UV-B辐射对小麦叶抗氧化系统的影响

研究了温室种植的小麦在０（ＣＫ）、８．８２ｋＪ／ｍ＾２（Ｔ１）和１２．６ｋＪ／ｍ＾２（Ｔ２）三种剂量的紫外线Ｂ（ＵＶ－Ｂ）辐射下抗氧化系统的变化及其原因。ＵＶ－Ｂ辐射诱导了Ｈ２Ｏ２的合成，还原型抗坏血酸和还原型谷胱甘肽含量的增加、过氧化氢酶、愈创木酚过氧化物酶、抗坏血酸过氧化物酶和谷胱甘肽还原酶活性升高，而类胡萝卜素稍有所降低、超氧歧化酶（ＳＯＤ）活几乎不受ＵＶ－Ｂ辐射影响，分析表明，ＵＶ－Ｂ辐射     

重金属Cd、Cu对小麦(Triticum aestivum)幼苗生理生化过程的影响及其毒性机理研究

对Cd、Cu单因子处理下小麦幼苗叶片和根系的SOD、POD酶活、可溶性蛋白含量以及叶片中叶绿素含量的变化进行了研究.结果表明,Cd、Cu胁迫下,小麦幼苗受到损伤的明显症状之一是叶片叶绿素含量下降;小麦植株叶片POD、SOD酶活能够被诱导而升高;重金属Cd、Cu对小麦幼苗根系的损伤较叶片大;重金属对小麦幼苗的毒害机理之一是抑制了蛋白质的生物合成;重金属引起的各个生化指标随着处理浓度和处理时间的变化远比有机污染物(如豆磺隆)简单.     

Ecotoxicological effects of polycyclic musks and cadmium on seed germination and seedling growth of wheat (Triticum aestivum)

Single and joint toxic e ects of polycyclic musks including 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2- benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronapthalene (AHTN) and cadmium (Cd) on seed germination and seedling growth of wheat (Triticum aestivum) were investigated. The results showed that the toxicity sequence of HHCB toxic to wheat seed germination and seedling growth was similar to that of AHTN, that is, germination rate > shoot elongation > root elongation, while the toxicity of Cd was in the sequence of root elongation > shoot elongation > germination rate, according to the LC50 and EC50 values. It is suggested that polycyclic musks and Cd had di erent toxicological mechanisms. Root and shoot elongation of wheat might be good bioindicators for the contamination of polycyclic musks and Cd in soil. The mixture of polycyclic musks and Cd had synergistic e ects on T. aestivum according to the equi-toxic mixture approach when root elongation was selected as the toxicological endpoint. Thus, the joint toxicity of HHCB and Cd was significantly higher than the single toxicity of HHCB or Cd, which was also confirmed by the EC50 mix value of the mixture (EC50 mix = 0.530 TUmix). The EC50 mix value of the mixture of AHTN and Cd was 0.614 TUmix, which indicated that the mixture toxicity was strengthened when AHTN coexisted with Cd.     

土霉素对小麦种子发芽与幼苗生长发育的生态毒性

研究了土霉素对小麦种子发芽以及早期幼苗生长发育的生态毒性效应.结果表明,土霉素对小麦种子芽长及根长的抑制效应显著(p<0.01),而且它们之间具有良好的剂量-效应关系.根据线性回归方程得出土霉素对小麦种子芽长和根长的半抑制浓度为65.5 mg/L和34.7 mg/L.然而,土霉素对小麦种子的发芽率并没有显著的影响.研究还表明,0.15~2.4 mg/L土霉素暴露21 d后,小麦叶片中的叶绿素含量降低了35.6%~47.3%,叶片及根部的可溶性蛋白含量也均呈显著下降趋势.暴露7 d后,0.15~2.4 mg/L土霉素对小麦叶片和根部SOD与POD活性的抑制效应不显著,但随着暴露时间的延长,土霉素对小麦的SOD与POD酶活性抑制率显著下降;2.4 mg/L土霉素暴露21 d后,小麦根部的SOD活性下降72.3%,说明土霉素对小麦幼苗体内的抗氧化系统具有破坏作用.该实验结果显示,低浓度土霉素长期暴露对小麦幼苗的生长发育具有不良的生态毒性效应.     

人工合成麝香对小麦种子发芽的生态毒性

采用土培实验,研究了佳乐麝香(HHCB)和吐纳麝香(AHTN)对小麦种子发芽的生态毒性,测定了这2种人工合成麝香对小麦种子发芽率、根伸长抑制率和芽伸长抑制率的影响.结果表明,小麦种子的发芽率与这2种人工合成麝香浓度之间剂量-效应关系不明显,低剂量条件下(佳乐麝香≤150 mg·kg-1,吐纳麝香≤200 mg·kg-1...     

水杨酸对小麦高盐毒害的缓解作用

以盐敏感品种中国春、农大８５０２１和抗盐品种冬６８、茶淀红等４个品种小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）为材料,研究盐分胁迫对小麦种子萌发和幼苗生长的影响以及水杨酸对盐害的缓解作用．结果表明,水杨酸能够相对提高盐分胁迫条件下小麦种子萌发的数量、速度和质量;提高幼苗根和叶内游离脯氨酸、可溶性糖等渗透调节物质的含量,增强其渗透调节能力,同时提高幼苗体内超氧化物歧化酶、过氧化物酶等细胞保护酶的活性,抑制膜脂过氧化作用产物丙二醛的积累,降低叶片质膜透性和盐分胁迫对细胞膜的伤害．所有这些变化都有利于缓解盐害,提高小麦抗盐性     

磺胺甲恶唑对小麦叶片蛋白和叶绿素含量及SOD酶活性的影响

为了探明磺胺甲恶唑(sulfamethoxazole,SMZ)的生态毒理效应,通过实验室人工控制毒理实验,研究了低浓度SMZ暴露对小麦体内超氧化物歧化酶(SOD)活性、叶绿素(CHL)和蛋白质(SP)含量的影响.结果显示:染毒7d后,各浓度组小麦叶片的SOD活性均被显著诱导(P＜0.0l),并且染毒浓度的升高增强了SOD的活性,表明SMZ暴露胁迫下,小麦可启动自身的保护机制以最大限度地减少自由基损伤.而小麦叶片的CHL含量,随着SMZ染毒浓度的增加而逐渐降低.并且当SMZ暴露浓度较高时,小麦叶片的CHL含量被显著抑制(P＜0.05)).当SMZ染毒浓度为0.05～ 0.50 mg· L-1时,SP的含量被显著诱导(P＜ 0.01));1.00 mg·L-1SMZ对SP的含量产生显著(P＜0.01)抑制,这说明SMZ染毒剂量将对蛋白质的合成产生严重影响.综上,SOD的活性变化可反映出SMZ暴露对小麦的污染效应及其生态毒性作用,但将其作为评估SMZ污染暴露的生物标志物有待于进一步深入研究.     

(N-[2-(2-氧-1-咪唑烷基)乙基]-N '-苯基脲(EDU)对环境臭氧胁迫下的水稻和小麦生长的影响

通过对作物定期喷施不同浓度(0、150、300和450 mg·L-1)的N-[2-(2-氧-1-咪唑烷基)乙基]-N'-苯基脲(ethy lenediurea,EDU)溶液,研究EDU对环境O3胁迫下水稻“粤晶丝苗2号”(Oryza sativa L.Yuejingsi 2)和小麦“北农9549”(Triticum a...     

Impact of dissolved organic matter on bioavailability of chlorotoluron to wheat

Chlorotoluron (Chl) is a phenylurea herbicide and is widely used for controlling weeds. While it has brought great benefits to crop production, it has also resulted in contamination to ecosystem. In this study, we investigated accumulation of chlorotoluron (Chl) and biological responses of wheat plants as affected by dissolved organic matter (DOM). Wheat seedlings grown under 10 mg kg⁻¹ Chl for 4 d showed a low level of chlorophyll accumulation and damage to plasma membrane. The growth was inhibited by exposure of chlorotoluron. Treatment with 50 mg DOC kg⁻¹ DOM derived either from sludge (DOM-SL) or straw (DOM-ST) attenuated the chlorotoluron toxicity to plants. Both DOMs decreased activities of catalase, peroxidase and superoxide dismutase in Chl-treated seedlings. However, an increased glutathione S-transferases activity was observed under the same condition. Wheat plants treated with Chl in the presence of DOM accumulated less Chl than those treated with Chl alone. Moreover, in the presence of DOM, bioconcentration factor (BCF) decreased whereas translocation factors increased. Analyses with FT-IR spectra confirmed the regulatory role of DOMs in reducing Chl accumulation in wheat.     

Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere

A 2-year open-top chamber experiment with field-grown winter wheat (Triticum aestivum L. cv. Astron) was conducted to examine the effects of ozone on plant growth and selected groups of soil mesofauna in the rhizosphere. From May through June in each year, plants were exposed to two levels of O₃: non-filtered (NF) ambient air or NF+ 40 ppb O₃ (NF+). During O₃ exposure, soil sampling was performed at two dates according to different plant growth stages. O₃ exposure reduced above- and below-ground plant biomass in the first year, but had little effect in the second year. The individual density of enchytraeids, collembolans and soil mites decreased significantly in the rhizosphere of plants exposed to NF+ in both years. Differences were highest around anthesis, i.e. when plants are physiologically most active. The results suggest that elevated O₃ concentrations may influence the dynamic of decomposition processes and the turnover of nutrients.