The frost injury index and advection cold injury index of tropical herbage and the hot injury index of temperate herbage are found.

Single cell of INA bacteria can not act as ice nucleus, therefor the key to the study on the relationships between INA bacteria and frost injury to plants is to study the population of INA bacteria.

Based on investigations, researches and scientific experiments, the cool injury index and frost index to crops that fit the fact of heilongjiang Province are analyzed and obtained.