Fig. 3

Expression analysis of OsS40 genes in rice plants growing under different nitrogen concentrations. a Phenotypes of 13 weeks (90DAG) and 21 weeks (147DAG) old rice plants growing under normal nitrogen (Normal-N) as a control, low nitrogen (Low-N) or high nitrogen concentration (High-N). The nitrogen nutrient was applied to the growth media of growing seedlings during the entire development. b and c Plants were characterized by the chlorophyll content (μg/cm2) and relative photochemical efficiency of photosystem II (Fv/Fm) of entire rosettes. The error bars indicate the standard error of ten independent measurements for chlorophyll content and five independent measurements for chlorophyll photosystem II efficiency. d Quantitative real-time PCR analysis of the six differentially expressed OsS40 genes along with senescence marker OSH36 gene. Transcript levels are expressed relative to that of rice actin in each sample, and values are mean ± S.D. Student t-test was used to generate P value. *P ≤ 0.05, **P ≤ 0.01 and ***P ≤ 0.001