Index >> Biotechnology in Agriculture >> Frost Control Biotechnology

Frost tolerant plants, however, have endogenous ice-tolerance mechanisms.

How does frost sensitive plants overcome frost injury. There appears to be a super cooling mechanism in such plants to avoid ice formation. Ice nucleation or initiation of ice embryos is caused by the orientation of water molecules by organic and inorganic substances. Several plant-associated bacteria are highly active in ice nucleation and may be responsible for frost injury and the biotechnological implications of this activity have been studied with reference to frost injury at temperatures above minus 5°c.

These epiphytic bacteria are known to occur on frost resistant as well as frost susceptible plants and are known to be killed by disinfectants and V.V. light.

The genes conferring ice nucleation characteristic have been partially characterized from P. syringae, P. fluorescens and E. herbicola and are known to be a single contiguous region of approximately 4000 bp. They have been cloned in Escherichia coli.

Streptomycin and oxytetracycline as well as copper hydroxide applica­tions to leaf surfaces reduced the incidence of frost injury, despite the fact that dead cells were also known to be active as ice nucleating agents. Likewise, non-ice nucleation-active bacteria can also reduce the population of ice-nucleating ones both in the green house and the field by limiting nutrients to the ice nucleating bacteria.