Uptake, translocation and metabolism of "%C-labelled formaldehyde in the leaves of Epipremnum aureum (Golden Potho) and Ficus benjamina (Weeping Fig) were investigated. Plants were exposed in light and dark to "%C-formaldehyde (500 µg m −$ ) in gas exposure chambers. The amount of "%C-incorporation into the soluble (waterextractable) and insoluble fractions of leaves, stem sections and roots was determined. The soluble "%C-activity was fractionated by ion exchange chromatography followed by thin-layer chromatography\autoradiography. Approximately 60-70% of the applied "%C-formaldehyde was recovered from the plants. In the light about five times more "%C-formaldehyde was assimilated than in the dark. The amount of "%C-label derived from "%C-formaldehyde, which was incorporated into acid-stable metabolites, was enhanced to an even larger extent in the light. The "%C-activity pattern closely resembled the general labelling spectrum of photosynthates, obtained after a "%CO # exposure. A substantial amount of labelled material, mostly sucrose, was translocated into the stems and roots. Our results suggest that in the light "%C enters the Calvin cycle after an enzymatic two-step oxidation process of "%C-formaldehyde to "%CO # . The activities of the respective enzymes, formaldehyde dehydrogenase and formate dehydrogenase, were determined. Among 27 ' leafy ' indoor decorative plants, a screening experiment revealed no outstanding species with regard to its capacity for metabolism of formaldehyde, and rate of uptake through stomata was too low to justify claims that plants contribute usefully to indoor air purification.

No abstract

Neonatology is a medical speciality where the tension between economics and the benefit of patients is extremely high. We found a moderate level of cost consciousness among NICU physicians and nurses.

A new method is presented to follow the turn over of the D-1 reaction center polypeptide of photosystem II in intact spruce needles or spinach leaves by incorporation of [14C]leucine. Like in other organisms the synthesis and degradation of this protein is strongly light-dependent and very fast. The synthesis rate under moderate light intensities in healthy spruce needles is about 9 nmol [14C]leucine mg-1 Chl h-1. The half-life time of the D-1 protein under these conditions is less than 30 min. In order to demonstrate the usefulness of this method for the stress physiology of photosynthesis, first experiments are shown comparing the turnover of the D-1 protein in spruce needles with different age and different degree of dam age.

The incorporation of 14C‐leucine into the total‐protein fraction of needles of Norway spruce (Picea abies [L.] Karst.) during short time incubation was used as a measure of protein synthesis in the light and in the dark. Light saturation curves, obtained for needles of different ages (new flush and 1 and 2 years old) or at different seasons (summer‐winter) followed the Michaelis‐Menten algorithm, exhibiting marked differences with regard to light saturation (Vmax) and the half‐saturation constant (K5. 2). The light saturation curves of ATP level (mg g−1 fresh weight) and of leucine incorporation into protein (nmol mg−1 h−1) matched each other, suggesting that photophosphorylation may be decisive for the rate of protein synthesis in the light. This is confirmed by the action spectrum of leucine incorporation. which resembled an action spectrum of leaf photosynthesis, and also by partial inhibition of protein synthesis by 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU), an inhibitor of non‐cyclic photophosphorylation. Light stimulated protein synthesis showed pronounced seasonal fluctuations with a summer maximum. Furmigation of 5 years old spruce trees for 3 months with SO2 in combination with O3 and/or NO2 caused a distinct enhancement of the protein synthesis rate in the light and, at a reduced absolute level, also in the dark. A similar result was obtained for 40 to 70 years old spruce stands when healthy and sick trees were compared: the latter being afflicted by the novel type of forest decline, which is characterized by yellowish bronze discolouration of sun‐exposed older needles and partial loss of older needle generations (3 to 4 years old). The 1 year old needles of the unhealthy trees showed a markedly increased 14C‐leucine incorporation rate which, in the dark, was even more pronounced than in the light. Stress‐physiological mechanisms, which could possibly explain this stimulation, are discussed.