Fig. 1

Experiment design, ear development, biomass accumulation in the kernel, agronomic traits changes in the plants and physiological changes in the ear leaf response to drought stress. a Schematic diagram of the experiment design, the stage of drought stress treatment and samples collection. b and c Morphological characteristics of the ears at the V9 stage under normal conditions (b) and drought conditions (c). d Mature ears from plants under control and drought conditions. e and f Morphological characteristics of the kernels and the basal endosperm transfer cell layer (BETL) at the 5DAP stage under normal conditions (e) and drought conditions (f). g Radar chart of agronomic traits changes of maize plants grew under control and drought stress conditions (at the V9 stage and 5 DAP stage). h Net photosynthesis, relative water content, soluble sugar content, and solute potential of the ear leaf at the 5DAP stage under control and drought conditions. All the plants were grown under natural conditions, normal nutrients, well-watered soil in the field until the designated stages. Two different drought stress treatments (5 days drought stress at the V9 stage (when the 10th leaf appeared) and 5DAP stage (when the silk appeared)) and a normal control were performed. The upper ear (at the V9 stage), the ear leaf and kernels on the upper ear (at the 5 DAP stage) from drought stress and control plants was collected for morphological analysis. After re-watering, the remaining plants were grown to maturity under suitable conditions, and then the agronomic traits were determined (original data in Additional file 1: Table S1). At least three biological repeats were sampled for a treatment, and each repeat contained organs from 4 plants. Values are the means of the replicates ± sd. ** was statistical significance with P < 0.01 by using a t-test