Dong Bing-Bing, Chen You-Yuan, Hui Hong-Xia, Lu Wei-Jia, Yang Xiu-Qing, Liu Yi-Fan
College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
Huan Jing Ke Xue. 2016 Oct 8;37(10):4044-4053. doi: 10.13227/j.hjkx.2016.10.048.
Considering the serious pollution of heavy metal-chromium (Cr) in soil, there is an urgent need for effective selection of Cr-tolerant plant species. In order to gain fundamental insights into the tolerance and accumulation capabilities of L. and (L.) Voigt under Cr stress, a pot experiment was conducted to investigate their growth, physiology and accumulation characteristics under Cr(Ⅲ) and Cr(Ⅵ) stress. The results showed the growth parameters could intuitively reflect the toxicity levels of Cr for plants. For instance, a low-level Cr(Ⅲ) (<250 mg·kg) in soil was good for plant growth as indicated by the significant elevation of plant height, root length and biomass in (<0.05). However, Cr(Ⅵ) at all concentrations (≥25 mg·kg) in the soil inhibited the growth of both plant species, and the root length was particularly sensitive to the toxicity of Cr. The physiological parameters of plant represented both the toxicity of Cr and the tolerance of plants under Cr stress. A decrease of root activity and an increase of malonaldehyde content were observed under Cr stress, which indicated the physiological metabolism of plants was disturbed. In the presence of both Cr species, the proline content increased, which served as an indicator for both high Cr toxicity and increase of osmotic balance in plants. A rise in SOD and POD activity reflected the defense ability of plants against oxidative stress caused by Cr. In addition, the Cr-accumulation related parameters were the major standards for tolerant species selection. The Cr(Ⅵ) accumulation capacities of both plant species were greater than their Cr(Ⅲ) accumulation capacities. The maximum accumulation amounts of and reached 957.4 mg·kg and 743.3 mg·kg in roots and 394.7 mg·kg and 340.4 mg·kg in shoots, respectively. In comparison with , displayed a stronger Cr accumulation capacity in roots with a maximum bioaccumulation factor of 15.55. However, the transport ability of was superior to . All of the parameters demonstrated that both and could be used as alternative plants for phytoremediation of Cr-contaminated soil.
鉴于土壤中重金属铬（Cr）污染严重，迫切需要有效筛选耐铬植物物种。为了深入了解羽叶鬼针草（Bidens maximowicziana Oett.）和狼把草（Bidens tripartita L.）在铬胁迫下的耐受能力和积累能力，进行了盆栽试验，以研究它们在Cr(Ⅲ)和Cr(Ⅵ)胁迫下的生长、生理和积累特性。结果表明，生长参数能直观反映铬对植物的毒性水平。例如，土壤中低水平的Cr(Ⅲ)（<250 mg·kg）有利于植物生长，羽叶鬼针草和狼把草的株高、根长和生物量显著增加（P<0.05）。然而，土壤中所有浓度（≥25 mg·kg）的Cr(Ⅵ)均抑制了两种植物的生长，且根长对铬的毒性尤为敏感。植物的生理参数既反映了铬的毒性，也反映了植物在铬胁迫下的耐受性。铬胁迫下观察到根活力下降和丙二醛含量增加，这表明植物的生理代谢受到干扰。在两种铬形态存在的情况下，脯氨酸含量增加,这既是高铬毒性的指标，也是植物渗透平衡增加的指标。超氧化物歧化酶（SOD）和过氧化物酶（POD）活性的升高反映了植物对铬引起的氧化应激的防御能力。此外，铬积累相关参数是筛选耐性物种的主要标准。两种植物对Cr(Ⅵ)的积累能力均大于对Cr(Ⅲ)的积累能力。羽叶鬼针草和狼把草在根中的最大积累量分别达到957.4 mg·kg和743.3 mg·kg，在地上部分分别达到394.7 mg·kg和340.4 mg·kg。与狼把草相比，羽叶鬼针草在根中表现出更强的铬积累能力，最大生物积累系数为15.55。然而，狼把草的转运能力优于羽叶鬼针草。所有参数表明，羽叶鬼针草和狼把草均可作为铬污染土壤植物修复的替代植物。
