以水耕培養Ipomoea aquatica評估不同化學型態重金屬對植物體吸收重金屬之影響

Phytoextraction of Heavy metal by Ipomoea aquatica (water spinach) in hydroponic solution: Effects of Heavy metal speciation

黃朧丘(Lung-Chiu Huang)

指導教授 ： 張時獻

中山醫學大學/健康管理學院/公共衛生學系碩士班/碩士(2008年)

https://doi.org/10.6834/CSMU.2008.00011

摘要

本研究使用水耕栽種方式探討水溶液中不同化學型態重金屬對植物吸收重金屬之影響。研究中以MINEQL+化學型態平衡模式估計重金屬在溶液中的化學型態，研究內容共分二部分，第一部分:添加EDTA與Triton X-100(10-5與10-4 M)評估不同化學型態的鎘(0.3-3 mg L-1)對Ipomoea aquatica的生物毒性與生物累積；第二部分:不同型態的鎘(1-3 mg L-1)和鋅(1.5-6 mg L-1)對I. aquatica吸收鎘與鋅的交互作用影響，並以統計方法推估植體吸收重金屬鎘與鋅的交互作用

第一部分結果顯示，水耕栽種14天後，單一添加Cd離子 (0.3、1、3 mg L-1)、EDTA(10-5、10-4 M)或Triton X-100 (10-5、10-4 M)其濃度皆會明顯抑制蕹菜根部生長，雖其未達統計顯著，但已遠遠造成植物體的變異。在單一添加0.3~3 mg L-1 Cd時，I. aquatica根部濃度可高達668-1124 mg Kg-1，表示蕹菜為具潛力之鎘超累積植物(植體 > 100 mg Kg-1)。而在混合添加EDTA與Cd離子中的Cd化學型態探討發現，不論是自由態、錯合態及螯合態的Cd其對於植體的根長、根重及莖重皆有抑制且呈負相關，但主要影響根長的因子仍是自由態與錯合態的Cd。而在BCFs的結果發現根部的BCFroot(40-2227)比莖部的BCFshoot(17-144)明顯的增加，隨鎘與EDTA的增加而減少。

第二部份同樣水耕栽種14天後，以單一與混合添加Cd離子 (1、3 mg L-1)、Zn離子 (1.5、6 mg L-1)和EDTA (2.5×10-5 M)探討植物吸收重金屬Cd及Zn的交互作用。結果顯示，I. aquatica植體中的Cd和Zn係以水溶液中水溶性的金屬離子形式(自由態和錯合態)進入到植體累積，同時也以自由態及錯合態對植物的質量造成抑制的現象。而在交互作用結果顯示，所添加的重金屬與螯合劑彼此間沒有交互作用現象。

關鍵字

植物萃取 ； 重金屬型態 ； 交互作用 ； Ipomoea aquatica

並列摘要

This study employed Ipomoea aquatica (water spinach) in hydroponics system to investigate the effects of cadmium and zinc speciation on phytotoxicity and heavy metals accumulation. The heavy metals speciation was estimated by a aquatic chemical equilibrium model, MINEQL+. First, the influences of cadmium speciation on the growth of I. aquatica and on its cadmium accumulation in the presence and absence of EDTA (chelating agent) and Triton X-100 (TX-100, nonionic surfactant) were investigated. Second, the interaction of cadmium and zinc speciation on the growth of I. aquatica also was evaluated.

Results indicate that the root length was a more sensitive parameter than root weight and shoot we indicated that ight. Root elongation was affected by Cd in the Cd-EDTA solution and TX-100 in the Cd-TX-100 solution. Both the root length and the root biomass were negatively correlated with the total soluble Cd ions. In contrast, Cd phytoextraction of I. aquatic was correlated with the aqueous Cd ions in the free and complex forms rather than in the chelating form. Additionally, the high Cd bioconcentration factors of I. aquatica (375 to 2227 L kg-1 for roots, 45 to 144 L kg-1 for shoots) imply that I. aquatica is a potential aquatic plant to remediate Cd-contaminated wastewater.

Similarly, the metal accumulation and plant biomass of in I. aquatica significantly correlated with Cd and Zn in the free phases (free ion and complex form). The interaction of cadmium and zinc speciation is unlike to affect the growth and metal accumulation of I. aquatica.

並列關鍵字

phytoextraction ； heavy metals speciation ； interaction ； Ipomoea aquatica

參考文獻

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