Mercury in some chemical fertilizers and the e ect of calcium superphosphate on mercury uptake by corn seedlings (Zea mays L.)

Mercury (Hg) contents in ten chemical fertilizers were determined, and the e ect of calcium superphosphate (CSP) on the uptake and translocation of Hg in corn seedlings was investigated by pot experiments. CSP was applied at the levels of 0, 66.7, and 133.4 mg P2O5/kg to Hg-treated (2 mg/kg) and untreated soils. CSP had the highest Hg content (5.1 mg/kg), followed by the NPK compound fertilizer 15-5-5 (15% N, 5% P2O5, 5% K2O) (1.2 mg/kg), then by nitrogen fertilizers (except for ammonia sulfate) and potassium fertilizers. Application of CSP did not obviously influence the biomass of corn roots, but it significantly increased the biomass of corn shoots in Hg-treated soil. Application of CSP at the levels of 66.7 and 133.4 mg P2O5/kg did not obviously influence the uptake of Hg by corn seedlings on soils without Hg treatment, but it decreased the Hg uptake of corn seedlings significantly on Hg-treated soils. The transfer coe cient of Hg in corn seedlings improved slightly on soils without Hg treatment, but decreased slightly on Hg-treated soils with the application of CSP. These results implied that CSP could ameliorate Hg toxicity to corn seedlings by inhibiting the uptake and the translocation of Hg in plants on Hg-polluted soils.     

Uptake and accumulation of copper by roots and shoots of maize (Zea mays L.)

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｃｏｎｔｅｎｔｏｆＣｕｉｎｔｈｅｅｎｖｉｒｏｎｍｅｎｔｉｓｕｓｕａｌｌｙ20ｔｏ30ｐｐｍｉｎｎｏｎｃｏｎｔａｍｉｎａｔｅｄｓｏｉｌ(Ｎｒｉａｇｕ,1979;Ｓａｌｏｍｏｎｓ,1984),ｂｕｔｉｓｍｏｒｅｔｈａｎ2000ｐｐｍｉｎｍｉｎｉｎｇａｒｅａｓａｎｄｉｎｔｈｅｖｉｃｉｎｉｔｙｏｆｓｍｅｌｔｅｒｓ(Ｆｒｅｅｄｍａｎ,1980;Ｈｕｍｐｈｒｅｙｓ,1984).ＩｔｈａｓｂｅｅｎｄｅｍｏｎｓｔｒａｔｅｄｔｈａｔｃｏｐｐｅｒｓｏｌｕｂｉｌｉｔｙｄｅｐｅｎｄｓｏｎｐＨｉｎｓｏｉｌｓ,ａｎｄｉｔｉｓｏｂ…     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

不同改良剂对微碱性土壤镉形态及小麦吸收的影响

研究过磷酸钙、石灰和硅钙镁肥单一施用对土壤Cd形态和小麦植株不同器官Cd含量的影响,以期为微碱性Cd污染土壤安全利用提供理论参考.通过盆栽试验,研究不同改良剂对小麦成熟期土壤Cd形态以及二乙基三胺五乙酸（DTPA）提取态镉含量的影响,分析小麦不同器官中Cd的含量.结果表明：过磷酸钙显著降低了土壤的pH值,石灰和硅钙镁肥显著提高了土壤的pH值.3种改良剂均可以显著降低土壤DTPA提取态镉含量,其中施用硅钙镁肥（3%）的效果最好,降幅为73.60%.添加硅钙镁肥可显著降低土壤可交换态镉含量,同时增加残渣态镉含量,其中硅钙镁肥（3%）处理效果最佳,土壤可交换态镉含量降幅为63.30%,残渣态镉含量增幅为56.20%.3种改良剂均可显著降低小麦地上部、地下部Cd含量,其中硅钙镁肥处理对小麦地上部及地下部Cd含量降低效果最佳.硅钙镁肥（1.2%）处理对小麦籽粒镉含量降低效果最好,降幅为90.85%.土壤pH值与土壤DTPA提取态Cd含量达到了极负显著水平,土壤DTPA提取态Cd含量与小麦各器官中Cd呈极显著正相关.因此,施用不同改良剂可不同程度的降低土壤中Cd的生物有效性和小麦植株不同器官中Cd的含量,缓解Cd对植株的胁迫效应. 3种改良剂在同等剂量水平下,硅钙镁肥对小麦器官中镉的降低效果最佳.     

Quantification of the effects of management factors on maize (Zea mays L.) and cotton (Gossypium hirsutum L.) residues decomposition rate

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｄｅｃｌｉｎｅｉｎｏｕｔｐｕｔｏｆｓｏｉｌｒｅｓｏｕｒｃｅｓｉｎｒｅｃｅｎｔｙｅａｒｓｈａｓａｒｏｕｓｅｄｇｒｅａｔｅｒｉｎｔｅｒｅｓｔｆｒｏｍｓｅｖｅｒａｌｃｉｒｃｌｅｓ,ｉｎｃｌｕｄｉｎｇｅｎｖｉｒｏｎｍｅｎｔａｌｉｓｔｓ,ｐｏｌｉｃｙｍａｋｅｒｓ,ｓｏｉｌｓｃｉｅｎｔｉｓｔｓ ,ａｎｄｆａｒｍｅｒｓ,ｓｕｇｇｅｓｔｉｎｇｔｈｅｎｅｅｄｆｏｒｃｏｎｔｉｎｕｏｕｓｅｖａｌｕａｔｉｏｎｏｆｔｈｅｐｏｔｅｎｔｉａｌｅｎｄｕｒａｎｃｅｏｆｃｕｒｒｅｎｔａｇｒｉｃｕｌｔｕｒａｌ…     

细胞分裂素类物质对镉胁迫下玉米幼苗生长和抗氧化酶活性及脯氨酸含量的影响

采用水培试验,研究了镉胁迫下喷施细胞分裂素类物质6-苄氨基嘌呤(6-BA)和激动素(KT)对玉米幼苗生长、叶片叶绿素含量、脯氨酸含量、植株镉含量和活性氧清除酶活性的影响.结果表明,与单纯镉胁迫相比,喷施6-BA和KT提高了玉米幼苗的生物量、根和地上部镉含量、叶绿素和脯氨酸含量,降低了叶片丙二醛(MDA)含量,促进了叶片过氧化物酶(POD)和过氧化氢酶(CAT)活性的升高,但对超氧化物歧化酶(SOD)活性的影响不明显.说明细胞分裂素类物质6-BA和KT可缓解镉胁迫对玉米幼苗的伤害,其机制可能与细胞分裂素物质能维持叶绿素稳定、刺激细胞内H2O2清除酶类活性及促进脯氨酸积累有关.当6-BA浓度在0～20mg·L-1之间时,其对玉米幼苗镉胁迫的缓解效应随喷施浓度的提高而增强,而KT的最适喷施浓度为70mg·L-1.     

Effects of field application of phosphate fertilizers on the availability and uptake of lead, zinc and cadmium by cabbage (Brassica chinensis L.) in a mining tailing contaminated soil

A field trial was conducted to evaluate the reduction of bioavailability of heavy metals including lead (Pb), zinc (Zn) and cadmium (Cd) in a soil contaminated by mining tailings in Shaoxing, Zhejiang, China. Three commercial phosphate (P) fertilizers including phosphate rock (PR), calcium magnesium phosphate (CMP), and single superphosphate (SSP) were applied to the plot at three P application rates, 50, 300, and 500 g/m2 with 9 treatments and control (CK). Plants, water soluble and exchangeable (WE) extra...     

化学氮肥对蔬菜硝酸盐污染影响的研究

蔬菜是一种容易富集硝酸盐的作物,菜农为了获得高产,而超量施用化学氮肥,致使蔬菜硝酸盐累积量剧增,品质恶化。研究表明：筛选出氯化铵和硫酸铵两种氮肥;施氮剂量每hm²以200kg为临界值;施氮安全始期,以追氮后8天上市为宜;化学氮肥与厩肥、土杂肥配用,能有效控制和降低蔬菜硝酸盐的累积分别达67.4％和45.7％。硝酸盐是亚硝胺的前体物,应减轻其对人体健康的潜在危害,并提高蔬菜品质。     

金鱼(Carassius auratus L.)对水中游离态铅的吸收积累及鳃分泌粘液的自身保护作用

研究了金鱼在铅暴露实验中的铅吸收过程及鱼鳃分泌物的自身保护作用，水相Ｐｂ＾２＋的鳃吸收机理以及分泌粘液对铅的络作用。结果表明，金鱼因铅暴露导致粘液分泌量增加。结合到鳃上的铅与水相Ｐｂ＾２＋活度关系可用Ｌａｎｇｍｕｉｒ吸附等温式表述。     

金鱼(Carassius auratus L.)对水中游离态铅的吸收积累及鳃分泌粘液的自身保护作用

研究了金鱼（ Ｃａｒａｓｓｉｕｓａｕｒａｔｕｓ Ｌ．） 在铅暴露实验中的铅吸收过程及鱼鳃分泌物的自身保护作用、水相Ｐｂ２＋ 的鳃吸收机理以及分泌粘液对铅的络合作用．结果表明，金鱼因铅暴露导致粘液分泌量增加．结合到鳃上的铅与水相Ｐｂ２＋ 活度关系可用Ｌａｎｇｍｕｉｒ 吸附等温式表述．据此估算的最大结合量为０－９４２４ ｍ ｍｏｌ／ｋｇ（干重） ．非常接近１ 的Ｈｉｌｌ 常数（１－０１２）说明金鱼鳃上仅有一种类型的Ｐｂ２＋ 结合位点．平均每尾金鱼鳃上Ｐｂ２＋ 的结合位点数达１－６２ ×１０－ ５ ｍ ｍｏｌ，结合的条件稳定常数（ｌｏｇ ＫＰｂ鳃） 为４－８ ．血液铅含量与鳃铅含量间呈显著线性关系．金鱼吸收Ｐｂ２＋ 的主要过程为：Ｐｂ２＋ 结合到鳃上，其后被动扩散或载体转运穿过鳃上皮，进入血液循环．