Measurement of Glucose, Fructose, Sucrose, PRO and GB content
The content of sucrose, fructose, and glucose were measured using assay kits (Comin Biotechnology, Suzhou, China). Sucrose, fructose, and glucose content were measured at OD480, OD480, and OD505, respectively. The proline (PRO) and glycine betaine (GB) assay kit (Comin Biotechnology, Suzhou, China) was used to measure the PRO and GB content at OD520 and OD525 in soybean leaves, respectively.