Physiological approaches for increasing nitrogen use efficiency in rice
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Physiological approaches for increasing nitrogen use efficiency in rice P. Vijayalakshmi • T. Vishnu Kiran • Y. Venkateswara Rao B. Srikanth • I. Subhakara Rao • B. Sailaja • K. Surekha • P. Raghuveer Rao • D. Subrahmanyam • C. N. Neeraja • S. R. Voleti
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Received: 10 February 2013 / Accepted: 13 August 2013 / Published online: 12 October 2013 Ó Indian Society for Plant Physiology 2013
Abstract Nitrogen (N) plays an important role in plant growth, development and also one of the major factor for developing a high-yielding rice cultivars. Nitrogen use efficiency (NUE) in plants is a complex phenomenon that depends on a number of internal and external factors, which include soil N availability, its uptake and assimilation of carbon and nitrogen. An increased awareness of the regulatory mechanisms controlling Nitrogen economy is imperative to enhance nitrogen uptake and use efficiency so as to reduce excessive input of fertilizers, while maintaining an acceptable yield. The physiological, biochemical, molecular aspects like QTL, mi RNA technology and transgenic approaches as well as NUE can be targeted to improve rice productivity. Yield being complex and multigenic trait linkages between carbon and nitrogen pathways are essential. An attempt on complex interactions between the two major physiological pathways linked by photosynthesis and photorespiration in global climate change for enhancing NUE in relation to rice yield was reviewed. Keywords Nitrogen use efficiency Rice Biological approaches miRNA Hormones Photorespiration
P. Vijayalakshmi T. V. Kiran Y. V. Rao B. Srikanth I. S. Rao B. Sailaja K. Surekha P. R. Rao D. Subrahmanyam C. N. Neeraja S. R. Voleti (&) Plant Physiology, Directorate of Rice Research, Rajendranagar, Hyderabad 500 030, India e-mail: [email protected]
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Introduction Nitrogen(N) is one of the essential macronutrients required to sustain plant life. As it is the key substrate in many important structural, genetic and metabolic compounds of plant cells. It is a major component of chlorophyll, the compound by which plants use sunlight energy to produce sugars from water and carbon dioxide by photosynthesis. It is also a major component of amino acids, the building blocks of proteins. N is a significant component of nucleic acids such as DNA, the genetic material that allows cells to grow and reproduce. As Nitrogen constitutes 70 % of the atmospheric gases, atmospheric nitrogen can also be used by plants after reduction by soil microorganisms. Soil contains both NH4? and NO3– forms of N. They are available in the soil as mobile form and crop plants are able to utilize only 30–40 % of the applied N (Raun and Johnson 1999). Thus, more than 60 % of the soil N is lost through a combination of leaching, surface run-off, de nitrification, volatilization, and microbial consumption.The majority of crops except nitrogen-fixing legumes receive an application of nitrogen, the major requirements are for the production of seeds (Mengel et al. 2006) and forage
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