In recent years,abnormal climate activities, high temperature, drought, freezing damage and other frequent occurrence, coupled with the impact of human activitie,soil  consolidation,acidification,salinization and soil pollution are becoming more and more serious.In agricultural production activities, how to effectively deal with the effects of the above abiotic stress factors to ensure the healthy growth of crops has become the focus of research in recent years.With the deepening of relevant research,there are more and more evdence to show that the betaine for agricultural grade plays an important role in plant resistance to abiotic stress.

Betaine is a quaternary ammonium alkaloid, widely existing in animals and plants.It is a secondary product of metabolism,and its unique molecular properties makes it have polar and non-polar. It can combine to hydrophilic and hydrophobic regions of biological macromolecules, such as enzymes or protein complexes, and is an important non-toxic osmotic regulatory substance in higher plants。

Betaine can stablize the structure and function of biological macromolecules under the condition of osmotic stress,meanwhile,it also can reduce the damage to cell membrane, enzyme and protein structure and function under the condition of infiltration water loss,so as to improve the resistance of plants to various stress factors,and the stability of the Krebs cycle Ⅱ key enzyme and the terminal oxidases, optical system, peripheral peptides and various physiological functions. It has important physiological significance to maintain normal respiration and photosynthesis under the influence of drought, salt and alkali, cold and other adverse environment in the growth process of plants.A large number of studies have confirmed that applying exogenous betaine can greatly improve the resistance of a variety of crops, fruit trees and forest trees to saline-alkali, drought, high temperature, freezing and other stresses.