Cytology Observation And Molecular-cytogenetic Characterization Of Rhizophora Apiculota Transformed Salt-tolerant Tomato

Since 1992,in the Institute of Biological Science and Technology of Hainan University,the pollen tube introduction method was used to breed tomato with total DNA of Rhizophora apicularta,a salt-tolerant,seashore-grown plant. The salt-tolerant transformed tomato was firstly obtained and planted on the seashore beach and watered directly with full seawater. This study is focus on the all-around analysis of the transformed tomato,which are investigated respectively on morphological,anatomical structure of the leaves,chromosome level and molecular level. From the tests,we have obtained some structural variant features related with salt resistance and demonstrated the successful introduction of Rhizophora apicularta DNA into tomato.This thesis contains two parts. In the first part,the morphological and anatomical structures of the leaves were investigated. As to the morphology,some difference between control and transformed tomato were found. The leaf dimensions of the transformed tomato with unextended leaves were smaller than that of control. These structure changes should help to decrease the evaporation of water effectively and release the physiological drought resulted from saline. The observation results on the anatomical structure of the leaves showed various changes in the transformed tomato:hollow stomata,well-developed epidermal hairs and aqueous tissue,unwell-developed vascular tissue and excretory structure consisted of multicell different from epidermic cells. These differently structural characteristics have higher relationship to their improvement to salt resistance. The second part is the investigation of molecular-cytogenetic characterization of the transformed tomato by means of Southern blot and genomic in situ hybridization (GISH). Southern blot showed the foreign DNA segments were inserted into the transformed tomato genome. Using GISH,the Rhizophora apiculota DNA sequences on tomato chromosomes were characterized. The observed cell showed signal spots and their location in different region of chromosomes in different lines.The experimental results mentioned above demonstrated that Rhizophora apiculota DNA have been introduced into tomato and integrated with tomato genome. The obvious improvement in the salt tolerance among their progenies was most probably related with the variation of their genome.