## 4 Discussion
### Growth of S. miltiorrhiza with AMFs Inoculation  
A previous study indicates that _S. miltiorrhiza_ is a mycotrophic plant, which could be easily colonized by several AMF species (_Glomus_, _Acaulospora_, _Scutellospora_ and _Entrophispora_) [30]. This study also showed that roots of _S. miltiorrhiza_ seedlings were successfully colonized by _G.a_, _G.m_, _G.v_ and _G.i_. (Figure 1, Tables 1 and 3). Thus, it was reasonable for the present experimental design. The growth of plants is generally regulated by light, water and nutrients. Plants inoculated with AMFs can improve photosynthesis by increasing chlorophyll content [10], as well as by stimulating water and minerals uptake by the upregulating of transporter genes [5; 6; 16] and nutrients \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Treatment** & \multicolumn{2}{c}{**Dihydrogen**} & **Implicit Tanshinone** & **Tanshinone** & **Tanshinone** & **IIA** & **Total (\%, _DW_)** \\  & **Tanshinone I (\%, _DW_)** & **(\%, _DW_)** & **(\%, _DW_)** & **(\%, _DW_)** & **Total (\%, _DW_)** \\ \hline CK & 0.0524 \(\pm\) 0.0220 b & 0.1484 \(\pm\) 0.0286 c & 0.0525 \(\pm\) 0.0134 c & 0.2162 \(\pm\) 0.0677 c & 0.4695 \\ _G.m_ & 0.1033 \(\pm\) 0.0325 a & 0.2502 \(\pm\) 0.0393 ab & 0.1002 \(\pm\) 0.0194 ab & 0.4560 \(\pm\) 0.0526 a & 0.9097 \\ _G.v_ & 0.0781 \(\pm\) 0.0065 b & 0.1339 \(\pm\) 0.0356 c & 0.0382 \(\pm\) 0.0043 c & 0.3052 \(\pm\) 0.0986 bc & 0.5554 \\ _G.a_ & 0.0613 \(\pm\) 0.0024 b & 0.2914 \(\pm\) 0.1079 a & 0.0812 \(\pm\) 0.0043 b & 0.2978 \(\pm\) 0.0300 bc & 0.7317 \\ _G.i_ & 0.0817 \(\pm\) 0.0220 ab & 0.2618 \(\pm\) 0.0716 a & 0.1133 \(\pm\) 0.0256 a & 0.3743 \(\pm\) 0.0319 ab & 0.8311 \\ \hline \hline \end{tabular} CK means with non-AMF inoculation; _G.i._ means inoculation with AM fungus _Glomus versiferome; G.i._ means inoculation with AM fungus _Glomus integratum; G.m._ means inoculation with AM fungus _Glomus mosaic._ DW means dry weight. Different letters in the same column indicate significant differences at 0.05 level. Data are means \(\pm\) SD (\(n=5\)).  
\end{table} 
Table 7: Effect of AMFs on tanshinones concentration of _S. miltiorrhiza_ seedling roots. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Treatment** & \multicolumn{2}{c}{**Accumulation (mg/Plant, DW)**} & \multicolumn{2}{c}{**Distribution (\%)**} \\ \cline{2-5}  & **Leaf** & **Root** & **Leaf** & **Root** \\ \hline CK & 23.64 \(\pm\) 1.27 e & 69.04 \(\pm\) 7.73 e & 25.51 & 74.49 \\ _G.m_ & 50.92 \(\pm\) 6.06 b & 193.54 \(\pm\) 28.65 a & 20.83 & 79.17 \\ _G.v_ & 42.77 \(\pm\) 4.34 c & 167.05 \(\pm\) 23.31 c & 20.38 & 79.62 \\ _G.a_ & 35.50 \(\pm\) 2.89 d & 155.32 \(\pm\) 8.05 d & 18.60 & 81.40 \\ _G.i_ & 66.42 \(\pm\) 11.44 a & 192.59 \(\pm\) 9.95 ab & 25.64 & 74.36 \\ \hline \hline \end{tabular} CK means with non-AMF inoculation; _G.v._ means inoculation with AM fungus _Glomus versiferome; G.i._ means inoculation with AM fungus _Glomus integratum; G.m._ means inoculation with AM fungus _Glomus mosaic._ DW means dry weight. Different letters in the same column indicate significant differences at 0.05 level. Data are means \(\pm\) SD (\(n=5\)).  
\end{table} 
Table 8: Effects of AMFs on salvianic acid B accumulation of _S. miltiorrhiza_ seedling roots. utilization [31], as well as by enhancing productivity by strengthening disease resistance [8; 31]. In the present study, large and green leaves of inoculated seedlings could have a highly effective photosynthesis rate, which is beneficial for the accumulation of carbohydrates. In addition, AMFs inoculation enhances the root number by phytohormone regulating [32] and then influences root architecture by endogenous polyamines metabolism [33]. Moreover, AMFs inoculation equips extensive extra-radical mycelium, which would increase surface areas of roots in order to acquire more nutrients and water [34]. _S. miltiorrhiza_ inoculated with AMFs had longer roots and more lateral roots (Figure 3, Table 3). Therefore, those seedlings possess higher biomass than those with non-inoculation of AMFs (Table 4).