Studies On The Aluminum Toxicity Character And Its Al-resistant Mechanism In Wheat (Triticum Aestivum L)

Al toxicity is an important limited factor for crop production and quality in acid soil, and it has become the focused area of ongoing research in plant stress physiology and genetics. At present, however, Al toxicity and Al-resistant mechanism in plants and crops are still not clearly understood. Wheat is a kind of Al-sensitive crop and it is good model for studying the Al-resistant mechanism. Atlas 66,EM12 and Scout 66, which are three hexaploid wheat (Triticum aestivum L) were used as experimental materials in these studies. In order to explore some new pathway for Al toxicity, Al-resistant mechanism and genetic improvement, the effects of Al stress on the physiological and biochemical character of wheat and introduction of the CS gene into wheat have been studied respectively and the results obtained from the experiments are as follows.(1) The root elongation of wheat was inhibited severely and the part of root accumulated many Al iron. Atlas 66 is the Al-resistant material while EM12 and Scout 66 both are the Al-sensitive materials and the sensibility of EM12 to Al stress is a little less than that of Scout 66. The activities of SOD,POD and CAT were all increased firstly and then decreased with the increase of Al concentrations and the activity of POD had positive correlation with Al-resistance. The activities of three enzymes all changed indistinctively in the root and the leaf of Atlas 66. The content of MDA increased continuously with the increase of Al concentrations in the root and the leaf of Scout 66. The content of MDA increased continuously with the increase of Al concentrations in the root of Scout 66 and increased firstly and then decreased in the leaf. The content of MDA were all increased firstly and then decreased with the increase of Al concentrations, but all changed indistinctively. The contents of free proline were all also increased firstly and then decreased in the root and the leaf of wheat and had positive correlation with Al-resistance under the same Al concentration stress.(2) Three donor wheat all showed good character and had only a little genotypic difference in the aspect of calluse inducation,differentiation and regeneration which are all good genotypes for wheat transformation. In our experiments we obtained forty-seven regenerated plants altogether, twenty-six of which were proved to be positive transgenics by PCR confirmation. The total transformation frequency was 0.82% in our experiments.