Effects Of Exogenous Reactive Oxygen Species Substance And Their Depressors On Vitrification Of The Garlic Plantlet In Virto

Garlic (Allium sativum L.) is a very important vegetable and medicinal plant, which ismainly propagated by vegetations. It has low coefficient of multiplying venturing thepossibility of transmission of virus diseases which can result in a decrease of yield andquality of bulbs during propagation of garlic. It can not only remove virus diseases of garlicbut also increase coefficient of multiplying and modify ways of propagation of garlic bytissue culture technology.The phenomenon of vitrification exists universally in tissue cultured plantlets,which is a proper abnormal phenomenon in plant tissue culture. This aberrant growth formcauses significant losses to the micropropagation industry because of poor survival ofplantlets when they transplanted in fields which becomes the main obstacles ofmicropropagation. Effect of reactive oxygen species (ROS) on the development of plants isa hot research area. It reported that vitrification in virto had been connected with ROS, butit was short of systemic studyUsing the garlic variety 'Ershui zao'as test material, effects of different exogenousROS substance and ROS depressor on occurrence of vitrification and the physiologicalcharacters in the garlic plantlet in vitro were studied in this paper. The relationship ofvitrification and ROS was elucidated, it revealed that the vitrification of the garlic plantletwas enhanced by exogenous ROS in vitro effectively. The main results are as follows:1. Effects of different concentrations of exogenous ROS(Hydrogen peroxide:H₂O₂ andParaquat: PQ) substance on occurrence of vitrification and the physiological metabolism inthe garlic plantlet in vitro were remarkable, it revealed that the vitrification of the garlicplantlet was enhanced by exogenous ROS in vitro effectively, exogenous ROS substancecan enhance the vitrification of the garlic plantlet in vitro effectively. The higherconcentrations of exogenous ROS substance was, the more the vitrification plantlet rateswas and the more greave occurrence of vitrification was. Under different concentrations of exogenous ROS substance, the vitrification plantlet rates, tissue water content, MDAcontent, rate of electrolyte leakage, SOD activity, POD activity and CAT activity werehigher than control. But the chlorophyll content decreased with increase of theconcentration of exogenous ROS.2. Effect of different concentrations of exogenous ROS depressor(AsA and mannitol) onoccurrence of vitrification and the physiological metabolism in the garlic plantlet in vitrowas distinct, exogenous ROS depressors can restrain the occurrence of vitrification of thegarlic plantlet in vitro effectively.exogenous ROS depressor can restrain the vitrification ofthe garlic plantlet in vitro effectively. Under different concentrations of exogenous AsA andmannitol, the chlorophyll content, SOD activity, POD activity and CAT activity increaseddistinctly, while MDA content and rate of electrolyte leakage decreased evidently.3. ROS depressors (AsA) can delay occurrence of vitrification of the garlic plantlet invitro which was induced by ROS substance. At a certain exogenous H₂O₂ concentration, thevitrification plantlet rates, MDA content and rate of electrolyte leakage decreased withincrease of the concentration of exogenous AsA, but the trends of chlorophyll content, SODactivity and POD activity reversed.4. Tissue water content, MDA content, rate of electrolyte leakage, SOD activity, PODactivity and CAT activity of the vitrification plantlet in vitro were higher than that of thenormal plantlet in vitro ,while the chlorophyll content was lower.