Marcel Viana Pires

Passion flower hybrids and their use in the ornamental plant market: perspectives for sustainable development with emphasis on Brazil

The Passiflora L. (Passifloraceae) genus consists of about 500 species widely distributed throughout tropical and subtropical regions, commonly known as the passion flower. The passion flowers are considered ornamental plants because of the exotic beauty of their flowers and variant foliage. Since their introduction to the Old World, around 1625, seventeenth century, they have been used to decorate European glasshouses and gardens. Interspecific hybridization is used to produce single ornamental plants. However in some countries, such as Brazil, being centre of origin of many species, the potential value of these species has hardly been exploited. The beauty of these wild species and their hybrids is little known in Brazil. Therefore it is here intended to highlight the productive and commercial potential of the passion flowers for the purpose to generate an income in family agriculture, while maintaining the ecological balance and optimizing the use of natural resources.

ALUMINUM EFFECTS ON GROWTH, PHOTOSYNTHESIS, AND MINERAL NUTRITION OF CACAO GENOTYPES

A solution culture experiment was conducted in a greenhouse with two cacao genotypes (Catongo and Theobahia). Plants were subjected to seven aluminum (Al) concentrations and Al effects on growth, photosynthesis, and mineral content were assessed. Inter-genotypic differences for Fo, Fm and Fv fluorescences, as well as for Fv/Fm, were observed with increasing Al concentrations. There was a decreasing of Fo, Fm, Fv and Fv/Fm for the Catongo. Increasing Al concentration decreased photosynthetic rate, stomatal conductance and leaf transpiration rate, however, inter-genotypic differences in these parameters were not observed. The Al-treatments decreased content of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) in different plant parts, with the exception of K content in stems of Theobahia and in leaves of both genotypes. Theobahia showed higher tolerance to Al phytotoxicity, manifested mainly in the higher levels of Al in the growth medium. Inter-genotypic differences were observed in the growth and mineral nutrition.

Nitrogen-Use Efficiency, Nitrous Oxide Emissions, and Cereal Production in Brazil: Current Trends and Forecasts

The agriculture sector has historically been a major source of greenhouse gas (GHG) emissions into the atmosphere. Although the use of synthetic fertilizers is one of the most common widespread agricultural practices, over-fertilization can lead to negative economic and environmental consequences, such as high production costs, depletion of energy resources, and increased GHG emissions. Here, we provide an analysis to understand the evolution of cereal production and consumption of nitrogen (N) fertilizers in Brazil and to correlate N use efficiency (NUE) with economic and environmental losses as N2O emissions. Our results show that the increased consumption of N fertilizers is associated with a large decrease in NUE in recent years. The CO2 eq. of N2O emissions originating from N fertilization for cereal production were approximately 12 times higher in 2011 than in 1970, indicating that the inefficient use of N fertilizers is directly related to environmental losses. The projected N fertilizer forecasts are 2.09 and 2.37 million ton for 2015 and 2023, respectively. An increase of 0.02% per year in the projected NUE was predicted for the same time period. However, decreases in the projected CO2 eq. emissions for future years were not predicted. In a hypothetical scenario, a 2.39% increase in cereal NUE would lead to

Sistemas Agroflorestais como Estratégia de Adaptação aos Desafios das Mudanças Climáticas no Brasil

21 million savings in N fertilizer costs. Thus, increases in NUE rates would lead not only to agronomic and environmental benefits but also to economic improvement.

Detection of 1-aminocyclopropane-1-carboxylate oxidase activity in seeds of Stylosanthes humilis H.B.K

This paper analyzes the role of agroforestry systems (AFS) as an adaptative measure to climate change in Brazil. A treatment-effects model (Propensity Score Matching) was developed. We identified the main determinants of the use of AFS and if the municipalities in which this technique is used are less vulnerable to climate change. The results showed that socioeconomic variables (land ownership, financing options, access to information and technical assistance) and agronomic variables (water resources availability and soil quality) influence the adoption of agroforestry systems in Brazilian municipalities. Climate conditions (temperature and precipitation) also play an important role in the use of these systems, which confirms their role as an adaptative strategy. It was also concluded that the AFS have the potential to improve the Brazilian agricultural performance due to the fact that the land value tends to be higher in municipalities where these systems are used. Thus, the AFS can make the agricultural sector less exposed to the negative effects of climate change in both the present and in future scenarios.

Does shading explain variation in morphophysiological traits of tropical epiphytic orchids grown in artificial conditions

The activity of 1-aminocyclopropane-1-carboxylate oxidase (ACO) was characterized in seeds of the tropical legume Townsville stylo (Stylosanthes humilis) both in vitro (desalted extract of non-dormant seeds) and in vivo (entire dormant seeds). Optimum conditions for maximum in vitro ACO activity in a Trizma-HCl 100 mM buffered medium were: pH 7.0, temperature 32oC and cofactors and co-substrate at the following concentrations: NaHCO3 30 mM, sodium ascorbate 30 mM and FeSO4 50 µM. Rates of in vitro reaction catalyzed by ACO were shown to be constant within the interval 15-150 minutes from the onset of the reaction. The apparent Km for in vitro ACO, as determined from the non-linear curve fitting to the Michaelis-Menten equation, was 156±8.3 µM ACC with a Vmax 5.4±0.08 mmol (ET) g-1 h-1 on a fresh matter (FM) basis. In vivo (control basal medium: HCl-KOH 10 mM pH 7.0, 30oC, reaction time 15 hours) apparent Km was 230±27 µM ACC and Vmax 11.9±0.38 mmol (ET) g-1.h-1 on a FM basis. These data suggest that the enzyme exhibits a relatively low affinity for the substrate. The well-known inhibitors of ACO activity, α-aminoisobutyric acid, salicylic and acetylsalicylic acids, n-propylgallate and cobaltous ions, were highly effective in inhibiting ACO activity of Townsville stylo seeds.