ABSTRACT
Phosphorus is the necessary element for plant growth, and its concentration is one of the main indices for water eutrophication. Hence, it is significant to understand how woody plants purify phosphorus in eutrophic water. The purpose of this study is to reveal the P absorption and removal mechanism of Salix matsudana in eutrophic water with different P concentration. We selected new S. matsudana clone (A42) as experimental material and set three levels of P concentration (low P: 0.1, 0.2 mg·L-1; medium P: 1.0, 2.0 mg·L-1, high P: 10.0 mg·L-1), and the floating bed hydroponic experiment was conducted at the greenhouse from July to September, 2017. We found that S. matsudana efficiently removed P in water (removal rate >79% in 21 days). There was a positive correlation between the removal quantity and P concentration in the water. The removal ratio rose at first and then fell with increasing P. Owing to the purification of S. matsudana, the P concentrations ranging from 0.1 mg·L-1 to 1.0 mg·L-1 were reduced to minimum threshold concentration of eutrophication (0.016-0.032 mg·L-1) in seven days. The percentage of phosphorus input in water that assimilated by S. matsudana ranged from 29.0% to 66.9%. The quantity and ratio of assimilated P were respectively positive and negative relation with P concentration. Salix matsudana adapted to eutrophic water with different P concentrations and normally grew during experiment period, with root-shoot ratio being significantly increased with decreases of water P concentrations. The characteristic of phosphorus distribution in plant organs was: stem> leave>root, while the translocation factors (TF) of nitrogen and phosphorus were both greater than 3. When S. matsudana grew in eutrophic water with high phosphorus concentration, the TF of nitrogen and phosphorus significantly increased to 4.53±0.24 and 4.92±0.62 respectively. Our results indicated that S. matsudanais could purify the eutrophic water and it could normally grow. New clone of S. matsudana could effectively absorb phosphorus in the water and accumulated it in the stem, which could reduce secondary pollution. In conclusion, S. matsudana could be used for a short-term treatment on the eutrophic water with low P concentration, while for the long-term treatment it is adapted to eutrophic water with high phosphorus concentrations.
Subject(s)
Salix , Biodegradation, Environmental , Eutrophication , Hydroponics , Nitrogen , Phosphorus , Plant Development , WaterABSTRACT
Curcumin (Cur) is a major active component of the food flavor turmeric isolated from the powdered dry rhizome of Curcuma longa Linn., which has been used in traditional Chinese medicine to ameliorate intracerebral ischemic damage and reduce brain edema. However, the effects of Cur on the disruption of the blood-brain barrier (BBB) induced by brain ischemia are still unclear. The effects of Cur on the disruption of BBB and changes of tight junction (TJ) proteins induced by oxygen glucose deprivation (OGD) were studied in BBB in vitro. The transendothelial electrical resistance and the flux of horseradish peroxidase in BBB in vitro were measured. The expression and localization of the TJ proteins occludin and zonula occludens-1 (ZO-1) were evaluated by Western blots and immunofluorescence microscopy. The protein levels of heme oxygenase-1 (HO-1) were also analyzed via Western blots. Cur attenuated OGD-induced disruption of paracellular permeability and increased the expression of HO-1 protein in rat brain microvascular endothelial cells (RBMECs). After administration of OGD, the expression of occludin and ZO-1 proteins was restored by Cur, and this effect was blocked by a HO-1 inhibitor, zinc protoporphyrin (ZnPP). Cur protects RBMECs against OGD-induced disruption of TJ and barrier dysfunction via the HO-1 pathway. We propose that Cur is capable of improving the barrier function of BBB under ischemic conditions and this beneficial effect might be reversed by a HO-1 inhibitor, ZnPP.
