%0 Journal Article %1 Evans_89 %A Evans, J. R. %D 1989 %J Oecologia %K bibtex-import, citeulikeExport gas\_exchange, nitrogen, review, unread %P 9--19 %T Photosynthesis and nitrogen relationships in C3 plants %V 78 %X Summary. The PhOtosynthetic capacity of leaves is related to the nitrogen content primarily because the proteins of the Calvin cycle and thylakoids represent the majority of leaf nitrogen. To a first approximation, thylakoid nitrogen is proportional to the chlorophyll content (50 mol thylak- oid N m o l - \~ Chl). Within species there are strong linear relationships between nitrogen and both RuBP carboxylase and chlorophyll. With increasing nitrogen per unit leaf area, the proportion of total leaf nitrogen in the thylakoids re- mains the same while the proportion in soluble protein in- creases. In many species, growth under lower irradiance greatly increases the partitioning of nitrogen into chloro- phyll and the thylakoids, while the electron transport capac- ity per unit of chlorophyll declines. If growth irradiance influences the relationship between photosynthetic capacity and nitrogen content, predicting nitrogen distribution be- tween leaves in a canopy becomes more complicated. **When both photosynthetic capacity and leaf nitrogen content are expressed on the basis of leaf area, considerable variation in the photosynthetic capacity for a given leaf nitrogen con- tent is found between species. The variation reflects differ- ent strategies of nitrogen partitioning, the electron trans- port capacity per unit of chlorophyll and the specific activi- ty of RuBP carboxylase. Survival in certain environments clearly does not require maximising photosynthetic capacity for a given leaf nitrogen content. Species that flourish in the shade partition relatively more nitrogen into the thylak- oids, although this is associated with lower photosynthetic capacity per unit of nitrogen.

@article{Evans_89, abstract = {{Summary. The PhOtosynthetic capacity of leaves is related to the nitrogen content primarily because the proteins of the Calvin cycle and thylakoids represent the majority of leaf nitrogen. To a first approximation, thylakoid nitrogen is proportional to the chlorophyll content (50 mol thylak- oid N m o l - \~{} Chl). Within species there are strong linear relationships between nitrogen and both RuBP carboxylase and chlorophyll. With increasing nitrogen per unit leaf area, the proportion of total leaf nitrogen in the thylakoids re- mains the same while the proportion in soluble protein in- creases. In many species, growth under lower irradiance greatly increases the partitioning of nitrogen into chloro- phyll and the thylakoids, while the electron transport capac- ity per unit of chlorophyll declines. If growth irradiance influences the relationship between photosynthetic capacity and nitrogen content, predicting nitrogen distribution be- tween leaves in a canopy becomes more complicated. **When both photosynthetic capacity and leaf nitrogen content are expressed on the basis of leaf area, considerable variation in the photosynthetic capacity for a given leaf nitrogen con- tent is found between species. The variation reflects differ- ent strategies of nitrogen partitioning, the electron trans- port capacity per unit of chlorophyll and the specific activi- ty of RuBP carboxylase. Survival in certain environments clearly does not require maximising photosynthetic capacity for a given leaf nitrogen content. Species that flourish in the shade partition relatively more nitrogen into the thylak- oids, although this is associated with lower photosynthetic capacity per unit of nitrogen.}}, added-at = {2019-03-31T01:14:40.000+0100}, author = {Evans, J. R.}, biburl = {https://www.bibsonomy.org/bibtex/288a7d8dff50793f843b76675e3838196/dianella}, citeulike-article-id = {1523680}, comment = {(private-note)FIeld and Mooney: A/nitrogen relationships follow a line that is irrespective of species or growth condition The variation between life-forms is also strikingly obvious when maximum leaf conductance is compared with leaf nitrogen content (Koerner et al. 1986), given that conductance is roughly proportional to the rate of CO2 assimilation (Koerner et al. 1979, Wong et al. 1979). the proportion of total nitrogen in RuBP carboxylase is not constant, but increases with increasing leaf nitrogen. If you have more rubisco, that can offset a lower specific activity (eg rice vs maize). So specific activity can vary. Most thylakoid N is in the reaction centres A greater proportion of leaf nitrogen is partitioned to the thylakoids under growth at low irradiance. 8-11 mmol RuBP carboxylase to 1 mol Chl or 1 to 1.4 RuBP carboxylase N per thylakoid N. The ratio decreases to 0.4 mol RuBPCase N per mol thylakoid N for many species when grown under low irradiance It can be assumed that RuBP carboxylase is never present in great excess, that it is close to co-limiting the rate of COz assimilation at high irradiance... Factors introducing curvature to the photosynthesis: nitrogen relationship: To reach light saturation requires progressively higher irradiances so that if measured at the same irradiance, the rate for the high nitrogen leaf will be underestimated. 2) the rate of CO2 assimilation is not always linearly related to the RuBP carboxylase content. Plotting Vc vs Rubisco creates a curved line, and The curvature has been ascribed to a drop in the p(CO2) between the intercellular space and the sites of carboxylation, due to the resistance to COs transfer imposed by the cell wall and liquid phase. It may also partly reflect the drop in p(CO2) across the leaf. The curvature is less noticeable in the photosynthesis: leaf nitrogen content relationship because the proportion of nitrogen in RuBP caboxylase generally increases with increasing leaf nitrogen due to the nonzero intercept The proportion of N devoted to electron transport doesn't vary with N treatment, but the overall quantity does. THe proportion of N that's in RUBISCO does though, at the expense of nucleic acids, etc. Increasing N per unit leaf area (as a result of varying N supply) leads (in this eg) to an increase in the calvin cycle enzymes and the thylakoids per cell rather than in the number of cells. a story similar to ours: Alocasia, shows that higher irradiance during growth actually reduces the thylakoid nitrogen while at the same time results in an increase in the electron transport capacity. This is matched by a similar increase in soluble protein such that the balance between electron transport and RuBP carboxylase activity is maintained. The ability to proliferate thylakoid membranes when grown in the shade is a feature of many species (Fig. 3) and occurs at the expense of both soluble protein and the' other' fraction. Without taking account of the costs of leaf synthesis and maintenance, acclimation to shade appears to increase the nitrogen cost of light saturated photosynthesis. However, if leaves are compared at low irradiances, acclimation can be seen to be beneficial due to the reduced rate of respiration for a given leaf nitrogen content (Terashima and Evans 1988). The ability to succeed in particular environments may be evident in the photosynthesis: nitrogen relationship. is good idea to take into account respiration rates also. PNUE high lower in woody plants leaf longevity affects carbon gain per unit N. (Berendse \& Aerts 1987)}, interhash = {08d0c6963bbd6fb7587aa3dc0db57f89}, intrahash = {88a7d8dff50793f843b76675e3838196}, journal = {Oecologia}, keywords = {bibtex-import, citeulikeExport gas\_exchange, nitrogen, review, unread}, pages = {9--19}, posted-at = {2007-07-31 06:15:51}, priority = {2}, timestamp = {2019-03-31T01:16:26.000+0100}, title = {{Photosynthesis and nitrogen relationships in C3 plants}}, volume = 78, year = 1989 }