Brassinolide as potential rescue agent for Pinellia ternata grown under microplastic condition: Insights into their modulatory role on photosynthesis, redox homeostasis, and AsA-GSH cycling.

Microplastic (MP), as a new pollutant, not only affects the growth and development of plants but also may affect the secondary metabolites of plants. The anti-tumor role of Pinellia ternata is related to secondary metabolites. The role of brassinolide (BR) in regulating plant resistance is currently one of the research hotspots. The paper mainly explores the regulation of BR on growth and physiology of Pinellia ternata under MP stress. The experimental design includes two levels of MP (0, 1%) and two levels of BR (0, 0.1 mg/L). MP led to a marked reduction in plant height (15.0%), Fv/Fm (3.2%), SOD and APX activity (15.0%, 5.1%), whereas induced an evident raise in the rate of O2·- production (29.6%) and GSH content (4.4%), as well as flavonoids (6.8%), alkaloids (75%), and ß-sitosterol (26.5%) contents. Under MP addition, BR supply significantly increased plant height (15.7%), aboveground and underground biomass (16.1%, 10.3%), carotenoid and GSH content (11.8%, 4.2%), Fv/Fm (2.9%), and activities of SOD, GR, and MDHAR (32.2%, 21.08%, 20.9%). These results indicate that MP suppresses the growth of P. ternata, although it promotes secondary metabolism. BR can alleviate the inhibitory effect of MP on growth by improving photosynthesis, redox homeostasis, and the AsA-GSH cycle.

[Effects of Ca2+ on photosynthetic parameters of Pinellia ternata and accumulations of active components in heat stress].

OBJECTIVE: To study the effect of exogenous Ca2+ on photosynthetic parameters of Pinellia ternate and accumulations of active components under high temperature stress. METHOD: The pigment contents of P. ternata leaves, photosynthesis parameters and chlorophyll fluorescence parameters of P. ternata leaves, the contents of guanosine, adenosine and polysaccharide in P. ternata tubers were measured based on different concentrations of exogenous Ca2+ in heat stress when the plant height of P. ternata was around 10 cm. RESULT: The contents of total chlorophyll and ratio of chlorophyll a/b were relatively higher by spaying Ca2+. Compared with the control, spaying 6 mmol x L(-1) Ca2+ significantly enhanced the net photosynthetic rate (Pn), transpiration (Tr) and stomatal limitation (L8), but reduced intercellular CO2 concentration (C) in P. ternata leaves. With the increase of Ca2+ concentration, maximal PS II efficiency (Fv/Fm), actual photosynthetic efficiency (Yield) and photochemical quenching coefficient (qP) initially increased and then decreased, however, minimal fluorescence (Fo) and non-photochemical quenching coefficient (NPQ) went down first and then went up. The contents of guanosine and polysaccharide and dry weight of P. ternata tubers showed a tendency of increase after decrease, and the content of adenosine increased with the increase of Ca2+ concentration. The content of guanosine and polysaccharide in P. ternata tubers and its dry weight reached maximum when spaying 6 mmol x L(-1) Ca2+. CONCLUSION: With the treatment of calcium ion, the inhibition of photosynthesis and the damage of PS II system were relieved in heat stress, which increased the production of P. ternata tubers.

[Effect of exogenous Ca2+ on protective infection of Pinellia ternata and accumulation of major components under high temperature stress].

OBJECTIVE: To study the effect of exogenous Ca2+ on protective infection of Pinellia ternata and accumulation of major components under high temperature stress. METHOD: The soilless cultivation experiment was applied, stress resistance index of P. ternata leaves, statistics the rate of lodge P. ternata,the content of oxalate in different places in the plant, the content of total alkaloids, total organic acids and glucosine in P. ternata tubers were measured based on different concentrations of exogenous Ca2+. RESULT: The test results showed that, at lower concentrations of Ca2+ treatments, the rate of lodge P. ternata was higher than that of the others. With Ca2+ concentration increasing, activities of SOD and POD initially increased and then decreased, however, proline level tended to be down then up. Soluble oxalic acid content was lower than the content of unhandled treatment in P. ternata leaves and tubers; with Ca2+ concentration increasing, soluble oxalic acidl content and yield showed a tendency of decrease after increase in the leaves and tubers. Compared with other treatments, spraying 400 mg x L(-1) Ca2+ significantly enhanced the accumulation of total alkaloid and guanosine in P. ternata tubers. At Lower concentrations of Ca2+, the content of total free organic acid was higher in the tuber. CONCLUSION: With the treatment of Ca2+ the capacity of heat resistance was improved in P. ternata plants, the rate of lodge P. ternata was postponed, growing period was extended and corresponding production has increased by spraying exogenous Ca2+.

[EMS mutation of suspension cells and selection of high temperature tolerant mutants from Pinellia ternata].

OBJECTIVE: To determine the optimal concentration and processing time of EMS mutation for suspension cells from Pinellia ternata. METHOD: Under four EMS concentration gradients (0.1% , 0.2%, 0.4%, 0.6%) and three processing time gradients (0.5, 1.0, 2.0 h), the suspension cells of P. ternata were mutagenized. RESULT AND CONCLUSION: The results showed that the survival rate was significantly different under the different concentrations of EMS and the different processing time. In the same processing time, the EMS concentrations were increased, but the suspension cells survival rate decreased gradually. The optimum EMS concentration for the mutagenesis was 0.4% and the best processing time was 1 hour.

[Study on the virus-free technology of Pinellia temata].

OBJECTIVE: To solve the degradation of production and quality of Pinellia caused by the virus accumulation, rapid propagation technical of virus-free Pinellia was researched. METHODS: Pinellia leaves,petioles as explants, technology of using high temperature (38 degrees C, 40d) and shoot tip culture producing virus-free Pinellia was explored. RESULTS: The results showed that leaves without virus spots was about 88.9% when explants were culture for 40d at high temperature (38 degrees C). 1.0 mg/L 6-BA and 0.1 mg/L NAA could induce seedling from shoot tip,seedling rate is up to 91.4%; MS added 0.5 mg/L 6-BA and 0.1 mg/L NAA was conducive to growth of the plantlets; added 0.5 mg/L KT and 0.5 mg/L NAA was in favor of inducing root and promoting root growth, the survival rate of the transplanting seedling could reach 89.5%. CONCLUSION: A reliable system of virus-free Pinellia propagation is established.

[Study on mathematical model of optimum fertilizer application to Pinellia ternate cultivation].

OBJECTIVE: To study the mathematical model of optimum fertilizer application to Pinellia by field experiments. METHOD: Three factors and 5 levels quadratic rotational combination design was applied to study the effects of N, P and K. RESULT AND CONCLUSION: N, P and K combination application can achieve the maximum yield of 29,921.4 kg x hm(-2), the amount of N, P2O5, K2O were 413.79, 224.79, 164.01 kg x hm(-2), respectively. The effects of the 3 factors were in following orders: P > N > K.

[Effects of salicylic acid on growth of Pinellia ternata].

OBJECTIVE: To study the effects of salicylic acid of different concentration (SA) on the growth of Pinellia ternate. METHOD: SA of different concentration was sprayed to the plant as it grew about 15 cm high. Plant height, total chlorophyll content, activity of SOD, MAD content, photosynthesis speed, intercellular CO2 concentration, the transpiration speed and the leaf temperature were measured after 3 times spray. RESULT: When 0.5 mmol x L(-1) SA was sprayed, the intercellular CO2 concentration, activity of SOD and photosynthesis speed were increased, while leaf temperature and MDA content were decreased. CONCLUSION: SA at the concentration of 0.5 mmol x L (-1) was suitable for the growth of P. ternate. It obviously decreased sprout tumble and increased the fresh weight of tuber and the alkaloid content.

[Clustered shoot induction and rapid propagation on Pinellia ternate].

OBJECT: To establish the rapid propagation system of Pinellia ternate. METHOD: The Clustered shoots were induced by the explant lamina and petiole from the terminal bud of Pinellia ternate tuber in test tube. RESULT: The plantlets could regenerate from the lamina and petiole directly without via the callus. The MS Medium with 2.0 mg/L 6-BA and 0.1 mg/L NAA was optimal for the induction of culstered shoots from explants of lamina; the MS with 2.0 mg/L 6-BA and 0.25 mg/L NAA was best for the explants of petiole; and the 1/2 MS with 1.0 mg/L KT and 2.0 mg/L NAA was the better medium for induction of roots. CONCLUSION: The regenerated rate of Pinellia ternata can improve by inducing the clustered shoots from the explants of lamina and petiole directly.