Molecular, physiological and biochemical responses of Theobroma cacao L. genotypes to soil water deficit.

Six months-old seminal plants of 36 cacao genotypes grown under greenhouse conditions were subjected to two soil water regimes (control and drought) to assess, the effects of water deficit on growth, chemical composition and oxidative stress. In the control, soil moisture was maintained near field capacity with leaf water potentials (ΨWL) ranging from -0.1 to -0.5 MPa. In the drought treatment, the soil moisture was reduced gradually by withholding additional water until ΨWL reached values of between -2.0 to -2.5 MPa. The tolerant genotypes PS-1319, MO-20 and MA-15 recorded significant increases in guaiacol peroxidase activity reflecting a more efficient antioxidant metabolism. In relation to drought tolerance, the most important variables in the distinguishing contrasting groups were: total leaf area per plant; leaf, stem and total dry biomass; relative growth rate; plant shoot biomass and leaf content of N, Ca, and Mg. From the results of these analyses, six genotypes were selected with contrasting characteristics for tolerance to soil water deficit [CC-40, C. SUL-4 and SIC-2 (non-tolerant) and MA-15, MO-20, and PA-13 (tolerant)] for further assessment of the expression of genes NCED5, PP2C, psbA and psbO to water deficit. Increased expression of NCED5, PP2C, psbA and psbO genes were found for non-tolerant genotypes, while in the majority of tolerant genotypes there was repression of these genes, with the exception of PA-13 that showed an increased expression of psbA. Mutivariate analysis showed that growth variables, leaf and total dry biomass, relative growth rate as well as Mg content of the leaves were the most important factor in the classification of the genotypes as tolerant, moderately tolerant and sensitive to water deficit. Therefore these variables are reliable plant traits in the selection of plants tolerant to drought.

Benign masseter muscle hypertrophy.

Idiopathic hypertrophy of the masseter muscle is a rare disorder of unknown cause. Some authors associate it with the habit of chewing gum, temporo-mandibular joint disorder, congenital and functional hypertrophies, and emotional disorders (stress and nervousness). Most patients complain of the cosmetic change caused by facial asymmetry, also called square face, however, symptoms such as trismus, protrusion and bruxism may also occur. The goals of the present investigation were: to report a case of idiopathic masseter hypertrophy, describe its symptoms and treatment. The patient reported bilateral bulging in the region of the mandible angle, of slow and progressive evolution. He did not complain of pain or discomfort, however there was bilateral otalgia, nighttime trismus and stress. In his physical exam we noticed bilateral masseter hypertrophy without local inflammatory alterations. We indicated surgical treatment with an extraoral approach. Complementary tests are indicated when there is diagnostic doubts. Treatment varies from conservative to surgical, and the later depends on surgeon skill and experience.