Dispersal mode constrains allocation of carbon and mineral nutrients in seeds of forest and savanna trees

Species vary in seed size and content of stored reserves, which can be related to dispersal strategies and type of habitat in which they are found. We compare seed carbon and nutrient reserves of anemochorous and zoochorous trees from the Cerrado of central Brazil. We measured seed dry mass, lipids, non-structural carbohydrates (starch and total soluble sugars), carbon and mineral nutrients in ten forest and 13 savanna species, each classified as having wind- or animal-dispersed seeds. We used phylogenetically independent contrasts to test for correlations among these traits. Seeds of anemochorous species were lighter, with higher concentrations of C, N, P, Ca and Mg. Lipids were the dominant carbon reserve for most anemochorous species, underpinning the importance of allocation to compact carbon reserves. Starch, lipids or soluble sugars were the major carbon reserve in zoochorous seeds. Savanna and forest species did not differ in seed mass or in total carbon reserves. However, seeds of forest species had higher concentrations of starch than seeds of savanna species. Lipid and starch negatively correlated across species, suggesting a trade-off between starch and lipids as major seed carbon reserves. Calcium was positively correlated with Mn and B, while Mg was positively correlated with C, N, P, K, S, Zn and B. Potassium, S and Cl were positively correlated, while P was positively correlated with Mg and Zn. Dispersal mode rather than vegetation type constrained seed mass and seed storage allocation patterns in forest and savanna trees. We provide evidence that similar mechanisms are involved in seed storage of carbon and mineral nutrients across species.

Dental caries prevalence in relation to socioeconomic status of nursery school children in Goiânia-GO, Brazil

The study was carried out to assess dental caries in the primary dentition of pre-school children in Goiânia-GO, Brazil, and to assess the influence of socio-economic status. The study population comprised 0-6-yr-old pre-school children (n = 2267) attending public (low SES children) and private (higher SES children) nursery schools. Mean dmft and percent caries-free were 0.09 (96.4%) at 1 year and younger, 0.40 (87.3%) at 2, 1.14 (69.9%) at 3, 2.18 (49.5%) at 4, 3.18 (36.1%) at 5, and 3.94 (29.4%) at age 6 years respectively. Caries prevalence was higher in those attending public nursery school than in those attending private schools (P < 0.05). Amongst children from public nursery schools the highest dmf component was untreated decay while in private nurseries it was filled teeth. The results indicate that social inequalities exist, which influence dental caries experience. It was concluded that oral health programmes for pre-school children emphasizing preventive measures and dental health education should be developed mainly in areas of social deprivation.