The Impact Of Endogenous H₂O₂ On Hyperhydricity Of Dianthus Chinensis L. And Its Control

Hyperhydricity was a common physiological obstacle in the process of plant tissue culture.Hyperhydric shoots show a malformation in plantlet morphology and an alteration in plantlet metabolism,and these plantlets survive very poorly when they are subcultured in fresh medium or transferred to an ex vitro environment,which seriously affected the large-scale industrialized production of plant tissue culture.It was found that the hyperhydricity of tissue culture was related to the metabolic disorder of reactive oxygen species,and that the apoplast,as the first line of defense for plants to sense and respond to biological or non-biological signals,was the main site for the production of reactive oxygen species.Therefore,Dianthus chinensis was used as a material to study the effects of different culture medium and active oxygen species'scavenger/inhibitors on hyperhydric rate and H₂O₂ content in apoplast.And the effects of glutathione and potassium silicate on ROS and physiological metabolism of plantlets were systematically analyzed in order to reveal the mechanism of hyperhydricity and to develop effective prevention and control measures.The main results were as follows:1.Reduced the pH value and the concentration of sucrose,increased the concentration of6-benzylamine,add 1-amino trimethylene carboxy,ethylene and abscisic acid to the medium,replaced agar with gellan,the hyperhydric rate of plantlets increased significantly,and the content of H₂O₂ in the apoplast was also increased.2.The hyperhydric rate and H₂O₂ content of plantlets decreased significantly after the addition of the active oxygen species'inhibitor?DPI?to the hyperdricity induction medium.3.The hyperhydric rate and H₂O₂ content in the apoplast were reduced to different degrees when Dianthus chinensis L.plantlets were cultured in hyperdricity induction medium supplemented with various reactive oxygen species scavengers such as catalase,vitamin B6,reduced glutathione,silver nitrate and ascorbic acid.4.When GSH was added to the hyperdricity induction medium,the contents of chlorophyll,soluble protein,GSH and AsA were significantly increased,while the content of malondialdehyde and the accumulation of H₂O₂ and O₂^·-were significantly decreased.5.When the hyperhydric plantlets were cultured in the medium supplemented with potassium silicate,the water content of the plantlets decreased and the content of chlorophyll and carotenoid increased.The activities of phenylalanine ammonia lyase,superoxide dismutase and catalase increased,while the accumulation of H₂O₂ and O₂^·-decreased,the hyperhydricity symptoms were alleviated,and the recovery rate increased.