Molybdenum (Mo) reserve in large seeds can complement Mo uptake by plants from soil, but the content of Mo in common bean (Phaseolus vulgaris L.) seed for this purpose is unknown. We hypothesized that 3.639 ± 0.751 μg Mo seed -1 would be suffi cient to complement Mo uptake by irrigated common bean plants from a Mo-poor soil. Th ree fi eld experiments were performed in a clayey Ultisol naturally infested by native strains of Rhizobium in Zona da Mata, Minas Gerais, Brazil. Treatments were arranged as 4 × 2 factorial combination of Mo contents in seeds [small (0.007 ± 0.007 or 0.248 ± 0.057 μg Mo seed -1 ) or large (3.639 ± 0.751 or 6.961 ± 1.844 μg Mo seed -1 )] and Mo spraying treatments (90 g ha -1 or unsprayed) with six replications. Phosphorus, N (25 kg ha -1 ), and K were applied together in the furrow during planting time. No topdressing N was applied. Final plant population and seed yield were evaluated in two experiments. Molybdenum contents in the seeds did not aff ect plant population. On average, unsprayed plants from seeds with small Mo contents yielded 1785 kg ha -1 , while those from seeds with large Mo content yielded 2109 kg ha -1 . Foliar application of Mo increased plant N status, plant growth, and yield in plants originated from seeds with small Mo content, but not in plants grown from seeds with large Mo content. We conclude that 3.639 ± 0.751 μg Mo seed -1 suffi ciently complement the Mo uptake by common bean plants from soil.

Adubações minerais e orgânicas promovem alterações nas condições físicas e químicas do solo, com conseqüente efeito na produtividade das culturas. Um experimento foi realizado no Município de Campos dos Goytacazes, RJ, de fevereiro de 2005 a julho de 2006, para comparar diferentes adubos orgânicos com a adubação mineral do maracujazeiro-amarelo quanto aos efeitos sobre as características químicas e físicas do solo adubado. O delineamento experimental foi em blocos casualizados, com quatro repetições e seis tratamentos, correspondentes às seguintes adubações por planta: (AM) adubação mineral = 100 g da fórmula NPK 20-5-20 + cobertura morta (CM); EB = 5 L de esterco bovino + CM; FOC = 500 g de farinha de ossos e carne + CM; RM = 5 L de raspa de mandioca + CM; TF C/CM = 5 L de torta de filtro + CM; TF S/CM = 5 L de torta de filtro - sem CM. A adubação mineral foi feita a cada 30 dias e as adubações orgânicas a cada 60 dias. Foram avaliados os atributos químicos: pH, condutividade elétrica, teores de P, K, Ca, Mg, Na, Al, H + Al, e matéria orgânica; e os físicos: granulometria, densidade do solo e das partículas, porosidade total, macro e microporosidade, capacidade de campo, ponto de murcha e água disponível em três diferentes profundidades (0-5, 5-10, 10-15 cm). Os adubos orgânicos aplicados no maracujazeiro promoveram mudanças significativas nas características químicas do solo, em comparação com a adubação mineral tradicional, em que houve aumento do pH e do H + Al em todas as profundidades, e redução dos teores de Al nas camadas mais profundas. Houve, ainda, aumento nos teores de nutrientes no solo e, por conseqüência, na soma de bases, principalmente na camada superior, sendo a torta de filtro o composto orgânico mais eficiente em promover tais melhorias, inclusive aumentando a CTC do solo. Apenas a torta de filtro promoveu alterações nas características físicas do solo, reduzindo as quantidades de areia grossa e aumentando as quantidades de silte, argila e matéria orgânica. As demais características físicas do solo não foram influenciadas pela adição de adubos orgânicos no maracujazeiro, em comparação com a adubação mineral tradicional.

2 Boron (B) deficiency causes a wide array of symptoms, not only among species of palms, but also within a single species (i.e. Cocos nucifera). A better understanding of the effects of B deficiency in coconut will be important to try optimizing a rational fertilization management in coconut plants. Thus, modification of PSII photochemistry (using a group of fluorescence parameters, called the JIPtest, that quantify the stepwise flow of energy through Photosystem II) and gas-exchange in boron deficient green dwarf coconut plants were investigated. Our results suggest that a modification of PSII photochemistry (non-stomatic effects) and gas-exchange (stomatic effects) were induced by boron deficiency. Such modifications are manifested by (1) increase the ratio of total dissipation to the amount of active reaction centers (RCs) [dissipation (DI)/RC] and (2) leaf-to-air vapor pressure difference (VPD leaf-air ). These modifications (on PSII photochemistry and gas-exchange) were caused by a decrease in energy absorbed per excited cross-section [absorption flux (ABS)/cross section of the 439 Downloaded by [University of California Santa Cruz] at 07:46 05 April 2015 440 L. G. R. Pinho et al. (SPAD readings), growth parameters (root DW and height plant). Our results demonstrate that by analyzing fluorescence (JIP test parameters) derived from the polyphasic fluorescence transients measurements were able to estimate the functional changes of PSII in B deficient coconut plants. The results in this study suggest that fluorescence analysis (JIP test) and instantaneous measurements of gas-exchange can be useful tools in assessing the physiological effects of B deficiency in green dwarf coconut. sample (CS 0 )], density of active reaction centers (RC/CS), maximal trapping rate of an exciton that will lead to Q A reduction measured over a cross-section of active and inactive RCs [trapping flux (TR)/CS 0 ], electron transport per excited cross-section [electron transport flux (ET 0 )/CS)], area above curve (proportional to the pool size of the electron acceptors QA on the reducing side of PSII), photosynthesis (A), stomatal conductance (g s ), transpiration (E), chlorophyll concentration

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