| Pseudostellaria heterophylla also called as “hair shen”?“four-leaf shen”?“rice shen” and so on.Sweet,bitter,flat,with the effect of Yi Qi Jianpi,Shengjin Runfei.Due to its unique medicinal effects,people dig and collect a large number of wild resources,resulting in a large reduction in the wild resources of the Pseudostellaria heterophylla and a single variety.Therefore,it is very necessary to cultivate rich breeding materials for the Pseudostellaria heterophylla.EMS is a typical chemical mutagenic agent with simple operation,high mutation frequency and strong specificity.At present,different scholars in agriculture use EMS solutions to treat seeds,leaves,cluster buds,callus,etc.of different crops,and obtain mutations of corresponding crops.As plant tissue culture is not limited by regions,seasons,and climate,annual production can be achieved.Many scholars use EMS combined with plant tissue culture technology to artificially induce crops and obtain mutant plants on some crops.In this study,the seeds,shoots,and callus of Pseudostellaria heterophylla were used as experimental materials.EMS at different concentrations and different treatment times were used to treat the seeds,shoots,and callus of Pseudostellaria heterophylla,to determine the appropriate EMS dose.The effects of EMS treatment on the main physiological indexes of the seeds,clumps and callus of Pseudostellaria heterophylla were also discussed.Tissue culture was carried out on different tissues of Pseudostellaria heterophylla treated by EMS,and the classification and analysis of cultured off spring were carried out.Some different types of Pseudostellaria heterophylla seedlings were initially obtained.Its main findings are as follows:1.Taking the seeds of Pseudostellaria heterophylla as the experimental material,the concentration of EMS was 0.0 %?0.2 %?0.4 %?0.6 %?0.8 % and 1.0 %.The treatment time was 12 h.The effects on seed germination and main biochemical indicators of Pseudostellaria heterophylla were studied.The results showed that EMSinhibited seed germination,When the concentration of EMS was 0.0%,the germination rate was 84.8% and the relative germination rate was 100%.When the concentration of EMS was 0.6%,the germination rate was 45.6% and 53.8%.When the concentration of EMS was 0.8%,the germination rate was 34.8% and 41.1%.When the concentration of EMS was 1.0%,the germination rate was only 18% and the relative germination rate was 21.2%.With the increase of EMS concentration,resulting in increased conductivity of seed leachate and MDA content of seeds and seedlings.With the increase of EMS concentration,the SOD and POD activities of seeds and seedlings showed a tendency to increase first and then decrease,When EMS concentration reached 0.6,the POD activity of seeds and seedlings reached the highest,82 u/g.min and 45 u/g.min,respectively.When EMS concentration reached0.8%,the SOD and POD activity of seeds and seedlings reached the maximum,and the SOD activity was 41.73 u/g.min,25.05 u/g.min,and the PPO activity was 67.08u/g.min and 43.32 u/g.min,respectively.The comprehensive analysis shows that the suitable concentration of EMS for dealing with Acanthopanax is 0.6 %-0.8 % and the treatment time is 12 h.2.Different concentrations of EMS were used to treat sprouts and callus at different times,and the changes of survival rate and main physiological indexes were determined.The results showed that with the increase of EMS concentration and the increase of treatment time,the survival rate and browning of callus were decreased,When EMS concentration was 0.8% and treatment time was 3 h,the survival rate of cluster buds was 53.22%.When EMS concentration was 1.0% and treatment time was2 h,the survival rate of cluster buds was 53.33%.When EMS concentration was 0.4%,0.6% and treatment time was 2 h,the survival rate of callus was 56.67% and 51.1%respectively.With the increase of EMS concentration and treatment time,SOD,POD and PPO activities were increased and decreased,and MDA content was increased.After the mutagenesis,the buds and callus of the Pseudostellaria heterophylla were bred.During the culture process,the SOD,POD,and PPO activities in the first three days showed a downward trend,followed by a slow increase,and the MDA content showed a slow decline.The author believes that the suitable treatment for thesprouting of the Pseudostellaria heterophylla is 1.0 % EMS treatment of 2h,and the suitable treatment for the healing tissue of the Pseudostellaria heterophylla is 0.6 %EMS treatment of 2h.3.The suitable EMS dose is used to treat the seeds,clumps,and callus of the Pseudostellaria heterophylla,and then tissue culture is carried out.It can be divided into 4 categories according to the histological seedling phenotype:CK is a normal leaf,oval in shape,and the leaf edge is a continuous arc,without any teeth and engravings.(1)is long leaves,there is no change in the width from petiole to tip,and the edge is smooth without any teeth and cuts.(2)there are two main veins,the leaf margins are multi-serrated and the middle is broken.(3)there two leaves grow together near the petiole,the veins are clear,and the edges are smooth without any teeth and cuts.(4)main stems,petioles,and veins of the seedlings are reddish-brown in color,and the leaves are oval in shape.The leaf shape is similar to that of normal ginseng,and the stem nodes are not as common as normal ginseng and are relatively loose.The results showed :CK had the highest relative chlorophyll content of 55.7,the largest stomatal number of 57 and the lowest PPO activity of 23.2 u/g.min in one field of vision;and POD,SOD and PPO activities of 55.0 u/g.min,67.9 u/g.min and 43.5u/g.min,respectively.The order of POD and SOD activity was(2)>CK>(4)>(3)>(1);the order of PPO activity was(2)>(4)>(3)>(1)>CK;the relative chlorophyll content was CK>(2)>(4)>(3)>(1);the stomatal number was CK>(4)>(2)>(1)>(3). |
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