Ammonia Emission from Leaves of Different Rice (Oryza sativa L.) Cultivars

NH3 emission from leaves of three rice (Oryza sativa L.) cultivars, Akenohoshi, Shirobeniya and Kasalath, was examined using a simple open chamber system. In the three cultivars, NH3 emission rate (AER) and NH4+ content of leaves decreased with decreasing NH4+ concentration in the root medium, but these values differed significantly with the cultivar. In the daytime, AER, NH4+ content and glutamine synthetase (GS) activity in leaves changed similarly with maximum values around midday. Akenohoshi showed significantly lower AER and NH4+ content but higher GS activity than Kasalath. The difference in AER among the rice cultivars may be related to the activity of GS involved in photorespiratory NH3 recycling. Akenohoshi can be a breeding material useful for improving N recycling.