In Response To Low Temperature Resistant Maize Variety Selection And Seedling To Temperature Change

38different genotypes of maize varieties were used to evaluate low-temperature toleranceat germination and seedling stage respectively. By analysis on germination rate, germinationpotential, root length, shoot length and other physiological and biochemical indicators, thevarieties of this study were classified into low-temperature tolerant varieties, low-temperaturesensitive varieties and moderately low-temperature sensitive varieties. Then the low-temperaturesensitive varieties and low-temperature tolerant varieties were screened out for studying theresponse of maize different genotypes to low temperature injury in different growing period byanalyzing physiological characteristics of protective enzyme activity, osmotic adjustmentsubstances contents and membrane lipid oxidation. The results are as follows:a. Effect of screening on different genotypes of maize at germination and seedling stage.Low-temperature tolerant varieties: Zhengdan958, Nan Bei4, Xin Dan22, Jin Shan27,Long Dan32, Kuan Cheng12, Xin Yu4, Jiu Long10, Qiang Sheng1, Ze Yu16, Zhe Dan37, JiDan522, Jiu Long10, Kuan Cheng10, Jiu Long2, Feng He10and other Jing Hua8.Moderately low-temperature sensitive varieties: Xing Ken3, Hong Yu319,Gan Yu1,DeMeiya1, Ke Dan8, Li Yu18, Jian Yu2, Hai Yu5, Ken Yu7, Sui Yu7, Jin Dan42, Sui Yu19, ZeYu19and Tang Yu15.Low-temperature sensitive varieties: Ping Quan13, Jin Shan8, Long Dan46, Lei Ao150,Liang Yu188, Long Feng7and Long Yu8.b. Effects of low temperature on growth characteristics of different genotypes of maizeSeedlings10℃and5℃low temperature decreased the dry matter accumulation of Low temperatureresistant maize Zheng Dan958and low temperature sensitive maize Jin Shan8, that illustratedlow temperature could inhibit the growth of maize seedings and lead to the decrease of drymatter, and the inhibition was more serious as the temperature drop; dry matter accumulationwas in a certain extent increased at15℃, that indicated15℃low temperature had lessinhibition of growth; dry matter accumulation was significantly increased at25℃and thegrowth of maize seedling was good. At low temperature SOD activity and POD activityincreased at first and then decreased; the protective enzyme activity changed greatly at leaf stage and second leaf stage; with the extension of low temperature processing time, the proline contentof aerial part and underground part decreased first and then increased and there was nosignificantly difference during the three stage of the study. These results indicated that theresistance mechanism in low-temperature tolerant varieties was stronger than it inlow-temperature sensitive varieties, through the analysis of protective enzymes and otherphysiological and biochemical index in the different low-temperature sensitivity maizephenotype.