Influence of Elevated CO2 on kinetics and expression of high affinity nitrate transport systems in wheat
The rate of nitrate uptake was studied in ambient (AC) and elevated (EC, 600 ± 50 μmol mol−1) carbon dioxide conditions in wheat seedlings adapted to low nitrogen (uninduced) or high nitrogen (induced) conditions. Twenty five days old seedlings grown in climate controlled growth chambers were incubated in a range of nitrate concentrations (0.01–1 mM). Rate of uptake observed in low N adapted seedlings was used to calculate kinetics of constitutive high affinity transport system (CHATS). The difference in uptake observed between induced and uninduced seedlings were indicative of inducible high affinity transport system (IHATS). In both the CO2 levels, the nitrate uptake was biphasic in induced as well as uninduced seedlings, i.e. the rate of nitrate uptake saturated at about 0.08–0.1 mM and then a sharp increase in the rate of nitrate uptake was noticed in seedlings incubated in solutions of 0.5 mM nitrate and the uptake increased linearly in both induced as well as uninduced seedlings in the concentration beyond 0.5 mM. Hence, uninduced seedlings growing under EC took up nitrate more efficiently as compared to the seedlings growing under AC suggestive of efficient CHATS in EC grown plants. Growth under EC decreased both the affinity and rate of nitrate uptake in induced seedlings. However, the expression of TaNRT2.1, TaNRT2.2, TaNRT2.3 genes were highly induced by EC when the N supply level was low. Recent evidences suggest the involvement of ECO2-triggred synthesis of nitric oxide (NO) as a mediator of high affinity nitrate transporter activity in plants. The observed negative impact of EC on IHATS might also be an after effect of NO perturbation. EC could modify the inorganic nitrogen uptake by altering the access to or accessibility of nutrients in soil or by altering the kinetics of CHATS.
KeywordsElevated carbon dioxide Kinetics Nitrate transporter Wheat
Authors are thankful to the ICAR-Indian Agricultural Research Institute for funding and providing the necessary facilities.
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Conflict of interest
The authors declare that they have no conflict of interests.
- Barber, S. A. (1984). Soil nutrient bioavailability. A mechanistic approach (pp. 55–86). New York: Wiley-Interscience Publication.Google Scholar
- Bloom, A. J., Burger, M., Kimball, B. A., & Pinter Jr, P. J. (2014). Nitrate assimilation is inhibited by elevated CO2 in field-grown wheat. Nature Climate Change, 4(6), 477.Google Scholar
- Du, S., Zhang, R., Zhang, P., Liu, H., Yan, M., Chen, N., et al. (2016). Elevated CO2-induced production of nitric oxide (NO) by NO synthase differentially affects nitrate reductase activity in Arabidopsis plants under different nitrate supplies. Journal of Experimental Botany, 67(3), 893–904.CrossRefPubMedGoogle Scholar
- Faure-Rabasse, S., Le Deunff, E., Laine, P., Macduff, J. H., & Ourry, A. (2002). Effects of nitrate pulses on BnNRT1 and BnNRT2 genes mRNA levels and nitrate influx rates in relation to the duration of N deprivation in Brassica napus L. Journal of Experimental Botany, 53, 1711–1721.CrossRefPubMedGoogle Scholar
- Glass, A. D. M., & Siddiqi, M. Y. (1995). Nitrogen absorption in higher plants. In H. S. Srivastava & R. P. Singh (Eds.), Nitrogen nutrition in higher plants (pp. 21–55). New Delhi: Associated Publishers.Google Scholar
- Harris, G. (1998). An analysis of global fertilizer application rates for major crops. http://www.fertilizer.org/crops/crops/harris. Accessed 3 May 2006.
- Lambers, H., Van Der Werf, A., & Konings, H. (1991). Respiratory patterns in roots in relation to their functioning. In Y. Waisel, A. Eshel, & U. Kafkafi (Eds.), Plant roots: The hidden half (pp. 229–263). New York: Marcel Dekker.Google Scholar
- Lekshmy, S., Jain, V., Khetarpal, S., Pandey, R., & Singh, R. (2009). Effect of elevated carbon dioxide on kinetics of nitrate uptake in wheat roots. Indian Journal of Plant Physiology, 14, 16–22.Google Scholar
- Lekshmy, S., Jain, V., Khetarpal, S., Verma, R., Sailo, N., & Pandey, R. (2016). Influence of elevated carbon dioxide and ammonium nutrition on growth and nitrogen metabolism in wheat. Indian Journal of Agricultural Sciences, 86(1), 25–30.Google Scholar
- Lekshmy, S., & Jha, S. K. (2017). Selection of reference genes suitable for qRT-PCR expression profiling of biotic stress, nutrient deficiency and plant hormone responsive genes in bread wheat. Indian Journal of Plant Physiology, 22(1), 101–106.Google Scholar
- Li, J., Zhou, J.-M., Duan, Z.-Q., Du, C.-W., & Wang, H.-Y. (2007). Effect of CO2 enrichment on the growth and nutrient uptake of tomato seedlings. Pedosphere, 17, 343–351.Google Scholar
- Matt, P., Geiger, M., Walch-Liu, P., Engels, C., Krapp, A., & Stitt, M. (2001). Elevated CO2 increases nitrate uptake and nitrate reduction activity when tobacco is growing on nitrate but increases ammonium uptake and inhibits nitrate reductase activity when tobacco is growing an ammonium nitrate. Plant, Cell and Environment, 24(1119–1137), 1.Google Scholar
- Pilbeam, D. J., & Kirkby, E. A. (1990). The physiology of nitrate uptake. In Y. P. Abrol (Ed.), Nitrogen in higher plants (pp. 39–64). New York: Wiley.Google Scholar
- Prentice, I. C., Farquhar, G. D., Fasham, M. J. R., Goulden, M. L., & Heimann, M. (2001). The carbon cycle and atmospheric carbon dioxide. In J. T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, & D. Xiaosu (Eds.), Climate change 2001: The scientific basis. Contribution of working group I to the third assessment report of the intergovernmental panel on climate change (pp. 183–239). New York NY: Cambridge University Press.Google Scholar
- Zhao, X. Q., Li, Y. J., Liu, J. Z., Li, B., Liu, Q. Y., Tong, Y. P., et al. (2004). Isolation and expression analysis of a high-affinity nitrate transporter TaNRT2. 3 from roots of wheat. Acta Botanica Sinica, 46(3), 347–354.Google Scholar