Figure 6.

The relative expression patterns of eight candidate genes involved in indole-3-acetic acid (IAA) biosynthesis and signal transduction and lignin biosynthesis pathways, growth phenotypes, physiological responses (IAA and lignin contents), and their Pearson correlations in the mesocotyl and coleoptile of two maize inbred lines (ly119-2 and ZRX87-1) under 3 cm seeding depth + 0 mg/L serotonin (5-HT) application (CK(+)), 20 cm seeding depth + 0 mg/L 5-HT application (CK(-)), and 20 cm seeding depth + 2.5 mg/L 5-HT application (T4) treatments. (A) The relative expression levels of the eight candidate genes. Different lowercase letters among treatments within the mesocotyl of coleoptile of a single maize line indicate significant differences at p < 0.05. (B) The correlational relationships in the mesocotyl among growth phenotypes (mesocotyl length, coarse, and weight), physiological responses (IAA and lignin contents), and eight candidate genes were analyzed by the Genescloud tool (https://www.genescloud.cn, accessed on 13 October 2023). Lines represent significant correlations (p < 0.05). (C) The correlational relationships in the coleoptile among growth phenotypes (coleoptile length, coarse, and weight), physiological responses (IAA and lignin contents), and eight candidate genes were analyzed by the Genescloud tool (https://www.genescloud.cn, accessed on 13 October 2023). Lines represent significant correlations (p < 0.05).