nitrogen supply in rice (Oryza sativa L.) seedlings. J. Plant Growth Regul. 31:47-52
 Makino, A. and T. Mae. 1999. Photosynthesis and plant growth at elevated levels of CO2. Plant Cell Physiol. 40: 999-1006.
 Marschner, H.1995.Mineral Nutrition of higher plants. Academic Press London.
 Morison, J. I. L. and M. D. Morecroft. 2006. Plant Growth and Climate Change. Blackwell Publishing Ltd.
 Nakano, H., A. Makino and T. Mae. 1997. The effect of elevated partial pressures of CO2 on the relationship between photosynthetic capacity and N content in rice leaves. Plant physiol. 115: 191-198.
 Novozamsky, I., R. van Eck, J.Ch. van Schouwenburg and I. Walinga. 1974. Total
nitrogen determination in plant material by means of the indophenol blue method.
Neth.J.Agr.Sci. 22: 3-5.
 Pang, J., J. G. Zhu, Z. B. Xie, G. Liu, Y. L. Zhang, G. P. Chen, Q. Zeng and L. Cheng. 2006. A new explanation of the N concentration decrease in tissues of rice (Oryza sativa L.) exposed to elevated atmospheric pCO2. Environ. Exp. Bot. 57: 98-105.
 Pan, S. G., S. G. Huang, J. Zhai, J. P. Wang, C. G. Cao, M. L. Cai, M. Zhan and X. R. Ming. 2012. Effects of N management on yield and N uptake of rice in central china. J. Integr. Agr. 11:1993-2000.
 Rogers, H. H., G. B. Runion and S. V. Krupa. 1994. Plant responses to atmospheric CO2 enrichment with emphasis on roots and the rhizosphere. Environ. Pollut. 83: 155-189.
 Rogers, H. H., S. A. Prior, G. B. Runion and R. J. Mitchell. 1995. Root to shoot ratio of crops as influenced by CO2. Plant Soil. 187: 229-248.
 Roy, K. S., P. Bhattacharyya, S. Neogi, K. S. Rao and T. K. Adhya. 2012. Combined effect of elevated CO2 and temperature on dry matter production, net assimilation rate, C and N allocations in tropical rice (Oryza sativa L.). Field Crops Res. 139: 71-79.
 Roy, R. N. and R. V. Misra. 2002. Economic and environmental impact of improved nitrogen management in Asian rice-farming systems. Proceedings of the 20th Session of the International Rice Commission. Bangkok.
 Seneweera, S., A. Makino, N. Hirotsu, R. Norton and Y. Suzuki. 2011. New insight into photosynthetic acclimation to elevated CO2: The role of leaf nitrogen and ribulose-1,5-bisphosphate carboxylase/oxygenase content in rice leaves. Environ. Exp. Bot. 71: 128-136.
 Shah, F., J. Huang, K. Cui, L. nie, T. Shah, C. Chen and K. Wang. 2011. Impact of high-temperature stress on rice plant and its traits related to tolerance. J. Agr. Sci. 149: 545-556.
 Shimono, H. and J. A. Bunce. 2009. Acclimation of nitrogen uptake capacity of rice to elevated atmospheric CO2 concentration. Ann. Bot. 103: 87-94.
 Shimono, H. and M. Okada. 2013. Plasticity of rice tiller production is related to genotypic variation in the biomass response to elevated atmospheric CO2 concentration and low temperatures during vegetative growth. Environ. Exp. Bot. 87: 227- 234
 Shimono, H., M. Okada, Y. Yamakawa, H. Nakamura, K. Kobayashi and T. Hasegawa. 2008. Rice yield enhancement by elevated CO2 is reduced in cool weather. Glob Change Biol. 14: 276-284.
 Shimono, H., M. Okada, Y. Yamakawa, H. Nakamura, K. Kobayashi and T. Hasegawa. 2009. Genotypic variation in rice yield enhancement by elevated CO2 relates to growth before heading, and not to maturity Group. J. Exp. Bot. 60: 523-532.
 Taub, D. R., and X.Wang. 2008. Why are nitrogen concentrations in plant tissues lower under elevated CO2? A critical examination of the hypotheses. J. Integr. Plant Biol. 50: 1365-1374.
 Terashima, I., S. Yanagisawa and H. Sakakibara. 2014. Plant responses to CO2: background and perspectives. Plant Cell Physiol. 55: 237-240.
 Timothy, W. and Joe, E. 2003. Rice fertilization. Mississippi Agricultural and forestry Experiment station.
 Tsutsumi, K., M. Konno, S. I. Miyazawa and M. Miyao. 2014. Sites of action of elevated CO2 on leaf development in rice: Discrimination between the effects of elevated CO2 and nitrogen deficiency. Plant Cell Physiol. 55: 258-268.
 Wang, L., P. Pedas, D. Eriksson, and J. K. Schjoerring. 2013. Elevated atmospheric CO2 decreases the ammonia compensation point of barley plants. J. Exp. Bot. 64: 2713-2724.
 Wanga, Y., M. Frei, Q. Song and L. Yang. 2011. The impact of atmospheric CO2 concentration enrichment on rice quality – A research review. Acta Ecolo. Sinica. 31: 277-282.
 Wang, Y., Q. Song, M. Frei, Z. Shao and L. Yang. 2014. Effects of elevated ozone, carbon dioxide, and the combination of both on the grain quality of Chinese hybrid rice. Environ. Pollut. 189:9-17.
 Wassmann, R., S. V. K. Jagadish, S. Heuer, A. Ismail, E. Redona, R. Serraj, R. K. Singh, G. Howell, H. Pathak and K. Sumfleth.2009. Chapter two: Climate Change Affecting Rice Production: The Physiological and Agronomic Basis for Possible Adaptation Strategies. Adv. Agron. 101: 59-122.
 Weerakoon, W. M., D. M. Olszyk and D. N. Moss. 1999. Effects of nitrogen nutrition on responses of rice seedlings to carbon dioxide. Agr. Ecosys. Environ.72: 1-8.
 Yoshida, S. 1981. Fundamentals of rice crop science. The international rice research institute, Los banos, laguna, Philippines.
 Yu, q. g., j. Ye, S. N. Yang, J. R. Fu, J. W. Ma, W. C. Sun and Q.Wang. 2013. Effects of nitrogen application level on rice nutrient uptake and ammonia volatilization. Rice Sci. 20: 139-147.
 Zhang, G., H. Sakai, T. Tokida, Y. Usui, C. Zhu, H. Nakamura and T.Hasegawa. 2013. The effects of free-air CO2 enrichment (FACE) on carbon and nitrogen accumulation in grains of rice (Oryza sativa L.). J. Exp Bot. 64: 3179-3188.
Evaluation of the Response of Rice Genotypes to Different Levels of Nitrogen in the Nutrient Solution Grown under Ambient and Enriched Air CO2
September 14, 2014
Department of Agronomy and Plant Breeding
Isfahan University of Technology, Isfahan 84156-83111, Iran.
Degree: M.Sc Language: Farsi
Supervisor: Hamid Reza Eshghizadeh, [email protected]
Rice plays an important role in feeding half of the world’s population, most of which are living in developing countries, including Iran. This crop occupies one third of the agricultural lands dedicated to cereal production and provides 35-60 percent of the calories consumed by 2.7 billion people. According to the Intergovernmental Panel on Climate Change (IPCC), CO2 concentration in the atmosphere is expected to reach 700 µM M-1 by the end of the 21st century. Various researches have shown that the response of rice to increasing CO2 in the atmosphere depends on the used cultivar and supply of nitrogen fertilizer. Therefore, the first experiment of this study evaluated the responses of 28 rice genotypes belonging to three varietal groups (local and improved genotypes from north and genotypes from the center of Iran) to two levels of nitrogen (2.85 and 1.42 mM N- ammonium nitrate in Yoshida’s nutrient solution). Treatments were arranged as factorial experiment in a completely randomized design. The results showed that tiller numbers, leaf area, SPAD index, shoot and root dry weight, plant total dry weight, plant height, and root length were significantly affected by genotype, N concentration and the interaction between genotype and N concentration. Considerable variation was observed among genotypes in response to the reduced N concentration in the nutrient solution. َAmong improved genotypes from north, Fajr and Khazar had the highest and Nemat and Shirudi had the lowest nitrogen use efficiency (NUE). While, among local genotypes from north, the highest NUE belonged to Hassani and Kazemi and the lowest NUE belonged to Tarom-Mantaghe and Ahlami-Tarom cultivars. Also, the highest and lowest NUE were achieved for Line 2- Firozan and Zayanderood among genotypes that are cultivated in the center of Iran. In the second experiment, the responses of four rice genotypes (Shirudi, Fajr, TaromMantaghe and Hasseni, chosen based on the results of the first experiment) were investigated to four levels of nitrogen (0.712, 1.42, 2.85, 3.79 mM of ammonium nitrate in the Yoshida nutrient solution) and two levels of air carbon dioxide (ambient; 360±50 µM and enriched; 700±50 µM). In the second experiment, rice plants were harvested at two different stages. The first harvest was done 30 days after treatments were imposed. Increasing CO2 concentration increased chlorophyll content, leaf area and the root/ total plant dry weight ratio. The interaction effects of carbon dioxide and genotype were significant on shoot dry weight, chlorophyll and carotenoid content. Shoot dry weights of Shirudi, Hasseni and Fajr cultivars were increased and that of TaromMantaghe was decreased as a result of increased CO2 concentration, although the increase in shoot dry weight was not statistically significant for Fajr genotype. In the second harvest, which was done 60 days after treatments were imposed, increasing CO2 concentration decreased leaf area, the concentration and the content of nitrogen in shoots and increased nitrogen use efficiency and the concentration of nitrogen in roots which led to an increase in shoot: root nitrogen concentration. was significantly reduced in Shirudi and TaromMantaghe cultivars. The reduction in leaf area was only significant in Shirudi and TaromMantaghe. Increased CO2 concentration increased chlorophyll content in Hasseni and Fajr but decreased chlorophyll content in Shirudi and