【作者】 奚岭林；

【导师】 杨建昌；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2006， 硕士

【摘要】 镉(Cd)和铅(Pb)是农田土壤的污染物质。随着工业的发展,Cd和Pb污染日趋严重,对人类健康和农业生产构成了严重威胁。本研究以3个当地高产水稻品种扬稻6号(籼稻)、武运粳7号和扬粳9538(粳稻)为材料,探讨了在不同Cd、Pb浓度、不同土壤水分和不同施氮量下Cd、Pb对水稻产量与品质的影响及其在植株内的吸收和分配特点。主要结果如下:1.扬稻6号在低浓度Cd处理下,产量比对照(未加Cd处理)增加,而在高浓度条件下,产量比对照下降。武运粳7号和扬粳9538随着Cd浓度的上升,产量表现为下降趋势。扬稻6号在低浓度Pb处理下,产量比对照下降2.65%,在高浓度下比对照下降3.92%;武运粳7号和扬粳9538的产量在Pb处理下均比对照下降。Cd、Pb处理降低了稻米淀粉谱的崩解值,增加了消减值,表明Cd和Pb降低了稻米的食味品质。Cd、Pb在水稻植株中各器官的浓度和积累量分布很不均匀,总的趋势表现为高浓度处理>低浓度处理、根>茎鞘>叶>穗。高浓度Cd处理显著提高了谷粒各部位的Cd浓度和积累量。高浓度Pb处理显著提高了扬稻6号谷粒各部位的Pb浓度和颖壳中Pb的积累量,但对扬粳9538的影响不大。2.在无Cd处理下,轻-干湿交替灌溉(MD)的产量较水层灌溉(WW)和重-干湿交替灌溉(SD)显著增加。Cd和Pb处理后,MD和SD的产量均较WW降低,且处理间达显著差异。在MD和SD条件下,Cd处理使扬粳9538的崩解值显著比对照升高,消减值显著比对照下降;Pb处理使扬粳9538的崩解值比对照显著上升,消减值与对照相比变化不大。说明在干湿交替灌溉条件下,Cd、Pb能提高稻米的食味品质。随着土壤水分的降低,水稻各器官中Cd、Pb的浓度与积累量均增加。说明低土壤水分促进了水稻对Cd、Pb的吸收。干湿交替灌溉降低了颖壳和糠层Cd的积累量,显著增加了精米中的Cd积累量,表明低土壤水分能促进Cd向籽粒运送。3.在相同重金属处理条件下,水稻产量随着施N量的增加而增加。在同一N素水平下,Cd或Pb处理均使产量较对照下降。Cd处理后,随着施N量的增加,崩解值减小,消减值增大;Pb处理后,在中氮(MN)水平下,崩解值显著增加,而消减值显著降低,而在HN下结果则相反。随着施氮量的增加,水稻植株各器官中的Cd、Pb浓度和积累量均明显增加。4.高浓度Cd或低浓度和高浓度Pb处理均能诱导水稻叶片中新的过氧化氢酶(CAT)同工酶的表达。在不同土壤水分或不同施氮量条件下,Cd和Pb处理能抑制超氧化物歧化酶(SOD)或过氧化物酶(POD)或CAT部分同工酶的表达,同时增强部分同工酶的表达,抑制或增强的酶带类型及程度因Cd或Pb处理浓度、土壤水分状况或施氮量的不同而异。更多还原

【Abstract】 Cadmium (Cd) and lead (Pb) are important contaminants in agricultural soil and threatening agriculture and human health. In this study, three high-yielding rice cultivars currently used in the local production, Yangdao 6 (indica), Wuyunjing 7 and Yangjing 9538 (japonica), were pot-grown, and different treatments of Cd and Pb concentrations, various soil moistures and nitrogen (N) levels were conducted to clarify the effects of Cd and Pb on the grain yield and quality of rice and their uptakes and distributions in the plants. The main results are as follows:1. The grain yeild of Yangdao 6 was increased at a low concentration of Cd, whereas it was reduced at a high concentration, when compared with that at the control (without Cd). The grain yields of Wuyunjing 7 and Yangjing 9538 were reduced with the increase in Cd concentrations. The yield of Yangdao 6 was reduced by 2.65% at the low concentration of Pb, and reduced by 3.92% at the high concentration. Pb treatments, either at a low or a high concentration, reduced the grain yields of Wuyunjing 7 and Yangjing 9538. Both Cd and Pb treatments reduced the breakdown value and increased the setback value in the starch-profile, suggesting that Cd and Pb make the poorer in the eating and tasting quality of rice. Cd and Pb were not distributed uniformly in each part of rice plants. The accumulation of Cd or Pb in plants was higher at high concentrations than at low concentrations, and that in roots>stems>leaves>panicles. Cd at a high concentration significantly increased Cd accumulation in each part of a grain. Pb at a high concentration significantly increased Pb concentration in grains and accumulation in husks of Yangdao 6, whereas it had no significant effect on those of Yangjing 9538.2. The grain yield was high under moderate dry-wet alternate irrigation (MD) than that under well watered (WW) or under severe dry-wet alternate irrigation (SD) when Cd or Pb was not added into the soil. The grain yield was significantly reduced under MD and SD when Cd or Pb was treated. Under both MD and SD, the Cd treatment increased the breakdown value and reduced the setback significantly. Pb treatment significantly increased the breakdown value of Yangjing 9538, but little affected the setback value, suggesting that both Cd and Pb improve the eating and tasting quality when dry-wet alternate irrigation was imposed. The concentration and accumulation of Cd and Pb in the plants were increased with the decrease of soil moisture, indicating that low soil moisture could enhance the uptake of Cd and Pb in plants. The dry-wet alternate irrigation reduced the accumulation of Cd in the husk and chaff, whereas increased Cd in the polished rice, indicating that low soil moisture enhances the translocation of Cd to kernels.3. Under the same heavy metal treatment, the grain yield was increased with the increase in N levels. Cd or Pb treatment reduced the yield when N level was the same. Under the Cd treatment, the breakdown value was reduced and the setback value was increased with the increase in N levels. Under the Pb treatment, the breakdown value was increased while the setback value eas reduced when MN was applied, and the result was reversed when HN was applied. The accumulations of Cd and Pb in plants were increased with the increase in N levels.4. Cd at a high concentration and Pb at both low and high concentrations induced the expression of catalase (CAT) isozymes in rice leaves. Under different treatments of soil moisture and N levels, Cd or Pb inhibited the expression of some isozymes, meanwhile enhanced the expression of some new isozymes, of superoxide dismutase (SOD), or peroxidase (POD) or CAT. The types and degrees of the isozymes inhibited or enhanced varied with the concentrations of Cd or Pb, soil moistures and N levels.更多还原