不同氮肥品种对不同类型土壤苋菜镉累积的影响

为探究不同氮肥品种对不同类型土壤苋菜镉(Cd)累积的影响,采用盆栽试验,以苋菜(Amaranshus mangostanus L.)为供试作物,在黄棕壤和赤红壤上设置尿素、硫酸铵、硝酸钠、硝酸铵及无肥(CK)5种处理,氮肥施用量均为N 200 mg/kg。结果表明:在黄棕壤上,尿素处理下苋菜地上部和地下部Cd含量和Cd累积量增幅最大,分别增加了59%、90%和243%、259%;在赤红壤中,硫酸铵处理下苋菜地上部和地下部Cd含量和Cd累积量增幅最大,分别增加了56%、114%和141%、293%。在两种土壤上施用硝酸钠显著降低了苋菜对Cd的吸收和累积,其中地下部Cd累积量分别低至0.03和0.06μg/盆。因此,建议在黄棕壤上施用尿素,在赤红壤上施用硫酸铵,在提高苋菜生物量的同时,还能强化苋菜对Cd的吸收累积效果。     

添加有机酸对土壤镉形态转化及苋菜镉积累的影响

植物根系分泌的低分子量有机酸能够与土壤中的镉形成镉–有机酸复合体,从而影响根际镉的移动性。本文通过添加有机酸对土壤镉形态转化的研究,阐明有机酸与镉生物积累的关系。采用盆栽试验及土壤培养等方法,研究了添加苹果酸、柠檬酸对赤红壤和黄棕壤中镉的形态转化以及超积累型苋菜天星米镉生物积累的影响。结果表明,与Cd 25 mg/kg处理比较,Cd 25 mg/kg＋苹果酸、Cd 25mg/kg＋柠檬酸处理对苋菜生物量未产生影响,但显著增加苋菜根系及地上部镉含量;添加苹果酸、柠檬酸处理显著降低土壤专性吸附态Cd含量,却显著增加了交换态Cd、碳酸盐结合态Cd和有机结合态Cd含量。说明添加苹果酸、柠檬酸还能够通过影响土壤镉形态转化而促进苋菜对镉的积累。     

不同白菜品种吸收累积重金属镉的差异研究

本文采用盆栽土培试验研究了河北省40个白菜栽培品种吸收累积重金属Cd的差异。结果表明,在土壤加入Cd含量为0、1．0~5．0mg／kg的条件下,河北省40个白菜品种地上部的Cd含量变化范围分别为0．009~0．037mg／kg、0．029~0．121mg／kg和0．166~0．684mg／kg。相同土壤Cd含量条件下,白菜早心白、多抗55、新乡小包23比白菜品种新北京三号和北京小杂60地上部的Cd含量高2～3倍,品种间存在明显的差异。在土壤加入Cd含量为5．0mg／kg的条件下,白菜新北京三号和北京小杂60地上部Cd含量均显著低于其他白菜品种,分别为0．166mg／kg和0．196mg／kg。该土壤条件下,白菜新北京三号和北京小杂60地上部Cd富积系数也最低．均为2．51：早心白地上部的Cd富积系数最大,为7．01,其Cd富积系数是白菜新北京三号和北京小杂60的2．8倍。     

我国磷矿磷肥中镉的含量及其对生态环境影响的评价

本文收集了全国36个矿区67个磷矿标本和全国30个主要磷肥厂的磷肥样品,对其含镉量进行了分析和评价。67个磷矿含镉量范围为0.1-571mg kg^-1Cd,平均为15.3±74mg kg^-1。如果除去广西等四个贮量较小但含镉较高的矿区,其余矿区磷矿平均含镉为0.98mg kg^-1Cd。30个磷肥样品平均含镉0.60±0.63mg kg^-1Cd,变幅为0.1-2.93mg kg^-1。其中普钙平均为0.75±0.65mg kg^-1Cd,钙镁磷肥为0.11±0.03mg kg^-1Cd。热法磷肥在生产过程中含镉量因挥发而降低。根据我国磷肥通常用量和作物吸镉特点,认为长期施用国产磷肥,不至产生污染环境问题。     

施用磷肥对土壤NO3——N累积的影响

在黄土高原南部的国家黄土肥力和肥料效益监测基地进行的长期定位试验结果表明 ,在小麦 玉米轮作中 ,当年施氮量为N 352kg/hm2 时 ,单施氮肥或氮钾配合的 0～4m土壤剖面的NO3--N累积量达 1000kg/hm2 以上 ,其中约 50%～60%的NO3--N分布在 2～ 4m以下的土层中 ,而氮磷配合的 0～ 4m土壤剖面的NO3--N累积量仅为 220kg/hm2,且 80 %的NO3--N分布在 0～2m的土层中 ,增施磷肥由于增加了氮的吸收和对水分的利用而有效地降低了土壤中NO3--N的累积。     

不同马铃薯品种对Cd、Pb吸收累积的差异

采用田间试验法,以中南地区主要种植的11个马铃薯品种为研究对象,测定马铃薯植株各部位重金属Cd、Pb含量,探讨不同品种的马铃薯对Cd、Pb的吸收累积差异,为马铃薯的安全种植提供实践参考。结果表明:Cd—Pb复合污染下,马铃薯块茎鲜重、茎叶鲜重以及根、茎叶、块茎中Cd、Pb含量在品种间均表现出显著差异。11个马铃薯品种块茎Cd含量范围为0.39～0.67 mg/kg,超标率100%,块茎Pb含量为0.16～0.43 mg/kg,超标率81.8%。马铃薯各部位Cd、Pb含量均呈现根茎叶块茎的分布特点;马铃薯对Cd的富集系数为2.35～5.56,对Pb富集系数为0.11～0.22,马铃薯富集转运Cd的能力大于Pb。尽管复合重金属靶标危险系数(TTHQ)法评价显示,金湘等5种马铃薯的TTHQ值1,对人体健康风险较小,但结合块茎Cd、Pb含量,建议污染区种植的马铃薯作为工业原料使用更安全。     

镉胁迫条件下磷肥对结缕草光合特性的影响

采用盆栽试验,研究镉(50 mg·kg-1)胁迫下不同磷肥水平(50、100、150 mg·kg-1)对结缕草生长及光合特性的影响。结果表明,镉胁迫下结缕草的生长和光合特性受到抑制,施加100 mg·kg-1磷肥的结缕草叶长比只受镉胁迫组增加53.33%,根长增加70.5%,叶绿素a+b含量增加42.85%,净光合速率(Pn)增加54.75%,蒸腾速率(Tr)增加94.05%,水分利用效率(WUE)增加45.85%,PSⅡ原初光能转化效率(Fv/Fm)增加12.84%,且与镉胁迫组差异显著。施加150 mg·kg-1磷肥结缕草叶片的胞间二氧化碳浓度(Ci)、表观光电子传递效率(ETR)比镉胁迫组降低。除气孔导度(Gs)在50 mg·kg-1磷肥处理后显著增加,结缕草叶长、根长、叶绿素含量、Pn、Tr、Fv/Fm、Ci和ETR等指标均随磷肥浓度增加呈现先增加后减少的趋势。通过结缕草生长和光合指标可以看出,施用磷肥可以缓解镉对结缕草的胁迫,施加100 mg·kg-1磷肥效果显著。     

磷肥杂质对土壤生态环境的影响

阐述了磷肥中有毒有害成分重金属镉（Ｃｄ）放射性元素和三氯乙烯土壤生态环境的影响,论述了施用磷肥对土壤和作物产品重金属含量的影响;讨论了土壤、作物和肥料Ｃｄ含量标准的制定;指出一般农田短期内不存在Ｃｄ污染,但对长期大量施用磷肥的地区和特定作物施用磷肥须谨慎。在出现施肥水平下,磷肥中放射性杂质不会导致土壤放射性污染。     

外源铁对不同品种番茄光合特性、品质及镉积累的影响

【目的】在人工模拟镉污染土壤条件下,讨论了叶面喷施Fe对番茄Cd积累及化学形态的影响,旨在为镉污染土壤上番茄的安全生产提供理论依据。【方法】采用土培试验研究了在重金属Cd(10 mg/kg)污染条件下,叶面喷施不同浓度Fe(0、200和400μmol/L,Fe SO4·7H2O)对2个番茄品种(‘4641’和‘渝粉109’)生长、光合特性、品质及果实Cd形态和Cd积累量的影响。【结果】叶面喷施Fe提高了番茄的根、茎、叶、果实干重及植株总干重,增幅分别为20.4%~48.6%、13.3%~56.0%、16.0%~63.1%、9.8%~16.5%和21.6%~40.3%,随着喷施Fe浓度的增加,番茄各部位干质量及总干质量呈先增加后降低的趋势,比较两个番茄品种,‘4641’耐Cd性更强,而‘渝粉109’对Fe的反应更为敏感;随着喷施Fe浓度的增加,2个番茄品种的叶片净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)呈先增加后降低趋势,在Fe 200μmol/L时最大,品种‘4641’的Pn、Gs和Tr较对照分别增加了8%、11%和2.9%,而‘渝粉109’较对照分别增加了28.7%、15.5%和18.8%。而喷Fe处理却降低了番茄叶片胞间CO2浓度(Ci),比较2个供试番茄品种,‘4641’光合作用和蒸腾作用强度均高于‘渝粉109’;喷Fe提高了2种番茄果实的硝酸盐含量以及渝粉‘109’还原糖含量,降低了‘渝粉109’果实氨基酸含量,喷施高浓度Fe(400μmol/L)能提高2种番茄果实Vc含量,与对照相比,‘4641’和‘渝粉109’果实硝酸盐增加的幅度分别为18.1%~22.2%、2.3%~22.0%,Vc较对照分别增加了8.2%和13.2%;番茄果实中Cd的主要存在形态为残渣态,其次为盐酸提取态,去离子水提取态和乙醇提取态所占比例较小,残渣态Cd(FR)和盐酸提取态Cd(FHCl)为活性偏低形态Cd,占Cd提取总量的70.8%,去离子水提取态(FW)和乙醇提取态(FE)为活性较高形态Cd,仅占Cd提取总量的11.8%,有效地抑制了Cd的毒害作用。叶面喷施Fe降低了番茄果实各形态镉含量;番茄中Cd主要积累在叶和茎中,而果实和根的积累量较少;喷Fe降低了番茄叶、根、茎、果实的Cd含量,降低幅度分别为7.1%~21.9%、35.6%~50.4%、13.0%~37.0%和2.8%~8.2%,但喷施高浓度Fe(400μmol/L)相比低Fe(200μmol/L)时的番茄各部位Cd含量有所增加,无论是非否喷施Fe,叶、茎、果实中的Cd积累量以及总Cd积累量总是以‘4641’‘渝粉109’,表明在Cd污染土壤上种植‘4641’较‘渝粉109’风险更大。【结论】叶面喷施适量Fe能够促进番茄的光合作用和蒸腾作用,提高了番茄各部位的干重,降低了Cd对番茄的毒害效应,同时减少了番茄各部位Cd含量。     

不同磷肥对镉胁迫下茄子苗期光合作用及抗氧化酶系统的影响

探究在石灰性土壤中施加不同磷肥对镉胁迫下茄子苗期光合作用及抗氧化酶系统的影响,为选出合理有效的磷肥、缓解镉毒害作用提供依据。采用盆栽试验,使用黄土状石灰性褐土种植茄子,通过双因素分析法研究了4种磷肥[磷酸一铵(MAP)、过磷酸钙(SSP)、磷酸二铵(DAP)、磷酸氢钙(DCP)]和4个施磷水平[0、0.15、0.25、0.35g·kg-1(以每千克土中P含量计),分别用P0、P1、P2、P3表示]在土壤镉(5mg·kg-1Cd)环境下,对茄子苗期叶片中叶绿素、光合作用、丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)的影响。研究结果表明,Cd胁迫下茄子叶片中叶绿素受损,通过施加不同磷肥,叶绿素含量均呈增长趋势,在SSP施磷类型P3水平下,叶绿素a、叶绿素b、类胡萝卜素和总叶绿素含量分别增加57%、120%、53%和76%。不同磷肥均显著提高光合作用的强度,降低Cd的胁迫。具体来看,净光合速率(Pn)、气孔导度(Gs)均表现为MAP≥DAP≥SSP>DCP,MAP施磷类型P3水平下,Pn为17.4μmol·m-2·s-1,Gs为0.2mmol·m-2·s-1,蒸腾速率(Tr)在DCP施磷类型P3水平下,较P0增加了165%,胞间CO₂浓度(Ci)在DAP施磷类型P3水平下提高幅度最为明显,较P0提高了28%。施用磷肥可以显著增加抗氧化酶系统的活性,但不同磷肥对抗氧化酶系统活性的提升效果不同,其中磷酸二铵对MDA含量的降低幅度最为明显,为41%;磷酸一铵对SOD、POD和CAT活性的增加最显著,分别增加了43%、106%和66%;过磷酸钙对APX和GR的活性增幅最大,分别为54%和93%。因此,施加不同磷肥可以缓解Cd胁迫下对茄子叶片的毒害,增强光合作用,提高抗氧化酶活性的作用。     

Crop uptake of cadmium from phosphorus fertilizers: I. Yield and cadmium content

We investigated the effects of different P fertilizers on the yields and Cd contents of oat (Avena sativa L.), ryegrass (Lolium multiflorum L.), carrot (Daucus carota L.), and spinach (Spinacia oleracea L.). These crops were grown in the greenhouse using soils treated with lime to achieve three pHs ranging from 4.77 to 5.94 for a sandy soil and 4.97 to 6.80 for a loam soil. The crop yields were generally not affected by liming or application of different kinds of P fertilizers, with a few exceptions. Application of Cd-containing NPK fertilizers in all cases tended to increase the Cd concentrations in crops, and the highest Cd concentrations in crops were obtained when the high-Cd NPK fertilizer was applied (adding 12.5 μg Cd kg^?1 soil). Cadmium concentrations in crops in most cases decreased with increasing soil pH. The highest percent recovery of the added Cd by plant species in the sandy soil was found for inorganic Cd-salt and in the loam soil for low-Cd NPK fertilizer. Phosphate rock resulted in the lowest recovery of the added Cd by all the plant species in both soils, but was also an insufficient P-source of its low solubility.     

Crop uptake of cadmium from phosphorus fertilizers: II. Relationship with extractable soil cadmium

In a greenhouse experiment, effects of different phosphate fertilizer applications on soil Cd extracted by DTPA and NH₄NO₃ in relation to plant uptake of Cd were investigated. The soils used were a sand and a loam treated with lime to achieve three pHs ranging from 4.77 to 5.94 for the sandy soil and 4.97 to 6.80 for the loam soil. Oat (Avena sativa L.), ryegrass (Lolium multiflorum L.), carrot (Daucus carota L.), and spinach (Spinacia oleracea L.), were used as test species. Application of the high-Cd NPK fertilizer (adding 12.5 μg Cd kg^?1 soil) significantly increased the extractable soil Cd, especially the DTPA-extractable Cd. Use of phosphate rock adding as much Cd as the high-Cd NPK fertilizer did not increase the extractable Cd in either of the soils. Both DTPA- and NH₄NO₃-extractable Cd decreased with the increases in soil pH. The Cd concentrations and total Cd uptake of plants were significantly correlated with the soil Cd extracted by DTPA and NH₄NO₃.     

The phosphorus requirement of Amaranthus mangostanus L. exceeds the 'change point' of P loss

Due to the high economic value of vegetables, farmers in China often apply more fertilizer than is required for plant growth. This leads to phosphorus accumulation in soils, which can pollute the aquatic environment. This conflict arises because vegetables often use nutrients inefficiently, and require high phosphorus levels in the growth medium. In this study, amaranth ( Amaranthus mangostanus L.) was grown in soils with 14.7, 23.8, 45.3, 54.6, 74.2, 101 or 116 mg Olsen-P/kg, and with and without phosphorus fertilizer (175 mg P/kg or equivalent to 385 kg P/ha). The yield of amaranth was positively correlated with soil Olsen-P content. CaCl₂-P content was positively correlated with Olsen-P content and CaCl₂-P markedly increased at Olsen-P contents exceeding 53.8 mg P/kg in the pot experiment or 55.9 mg P/kg in the field survey. These values were regarded as the 'change points' for phosphorus loss; to achieve 85 or 95% of maximum amaranth yield, the amaranth crop required 91or 101 mg Olsen-P/kg soil, respectively, and application of 175 mg P/kg was still able to significantly increase amaranth yield at an Olsen-P level of 74.2 mg P/kg soil. These results indicated that the phosphorus requirement of amaranth exceeded the 'change point' (53.8 or 55.9 mg Olsen-P/kg); the C _min (minimum concentration in the media at which no net influx occurs) of phosphorus for 3-week-old amaranth was 1.55 μ m . This value is much higher than that reported for other crops, and may explain the inefficient P use of amaranth. The high C _min value also indicates that the phosphorus requirement of amaranth is beyond the 'change point' of P loss.     

不同氮磷钾肥对土壤pH和镉有效性的影响

采用土壤培养方法研究了不同氮、磷、钾肥对土壤pH和镉有效性的影响。结果表明,在培养60 d时,所有氮肥处理均降低了土壤pH,增加了Cd的提取量;但高量尿素和氯化铵处理土壤pH降低最多,提取的Cd也最多;硫酸铵提取的Cd较对照增加最小。所有磷肥处理均引起土壤pH小幅降低,但对土壤Cd提取量的影响以普钙稍大。3种钾肥处理均降低了土壤pH,其中氯化钾在0 d时提取的Cd在所有钾肥处理中为最高,其提取能力15 d后逐渐消失,试验结束时所有钾肥处理对Cd提取量均低于对照。本研究进一步表明,在土壤Cd含量处于污染临界值附近或已受Cd污染的土壤上,应避免施用高量的酸性肥料如尿素、氯化铵、普钙,以及其他酸性物料。在常用磷、钾肥中,磷酸二铵和硫酸钾在Cd污染土壤上施用更为适合。     

Effects of arbuscular mycorrhizal inoculation on cadmium accumulation by different tobacco (Nicotiana tabacum L.) types

The effect of arbuscular mycorrhiza (AM) on cadmium (Cd) uptake by tobacco (Nicotiana tabacum L.) was studied in a pot experiment. Three commercial varieties, Basma BEK, K326 and TN90, representing three distinct tobacco types, were each grown in a different soil with nutritional conditions matching as closely as possible their requirements for field production. Cd concentrations in these soils were within the background range. Each variety was either non-mycorrhizal or inoculated with one of five AM fungal isolates. Cd concentration in leaves was decreased by inoculation with selected isolates in the K326 and TN90 variety grown in acidic soils. In contrast, it was increased by inoculation with most isolates in the Basma BEK variety grown in a basic soil with low Cd availability. Besides, plants of all three varieties had significantly higher leaf concentrations of phosphorus and nitrogen in some inoculated treatments. The percentage of root colonisation was mostly low in the inoculated treatments. In the Basma BEK and TN90 variety, the tested AM fungal isolates differed in their ability to colonise roots, but no correlation was found between the root colonisation of an isolate and its effects on the Cd concentrations in tobacco leaves. One isolate influenced most pronouncedly Cd concentrations and improved mineral nutrition in all the three combinations of variety and soil despite its low colonisation levels. AM symbiosis probably affected Cd uptake of tobacco by indirect mechanisms such as stimulation of root growth or mycorrhizal plant mediated changes in chemical or biological soil properties.     

不同磷水平下玉米和小麦植株亚细胞中镉的积累

Corn and wheat plants were grown in a nutrient culture solution at four levels of phosphorus (0,0.12,0.60 and 3.0mmol L^-1) and two levels of cadmium(0 and 4.0umol L^-1) in greenhouse for a 18-day period.The concentrations of phosphorus and cadmium in cell wall,cytoplasm and vacuoles of roots and leaves were examined by cell fractionation techniques.With increasing phosphorus in medium,the contents of P in cell wall,cytoplasm and vacuoles of corn and wheat roots and leaves increased.The highest content of P was observed in cell wall,next in vacuoles,and the lowest in cytoplasm.The wheat subcellular fractions in both roots and leaves hab higher concentrations of phosphorus than those of corn.Increasing phosphorus in medium significantly inhibited the intracellular Cd accumulation in both species,However,at P concentration up to 3.0mmol L^-1,the Cd content in cell wall was increased.Increasing phosphorus resulted in reduction of the subcellular Cd content in cell wall was increased.Increasing phosphorus resulted in reduction of the subcellualr Cd content in corn and wheat leaves.Compared with corn,the wheat roots had a higher Cd content in the cell wall and vacuoles and a lower in cytoplasm,while in leaf subcellular fractions the wheat cell had a higher Cd content in its vacuoles and a lower one in its cytoplasm,The results indicate that phosphorus may be involved in sequestration of Cd ionic activity in both cell wall and vaculoes by forming insoluble Cd phosphate.     

不同施肥条件下覆膜对玉米干物质积累及吸磷量的影响

为了探明覆膜对不同施肥条件下玉米生长及磷素吸收的影响,采用田间试验法,研究了覆膜对不同施肥条件下玉米全生育期干物质积累、地上部磷含量、吸磷量、磷分配以及磷收获指数的影响。结果表明:1）覆膜处理能够显著增加玉米不同生育期地上部干重,其中苗期和拔节期玉米地上部干重增加幅度最大,达24.9%～126.3%。覆膜对单施磷肥条件下玉米苗期生长的促进作用较明显,而生长后期则对氮、磷、钾配施条件下的促进作用较明显。2）覆膜处理显著提高玉米生长前期,尤其是苗期地上部含磷量、磷素累积量,且单施磷肥处理效果强于其他施肥处理;覆膜后,单施磷肥处理玉米苗期地上部含磷量、磷素累积量分别较不覆膜增加56.3％和253.0％。覆膜对不同施肥条件下玉米磷素收获指数影响不显著。     

不同形态氮肥对苗期玉米镉富集的影响

为了探究不同形态氮肥对苗期玉米生长及富集镉(Cd)的影响,采用室内水培试验,在重金属Cd处理下,分别施加4和8 mmol/L N含量的硝态(NO3-)、铵态(NH4+)、酰胺态(尿素)氮肥培养12 d后,比较不同施氮处理下玉米的生长状况和吸收富集Cd的差异.研究结果表明:与不添加重金属Cd的全营养液培养处理相比,添加重...