The Salt Tolerance Analyses Of Progenies From Maize Shoot Under Salt Stress

It is crucial to select and cultivate high-quality salt-tolerant maize varieties to use salinization soil utilization.Based on the previous research of our research group,the four skeleton inbred lines were selected in this experiment as materials to establish the relevant salt stress treatment systems of maize shoot respectively.The seeds of progennis from salt stressed shoots were analyzed salt tolerance and the physiological changes and the key genes during seeds germination process.The primary results are as follows:1.Establishment of salt treatment system for diverse germplasm materials.The experiment had established salt stress treatment systems for salt-sensitive materials(Chang 7-2,PH4CV)and salt-resistant materials(Zheng 58,PH6WC).By utilizing the method of plumule culture,the salt-sensitive materials were normally cultured after 25 days of salt stress treatment in the culture medium containing NaCl(100 mM,200 mM,100 mM)for three consecutive times,and finally the salt-treated seeds of T0 generation were obtained by selfing,and then the seeds of T1 and T2 generations were acquired by selfing within the seeds of T0 generation.Under condition that the NaCl concentrations of salt-tolerant materials plumule were 100 mM,250 mM,and 400 mM respectively,the induction process was identical with that of salt-sensitive materials after 21 days of salt stress.2.Salt tolerance of seed germination of progeny treated with salt stress analysis.By means of salt stress treatment,the materials of Zheng 58-T1,T2 generation and PH6WC-T0,T1 generation were harvested 10 lines each,PH4CV-T0 generation was harvested a total of 2 lines,and Chang 7-2-T0 generation was obtained a total of 1 strain.Comprehensive analysis of salt tolerance index,dry weight,fresh weight,seedling length,root length and other indicators through salt-tolerant germination of the progenies of Zheng 58 and PH6 WC,20% of the induced strains showed enhanced salt tolerance in two generations,among which the S6 strain Zheng 58 and the S3 and S7 strains PH6 WC significantly increased the salt tolerance index and growth,and the dry weight growth of the S6 strain Zheng 58-T1 and T2 generations increased obviously by 11.7 % and 8.8%;the dry weight growth of S3 and S7 lines increased by 18.1 % and 17.2 % within the PH6WC-T1 generation.The salt-resistant material in the T1 generation of each of the progeny treated with Zheng 58 showed the equivalent resistance in the T2 generation.3.Analyzing diversities of enzyme activity and some other physiological indicators during seed germination process of progeny.The salt-tolerant strains Zheng 58 and PH6 WC treated progenies were selected to analyze the protective enzyme activity at seedling stage,and the salt-tolerant strains had higher protective enzyme activity.Under salt stress,the SOD and POD activities of the seedlings and roots of Zheng 58-T1 generation S6 lines were significantly increased by 78.5 %,74.7 % and 149%,75.5 %;the SOD activities of T2 generation S6 lines were increased by 9.3 %;within the PH6WC-T1 generation,the SOD and POD activities of the seedlings and roots of the S7 strain were dramatically increased by 5 %,10 %,105 %,and 44.4 %.We analyzed the CAT enzyme activity of correlated strains during maize seeds germination process and identified that the correlation between CAT enzyme activity level and salt tolerance of each strain was not significant.4.Analysis of the expression patterns of genes related to salt resistanceThe detection of relevant genes qRT-PCR in progenies was used to analyze the differential expression during progenies’ seed germination.First and foremost,the results of the differential expression of the histone H4 gene(Zm00001d039733)indicated that the expression levels of S6 strains in the T1 generation at 0h,6h,2d,and 4d were reduced by 23 %,73 %,32 %,8 %,21 % compared with the controls,respectively;the expression of S6 strain in T2 generation was reduced by 57 %,19 %,27 % in seedlings and roots at 2d and 4d;Secondly,the analysis results of enzyme activity and salt resistance related genes implied that the expression levels of genes related to POD and SOD in Zheng 58-S6 and PH6WC-S3 lines all had risen by 17 %,15 %,32 %,and 131 % at 4d.Proline,glycosyltransferase,glutathione S-transferase,ion transport and other related genes are up-regulated or down-regulated to reflect various responses of plants under stress.In conclusion,it is preliminarily conjectured that the enhanced salt resistance of the parent and filial generation is associated with the establishment of a salt treatment system with the main useful genes.