| Salvia miltiorrhiza Bunge is one of the traditional Chinese herbal medicines.It has functions of promoting blood circulation,removing blood stasis and so on.The market demand and price have been rising continuously in recent years because of its remarkable clinical efficacy.The active components of S.miltiorrhiza were specifically distributed in the root tissues.The morphological structure of the root,especially the number roots,has a significant effect on the content of active components in root system of S.miltiorrhiza.In this study,the gradient concentration treatments of phosphorus were set up with the seeds and seedlings of S.miltiorrhiza.Through compared the changes of morphological indexes and main active constituents of S.miltiorrhiza roots in different phosphorus treatments on different growth stages,the effects of phosphorus levels were studied on the root growth of S.miltiorrhiza.The regulation of the content of active components provided the reference to increase production and develop component-oriented cultivation techniques of S.miltiorrhiza.The main conclusions of this study are as follows:1.S.miltiorrhiza seedlings were cultured in 1/2 MS medium and cultivated under constant temperature for 60 days.The root number and root dry weight of S.miltiorrhiza were the highest when the phosphorus concentration was 0.625 mM/L,which were 1.31 and 1.35 times as high as that of the control group(phosphorus concentration was 1.25 mM/L).From the germination of S.miltiorrhiza seedlings to the seedling stage,the phosphorus concentration ranged from 0.313 to 0.625 mM/L could effectively promote the differentiation and development of S.miltiorrhiza roots.When the concentration of phosphorus was 0.0 mM/L,the contents of rosmarinic acid,salvianolic acid B and the lithospermic acid in roots and leaves of S.miltiorrhiza were the highest,which were 1.42-2.66 times as high as that of the control group.The contents of tanshinone IIA and tanshinone I were the highest in the control group.The cryptotanshinone content was the highest when the phosphorus concentration was 0.0313 mM/L,and gradually decreased with the increase of the phosphorus concentration.There was little significant difference in total tanshinone content of each phosphorus treatment.Therefore,the phosphorus starvation can significantly increase the content of phenolic acids in roots and leaves of S.miltiorrhiza in the seedling stage of S.miltiorrhiza.The increase of cryptotanshinone could be significantly induced by low P stress,but it has no significant difference in the total tanshinone content2.To choose 1/2 modified Hogland nutrient solution as the culture medium,vermiculite and perlite(1:5)as culture substrate,the results showed that the phosphorus concentration 0.5 mM/L could effectively promote the lateral root number and root diameter of the seedling root system in S.miltiorrhiza,which were 1.08 and 1.15 times as high as that of the control group(1.0 mM/L).The root diameter of 150 d was the highest for the treatment of P concentration of 0.5 mM/L.Compared with other treatments,the root system had the lowest indexes without phosphorus.Therefore,mild phosphorus starvation condition can significantly promote the increase of root number and root diameter during the growth of S.miltiorrhiza seedlings,but has no significant effect on root length.Excessive phosphorus starvation can lead to a significant decrease in total root biomass of S.miltiorrhiza.The contents of total phenolic acid,cryptotanshinones,tanshinone I,and tanshinone II A in the roots all reached the maximum at the concentration of 4.0 mM/L,which were 1.84,1.52,2.00,and 1.36 times of the control group respectively.The contents of rosmarinic acid and salvianolic acid B in the leaves of S.miltiorrhiza were the highest when they were treated with 0.5mM/L P,which were 1.7% and 5.4%,2.33 and 2.75 times that of the control group,respectively.The content of total phenolic acids in leaves of S.miltiorrhiza was the highest at the phosphorus concentration of 0.5 mM/L and the transplanted for120 days,which was 4.65 times as high as that of the control group.With the extension of the growth period,the differences between the treatments were decreased in ingredient content.Therefore,different phosphorus supply conditions can significantly regulate the content of active ingredient in leaves and roots of S.miltiorrhiza.3.In the spatial heterogeneity experiment of nitrogen and phosphorus in S.miltiorrhiza,the number of red roots in NPHD was the largest,and it was 1.70 times of blank group on 180 days after been transplanted.The root length of S.miltiorrhiza was the largest in the blank group,which was significantly higher than that of other treatments and NPHD treatment.The difference between the other treatments was not significant.The content of total phenolic acidsin half amount of nitrogen and phosphorus treatment(1/2NPFD)was 10.28%,it was the highestin all treatments,,was 1.17 times of the blank group.On 180 days after seeding was transplanted,the total tanshinone content of the blank group was significantly higher than that of the other treatments.Under the condition of single-sided application of nitrogen and phosphorus mixture(NPHD)and single-side application of nitrogen and phosphorus separate(NPFD),the total phenolic acid content of the roots in the individual plant was significant higher.Compared with other treatments,the total mass of total tanshinone perplant was the highest in the blank group.There was no significant difference among other treatments.Therefore,compared with the uniform distribution of nitrogen and phosphorus,the spatial heterogeneity distribution was conducive to increase the root biomass of S.miltiorrhiza,increased the number of roots and promoted the accumulation of total phenolic acids in roots.The condition of low phosphorus and low nitrogen can promote the accumulation of total tanshinone in single plant.Tanshinone total quality of the root system in individual plant was mainly affected by the root morphology.The more root surface area has the higher content. |
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