Accumulation and tolerance characteristics of cadmium in a potential hyperaccumulator--Lonicera japonica Thunb

Lonicera japonica Thunb.: ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Lonicera japonica Thunb. (Caprifoliaceae), a widely used traditional Chinese medicine, was known as Jin Yin Hua (Chinese: ), Ren Dong and Japanese honeysuckle. It was taken to treat the exopathogenic wind-heat, epidemic febrile diseases, sores, carbuncles and some infectious diseases. At the same time, Lonicera japonica could be used as healthy food, cosmetics, ornamental groundcover, and so on.

AIM OF THE REVIEW

The present paper reviewed the ethnopharmacology, the biological activities, toxicology and phytochemistry of Lonicera japonica.

MATERIALS AND METHODS

Information on Lonicera japonica was gathered via the Internet (using Google Scholar, Baidu Scholar, Elsevier, ACS, Medline Plus, CNKI and Web of Science) and libraries. Additionally, information also was obtained from some local books and brilliant scholars on ethnopharmacology.

RESULTS

More than 140 chemical compounds have been isolated, and the main compositions are essential oils, organic acids and flavones, etc. Lonicera japonica and its active principles possess wide pharmacological actions, such as anti-inflammatory, antibacterial, antiviral, antioxidative and hepatoprotective activities.

CONCLUSIONS

As an important traditional Chinese medicine, further studies on Lonicera japonica can lead to the development of new drugs and therapeutics for various diseases, and how to utilize it better should be paid more attentions.

Effects of cadmium hyperaccumulation on the concentrations of four trace elements in Lonicera japonica Thunb

Hyperaccumulators are important in the phytoremediation of cadmium (Cd)-contaminated soil. In this study, Cd accumulation and the interactions between Cd and four other trace elements (Fe, Mn, Cu, and Zn) in Lonicera japonica Thunb. were investigated. As a result of exposure to soil containing 50 mg kg(-1) Cd, stem and shoot Cd concentrations reached 344.49 ± 0.71 and 286.12 ± 9.38 μg g(-1) DW respectively, without showing symptoms of visible damage to the plants. This suggests that L. japonica has a strong tolerance to Cd. It is proposed that trace metal elements are involved in the Cd-detoxification mechanisms shown by hyperaccumulators. There is a synergistic interaction in accumulation and translocation between Cd and Fe and a significantly negative correlation between Cd and Cu or Zn concentrations in L. japonica plant tissues. The imbalanced trace element concentrations influences detoxification processes to Cd, therefore, L. japonica could be considered as a new Cd-hyperaccumulator model to investigate the metal tolerance strategies of plants.

Growth Responses and Metal Accumulation in an Ornamental Plant (Osmanthus fragrans var. thunbergii) Submitted to Different Cd Levels

To characterize the effects of Cd supplies on the accumulation efficiency of Cd, Pb, Zn, and Cu in an ornamental plant (osmanthus, Osmanthus fragrans var. thunbergii), a pot experiment using current-year osmanthus in field was carried out in western China. Biomass and its components showed a decreasing tendency as Cd supply increased, though insignificant differences were observed between treatments with a low and no Cd supply. Cd supplies increased the concentrations of Cd and Pb in plants, but the concentrations of Zn and Cu in plant showed a decreasing tendency with the increase of Cd supplies. Cd supplies also increased Cd accumulation for the plant, although the highest Cd accumulation was observed at a low Cd supply (T1). A higher Pb accumulation in the osmanthus was also detected in T1 than the other treatments. However, Zn and Cu accumulations decreased with the increase of Cd supplies. The examined osmanthus showed relative higher Cd and Pb transfer efficiencies in the presence of Cd supplies, but Cd supplies can limit the transfer of Zn and Cu. The results suggested that the examined osmanthus has potential for use in metal-contaminated environments due to phytoremediation application in the soil.

Accumulation and tolerance characteristics of cadmium in a halophytic Cd-hyperaccumulator, Arthrocnemum macrostachyum

The potential of the extreme halophyte Arthrocnemum macrostachyum was examined to determine its tolerance and ability to accumulate cadmium for phytoremediation purposes. A glasshouse experiment was designed to investigate the effect of cadmium from 0 to 1.35 mmol l(-1) on the growth and the photosynthetic apparatus of A. macrostachyum by measuring chlorophyll fluorescence parameters, gas exchange and photosynthetic pigment concentrations. We also determined ash, cadmium, calcium, copper, iron, manganese, magnesium, phosphorous, sodium, and zinc concentrations, and C/N ratio. A. macrostachyum demonstrated hypertolerance to cadmium stress; it did not show phytotoxicity at shoot concentration as high as 70 mg kg(-1). The bioaccumulator factors exceeded the critical value (1.0) for all Cd treatments, and the transport factors indicated that this species has higher ability to transfer Cd from roots to shoots at lower Cd concentrations. At 1.35 mmol l(-1) Cd A. macrostachyum showed 25% biomass reduction after a month of treatment. Long-term effects of cadmium on the growth were mainly determined by variations in net photosynthetic rate (P(N)). Reductions in P(N) could be accounted by higher dark respiration and lower pigment concentrations. Finally, A. macrostachyum has the basic characteristics of a Cd-hyperaccumulator and may be useful for restoring Cd-contaminated sites.

Cadmium accumulation and growth responses of a poplar (Populus deltoidsxPopulus nigra) in cadmium contaminated purple soil and alluvial soil

To characterize the phytoextraction efficiency of a hybrid poplar (Populus deltoidsxPopulus nigra) in cadmium contaminated purple soil and alluvial soil, a pot experiment in field was carried out in Sichuan basin, western China. After one growing period, the poplar accumulated the highest of 541.98+/-19.22 and 576.75+/-40.55 microg cadmium per plant with 110.77+/-12.68 and 202.54+/-19.12 g dry mass in these contaminated purple soil and alluvial soil, respectively. Higher phytoextraction efficiency with higher cadmium concentration in tissues was observed in poplar growing in purple soil than that in alluvial soil at relative lower soil cadmium concentration. The poplar growing in alluvial soil had relative higher tolerance ability with lower reduction rates of morphological and growth characters than that in purple soil, suggesting that the poplar growing in alluvial soil might display the higher phytoextraction ability when cadmium contamination level increased. Even so, the poplars exhibited obvious cadmium transport from root to shoot in both soils regardless of cadmium contamination levels. It implies that this examined poplar can extract more cadmium than some hyperaccumulators. The results indicated that metal phytoextraction using the poplar can be applied to clean up soils moderately contaminated by cadmium in these purple soil and alluvial soil.