[Dynamics of seed rain of Tripterygium hypoglaucum and soil seed bank].

Tripterygium hypoglaucum is an endangered species in arid areas of Xiannvshan Chongqing, China. The dynamic characteristics of seed rain and soil seed bank of T. hypoglaucum were studied in this paper．Results showed that T. hypoglaucum years of mature seeds distribution number up to October; the seed rain occurred from the last ten-day of September to in the first ten-day of November and the peak of scattered seed rain concentrated in the October．The numbers of soil seed bank at 2-5 cm soil layer,mainly concentrated in the 1.5-3.5 m range. T. hypoglaucum seeds to the wind as a force for transmission, the transmission ability is strong, but in the process of natural reproduction, full mature seed rate is low, the soil seed bank seeds seed short-lived factors these were unfavorable for the natural reproduction of T. hypoglaucum population.

Effects of plant stress signal molecules on the production of wilforgine in an endophytic actinomycete isolated from Tripterygium wilfordii Hook.f.

The endophytic actinomycete F4-20 was isolated from Tripterygium wilfordii Hook.f. and was confirmed to produce wilforgine, a secondary metabolite discovered in its host. F4-20 showed a close phylogenetic relationship to Streptomyces species. To seek elicitors that may enhance the production of wilforgine in F4-20, four plant stress molecules were applied to the in vitro liquid cultures. Results showed that methyl jasmonate (MeJA), salicylic acid (SA), and hydrogen peroxide (H2O2) inhibited bacterial growth, whereas glutathione (GSH) treatment significantly increased bacterial growth. The wilforgine contents in the mycelia of F4-20 were reduced by MeJA and GSH but were induced by SA and H2O2. When added in the end of the culture period (7 day), 1 mM SA and 5 mM H2O2 resulted in 69.35 ± 1.71 and 71.80 ± 3.35 µg/g DW of wilforgine production, 1.55 and 1.60 fold to that of control (44.83 ± 1.35 µg/g DW), respectively. Though this improved production was about 6.5 times lower than that of the natural root (454.00 µg/g dry root bark), it provided an alternative method for the production of valuable plant secondary metabolites.

Tripterygium wilfordii bioactive compounds as anticancer and anti-inflammatory agents.

1. Bioactive compounds from medicinal plants with anticancer and anti-inflammatory effects have become key resources in drug discovery fields for the treatment of various malignancies and immunological disorders. 2. Tripterygium wilfordii (TW) is a medicinal plant that exhibits profound immunosuppressive effects and has been used in herbal regimens for the treatment of immunological diseases for thousand years in China. 3. Procedures for the isolation and characterization of TW bioactive compounds have been well established. Over the past three decades, more than 46 diterpenoids, 20 new triterpenoids, 26 alkaloids and other small molecules have been identified from TW. 4. Triptolide, celastrol and tripchlorolide are among the bioactive compounds conferring the immunosuppressive and anticancer activities of TW. Accumulated evidence suggests that the TW bioactive compounds exert their pharmacological actions by modulating the transcriptional activity of nuclear factor-κB signalling molecule. 5. Triptolide derivatives with improved water solubility have emerged as promising drug candidates. Clinical trials are being conducted on the derivatives to provide encyclopaedic knowledge on triptolide pharmacokinetics in patients.

[Effects of exogenous abscisic acid (ABA) on the photosynthesis and chlorophyll fluorescence parameters of Tripterygium wilfordii seedlings exposed to low temperature].

Taking one year-old Tripterygium wilfordii cutting seedlings as test materials, this paper studied the effects of foliar spraying 0, 5, 10, 15, 20, and 25 mg x L(-1) of abscisic acid (ABA) on the leaf photosynthesis and chlorophyll fluorescence characteristics of the seedlings under low temperature stress. Spraying 20 mg x L(-1) of ABA increased the cold- resistance of the seedlings significantly, manifesting in the slowing down of the decrease amplitudes of leaf net photosynthetic rate (P(n)), transpiration rate (T(r)), stomatal conductance (g(s)), and intercellular CO2 concentration (C(i)) and the increase of photosynthetic capacity. After 6 days exposure to low temperature, the initial fluorescence (F(o)) decreased with increasing concentration of applied ABA, the maximum fluorescence (F(m)) and maximal photochemical yield (F(v)/F(m)) increased, the actual photochemical efficiency of system II (phi(PSII)) and photochemical quenching coefficient (q(P)) increased after an initial decrease, and the non-photochemical quenching coefficient (q(N)) showed a 'decreasing-increasing-decreasing' trend. The P(n), g(s), q(P), F(m), and F(v)/F(m) reached their peak values at 20 mg x L(-1) of ABA. In all treatments, with the increase of photosynthetically active radiation (PAR), the relative electron transport rate (rETR) increased first and decreased then, reached the peak when the PAR was 395 micromol x m(-2) x s(-1), and the peak value of the rETR in treatments 25 and 20 mg x L(-1) of ABA was 17.1% and 5.2% higher than that of the control, respectively. The light response curves of the psi(PSII) decreased with increasing PAR, whereas those of q(N) performed in adverse.