Effects of N‐supply on the rates of photosynthesis and shoot and root respiration of inherently fast‐ and slow‐growing monocotyledonous species

Abstract

Van der Werf, A., Van Nuenen, M., Visser, A.J. and Lambers, H. 1993. Effects of N-supply on the rates of photosynthesis and shoot and root respiration of inherently fast-and slow-growing monocotyledonous species. -Physiol. Plant. 89: 563-569.Are there intrinsic differences in the rates of photosynthesis, shoot-and root-respiration between inherently fast-and slow-growing monocotyledons at high and low nitrogen supply? To analyze this question we grew 5 monocotyledons, widely differing in their inherent relative growth rate at high and low nitrogen supply in a growth room. Nitrate was exponentially added to the plants, enabling us to compare inherent differences in plant characteristics, without any effect of species differences in the ability to take up nutrients. At high nitrogen supply, the fast-growing species from productive habitats had a higher photosynthetic nitrogen use efficiency and rate of root respiration than the slowgrowing ones from unproductive habitats. Only minor differences were observed in their rates of photosynthesis and shoot respiration per unit leaf area. At low nitrogen supply, the rates of photosynthesis and shoot-and root respiration decreased for all species, even though there were no longer any differences in these processes between inherently fast-and slow-growing species. The photosynthetic nitrogen use efficiency increased for all species, and no differences were found among species. Differences in the photosynthetic nitrogen use efficiency among species and nitrogen treatments are discussed in terms of the utilization of the photosynthetic apparatus, whereas differences in respiration rate are discussed in terms of the energy demand for growth, maintenance and ion uptake and their related specific respiratory energy costs. It is concluded that the relatively high abundance of slow-growing species compared to fast-growing ones in unproductive habitats is unlikely to be explained by differences in rates of photosynthesis and respiration or in photosynthetic nitrogen use efficiency.

Soil compaction–N interactions in barley: Root growth and tissue composition

“…Many studies of C and N partitioning and root tissue composition have been made on plants grown in hydroponics (Poorter and Bergkotte, 1992; Van der Werf et al, 1993). These have the advantage of experimental simplicity, but ignore the fact that under field conditions most roots experience some mechanical impedance to their growth.…”

Do plant functional types based on leaf dry matter content allow characterizing native grass species and grasslands for herbage growth pattern?

“…Nevertheless they varied in the expected direction, giving consistent correlations between the plants' agronomic features and LDMC. This effect of N fertilizer is well known for LLS (Fichtner and Schulze 1992;van der Werf et al 1993;Ackerly and Bazzaz 1995;Ryser and Lambers 1995;Knops and Reinhart 2000;Schippers and Olff 2000) and 10-cm stem height; the latter depending both on growth and development processes.…”

Briza media L.

“…Briza media is considered to be a species more common on nitrogen-poor soils than nitrogen-rich soils and it might be thought that such species would show adaptations for efficiency in utilization of nitrogen. However, van der Werf et al (1993) compared B. media, characteristic of nitrogen-poor soils, with Dactylis glomerata, characteristic of nitrogen-rich soils, at a range of nitrogen availabilities. They found that with a low nitrogen supply there was no difference in either the rate of photosynthesis or the photosynthetic nitrogen use efficiency, but with a high nitrogen supply the efficiency with respect to leaf nitrogen was significantly higher for D. glomerata than for B. media.…”