagei Stimpson, 1861, from a population located in Mendonça, state of São Paulo, Brazil. The crabs were sampled monthly (July 2005 to June 2007), at Barra Mansa reservoir. The specimens were captured manually or in sieves passed through the aquatic vegetation. The crabs were captured and separated by sex based on morphology of the pleon and on the number of pleopods. The following dimensions were measured: carapace width (CW); carapace length (CL); propodus length (PL); and abdomen width (AW). The morphological analysis of the gonads was used to identify and categorize individuals according to their stage of development. The morphological maturity was estimated based on the analysis of relative growth based on the allometric equation y = ax b. The gonadal maturity was based on the morphology of the gonads by the method CW50 which indicates the size at which 50% of the individuals in the population showed gonads morphologically mature to reproduction. The biometric relationships that best demonstrated the different patterns of growth for the juvenile and adult stages were CW vs. PL for males and CW vs. AW for females (p<0.001). Based on these relationships, the estimated value to morphological sexual maturity was 21.5 mm (CW) in males and 19.7 mm (CW) in females. The determination of the size at sexual maturity and the adjustment of the data based on the logistic curve (CW50) resulted in a size of 38.2 mm for males and 39.4 mm for females (CW). Based on the data obtained for sexual maturity for D. pagei, we can estimate a minimum size for capture of 40 mm (CW). This minimum size allows at least half of the population to reproduce and retains the juveniles and a portion of the adults in the population.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Boron (B) is the most deficient micronutrient in cotton (Gossypium hirsutum L.). It is generally accepted that B is immobile in cotton phloem, but some cultivars could remobilize the nutrient. In order to further understand B uptake and mobility in various cotton cultivars two experiments were conducted.In experiment-1, cotton cultivars were grown in B-10 enriched or natural abundance nutrient solutions for 4 weeks and transferred to nutrient solutions ranging from deficient to sufficient in B. In experiment-2 B-10 enriched boric acid was applied to cotton leaves and B mobilization was determined.In deficient plants, B previously supplied to roots was remobilized from older to younger plant tissues, but the amount was insufficient to maintain growth. Boron deficiency symptoms appeared and progressed with time. Boron applied to leaves was taken up and remobilized within 24 h. Boron mobilization was higher to plant parts above the treated region.Boron uptake and mobilization was similar among cotton cultivars. Boron applied to cotton leaves shows a preferential translocation to younger tissues. Foliar sprays of B to cotton may be used to cope with a temporary deficiency, but to achieve full growth and development B must be available to cotton throughout the plant cycle.