Immunolocalization of GA

Shoot apices were fixed in 3.7% (v/v) formalin acetic acid and prepared into paraffin sections. Paraffin sections were incubated with a 1:50 (v/v) dilution of polyclonal antibody to Gibberellic Acid (Immuno Clone Biosciences Co., Ltd, USA) overnight at 4 °C and then with a 1:200 (v/v) dilution of Goat AntiRabbit IgG HandL (Alexa Fluor 488) (Abcam, China) for 4 h at room temperature in the dark. Fluorescence signals were recorded using a Nikon A1 confocal laser scanning microscope (Nikon, Japan) with an excitation wavelength of 488 nm and an emission wavelength of 519 nm. Negative controls were specimens not incubated with anti-GA antibodies.