Representativeness of national parks in protecting freshwater biodiversity: A case of Brazilian savanna

The establishment of national parks are an important and often-used tool to protect biodiversity. However, when considering freshwater ecosystems, many of these areas in Brazil are habitat mosaics in which a small part of the ecosystem is protected and strongly influenced by the surrounding environment. By assessing the fish fauna and their diversity patterns in five national parks (NPs) within the Brazilian savanna, we discuss whether the establishment of new NPs or the expansion of their current conservation limits would potentially conserve additional species. We selected all national parks within the third largest drainage area in Brazil. To sample fish communities, we explored 60 streams through a standardised field protocol. We also simulated the potential impact of the enlargement or implementation of a new national park. Our results reinforce the importance of national parks and their surrounding areas to preserve fish species. The enlargement of national parks would result in an increase of potentially protected species; however, the same achievement would be obtained if their buffer zones were effectively managed and protected. We recommend an alternative conservation approach to increase protection of tropical savanna fish biodiversity, especially in developing countries such as Brazil with scarce financial resources available for management, monitoring and creation of protected areas.     

Laboratory evaluation of the effects of Manilkara subsericea (Mart.) Dubard extracts and triterpenes on the development of Dysdercus peruvianus and Oncopeltus fasciatus

BACKGROUND: Studies were carried out to evaluate the effects of Manilkara subsericea extracts and triterpenes on the development of two species of agricultural pest insects, Oncopelus fasciatus and Dysdercus peruvianus. RESULTS: All treatments of insects with M. subsericea extracts induced mortality, delayed development and inhibited moulting. Some extracts assayed (FH, FB and FD in D. peruvianus, and FH, FB and FEA in O. fasciatus) also produced body deformities in the few adults that emerged. Other extracts (FH, FEA, FB, FD and LET in both insects), however, induced either permanent (overaged) or extranumerary nymphs, both of which were unable to achieve the adult stage and reproductive status. The insects were also treated with triterpenes (α‐ and β‐amyrin acetates) which showed high lethality at 30 days after treatment and delayed the intermoult period so that overaged nymphs were detected. CONCLUSION: The results indicate that extracts and triterpenes from Manilkara subsericea act as potent growth inhibitors of phytophagous hemipteran nymphs. It is also concluded that the mixture of several different molecules in the extracts used produces synergic effects that do not occur after using the triterpenes (PFT) alone. These secondary metabolites in the M. subsericea extracts can potentially be used in integrated control programmes against crop pests. Copyright © 2012 Society of Chemical Industry     

Different cultures,different values: The role of cultural variation in public’s WTP for marine species conservation

Understanding the cultural variation in public preference for marine species is a necessary pre-requisite if conservation objectives are to include societal preferences in addition to scientific considerations. We report the results of a contingent study undertaken at three case-study sites: Azores islands (Portugal), Gulf of Gdansk (Poland) and Isles of Scilly (UK). The study considered species richness of five specific marine taxa (mammals, birds, fish, invertebrates and algae) as proxies of marine biodiversity and the aim of analysis was to estimate from a multi-site perspective public’s willingness to pay (WTP) to avoid increased levels of species loss (reduction of species richness) for different marine taxa. Results, based on 1502 face-to-face interviews, showed that income, education and environmental awareness of the respondents were significant predictors of WTP for marine species conservation. Results also indicated that respondents in each of the European locations had different preferences for marine taxa. In the Azores, although mammals and fish were valued highly, small differences occurred in the WTP among different taxa. Respondents in the Isles of Scilly put a relatively low value on fish while algae and marine mammals were highly valued. In Gdansk, respondents defined a clear order of preference for marine mammals > fish > birds > invertebrates and algae. These findings suggested that cultural differences may be important drivers of valuation and undermines the commonly held premise that charismatic/likeable taxa consistently have a disproportionately strong influence on WTP for biodiversity conservation. We conclude that conservation policy must take account of cultural diversity alongside biological diversity.     

Cadmium Effects on Sunflower Growth and Photosynthesis

The objective of this work was to evaluate the effects of cadmium (Cd) exposure on sunflower (Helianthus annuus L.) plant growth, chlorophyll content, and fluorescence. Sunflower plants were exposed to different concentrations of Cd (0, 5, 50, and 500 μ M) for 21 d. Growth parameters (organ length, fresh and dry weights) were determined and results compared with two parameters associated with photosynthesis degradation: chlorophyll content and fluorescence (an easy and non-destructive method). Exposure to Cd significantly decreased growth by decreasing shoot and root lengths and their fresh and dry weight. Cadmium also decreased significantly chlorophyll content and fluorescence efficiency in all treatments. Chlorophyll a (chl a) and chl b contents showed a significant correlation with chlorophyll fluorescence (F_v/F_m ratio). The EC₅₀ values showed that the roots' length was the most sensitive endpoint in this study, followed by the roots' and shoots' weight endpoints. Also, chl b showed higher sensitivity to Cd contamination than chl a. These data show that in complement to growth parameters, the use of photosynthetic parameters provides helpful information on plant response to Cd exposure.     

Effects of Seasonal Nitrate Flush on Nitrogen Metabolism and Soluble Fractions Accumulation in Two Rice Varieties

ABSTRACT

Two rice varieties, ‘Piaui’ (a landrace) and ‘IAC-47’ (an improved variety), were grown in nutrient solution containing 20 mg nitrate (NO₃ ^?)-nitrogen (N) L^{? 1} up to 32 days after germination (DAG). After this, a group of plants received 200 mg NO₃ ^?NL^{? 1}, while the other was kept at 20 mg NO₃ ^?NL^{? 1} up to 42 DAG. From 42 until 56 DAG, all plants received 5 mg NO₃ ^?NL^{? 1}. Plants were collected at 42 and 56 DAG, soluble fractions, nitrate reductase (NR) and GS enzymatic activities were determined. The nutritional history of the plants affected significantly the uptake and use of nitrogen (N), and should be taken into consideration in the studies of N-use efficiency. The variety ‘Piaui’ was more efficient than ‘IAC-47’ in N-uptake use, accumulating more NO₃ ^? in its tissues at the initial phases of its cycle for subsequent utilization.     

Yield Physiology of Dry Bean

Dry bean (Phaseolus vulgaris L.) is an important food legume for the world population. However, its average yield is low worldwide. The main reasons for low yield are biotic and abiotic stresses. Maximum economic yield of a crop can be achieved with appropriate balance between plant and environmental factors during crop growth cycle. Adopting appropriate management practices in favor of high yields can modify some of these factors. Hence, knowledge of yield physiology of dry bean is important for understanding yield formation components during crop growth and development and consequently improving yield. Dry bean growth cycle is divided into vegetative and reproductive growth stages. During vegetative stage, development of roots, trifoliate, node, and branches take place. Main features of reproductive growth stage are flowering, pod and grain formation. Important plant traits associated with yield are root and shoot dry matter yield, pod number, 100 grain weight, leaf area index, grain harvest index, and nitrogen harvest index. These plant traits are genetically controlled and also influenced by soil and plant management practices. Higher yield is possible only when there is an adequate balance among various physiological processes or yield components. The objective of this review is to discuss growth and development of bean plant including yield formation process or traits during crop growth cycle and importance of these yield components in determining yield.     

Dry Matter and Yield of Lowland Rice Genotypes as Influence by Nitrogen Fertilization

ABSTRACT

Rice is a staple food for more than 50% of the world's population and nitrogen (N) is one of the most yield limiting nutrients in lowland rice ecosystems. A field experiment was conducted for two consecutive years to evaluate dry matter production and grain yield of 12 lowland rice genotypes (BRS Jaçanã, CNAi 8860, BRS Fronteira, CNAi 8879, CNAi 8880, CNAi 8886, CNAi 8885, CNAi 8569, BRSGO Guará, BRS Alvorada, BRS Jaburu, and BRS Biguá) at five N rates (0, 50, 100, 150, and 200 kg ha^{? 1}). Genotypes showed significant variation in grain yield and shoot dry weight. Genotype BRSGO Guará was highest yielding, whereas genotype BRS Jaburu was lowest yielding and the remaining genotypes were intermediate in grain yielding potential. Grain yield and shoot dry weight were having significant quadratic increase with increasing N rates in the range of 0 to 200 kg ha^{? 1}. However, 90% of the maximum yield is often considered as an economical rate, which was 120 kg for shoot dry weight and 136 kg N ha^{? 1} for grain yield. Shoot dry matter was having significant positive quadratic association with grain yield across 12 genotypes.     

Enrichment of lithium in lettuce plants through agronomic biofortification

Abstract

Biofortification of crops with lithium (Li) is a new trend in agriculture and researches on this subject still scarce, therefore, this work aims to evaluate the accumulation potential and the effects in agronomic characteristics of lettuce (Lactuca sativa L.) submitted to foliar application of two Li chemical sources and different concentrations. The experiment was conducted in a greenhouse and the applications of lithium hydroxide (LiOH) and lithium sulfate (Li₂SO₄) were done via foliar spray at concentrations ranging from 0 to 40?mg dm^?3. The applications were divided into three applications distributed at 15, 25, and 35?days after transplanting. Positive and promising results were observed in agronomic characteristics and Li in accumulation. High concentrations of Li (40?mg dm^?3) may compromise the development of lettuce plants, however, lower concentrations applied (16 to 26?mg dm^?3 of Li) promoted an increase in dry weight of roots and shoot/root ratio, both chemical forms, and stem diameter and specific leaf area, Li₂SO₄, suggesting beneficial effect of this element. Li accumulation in shoots depend on the concentrations of this element in the applied solution of Li but not on its chemical form.     

Influence of nitrogen nutrition on growth,nitrate reductase and nitrite reductase of seedlings of maize (Zea mays L. cv LG12)

The effects of three N levels on etiolated and green leaves of Zea mays were studied. It was found that the activity of both nitrate reductase (NR) and nitrite reductase (NiR) was affected, although differently, and the former showed higher sensitivity. NR activity rose with N increase, but different values in the three groups of seedlings appeared only after the second day in light/darkness; both nitrate and light were necessary to obtain a high level of activity. The interference of the N supply on NiR was observed only in seedlings grown in light. Seedling growth was also affected and the leaf weight appeared to correspond with the level of N supplied. In seedlings grown in darkness, the nitrate accumulated in the leaf increased with the decrease of the supplied N, whereas in light/darkness the opposite occurred. Different values of the leaf protein in the three seedling groups appeared only under light/dark and after the second day and by SDS‐PAGE they were found to be quantitative.     

Permanent junctional reciprocating tachycardia in a dog

A 5-year-old male English Bulldog was presented with a 1-year history of paroxysmal supraventricular tachycardia (SVT) partially responsive to amiodarone. At admission the surface ECG showed sustained runs of a narrow QRS complex tachycardia, with a ventricular cycle length (R–R interval) of 260 ms, alternating with periods of sinus rhythm. Endocardial mapping identified the electrogenic mechanism of the SVT as a circus movement tachycardia with retrograde and decremental conduction along a concealed postero-septal atrioventricular pathway (AP) and anterograde conduction along the atrioventricular node. These characteristics were indicative of a permanent junctional reciprocating tachycardia (PJRT). Radiofrequency catheter ablation of the AP successfully terminated the PJRT, with no recurrence of tachycardia on Holter monitoring at 12 months follow-up.