Photosynthetic nitrogen use efficiency (PNUE, photosynthetic capacity per unit leaf nitrogen) is one of the most important factors for the interspecific variation in photosynthetic capacity. PNUE was analysed in two evergreen and two deciduous species of the genus Quercus . PNUE was lower in evergreen than in deciduous species, which was primarily ascribed to a smaller fraction of nitrogen allocated to the photosynthetic apparatus in evergreen species. Leaf nitrogen was further analysed into proteins in the water-soluble, the detergent-soluble, and the detergentinsoluble fractions. It was assumed that the detergentinsoluble protein represented the cell wall proteins. The fraction of nitrogen allocated to the detergent-insoluble protein was greater in evergreen than in deciduous leaves. Thus the smaller allocation of nitrogen to the photosynthetic apparatus in evergreen species was associated with the greater allocation to cell walls. Across species, the fraction of nitrogen in detergent-insoluble proteins was positively correlated with leaf mass per area, whereas that in the photosynthetic proteins was negatively correlated. There may be a trade-off in nitrogen partitioning between components pertaining to productivity (photosynthetic proteins) and those pertaining to persistence (structural proteins). This trade-off may result in the convergence of leaf traits, where species with a longer leaf life-span have a greater leaf mass per area, lower photosynthetic capacity, and lower PNUE regardless of life form, phyllogeny, and biome.

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Summary19 patients with premature ventricular complexes (PVCs) were administered disopyramide and mexiletine at 300 mg/day in a cross-over comparison of efficacy. The mean daily count of PVCs significantly decreased after both treatments. There was no significant difference between the 2 groups in terms of overall improvement or usefulness. In the global comparison, the usefulness was evaluated as having been higher with disopyramide in 9 patients (47.4%), equal for the 2 drugs in 5 patients (26.3%) and higher with mexiletine in 5 (26.3%). This suggests that these drugs exerted their efficacy by different mechanisms.