The invention relates to the technical field of rice stress-resistant cultivation, and discloses a
rice root system salt tolerance adjusting method based on exogenous
spermidine, which comprises the following core steps: in the
critical period of
rice root system development, directionally applying a
spermidine solution subjected to purity
verification to a
rice root system area, by accurately regulating and controlling the application concentration, frequency, duration and application environment conditions of
spermidine, the osmotic regulation capability and the anti-oxidation system function of a rice
root system in a high-salt environment with the
soil conductivity larger than or equal to 2 dS / m are improved, the salt tolerance of the
root system is remarkably improved, and then growth and development of rice are guaranteed. The spermidine is a straight-chain
polyamine compound with good
biocompatibility, the
chemical purity is not lower than 98%, no heavy
metal is left, and the contents of lead,
cadmium and mercury are all smaller than or equal to 0.1 mg / kg. According to the invention, precise targeted regulation and control of the salt tolerance of the rice
root system are realized, and the regulation effect is stable and remarkable.