N-acetylcysteine (NAC) biosynthesized reduced glutathione (GSH), which maintains redox homeostasis in plants under normal and stressful conditions. NAC significantly increased RWC in leaves of N-untreated rice plants. In conclusion, this study suggests that NAC may enhance rice yield through modulating physiological functions of rice plants. | Turkish Journal of Agriculture and Forestry Turk J Agric For (2015) 39: 204-211 © TÜBİTAK doi: Research Article N-acetylcysteine increased rice yield 1, 1, , 1 Mohd NOZULAIDI *, Md Sarwar JAHAN * **, Mohd KHAIRI , 1 1 2 Mohammad Moneruzzaman KHANDAKER , Mat NASHRIYAH , Yusop Mohd KHANIF 1 School of Agriculture and Biotechnology, Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin, Besut, Terengganu, Malaysia 2 Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia Received: Accepted: Published Online: Printed: Abstract: N-acetylcysteine (NAC) biosynthesized reduced glutathione (GSH), which maintains redox homeostasis in plants under normal and stressful conditions. To justify the effects of NAC on rice production, we measured yield parameters, chlorophyll (Chl) content, minimum Chl fluorescence (Fo), maximum Chl fluorescence (Fm), quantum yield (Fv/Fm), net photosynthesis rate (Pn), photosynthetically active radiation (PAR), and relative water content (RWC). Four treatments, N1G0 (nitrogen (N) with no NAC), N1G1 (N with NAC), N0G0 (no N and no NAC), and N0G1 (no N but with NAC), were arranged in a completely randomized design with five replications. Nitrogen significantly increased yield and yield parameters of rice plants. Moreover, NAC treatment increased panicle numbers, filled grains per panicle, and yield of rice plants. Nitrogen significantly increased Chl content, Chl fluorescence parameters (Fm, Fv/Fm ratio), Pn rate, and PAR in leaves of the rice plants. Furthermore, NAC treatment induced Chl content, Chl fluorescence (Fm, Fv/Fm ratio), Pn, and PAR in leaves of the rice plants regardless of N treatment. NAC significantly increased RWC in leaves of N-untreated rice plants. In conclusion, this study suggests that NAC may enhance rice yield through modulating .