Drought Tolerance Identification And The Study Of Physiology-Biochemical Resistant Mechanisms Of Maize

Different concentrations of Polyethylene glylol(PEG) are chosen to simulate different drought degrees which seedling stage maize encounters. The concentrations of PEG are: 0%, 5%, 10%, 15%, 20%. Six indexes are measured, which relate to drought tolerance of 22 inbred lines (POD activity, SOD activity, CAT activity, MDA content, Vc content and electric conductivity). Analysis to the relation among these six indexes and the drought tolerance are carried out coefficient. The primary results are as followings:1. It has preferable reliability to use different concentrations of PEG to simulate different drought degrees, which maize encounters in seedling stage. It can avoid the unilateralism of single concentration.2. The result of analysis among six indexes and drought tolerance index shows: Six indexes that we are choosing have very significant relations with maize drought tolerance. In six indexes, SOD activity has the strongest relations with maize drought tolerance, and electric conductivity is the second.3. It is available to appraise the drought tolerance of Maize by the fuzzy administering function D value of different concentrations. The correlation between D value and drought tolerance index is very significant(r=0.872**). The 22 inbred lines can be divided into three classes according to the D value of six drought tolerance indexes: the strongest, the middle and the weakest.According to SOD activity by Scott-Knott clustering, the inbred lines can be divided into two classes: the stronger and the weaker drought tolerance. The result of division in this way is similar to field result. So it is available to appraise the drought tolerance of maize in the way we used.4. SOD and electric conductivity are two better drought tolerance indexes out of previous six indexes. They can be used to identify the drought tolerance of maize in lab instead of in field.5. The way that using fuzzy administering function to analyze drought tolerance mechanisms of maize can make the difference of maize drought tolerance has quantitative measurement. In this way we can discuss the drought tolerance mechanisms further, and can guide the drought tolerance breeding to choose the good one and to get rid of disadvantageous characters.