%0 Journal Article %1 Westbeeketal_99 %A Westbeek, M. H. M. %A Pons, T. A. %A Cambridge, M. L. %A Atkin, O. K. %D 1999 %J Oecologia %K bibtex-import citeulikeExport %P 19--26 %T Analysis of differences in photosynthetic nitrogen use efficiency of alpine and lowland Poa species %V 120 %X Abstract This study investigates factors determining variation in photosynthetic nitrogen use e?ciency (/N) in seven slow- and fast-growing Poa species from al- titudinally contrasting sites. The species and their envi- ronmental origin were (in order of increasing relative growth rate): two alpine (Poa fawcettiae and P. costini- ana), one sub-alpine (P. alpina) and three temperate lowland perennials (P. pratensis, P. compressa and P. trivialis), as well as one temperate lowland annual (P. annua). Plants were grown hydroponically under identical conditions with free access to nutrients in a growth room. Photosynthesis per unit leaf area measured at growth irradiance (500 lmol mA2 sA1) was slightly higher in the slow-growing alpine species. At saturating light intensities, photosynthesis was considerably higher in the alpine species than in the lowland species. Car- boxylation capacity and Rubisco content per unit leaf area were also greater in the alpine species. Despite variation between the species, the in vivo specic activity of Rubisco showed little relationship to relative growth rate or photosynthetic rate. Both at light saturation and at the growth irradiance, /N was lowest in the slow- growing alpine species P. fawcettiae, P. costiniana and P. alpina, and highest in the fast-growing P. compressa and P. annua. The proportion of leaf nitrogen that was allocated to photosynthetic capacity and the in vivo catalytic constant of Rubisco accounted for most of the variation in /N at light saturation. Minor variations in intercellular CO2 partial pressure also contributed to some extent to the variations in /N at light saturation. The low /N values at growth irradiance exhibited by the alpine species were additionally due to a lower percent- age utilisation of their high photosynthetic capacity compared to the lowland species.

@article{Westbeeketal_99, abstract = {{Abstract This study investigates factors determining variation in photosynthetic nitrogen use e?ciency (/N) in seven slow- and fast-growing Poa species from al- titudinally contrasting sites. The species and their envi- ronmental origin were (in order of increasing relative growth rate): two alpine (Poa fawcettiae and P. costini- ana), one sub-alpine (P. alpina) and three temperate lowland perennials (P. pratensis, P. compressa and P. trivialis), as well as one temperate lowland annual (P. annua). Plants were grown hydroponically under identical conditions with free access to nutrients in a growth room. Photosynthesis per unit leaf area measured at growth irradiance (500 lmol mA2 sA1) was slightly higher in the slow-growing alpine species. At saturating light intensities, photosynthesis was considerably higher in the alpine species than in the lowland species. Car- boxylation capacity and Rubisco content per unit leaf area were also greater in the alpine species. Despite variation between the species, the in vivo specic activity of Rubisco showed little relationship to relative growth rate or photosynthetic rate. Both at light saturation and at the growth irradiance, /N was lowest in the slow- growing alpine species P. fawcettiae, P. costiniana and P. alpina, and highest in the fast-growing P. compressa and P. annua. The proportion of leaf nitrogen that was allocated to photosynthetic capacity and the in vivo catalytic constant of Rubisco accounted for most of the variation in /N at light saturation. Minor variations in intercellular CO2 partial pressure also contributed to some extent to the variations in /N at light saturation. The low /N values at growth irradiance exhibited by the alpine species were additionally due to a lower percent- age utilisation of their high photosynthetic capacity compared to the lowland species.}}, added-at = {2019-03-31T01:14:40.000+0100}, author = {Westbeek, M. H. M. and Pons, T. A. and Cambridge, M. L. and Atkin, O. K.}, biburl = {https://www.bibsonomy.org/bibtex/29401b9cee7d1fb0898195bdd7aa5fc53/dianella}, citeulike-article-id = {1524119}, comment = {(private-note)The slower growing alpine spp (fawcettiae and costiniana) had higher photosynthesis per leaf area because of the high nitrogen, chlorophyll and Rubisco contents per unit leaf area, but the low leaf area per unit leaf mass. Carboxylation capacity (Vcmax) and electron transport capacity (Jmax) and Rubisco content per unit leaf area were also higher in these species PNUE was lower in these species. This was mainly due to differences in nitrogen allocation to photosynthesis, and to the catalytic constant of Rubisco, also a little bit to differences in Ci. Slow-growing herbaceous species may have a high photosynthetic capacity which requires high light intensities for saturation. As a result, a lower proportion of their capacity is utilised under ambient sub-saturating light conditions, thus lowering /N, as found for grass species by Pons et al. (1994). Di?erences in /N may also be due to di?erences in the proportion of leaf organic nitrogen that is allocated to the photosynthetic apparatus (mp) and/or di?erences in the allocation of nitrogen to the di?erent components of the photosynthetic apparatus, e.g. light harvesting (LH), carbon reduction (CR) and electron transport (ET) (Evans and Seemann 1989; Pons et al. 1994). A major component of CR is Rubisco which may contain 627\% of leaf organic nitrogen (Evans and Seemann 1984; Makino et al. 1984; Evans and Austin 1986; Seemann et al. 1987; Evans 1989). In addition, di?erences in the kinetic properties of Rubisco could inuence PNUE. variation in in vitro kinetic properties of Rubisco in ter-restrial C3 plants is not large (Seemann et al. 1984; Kent and Tomany 1995) some of the methods are worth copying for your own methods eg. how the J and Vcmax are calculated. They also calculated Vcmax/Jmax, and found not much variation between species. Yes, comparison of Ci is valid. These guys found only a weak relationship between RGR and Ci. Calculated percent of allocated N in electron reduction, light harvesting, carbon reduction... somehow. at growth irradiance, but not at saturating irradiance, N investement in light harvesting influences PNUE The higher Vcmax in alpine species is not an isolated phenomenon. IN this case, there's no evidence of differences in Kcat, so it's higher because of higher rubisco concentration. Normally, low internal CO2 partial pressures limit in situ carboxylation capacity. However, by possessing greater Rubisco levels, alpine plants are able to exhibit similar light-saturated rates of photosynthesis to their lowland counterparts despite growing under conditions of low CO2 partial pressure. --- the alpine species had lower SLA, higher leaf N, higher A, higher Vcmsx, higher J, lower PNUE than the lowland spp. Higher rubisco concentrations rather than differences in the catalytic constant. Fol and Ho have higher Vc/J than these, similar RGRs to the alpine spp if slightly lower. much lower A (these spp 20umol m-2 s-1 compared to ours around 6) Fol lower PNUE Much lower Nla and Nmass similar to slightly lower SLA see image in "work stuff" Poorter and Evans 98 look at the different contributions to PNUE Pons et al. 94 look at other grasses and photosynthetic capacities with irradiance Garnier E, Gobin O, Poorter H (1995) Interspecifc variation in nitrogen productivity depends on the photosynthetic nitrogen use effciency and on nitrogen allocation within the plant. Ann Bot 76:667672 Poorter H, Remkes C, Lambers H (1990) Carbon and nitrogen economy of 24 wild species di?ering in relative growth rate. Plant Physiol 94:621627}, interhash = {526d3bbd189ffae5c70196c8d626728f}, intrahash = {9401b9cee7d1fb0898195bdd7aa5fc53}, journal = {Oecologia}, keywords = {bibtex-import citeulikeExport}, pages = {19--26}, posted-at = {2007-07-31 07:39:11}, priority = {2}, timestamp = {2019-03-31T01:16:26.000+0100}, title = {{Analysis of differences in photosynthetic nitrogen use efficiency of alpine and lowland Poa species}}, volume = 120, year = 1999 }