【作者】 刘华琳；

【导师】 董树亭； 张新荣；

【作者基本信息】 山东农业大学 ， 农业生态学， 2008， 博士

【摘要】 砷可通过水体-土壤-农作物进入食物链,这不仅影响作物生长发育,降低作物的产量和品质,还对人类健康构成巨大威胁。本文采用盆栽和室内砂培试验相结合的方法,研究了不同基因型玉米对砷污染的响应;探讨了砷作用对玉米产量、品质及生理生化的影响及解决途径。主要研究结果如下:1.砷胁迫下玉米基因型差异砷胁迫对不同基因型玉米生长发育影响显著,根长、株高、干物重降低,根条数增加。以生物量为指标,甜玉米和糯玉米不抗砷。不同基因型玉米对砷的吸收、积累能力差异显著,生物富集系数相差10.61倍,地下部砷的富集量相差16.35倍,转运系数相差21.13倍。以砷积累与转移为标准,筛选出SN2、KD8等饲用玉米对砷的抗性好于其它玉米品种。兼顾育种和环境治理多种因素,运用主成分分析,筛选出SN2、LX4等玉米品种相对抗砷。2.砷对产量的影响低浓度砷刺激玉米生长,籽粒产量增加;高浓度砷伤害玉米生长发育,产量降低。T2处理时,ZD958、JN218增产4.5%、3.2%;T4处理时,ZD958、JN218减产48.9%、39.1%。品种之间差异显著,JN218穗长、行粒数、穗粒数、千粒重的变动幅度均大于ZD958,即JN218对砷的敏感性大于ZD958。砷对产量构成因素的影响不同,对穗行数影响不大,对行粒数、穗长、千粒重影响较大。产量降低应是穗粒数减少和千粒重降低共同作用的结果。3.砷对品质的影响砷作用下,玉米籽粒蛋白质含量变化呈单峰曲线。T2处理,ZD958和JN218粗蛋白含量增加4.9%和2.5%;T4处理,ZD958、JN218粗蛋白含量下降22.3%和18%。随砷浓度增加,氨基酸总量变化呈单峰曲线。T2处理,ZD958和JZN218籽粒氨基酸总量最高,分别增加3.4%和4.7%;T4处理,籽粒氨基酸总量最低,两品种减少了21%。必需氨基酸与非必需氨基酸变化趋势一致,比例保持不变。其中Glu含量最高,除Cys、Met与砷浓度呈正相关外,其余氨基酸都负相关。砷影响淀粉的形成。随砷浓度的增加,淀粉含量先增加后降低。T2处理,淀粉含量最高,ZD958与JZN218淀粉含量增加4.8%和2.8%;T4处理,淀粉含量最低,比对照减少8%和10.8%。高浓度砷作用下,大粒径淀粉粒体积明显减少,小粒径淀粉粒体积增加。T4处理,ZD958大于14.9μm的淀粉颗粒体积降低了35.6%,JN218大于16.4μm的淀粉颗粒体积降低了26.4%。糊化特性与砷浓度之间存在显著的相关性。T4处理,ZD958、JN218的糊化温度低于对照,ZD958的峰值黏度低于对照。砷胁迫显著影响籽粒的糖代谢,总糖含量降低,Glc、Fru、Mal含量升高,Suc含量下降。ZD958总糖含量变化趋势是:T4＞CK＞T3,T4处理使总糖含量增加77.8%,T3处理使总糖减少7%。JN218的变化趋势是:T3＞T4＞CK,T3总糖含量增加38%,T4增加20%。砷胁迫下,玉米籽粒中Mn、Fe、K、Ca、Mg、S元素含量变化呈单峰曲线;砷元素含量与Se、B元素含量正相关;As元素含量与P元素含量负相关。砷胁迫下,籽粒大部分矿质元素之间呈极显著正相关。4.砷对生理特性的影响砷对玉米种子萌发、幼苗生长发育影响显著。种子发芽率、根长、苗高与砷浓度负相关,根数正相关。低浓度砷刺激玉米幼苗生长发育。高浓度砷使根系丛生,发黑,伸长受阻,根重量下降;叶片卷曲、失绿发黄;严重时不能开花结实,甚至死亡。砷在玉米体内的积累、迁移与砷浓度、生育时期和组织器官密切相关。不同生育时期,玉米对砷的吸收速率为:开花期＞成熟期＞拔节期。转运系数依次为:成熟期＞开花期＞拔节期,即玉米从地下部向地上部转运砷的能力随生育时期推进而加强。成熟期砷在玉米各组织器官的分布不均衡,依次为:根＞茎＞叶＞鞘＞籽粒＞其它(穗轴、苞叶、雄穗等);玉米植株砷含量的空间分布为:地下部＞下部＞中部＞上部。低浓度时,根茎结合部的砷浓度,与地中茎相近,与下部茎差异显著,说明根茎结合部具有拒砷能力。但范围有限,与砷浓度负相关,且存在品种间差异。砷在玉米体内可以发生形态转化,根、茎、叶、籽粒均有将无机砷转化为有机砷的能力,籽粒的转化效率最强,达60%以上,大大降低了砷毒害。砷胁迫对玉米的超微结构有影响。细胞核膜及线粒体膜系统解体,叶绿体基粒片层稀疏,出现大量的过氧化物体和黑色沉淀,玉米主要通过将砷分隔在液泡和细胞壁来减轻砷的毒害。砷胁迫使二维红外光谱图和荧光谱图发生显著变化。5.硒对砷胁迫具有调控作用硒有拮抗玉米砷毒害的作用,但有效量关系:即低浓度有拮抗砷的能力,表现为玉米幼苗主根长、株高、叶绿素含量等均增加,光合速率增加,最终产量增加、品质改善等,有效提高玉米中的蛋白质、脂肪、淀粉含量,并使淀粉颗粒变大,砷富集量明显降低。高浓度硒与砷发生协同作用,伤害玉米生长发育,使蛋白质、脂肪、淀粉含量明显降低。更多还原

【Abstract】 Arsenic can enter the food chain through water-soil-crops,which not only affects crop growth and development,reduces crop yield and quality,but also poses a tremendous threat to human health.In this dissertation,a combination of potted plants and greenhouse tests was used to study the different responses of genotypes’ maize to arsenic contamination;this dissertation also explored the effect of arsenic on maize production,quality and physiological and biochemical traits in order to find out the solution of arsenic pollution control.The results were as follows:1.Differenees of genotypes under arsenic stressArsenic stress significantly affected the growth and development of maize of different genotypes.Root length,plant height and dry weight decreased,and the number of the roots increased.Regarding biomass as a standard,sweet maize and sticky maize were of little anti-arsenic ability.There were significant differences in the absorption and accumulation of arsenic in maize of different genotypes.The concentration factor of the whole plant could reach up to 10.61 times and the concentration factor of root could reach up to 16.35 times while transportation coefficient would reach up to 21.13 times among different genotypes. Regarding accumulation and transportation of arsenic as a standard,we found out forage maize,such as SN2,KD8 was better resistant to arsenic than other genotypes.Taking various factors(breeding and environmental governance) into account and choosing principal component analysis,SN2,LX4 and some other varieties were proven to be as anti-arsenic genotypes.2.Effect of arsenic on yield of kernel At low concentrations of arsenic,the growth of maize enhanced and grain yield increased;at high concentrations of arsenic,the growth of maize was affected and yield decreased.At T2,the yield of ZD958,JN218 enjoyed an increase of 4.5%and 3.2%.At T4, the yield of ZD958,JN218 suffered a decrease of 48.85%and 39.13%.There were significant differences between two genotypes.The range of variation of ear length,the number of rows per ear,the number of kernels per row and 1000-kernel weight of JN218 was greater than that of ZD958 because JN218 was more sensitive to arsenic than ZD958.Arsenic had different impact on yield components:little impact on the number of rows per ear,greater impact on the number of kernels per row and weight of 1000 kernels.The decrease of grain yield should be deduced to the reducing of both the number of kemels per ear and weight of 1000 kernels.3.Effect of arsenic on quality in maizeUnder arsenic treatments,the content of grain protein was in a single peak curve.At T2 treatment,the increase of ZD958,JN218 were 4.9%and 2.5%respectively;at T4 treatment, the decrease of ZD958,JN218 were 22.3%and 18%respectively.With the increased concentration of arsenic,the content of grain amino acids was also in a single peak curve.At T2 treatment,the content of grain amino acids was the highest,an increase of 3.4%and 4.7%respectively;at T4 treatment,the content of grain amino acids was the lowest:the content of grain amino acids for two cultivars declined by 21%.The changes between essential amino acids and non-essential amino acids were the same and the ratio remained unchanged,with the highest content of Glu.With the increased concentration of arsenic,in addition to Cys,Met was positively correlated,the other amino acids had a negative correlation.Arsenic affected the formation of starch with the increased concentration of arsenic.At T2 treatment,the content of starch was the highest,an increase of 4.8%and 2.8%respectively; at T4 treatment,the content of starch was the lowest,a decrease of 8%and 10.8%respectively. Under high concentrations of arsenic,the volume of large size starch grains decreased significantly,while the volume of small size starch grains increased.At T4 treatment,the volume of starch grains which were more than 14.9μm decreased by 35.6%in ZD958;the volume of starch grains which were more than 16.4μm decreased by 26.4%in JN218.There was a significant correlation between the concentration of arsenic and pasting.The pasting temperature of T4 treatment was lower than that of CK in ZD958and JN218.The peak viscosity of ZD958 was significantly lower than that of CK.Arsenic stress affected sugar metabolism of grain significantly and reduced the content of total sugar.The content of Glc,Fru and Mal were increased,while the content of Suc were decreased.The turn of total sugar in ZD958 is:T4> CK> T3.At T4 treatment,total sugar content increased by 77.8%;while at T3,decreased by 7%.The turn of total sugar in JN218 was:T3> T4> CK.At T4 treatment,total sugar content increased by 38%,while T3 decreased by 20%.Under arsenic stress,the content of elements of maize grain,such as P,Mn,Fe,K,Ca, Mg,S was in a single peak.The content of As was relevant to that of Se,B;the content of As was negative to that of P.Under arsenic stress,most of mineral elements in grains were in significantly positive correlation.4.Effect of arsenic on the physiological characteristics of maizeArsenic affected seed germination,seedling growth and development significantly. Germination rate of seed,root length and plant height are the negative correlation to arsenic concentration,but the number of root is relevant.Low concentrations of arsenic stimulated the growth of maize seedlings,and high concentrations of arsenic decreased the growth of maize:,the root was black,its elongation was blocked and root weight dropped.Leaf curled, became less green and finally turned yellow.The plant was not able to blossom and fill,even turned out to suffer death.The accumulation and migration of arsenic is closely related to arsenic concentration, growth stages,tissues and organs.In different growth stages,the absorption rate of arsenic: bloom> mature> joint;transition coefficient:maturity> blossom > jointing.The transfer ability of arsenic from the underground to aboveground would promote and strengthen with growth stages.The distribution of arsenic in maturity is uneven in the tissues and organs, followed by:root> stem> leaf> sheath> grain> other(corncobs,bracteal,tassel,etc.);the spatial distribution of arsenic is:underground> lower> central> top.At low concentration,the arsenic concentration between root and stem was similar to the lower stem and significantly higher than upper stems,that is to say,this part has the ability to resist arsenic.But it had limited scope and had negative correlation to the arsenic concentration,and the existence of differences between the species.The change in arsenic valence can occur in the form of maize into the roots.Stems,leaves and seeds have the ability of changing inorganic arsenic into organic arsenic.The most conversion efficiention was grain which was more than 60%,thus greatly reduced the risk of arsenic poisoning.Arsenic stress affected ultra-structure.Cell membrane and mitochondrial membrane system collapsed and chloroplast sparse layer of particle was board,less levels,uneven distribution of a large number of peroxide and black precipitation.Arsenic would mainly be separated from the vacuole and the cell wall to reduce arsenic poisoning.As stress changed two-dimensional infrared spectrum of the fluorescence spectrum5.Selenium would regulate the arsenic stress.Selenium can play an antagonistic action to arsenic poisoning in maize.At the lower concentration,not only the main root length,plant height and chlorophyll content of maize seedlings increased,but also the photosynthetic rate and kernel yield increased and quality improved.Arsenic improved effectively the activity of POD and the content of protein,fat and starch increased.Starch particles were larger,arsenic concentration was significantly lower.At the higher concentration of selenium,it would increase the arsenic toxicity.更多还原