Control HN+As HN+ As+ AQDS Fis,3 Fe(IT)(a) and total As (b) concentrations in the culture solution for different treatments with femhydnite is the electron accepTor over the Error bar represent standard errors of three replicates. Wang et al(2009) Effect of microbial pla reduction on arsenic lity in paddy soil. J Environ sci. 1562-1568 3.00400 6.00700800 Fls.4 Results of scanning el icroscopy (a) and energy-dispersive spectroscopy (b) of biogenic iron minerals collected from the medium b ig. 5 X-ray diffraction imvestigation of ferrihydrite(a) and biogenic iron minerals(b).*: peaks of crystalline iron minerals
16 Wang et al(2009): Effect of microbial mediated iron plaque reduction on arsenic mobility in paddy soil. J Environ Sci,1562-1568
第一节植物的抗性 植物的避性 (二)植物对土壤污染物的避性 3.根分泌物对污染物的结合、降解作用 小麦品种 Carasinho(耐铝)和 Buck bolivar铝敏感)根分泌的低分子二羧酸 产酸量(μg/株) 产酸量(ug/g干根) 草酸苹果酸琥珀酸草酸苹果酸琥珀酸 Carasinho 67 211 80 192 566 218 Buck bolivar 36 27 162 117 42 标准误1256 25 63 118 59 (Christiansan-Wenigerd, 1992)
17 3. 根分泌物对污染物的结合、降解作用 第一节 植物的抗性 一、植物的避性 （二）植物对土壤污染物的避性 小麦品种Carasinho（耐铝）和Buck Bolivar(铝敏感）根分泌的低分子二羧酸 产酸量(μg/株） 产酸量(μg/g 干根） 草酸 苹果酸 琥珀酸 草酸 苹果酸 琥珀酸 Carasinho 67 211 80 192 566 218 Buck Bolivar 36 27 9 162 117 42 标准误 12 56 25 63 118 69 （Christiansan‐Wenigerd, 1992)
Organic acids detoxify Alt external to the root--commonly organic acids released Malate--Al-tolerant cultivars of wheat Citrate- Al-tolerant cultivars of snapbean(四季豆), maize, Cassia tora, soybean Cassia tora,决明属 oxalate-buckwheat and taro(F- malate and citrate-Al-tolerant triticale(X Triticosecale Wittmack) rapeseed, oats, radish and rye
18 Malate--Al-tolerant cultivars of wheat Citrate-Al-tolerant cultivars of snapbean（四季豆）, maize , Cassia tora, soybean; Cassia tora,决明属 oxalate-buckwheat and taro(芋) malate and citrate-Al-tolerant triticale (× Triticosecale Wittmack), rapeseed, oats, radish and rye. Organic acids detoxify Al3+ external to the root—commonly organic acids released
Al-sensitive wheat(cv. Scout 66) NO Al 1.0 AHMal 足0.5 AHOT No A AICI3 Al-Mal AH-Ox Al-Cit TRENDS in Plant Science Exposure to 10 HM of AlCl3, Al-malate(Al-Mal), Al-oxalate(Al-Ox)or Al-citrate(Al-Cit)at 1: 1 ratio. (b)Al accumulation (pink color)stained by (a) Root elongation during 20 h exposure 0.1% solution of Eriochome cyanine R
19 Al-sensitive wheat (cv. Scout 66) Exposure to 10 μM of AlCl 3, Al-malate (Al-Mal), Al-oxalate (Al-Ox) or Al-citrate (Al-Cit) at 1:1 ratio. (a) Root elongation during 20 h exposure (b) Al accumulation (pink color) stained by 0.1% solution of Eriochome cyanine R
Citrate content in the root tips of C tora. 15 8 v3 05 0 10 691215 Al concentration (uM Time(h Exposed to the 0.5mM CaCl2(ph 4. 5)solutions containing various concentrations of Al for 12 h(a) Exposed to the 0.5mM CaCI,(ph 4.5) solutions containing OmM (filled squires)and 50mM(open squires)Al for 12 h(b)
20 Exposed to the 0.5mM CaCl2 (pH 4.5) solutions containing various concentrations of Al for 12 h (a) Exposed to the 0.5mM CaCl2 (pH 4.5) solutions containing 0mM (filled squires) and 50mM (open squires) Al for 12 h (b). Citrate content in the root tips of C. tora