Effects of nitrogen supply on photosynthetic and anatomical changes in current-year needles of Pinus koraiensis seedlings grown under two irradiances

Abstract

We investigated the responses of photon-saturated photosynthesis rate (P sat ) and its simultaneous acclimation of anatomy and nitrogen use patterns of current needles of Korean pine (Pinus koraiensis) seedlings grown under factorial combinations of two nitrogen levels and irradiances. Although N supply resulted in a significant increase of N content in needles under both irradiances, the increase of P sat tended to be suppressed only in shade (S). The significant increase of P sat in full sunlight (O) was associated with the increase of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) and chlorophyll (Chl) contents. In contrast, small increase of Chl content and no increase of RuBPCO content were found in S (90 % cut of full irradiance), which would result in a small increase of P sat . This result suggests that extra N is stocked in needles under shade for the growth in next season. With N supply, a significant decrease of specific leaf area (SLA) was detected only in O. This decrease of SLA was due to the increase of density of needle. Furthermore, the increase of needle density was not due to the increased number and size of mesophyll cells, but the increased density of each mesophyll cell. Therefore, although SLA changed in O, the change did not involve anatomical adaptation to use increased N effectively, at least observable by light microscopy. Hence, even though the SLA would change, N deposition will improve the photosynthetic capacity of Korean pine seedlings, not through the development of needle anatomy but through improvement of the allocation of N in both irradiances.Additional key words: acclimation; anatomical plasticity; evergreen-species; net photosynthetic rate; nitrogen allocation and deposition; ribulose-1,5-bisphosphate carboxylase/oxygenase; specific leaf area.

Effects of water stress and nitrogen supply on leaf gas exchange and fluorescence parameters of Sophora davidii seedlings

“…As expected, the photosynthetic characters showed strong responses to water stress and N supply, which agreed with many previous studies (DaMatta et al 2002, Flexas et al 2006, Makoto and Koike 2007. Nevertheless, we found that water stress seemed to play the primary limitation roles in photosynthetic capacity and N supply could improve it but could not alter the declining tendency.…”

“…There is now substantial consensus that reduced CO 2 diffusion from the atmosphere to the site of carboxylation-as a result of both stomatal closure and reduced mesophyll conductance-is the main cause of decreased photosynthesis under most water stress conditions (Chaves and Oliveira 2004, Flexas et al 2004, Ennahli and Earl 2005, Grassi and Magnani 2005. On the other hand, many studies have well documented photosynthetic responses of plants to N availability, which included significant and positive correlation between photosynthetic capacity and leaf N content, suggesting that most of the N is used for the synthesis of components in the photosynthetic apparatus (Sugiharto et al 1990, Egli and Schmid 1999, Shangguan et al 2000, DaMatta et al 2002, Makoto and Koike 2007. Furthermore, N application often brought about an increase in cell wall rigidity and osmotic adjustment (Fife andNambiar 1997, Saneoka et al 2004).…”

Effect of nitrogen loading on the growth and photosynthetic responses of Japanese larch seedlings grown under different light regimes

“…Anatomical changes in needle mesophyll tissues would induce these results: a decrease in needle thickness and an increase in air space might increase the gross surface area of the mesophyll tissues. In fact, shading increased air spaces in the mesophyll tissues of an evergreen conifer (Makoto and Koike, 2007). In addition, air spaces in Pinus patula and Pinus radiata greatly affected the relationship between mesophyll tissues and light or needle N content (Niinemets et al, 2002).…”

“…2). This may be due to the role of rubisco in needles as a storage organ for N, as found in several woody species (Warren and Adams, 2001;Takashima et al, 2004;Makoto and Koike, 2007). Although the metabolic cost of the investment of N in LHC proteins (including Chl) is smaller than the cost of investment in rubisco and electron transport proteins (Hikosaka and Terashima, 1995;Lambers et al, 1998), LHC proteins are more stable and harder to restore than rubisco and electron transport proteins (Makino et al, 1994;Lambers et al, 1998).…”

Physiological responses of Abies faxoniana populations from different elevations to increased CO2 and N application

“…A net is generally positively correlated with foliar N, which is a major component of photosynthetic-related enzymes, such as Rubisco (Cao et al 2007;Han et al 2011). N application and elevated CO 2 have synergistic effects on photosynthesis (Makoto and Koike 2007;Granath et al 2009;de Oliveira et al 2012). However, some studies have found that a low N supply can decrease or eliminate the positive Table 2 Statistical significance of single and interactive effects of population, CO 2 , and N application on physiological and biochemical parameters based on a three-way ANOVA effect of elevated CO 2 on photosynthesis (Murray et al 2000;Zhao et al 2011).…”