| Panax ginseng C.A.Mey,P.quinquefolius L,and P.notoginseng（Burk.）F.H.Chen are representative plants of Panax species and have high medicinal and economic value.It takes at least 2-3years for the seeds to grow under natural conditions.The rapid propagation technology of artificial seeds based on somatic embryo culture is of great significance to the development of medicinal plants for Panax species.In this paper,embryos were used as the propagators to make artificial seeds of P.notoginseng by drip method.Single factor and orthogonal experiments were designed to study the effects of sucrose,sodium alginate,ion exchange time on the germination rate.Short-term storage of artificial seeds was also studied.The above studies aim to lay a foundation for further research on artificial seeds of P.notoginseng.In addition,the dynamic changes of nutrient composition,amylase activity and saponin in the endosperm during rooting of three representative plants of Panax species were discussed preliminarily,which provided references for the development of artificial endosperm.The main findings are as follows:1.Through the single factor and orthogonal design experiments,the optimal combination of artificial endosperm was selected.The results showed that sucrose was the main factor affecting the germination.Approximately 5mm of the embryos were placed into the artificial endosperm of this combination,and they were dropped into 2%Ca Cl2 solution with ion exchanged for 10 minutes.Under this artificial endosperm and ion exchange time,the germination rate was 83.5%.2.After the artificial seeds of P.notoginseng germinated,the growth indexes of the plants were measured.The results showed that:The plant height（3.37±0.21）cm,stem diameter（1.21±0.18）mm,root length（4.33±0.74）cm,leaf area（3.80±0.34）cm2·plant-1,fresh weight（0.14±0.05）g·plant-11 of the somatic embryos after embedding were significantly higher than those of the control,indicating that the growth status of the embedded somatic embryo was better than that of the unembedded one.3.The artificial seeds of P.notoginseng dried for 0d,1d,2d,and 3d were stored at a low temperature of 4°C for 10d,20d,and 30d,then transferred to MS solid medium without any hormones for cultivation at room temperature,and the germination rate was counted for 20 days.The results showed that the germination rate after drying treatment first decreased and then increased slowly with the increase of the number of drying days.4.In this paper,the dynamic changes of nutrient content,amylase activity and saponin in endosperm of different rooting stages of P.ginseng,P.quinquefolius and P.notoginseng were measured.The results showed that:The content of sucrose in the endosperm of the three medicinal plants decreased sharply after germination,and increased first and then decreased.Soluble total sugar and starch decreased and soluble protein content during the whole rooting process.The activity ofα-amylase in P.ginseng and P.quinquefolius firstly increased and then decreased,but theβ-amylase activity decreases first and then rises.Theα-amylase activity of P.notoginseng did not change significantly,but theβ-amylase activity is slowly increased and then decreased.Eight ginsenosides were identified in endosperm of P.ginseng,eight ginsenosides were identified in P.quinquefolius,and five ginsenosides were identified in P.notoginseng.In the process of rooting of the three,the saponin content showed an overall upward trend.When the radicles were extended to 5 mm,the ginsenoside content of P.ginseng and P.quinquefolius rose no longer,and some saponin contents began to decrease.However,the above phenomenon did not occur on P.notoginseng. |
