Biodiversity and Conservation of Plants in Brazil

Abstract:  With more than 56,000 species (excluding fungi), Brazil has one of the richest floras in the world—nearly 19% of the world flora. Our knowledge of the diversity and status of nonvascular plants in Brazil is still fragmentary, although localized studies on algae have revealed loss of species resulting from environmental pollution. Emphasis on local floral surveys, rather than wider taxonomic studies, has obscured estimates of national totals for most taxonomic groups. Knowledge of angiosperms, especially monocotyledons (of which 45% of the species are endemic), is more complete than most. For this group figures are more reliable, with some distribution patterns, endemism levels, and centers of diversity identified. Much, however, still awaits discovery. Coordinated efforts to catalog Brazil's flora are in progress and include projects such as the conservation priority-setting workshops of the Brazilian Ministry of the Environment, which have identified key conservation areas in the major biomes; development of threatened species lists for plants; and the assembly of type data on species of northeastern Brazil through the Darwin Initiative—all of which greatly assist in increasing our knowledge. These initiatives also underline the urgent need to expand the numbers and geographic spread of projects on plant systematics and taxonomy in Brazil, a measure that demands adequate provision of funding and training programs for plant specialists. Finally, Brazil's environmental agency (IBAMA) could play a proactive role in opening protected areas under its jurisdiction, thereby facilitating botanical research by university departments and research institutes.     

ASSAULT PREVENTION AS SOCIAL CONTROL: WOMEN AND SEXUAL ASSAULT PREVENTION ON URBAN COLLEGE CAMPUSES

Sexual assault on U.S.A. college campuses is increasingly recognized as an urgent and pervasive national problem. To prevent assault, school administrators and individual women promote and adopt safety strategies that often compromise women's free and independent use of the campus environment. Such strategies may fail to correspond to the actual nature of sexual assault on campus. Based on open-ended interviews with college personnel and women students, this study examines sexual assault and personal crime prevention strategies at two midwestern, urban universities. School and individual strategies are characterized according to type, goals, and orientation. Findings explore the relationship of strategies to sexual assault on campus, and implications of strategies for women's use of public space. Conclusions suggest means to increase real safety while enhancing women's freedom and mobility on and near campus.     

Development of a multi-factor model for predicting the effects of ambient ozone on the biomass of white clover

Results are presented from the UN/ECE ICP Vegetation (International Cooperative Programme on effects of air pollution on natural vegetation and crops) experiments in which ozone(O(3))-resistant (NC-R) and -sensitive (NC-S) clones of white clover (Trifolium repens cv. Regal) were exposed to ambient O(3) episodes at 14 sites in eight European countries in 1996, 1997 and 1998. The plants were grown according to a standard protocol, and the forage was harvested every 28 days for 4-5 months per year by excision 7 cm above the soil surface. Biomass ratio (NC-S/NC-R) was related to the climatic and pollutant conditions at each site using multiple linear regression (MLR) and artificial neural networks (ANNs). Twenty-one input parameters [e.g. AOT40, 7-h mean O(3) concentration, daylight vapour pressure deficit (VPD), daily maximum temperature] were considered individually and in combination with the aim of developing a model with high r(2) and simple structure that could be used to predict biomass change in white clover. MLR models were generally more complex, and performed less well for unseen data than non-linear ANN models. The ANN model with the best performance had five inputs with an r(2) value of 0.84 for the training data, and 0.71 for previously unseen data. Two inputs to the model described the O(3) conditions (AOT40 and 24-h mean for O(3)), two described temperature (daylight mean and 24-h mean temperature), and the fifth input appeared to be differentiating between semi-urban and rural sites (NO concentration at 17:00). Neither VPD nor harvest interval was an important component of the model. The model predicted that a 5% reduction in biomass ratio was associated with AOT40s in the range 0.9-1.7 ppm x h (microl l(-1) h) accumulated over 28 days, with plants being most sensitive in conditions of low NO(x), medium-range temperature, and high 24-h mean O(3) concentration.     

Effects of rooting medium and fertilizer rate on response of white clover to tropospheric ozone

Two white clover (Trifolium repens L.) clones with varying sensitivity to O(3) are being developed as a system to indicate effects of ambient concentrations of tropospheric O(3) on plants. One clone (NC-S) is highly sensitive to O(3) and the other (NC-R) is highly resistant. The system relies on periodic measurement of foliar injury, foliar chlorophyll, and forage production of NC-S and NC-R grown in 15-liter pots throughout a summer season. Relative amounts of foliar injury and ratios (NC-S/NC-R) for chlorophyll and forage weight can be used to estimate biologically effective ambient O(3) concentrations. The effect of variation in rooting media formulation and fertilizer rate on response of NC-S and NC-R to ambient O(3) was determined in the present study. In the rooting medium experiment, clover was grown in three mixtures of sandy loam topsoil:course washed sand:Metro Mix 220 (ratios (by volume) of 2:1:1, 2:1:5, and 6:1:1). In the fertilizer experiment, clover was grown in the 2:1:1 medium at four fertilizer rates (soluble 5-11-26 (N-P-K) at 0.0, 0.5, 1.0, or 2.0 g per pot). Ozone caused more foliar injury, more chlorosis, and a greater decrease in forage production of NC-S than of NC-R in all studies. Rooting media treatments affected both clones similarly and occasional clone x media interactions were judged to be random. Forage production by NC-S, relative to that of NC-R, was generally greater in the 0.0 fertilizer treatment, but the forage ratios were similar at all other fertilizer treatments. The relative response of NC-S and NC-R to O(3) is fairly stable under cultural conditions that support normal plant growth.     

Growth and yield responses of potato to mixtures of carbon dioxide and ozone

Elevated carbon dioxide (CO2) concentrations in the atmosphere can stimulate plant growth and yield, whereas ground-level ozone (O3) concentrations cause the opposite effect in many areas of the world. Recent experiments show that elevated CO2 can protect some plants from O3 stress, but this has not been tested for most crop species. Our objective was to determine if elevated CO2 protects Irish potato (Solanum tuberosum L.) from foliar injury and suppression of growth and yield caused by O3. An O3-resistant cultivar (Superior) and an O3-sensitive cultivar (Dark Red Norland) were exposed from within 10 d after emergence to maturity to mixtures of three CO2 and three O3 treatments in open-top field chambers. The three CO2 treatments were ambient (370 microL L(-1)) and two treatments with CO2 added to ambient CO2 for 24 h d(-1) (540 and 715 microL L(-1)). The O3 treatments were charcoal-filtered air (15 nL L(-1)), nonfiltered air (45 nL L(-1)), and nonfiltered air with O3 added for 12 h d(-1) (80 nL L(-1)). Elevated O3 and CO2 caused extensive foliar injury of Dark Red Norland, but caused only slight injury of Superior. Elevated CO2 increased growth and tuber yield of both cultivars, whereas elevated O3 generally suppressed growth and yield, mainly of Dark Red Norland. Elevated CO2 appeared to protect Dark Red Norland from O3-induced suppression of shoot, root, and tuber weight as measured at midseason but did not protect either cultivar from O3 stress at the final harvest. The results further illustrate the difficulty in predicting effects of O3 + CO2 mixtures based on the effects of the individual gases.     

Growth and yield responses of snap bean to mixtures of carbon dioxide and ozone

Elevated CO2 concentrations expected in the 21st century can stimulate plant growth and yield, whereas tropospheric O3 suppresses plant growth and yield in many areas of the world. Recent experiments showed that elevated CO2 often protects plants from O3 stress, but this has not been tested for many important crop species including snap bean (Phaseolus vulgaris L.). The objective of this study was to determine if elevated CO2 protects snap bean from O3 stress. An O3-tolerant cultivar (Tenderette) and an O3-sensitive selection (S156) were exposed from shortly after emergence to maturity to mixtures of CO2 and O3 in open-top field chambers. The two CO2 treatments were ambient and ambient with CO2 added for 24 h d(-1) resulting in seasonal 12 h d(-1) (0800-2000 h EST) mean concentrations of 366 and 697 microL L(-1), respectively. The two O3 treatments were charcoal-filtered air and nonfiltered air with O3 added for 12 h d(-1) to achieve seasonal 12 h d(-1) (0800-2000 h EST) mean concentrations of 23 and 72 nL L(-1), respectively. Elevated CO2 significantly stimulated growth and pod weight of Tenderette and S156, whereas elevated O3 significantly suppressed growth and pod weight of S156 but not of Tenderette. The suppressive effect of elevated O3 on pod dry weight of S156 was approximately 75% at ambient CO2 and approximately 60% at elevated CO2 (harvests combined). This amount of protection from O3 stress afforded by elevated CO2 was much less than reported for other crop species. Extreme sensitivity to O3 may be the reason elevated CO2 failed to significantly protect S156 from O3 stress.     

Effects of Chronic Doses of Ozone on Field-Grown Loblolly Pine: Seedling Responses in the First Year

A study was designed to examine responses of loblolly pine (Pinus taeda) to chronic exposure to ozone (O₃) in the field. Seedlings of four full-sib families of loblolly pine were planted in a field near Raleigh, NC, and exposed daily (May 27 to October 24, 1985) in open-top chambers to O₃ ranging from 0.5 to 1.96 times the O₃ concentration in non-filtered (NF) air. One-fourth of the plants in each plot were removed during each of two harvests (August and October) to measure effects of O₃ on plant growth. Plants of each family exhibited foliar symptoms characteristic of O3 injury after five months of exposure to any greater-than-ambient O₃ concentration, and one family exhibited symptoms after five months of exposure to NF air. Ozone dose-plant response relationships were quantified by regression for stem height, stem diameter, biomass, and other plant morphological and yield characteristics. All relationships were linear for three families, but one family exhibited no significant growth response relationship of O₃ dose. Dose-response equations suggest a maximum growth suppression of 10 percent for NF air compared to charcoal-filtered air (i.e., 0.5 × NF) in the first season of exposure.     

Variable Responses of Soybeans to Mixtures of Ozone and Sulfur Dioxide

Foliar injury and shoot fresh weight responses of soybeans (Glycine max L.) ‘Lee 68’ and ‘Dare’ exposed to mixtures of ozone (O₃) and sulfur dioxide (SO₂) were greater than additive (synergistic), less than additive (antagonistic), or additive. The result depended on the concentrations of O₃ and SO₂, the exposure duration, and the amount of injury caused by each gas singly. Synergism usually occurred when injury from O₃ or SO₂ singly was slight to moderate. Antagonism usually occurred when injury from either gas singly was severe. In many cases of antagonism, the injury and fresh weight effects of the mixture were less than those from SO₂ alone, suggesting that O₃ can sometimes protect soybeans from SO₂.     

Measurement of Photochemical Air Pollution with a Sensitive Monitoring Plant

With newly developed monitoring techniques, investigators used the sensitive tobacco variety, Bel-W3, as a monitor for photochemical air pollution at different locations within 75 miles of Cincinnati, Ohio. Observations during the summers of 1966 through 1968 revealed almost daily injury to monitoring plants, fairly uniform total seasonal injury at all locations, and a marked variation in both oxidant and injury from one season to another within the city. The relationship between oxidant level and injury was not found to be consistent.