Ion-mediated increases in xylem hydraulic conductivity: seasonal differences between coexisting ring- and diffuse-porous temperate tree species.

Ion-mediated changes in hydraulic conductivity (ΔKh) represent a mechanism allowing plants to regulate the rate of xylem transport. However, the significance of ΔKh for ring-porous (RPS) and diffuse-porous tree species (DPS) remains unknown. Here, we examined ΔKh in young branches of three coexisting, temperate RPS (Fraxinus excelsior, Quercus robur, Robinia pseudoacacia) and three DPS (Acer pseudoplatanus, Carpinus betulus, Fagus sylvatica) across the whole year, and assessed the relationships of ΔKh to branch anatomy. Ring-porous species exhibited twice as high ΔKh (10.3% vs 5.3%) within the growing season (i.e., during wood production) compared with DPS, and the production of the annual ring was identified as a crucial process affecting maximum ΔKh within the season. In addition, xylem in branches of RPS generally contained more axial parenchyma (AP; 18% vs 7%) and was characterized by a greater relative contact fraction between vessels and parenchyma (FVP; 59% vs 18%) than xylem in DPS. Simultaneously, ΔKh measured within the growing season was positively correlated with AP, FVP and bark proportions, suggesting that parenchyma in branches may be important for high ΔKh. Significant increase in ΔKh observed during the growing season may help RPS to restore conductive capacity after winter, better compensate transport loss by drought-induced embolism and thereby improve water delivery to leaves.

Dietary intake of energy and nutrients in relation to resting energy expenditure and anthropometric parameters of Czech pregnant women.

PURPOSE: The aim of this study was to evaluate the dietary intake of energy and nutrients (DIEN) of Czech pregnant women and to assess relationships with body size variables during pregnancy. METHODS: One hundred and fifty-two randomly recruited healthy pregnant Czech women, who were normoglycemic, euthyroid, nonsmokers, not anemic, and not users of chronic medications or abusers of alcohol or drugs from countryside and city with different education, were recruited for the study. Anthropometric parameters were measured and resting energy expenditure obtained by indirect calorimetry after 12 h of fasting during four phases of pregnancy. DIEN was evaluated from self-reported dietary intake records over 7 days. RESULTS: Positive correlations were demonstrated between measured resting energy expenditure and intake of energy, substrates and some minerals and vitamins, and negative correlations between DIEN and anthropometric parameters. Lower dietary intake of energy and differences between dietary intake of nutrients and recommended daily allowances during pregnancy of Czech women were documented. CONCLUSIONS: The difference between pregnancy body weight and ideal body weight was shown to be a determinant of DIEN. From recent knowledge on prevention of various pathological states, the supplementation or modification of nutritional intake of food with folate, iron, vitamin D, zinc, iodine and fiber for Czech pregnant women is recommended.

Prediction of nutritive intake energy and substrates of Czech pregnant women.

OBJECTIVE: Equations linking nutritional intake of energy and substrates (NIES) to anthropometry during pregnancy are currently unknown. The aim of this longitudinal study was to determine the predictive equations for NIES as an expression of dietary patterns. METHODS: In total, 152 randomly recruited healthy pregnant Czech women (non-smokers, non-users of long-term medications or abusers of alcohol or drugs, normoglycemic, euthyroid, and non-anemic) were divided into two cohorts: group 1 (n = 31) was used for the determination of equations for NIES during pregnancy, and group 2 (n = 121) for cross-validation of these equations. In both study groups, anthropometry was measured and resting energy expenditure obtained by indirect calorimetry after 12 h of fasting during four phases of pregnancy. NIES was evaluated from self-reported dietary intake records over 7 d. RESULTS: Strong relations were found between NIES and anthropometric parameters, especially the difference between pregnancy body weight and ideal body weight. By correlation analysis and linear regression, new predictive equations were derived for NIES during pregnancy using the difference between pregnancy body weight and ideal body weight. A high concordance was observed between values from the predictive equations and the actual assessed values of NIES in group 2. CONCLUSION: The proposed equations for nutritional intake of energy, protein, and fats have a reasonable prediction power during pregnancy in relation to physiologic birth outcome.