Fig. 3

ALA induced kinetic changes of gene expression in chlorophyll synthesis with tomato leaves under low temperature within 48 h. The tomato leaves treated with distilled water or 25 mg·L^− 1 ALA then exposed to normal condition (control and ALA) or low temperature (LT and LTA) 12 h later. The expression of genes were carried out when the low temperature started. The gene transcription levels in control plants at 0 h was normalized as 1. Data are expressed as the mean ± standard error of three independent biological replicates. The experiments were repeated for three times. Different letters above the bars indicate a significant difference determined by one-way ANOVA with Tukey’s test (P < 0.05). ALAD, aminolevulinic dehydratase gene; PBGD, porphobilinogen deaminase gene; UROD, uroporphyrinogen decarboxylase gene; CPOX, coproporphyrinogen III oxidase gene; PPOX, protoporphyrinogen IX oxidase gene; CHLM, Mg-protoporphyrin IX methyltransferase gene; POR, protochlorophyllide oxidoreductase gene; CHLG, chlorophyll synthase gene; CAO, chlorophyllide a oxygenase gene