4Steponkus P L, Lanphear F O. Refinement of the triphenyl tetrazolium chloride method of determining cold injury. Plant Physiol, 1967,42:1 423~1 426
5Levitt J. Responses of plants to environmental stresses, Vol 1. Chilling,freezing,and high temperature stresse. 2nd edition. New York: Academic Press, 1980