Fig. 1. NO- and H2S-mediated 15% polyethylene glycol-6000 (PEG)-induced stress responses in rice seedlings: Phenotypic, molecular, and metabolic alterations. A, Representative phenotypes of rice seedlings subjected to different treatments. B-D, Shoot length (B), root length (C), and number of roots per plant (D) of rice seedlings subjected to different treatments. Data were presented as mean ± SE (n = 3), and different lowercase letters on bars indicated significant differences at P < 0.05 using Duncan’s multiple range test. E, K-means clustering of genes in the MEgreenyellow module identified by weighted gene co-expression network analysis based on differentially expressed genes (DEGs). FPKM, Fragments per kilobase of transcript per million mapped reads. F, Sankey diagram showing the dynamic distribution of DEGs induced by PEG with NO2 and HS1. G, Differentially accumulated metabolites implicated in carbohydrate metabolism, phenylpropanoid biosynthesis, and flavonoid biosynthesis, together with module-trait correlation plots. The number below each module (located on the left) indicated the count of DEGs associated with that module. Correlation coefficients were reported outside parentheses; corresponding P-values were shown within parentheses. Positive correlations were denoted in red, and negative correlations in blue. Control, Distilled water; NO1, 25 µmol/L NO; NO2, 50 µmol/L NO; HS1, 25 µmol/L H2S; HS2, 50 µmol/L H2S; PEG, 15% polyethylene glycol-6000; PEG_NO1, PEG + 25 µmol/L NO; PEG_NO2, PEG + 50 µmol/L NO; PEG_HS1, PEG + 25 µmol/L H2S; PEG_HS2, PEG + 50 µmol/L H2S.