The seeds of NPB were surface-sterilized in 70% ethanol for 2 min, followed by gentle shaking in the 2.5% NaClO for 30 min, and washing several times with sterilized water. The sterilized seeds were soaked in distilled water for 4 days and germinated in an incubator. Then, the seedlings were grown hydroponically with deionized water at 25 °C for 7 days under the 12 h light/12 h dark conditions in the growth chamber. The rice seedlings were subsequently subjected to stress treatments: (1) the time-course treatment (0, 1, 3, 6, 12 and 24 h) with the hydroponic application of 200 mM NaCl, or 20% PEG-6000, or 100 μM ABA, respectively; (2) treated in the solution as follows: ① distilled water (Control); ② 50 μM ABA; ③ 50 μM ABA with the 12 h pretreatment of 5 mM CaCl2; ④ 50 μM ABA with the 12 h pretreatment of 5 mM EGTA. The shoot tissues were collected at the designated time points, immediately frozen in liquid nitrogen, and stored at −80 °C for RNA extraction.