Adding the betaine into the plant,can improve their resistance to the freeze  and the drought resistance of some plants.

Low temperature stress has an effect on the whole physiological process of plants,such as reactive oxygen metabolism,respiration, photosynthesis and nitrogen metabolism。The membrane system is the main location of freezing injury。The initial reaction of irreversible damage caused by low temperature is the change of lipid molecular structure in biofilm system。Oxygen free radicals and reactive oxygen species in plant body have strong air oxidation capacity, which can destroy the molecular structure of many microorganisms。

Oxygen free radicals, reactive oxygen species, and antioxidant and non-antioxidant chemicals that eliminate them remain in equilibrium under all normal standards, and do not easily lead to membrane lipid peroxides within a certain low temperature range;When the temperature drops or the low temperature delay time increases,the Oxygen free radicals and reactive oxygen species will increase significantly while the elimination amount will decrease,leading to the accumulation of oxygen free radicals and membrane lipid peroxides,resulting in the lot accumulation of membrane lipid peroxidation product malondialdehyde (MDA) and the increased membrane permeability and electrolyte leakage,thus damaging the  cytoplasmic system.

Low temperature stress also reduces the compressive strength of photosynthesis in plants,the researches show that the low temperature stress is significant harm to the whole physiological and biochemical process of plant photosynthetic pigment components of chloroplast submicrostructure, photosynthetic energy consumption and other key factors.