[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.

[Response of isozyme and stress indexes of Coptis chinensis to UV-B radiation].

OBJECTIVE: To study the physiological mechanism of anti-stress of Coptic chinensis and provide theoretical basis for its cultivation and promoting its quality. METHODS: Different degrees of the range of time and intensity of UV-B radiation were set in the experiment. Used the technique of polyacrylamide gelatin vertical board electrophoresis (PAGE) to analyse the isozyme and related stress index. RESULTS: The isoenzymic bands of SOD1 (Rf = 0.125), SOD2 (Rf = 0.312), CAT1 (Rf = 0.428), POD3 (Rf = 0.290), POD4 (Rf = 0.636) were induced by UV-B radiation after 3 hours, with the increase of the time of UV-B radiation, those isoenzymic bands was going to vanish or became unclear. Moreover, isoenzymic bands of CAT1 (Rf = 0.428), POD3 (Rf = 0.290) disappeared in advance under heavy intensity of UV-B radiation. Furthermore, the contents of MDA, soluble sugar, proline were higher dramatically than those of control group under UV-B radiation. However, excluding the increases of proline in UL group, the content of MDA, soluble sugar, proline of other groups commenced to decrease slowly and isoenzymic bands of soluble protein increase after 7 hours of UV-B radiation. CONCLUSION: The increase of the expression of antioxidase isozyme, accumulation of soluble sugar, soluble protein and other antioxidase matter is induced by the short-time UV-B radiation, which can protect Coptis chinensis from being harmed by UV-B radiation. However, regulation system of Coptis chinensis are broken, metabolism is disordered, the bands of antioxidase isozyme vanish or weaken, the bands of soluble protein are increased and widened, these phenomenon is caused by 7 hours of UV-B radiation.