Effects of habitat disturbance on the pollination system of Ammopiptanthus mongolicus (Maxim) Cheng f. at the landscape-level in an arid region of Northwest China.

Ammopiptanthus mongolicus is an ecologically important species in the arid region of Northwest China. Habitat disturbance can significantly affect plant mating success and ultimately species viability. Pollen limitation of plant reproduction occurs in many plant species, particularly those under habitat disturbance. However, previous investigations have demonstrated differences in pollen limitation between conserved and disturbed sites. We compared the phenology, pollen limitation, pollinators and breeding system of both sites to determine whether habitat disturbance has generated changes in these plant components. We found that the species differed in four aspects. First, blooming duration and flowering peak were longer in the disturbed site than in the conserved site. Second, A. mongolicus can be pollen-limited and pollen limitation was more intense in the conserved site than in the disturbed site. Third, Anthophora uljanini was found to be a frequent pollinator in the conserved site, while Apis mellifera was the most effective and frequent flower visitor. More pollinator visits were recorded in the disturbed site, which could explain the differences in reproductive success. Finally, seed set was higher in the disturbed site than in the conserved site. We found that outcrossing was dominant in both sites and that agamospermy and self-pollination played complementary roles to ensure reproduction. Differences in flower production influenced by artificial selection and pollinator type explain the different seed set in both sites, whereas habitat disturbance cause changes differences in the pollination process and limits pollen flow. The balance between artificial management and mating success is crucial to analysis of the pollination process and manipulation of A. mongolicus population size.

[Effect of Bushen Tongdu Capsule on RANK/RANKL/OPG pathway of collagen induced arthritis rats].

OBJECTIVE: To study the effect of Bushen Tongdu Capsule (BTC) on RANK/RANKL/ OPG pathway of collagen induced arthritis (CIA) rats, thereby laying theoretic evidence for treating rheumatic arthritis (RA) by Chinese medicine. METHODS: RA model was induced by CIA. Totally 42 rats were randomly divided into six groups, i.e., the normal control group, the model group, the low dose BTC (BSL) group, the medium dose BTC (BSM) group, the high dose BTC (BSH) group, and the Tripterygium Glycosides (TG) group, 7 in each group. BTC at the daily dose of 120, 240, and 480 mg/kg was given by gastrogavage to rats in the BSL, BSM, and BSH group respectively from the 13th day of modeling. TG at the daily dose of 24 mg/kg was given by gastrogavage to rats in the TG group. All medication was given once daily, 2 mL each time. Two mL normal saline was administered to rats in the normal control group and the model group. All medication lasted for 18 days. Samples were taken at day 31. The TRAP section of the ankle joint was fixed in 10% formalin for TRAP stain. Serum levels of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL), and macrophage colony-stimulating factor (M-CSF) were detected using ELISA. RESULTS: Compared with the normal control group, positive reactions of pathological ankle joint section, inflammation, and osteoclasia degree were significantly improved in the model group, serum levels of RANKL and M-CSF were up-regulated, levels of OPG and OPG/RANKL were significantly lowered (all P < 0.01). Compared with the model group, positive reactions of pathological ankle joint section, inflammation, and osteoclasia degree also significantly decreased in the BSH group and the TG group (all P < 0.01). RANKL and M-CSF were significantly down-regulated in each medicated group, while levels of OPG and OPG/RANKL were significantly up-regulated (all P < 0.01). Compared with the TG group, M-CSF was lower, but levels of OPG and OPG/RANKL were significantly up-regulated in the normal control group (all P < 0.01). RANKL and M-CSF were significantly up-regulated, while levels of OPG and OPG/RANKL were significantly down-regulated in the model group and each BS group (all P < 0.01). CONCLUSION: BTC could relieve bone damage of CIA rats possibly through regulating and controlling osteoclasts.

Bamboo charcoal affects soil properties and bacterial community in tea plantations.

Bamboo charcoal, a type of manufactured biochar, is produced by pyrolyzing bamboo residue under anoxic conditions. Its beneficial properties in absorption, catalyst support, and agricultural function have attracted significant attention; however, relatively few studies have examined its effects on the soil microbiota. In this study, we analyzed the effects of bamboo charcoal on soil physicochemical properties, enzymes, and microbial community structure in tea plantations and investigated the optimal amount of bamboo charcoal to be added to organic fertilizer. The results show that bamboo charcoal can further increase soil available nitrogen, total and available phosphorus and potassium, organic carbon content, pH, and urease activity. However, only the combined use of bamboo charcoal and organic fertilizer significantly increased total nitrogen, sucrase, and ß-glucosidase activities in the soil. Bamboo charcoal also significantly increased the Chao1 and Shannon indices of microbiota diversity in a concentration-dependent manner. The structure of the bacterial community changed significantly after the bamboo charcoal addition, with Proteobacteria, Actinobacteria, and Firmicutes increasing and Acidobacteria decreasing. This study provides fundamental insights into the suitability of bamboo charcoal application for the ecological remediation of diseased soils.

[Germination and seedling growth of Artemisia halodendron under different incubation environments].

Artemisia halodendron is a dominant species in mobile and semi-mobile dunes of Horqin Sand Land. To investigate the germination character and seedling growth under different temperature and light conditions, the germination rate, germination index and growth of radicle and plumule were measured after treatments in laboratory and heating cabinet incubations. In the laboratory the light and temperature were near to nature condition, while in the heating cabinet it was kept at 25 degrees C with varying durations of light supply, including 24-, 12- and 0-hour light per day. Germination rate (66.6%) and germination index (19.1%) under laboratory condition were both significantly lower than in the heating cabinet (P < 0.05). In the heating cabinet, the germination rate under 0-hour light was 70.2%, which was insignificantly lower (P > 0.05) than under 12- and 24-hour light conditions (both 73.4%), and the germination index under 24-hour light was 28.2%, which was significantly (P < 0.05) lower than under 0- and 12-hour light conditions (31.3% and 30.8%, respectively). Radicle and plumule growth responded to light more readily than the seed germination rate and germination index during the process of germination, and the radicle growth was inhibited by darkness while promoted by light, and the plumule lengths under 0- and 12-hour light conditions were 2.81 cm and 1.51 cm, respectively, significantly higher than under 24-hour light (1.21 cm) and natural condition (1.27 cm). It was concluded that temperature was a main factor in seed germination, and seedling growth was mainly influenced by light regime.