Complementary water and nutrient utilization of perianth structural units help maintain long floral lifespan in Dendrobium.

Most orchids have high ornamental value with long-lived flowers. However, the mechanisms by which orchids maintain floral longevity are poorly understood. Here, we hypothesized that floral longevity in Dendrobium is maintained by high resource investment and complementary water and nutrient utilization in different structural units of the perianth. To test this hypothesis, we determined which water- and nutrient-related traits are correlated with flower longevity in 23 Dendrobium species or cultivars, and examined variations of the related traits during flower development of one long-lived cultivar. We found that floral longevity was correlated with dry mass per unit area of perianths and total flower biomass, which indicates that maintaining floral longevity requires increased resource investment. During development of long-lived flowers, labella showed a high capacity for water storage and nutrient reutilization, which could partly remedy high water demand and biomass investment. Sepals and petals, in contrast, had stronger desiccation avoidance and higher metabolic activity with lower biomass investment. These findings indicate that Dendrobium flowers maintain longevity by complementary water and nutrient utilization strategies in the sepals, petals and labella, with labella consuming more water and nutrients to extend flower display, and sepals and petals using a more conservative strategy.

[Serum levels of fatty acid-binding protein and brain natriuretic peptide in children with pneumonia complicated by acute congestive heart failure].

OBJECTIVE: To assess the values of serum fatty acid-binding protein (FABP) and brain natriuretic peptide (BNP) in pneumonia complicated by acute congestive heart failure (CHF) in children. METHODS: Serum levels of FABP and BNP were determined using ELISA in 36 children with pneumonia complicated by CHF (pneumonia group) and 28 healthy children (control group). RESULTS: Serum levels of FABP and BNP in the pneumonia group at the acute stage were significantly higher than those in the control group and those at the recovery stage (P<0.01). Compared with the control group, serum levels of FABP and BNP in the pneumonia group at the recovery stage increased significantly (P<0.01). At the acute stage, 35 patients (97.2%) showed increased serum FABP level but 28 (77.8%) showed increased serum BNP level (P<0.05) in the pneumonia group. At the recovery stage, the incidence of abnormal serum FABP (72.2%) was significantly higher than that of BNP (44.4%) in the pneumonia group (P<0.05). CONCLUSIONS: Serum levels of FABP and BNP can be regarded as biochemical markers of myocardial damage in children with pneumonia complicated by CHF and serum FABP appears to be a more sensitive one. Serum FABP and BNP remained at higher levels through the recovery stage, suggesting that myocardial damage existed though the clinical symptoms were improved at the stage.