| Maize is an important crops used as food, feed or energy. Drought is one of the environmental factor which affect the high and stable yield of corn in China and around the world. The nine main maize cultivars in Liaoning Province were used as materials, we selected several maize varieties with different drought resistance, further more, the effects of drought stress on the physiological and biochemical indexes and final yields of Maize was studied. On this basis, we cloned a drought related gene p5cs and analysed its structure and function using bioinformatics, at the same time, the tissue-specific expression of p5cs in different times under drought stress were studied. The main results are as follows:1. Nine leading varieties in Liaoning province, including Fuyu20, Danyu39 and others were used as materials, we studied the effects of water stress on seed germination characteristics of maize. The results showed that the germination rate, germination energy, germination drought resistance index, transformation percentage of stored substance, length of seedling and length of root all were affected more seriously with the increasing of stress strength. But significant differences among varieties were found, Fuyu20 and Fuyou99 were the typical drought-resistant varieties, Zhengdan958 and Danyu39 were drought-sensitive varieties.2. Five maize varieties with different drought resistance were used as experimental materials, the effects of water stress time and strength on the physiological indexes of maize seedling were studied, and the differences among varieties were analyzed. The results showed that the proline content first increased and then decreased with the stress time elapsed; the content of MDA, soluble proteins and soluble sugar, the activity of SOD, POD and CAT were increased with the strengthen water stress, and were positively correlated with the stress time. All the indexes determined above have significant differences among drought resistant varieties.3. Using potted dehydration of Fuyou 99, Liaodan 33, Danyu 39 were at seedling stage, jointing stage and silking stage water stress treatment. The results showed that:under water stress at different growth stages, maize leaf relative water content decreased, relative conductivity increased and seedling stress had the greatest effect. The effect of water stress on plant height and ear height was the biggest at the jointing stage, which decreased by 12.4% and 15.43% respectively. The effect of water stress on the spike grain weight,100 grain weight, ear row number and row grain number was the biggest at the silking stage, respectively, which decreased by 35.35%,10.11%,6.01% and 28.82% respectively. The effect of water stress on the yield of three maize varieties had significant difference, especially Danyu 39, the injury rate reached 79.1%.4. Cloned maize p5cs gene was 1437bp, encoding 478 amino acids. Compared with other species, maize and sugarcane P5CS highest homology. Analysis of hydrophobicity and transmembrane structure, the highest hydrophobic ratio is 3.88, the highest hydrophilic ratio is 1.21, no transmembrane structure. Analysis of signal peptides and phosphorylation sites, found no signal peptide sequence, containing 32 threonine protein may be kinase phosphorylation sites. To predict the secondary structure, that consists of 44.56% alpha helix,21.34% extension,9% beta turn and 25.10% random coil.5. Semi quantitative RT-PCR analyzed the p5cs tissue and organ specific expression, and the specific expression under different drought stress time. The study found:p5cs highest expression in the leaves, with prolonged drought stress time the expression of p5cs increased gradually and reached a peak at 24 h, and finally stabilized. |
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