Induction and growth curve of calli from leaf and nodal explants of genipap.

The aim of this study was to determine the effect of the auxin 2,4-D (2,4-dichlorophenoxyacetic) in calli formation from leaf and nodal segments of genipap and to characterize its growth curve. Explants obtained from shoots previously established from in vitro seedlings were used for calli induction. The experimental design was completely randomized in a 3x5x2 factorial with three accessions (NB, SA, SAL), five concentrations of 2,4-D (0.0; 2.0; 4.0, 6.0 or 8.0 mg L-1) and two times of measurement for calli fresh weight (30 and 60 days). There was callus formation in all treatments tested. It was observed that the best response for callus induction from leaf segments was with 2.0 mg L-1 of 2,4-D. For the nodal segment, the response among the accessions was different due to 2,4-D concentrations. The growth curve was plotted according to the fresh weight of callus obtained at intervals of 10 days up to 60 days. Through the established growth curve, the nodal-derived calli from accession SA should be transferred to a new medium, after 40 days of culture

The dust properties and physical conditions of the interstellar medium in the LMC massive star forming complex N11

We combine Spitzer and Herschel data of the star-forming region N11 in the Large Magellanic Cloud to produce detailed maps of the dust properties in the complex and study their variations with the ISM conditions. We also compare APEX/LABOCA 870um observations with our model predictions in order to decompose the 870um emission into dust and non-dust (free-free emission and CO(3-2) line) contributions. We find that in N11, the 870um can be fully accounted for by these 3 components. The dust surface density map of N11 is combined with HI and CO observations to study local variations in the gas-to-dust mass ratios. Our analysis leads to values lower than those expected from the LMC low-metallicity as well as to a decrease of the gas-to-dust mass ratio with the dust surface density. We explore potential hypotheses that could explain the low observed gas-to-dust mass ratios (variations in the XCO factor, presence of CO-dark gas or of optically thick HI or variations in the dust abundance in the dense regions). We finally decompose the local SEDs using a Principal Component Analysis (i.e. with no a priori assumption on the dust composition in the complex). Our results lead to a promising decomposition of the local SEDs in various dust components (hot, warm, cold) coherent with that expected for the region. Further analysis on a larger sample of galaxies will follow in order to understand how unique this decomposition is or how it evolves from one environment to another.Comment: 24 pages, 16 figures, accepted for publication in MNRA

Agricultural Performance of Diverse Pastures of Complementary Species and Monoculture Pastures Defoliated According to the Leaf Regrowth Stage Window of Opportunity Criterion

In a diverse pasture of complementary species (DPCS), individual species fulfil agro-ecological functions that confer growth asynchrony and complementarity of ecosystem functions. These attributes provide yield consistency with a more even forage supply pattern across the year compared to monocultures. A common leaf regrowth stage window opportunity (LSWO) for the diverse species enables pasture defoliation that stimulates growth and persistence. The study assessed seasonal and annual growth traits of Lolium perenne (Lp), Bromus valdivianus (Bv) and Dactylis glomerata (Dg) as single grass species (Mono) sown with Trifolium repens (Tr) and as DPCS with the four species (Lp+Bv+Dg+Tr=Mix). The defoliation criteria applied (LSWO of a target species: Lp, Bv or Dg) resulted in eleven grazing events for MonoLp and MixLp, ten grazing events for MonoBv and MixBv, and nine grazing events for MonoDg and MixDg in a year. MixBv and MixDg displayed synchronized overlaps of the three species LSWOs during the seasons and across the year. MixLp had Bv and Dg being grazed slightly earlier than their LSWOs. There were no significant differences in annual herbage accumulation for all treatments. Significant differences were found within seasons, and the seasonality of the pasture growth was reduced in the DPCS when compared to their respective Mono establishment. This resulted in a more evenly distributed pasture feed resource throughout the year and can mitigate the negative impacts of extreme climatic events (longer periods of soil water restriction or saturation). The LSWO criterion enabled the successful management of monocultures and DPCS

Local-density approximation for exchange energy functional in excited-state density functional theory

An exchange energy functional is proposed and tested for obtaining a class of excited-state energies using density functional formalism. The functional is the excited-state counterpart of the local-density approximation functional for the ground state. It takes care of the state dependence of the energy functional and leads to highly accurate excitation energies

Avaliação da longevidade de grãos de pólen de de Manihot esculenta spp. flabellifolia por teste colorimétrico e fluorescência.

O conhecimento sobre a longevidade e viabilidade polínica é crucial para o melhoramento genético de uma espécie. Este trabalho teve como objetivo avaliar a longevidade do pólen de Manihot esculenta spp flabellifolia por meio de teste colorimétrico e pelo método de reação fluorocromática. Como material vegetal foram utilizados grãos de pólen do acesso FLA 029V-01. Para avaliação da longevidade polínica foram utilizadas flores estaminadas em quatro estádios distintos: 1 ? pré-antese; 2 ? antese; 3 ? 24 horas após antese e 4 ? período superior a 24 horas da antese. Para avaliação da viabilidade polínica foram utilizados os métodos de fluorescência e colorimétrico com o uso do corante carmim acético 1%. A viabilidade nos testes colorimétricos variou de 90% no pólen em antese a 75% nos grãos após um período superior a 24 horas à antese. Já nos testes por reação fluocromática a porcentagem de pólen viável foi de 81% para o pólen avaliado na antese e 50% no pólen na pré-antese, não ocorrendo germinação quando se utilizou de grãos de pólen 24 horas após a antese. Os resultados indicam que a perda de viabilidade em Manihot esculenta parece ser bem marcante 24 horas após a antese e o teste colorimétrico superestimou a viabilidade polínica não sendo recomendado para este tipo de avaliação