土培条件下东南景天对镉的耐性和富集特性的研究

[目的]探讨土培条件下东南景天矿山与非矿山生态型植物对Cd耐性和富集能力的差异。[方法]采用土培盆栽的方法,以向水稻土中加入不同量的镉作为处理,研究东南景天两种生态型植物在不同镉含量土壤中的生长反应以及体内镉含量与积累量变化。[结果]两种生态型植物对土壤中不同含量Cd的生长反应不同,矿山生态型对土壤Cd的耐受阈值为300 mg/kg,非矿山生态型为50 mg/kg。矿山生态型地上部最大Cd含量为893 mg/kg,根部最大Cd含量为344 mg/kg;而非矿山生态型地上部和根部最大Cd含量分别为124和212 mg/kg。矿山生态型地上部Cd含量大于根部Cd含量,而非矿山生态型根部Cd含量大于地上部。矿山生态型地上部Cd积累量最大值为151.67μg/株;而非矿山生态型为11.99μg/株。两种生态型植物相比较,在相同Cd处理水平下,矿山生态型地上部Cd含量和Cd积累量均显著高于非矿山生态型。[结论]矿山生态型东南景天对土壤Cd的耐受和富集能力显著大于非矿山生态型。从植物对土壤镉的耐性、地上部与根部Cd含量及其比值来看,矿山生态型东南景天是一种Cd超积累植物。     

耐Cd细菌的筛选及富集作用研究

筛选和分离获得了1株耐受Cd2+400 mg/L的细菌。经形态学观察、生理生化鉴定1、6S rDNA序列同源性比对,初步鉴定该菌株为阴沟肠杆菌(Enterobacter cloacae)。质粒消除实验结果初步判定该菌株的耐Cd特性与质粒编码无关。透射电镜观察结果显示:经Cd处理后菌体呈现形态学变化和胞外Cd沉淀反应。该菌株对Cd的富集量达到(54.01±3.21)mg/g。     

复合抗旱剂配方筛选初步研究

为了提高作物的抗旱能力和产量,进行了小麦复合抗旱剂配方筛选研究,以‘晋麦47号’小麦为材料,通过种子发芽势、发芽率、干物质、叶绿素荧光参数和产量等指标,对自研的16个配方制剂在干旱胁迫下进行了种子发芽、幼苗生长和抽穗期3个阶段的筛选。结果表明,Kh-13和Kh-1 2个配方效果较好,能促进种子萌发,利于苗齐苗壮,促进幼苗生长发育,增加干物质积累,提高个体质量,保持叶片相对含水率,促进光合作用,增强抗逆能力,在抽穗期前后喷施能促进幼穗发育,提高小麦穗粒数,增加产量。Kh-13和Kh-1处理的种子发芽势显著分别提高了2.00倍和1.66倍;发芽率显著分别提高了50%和50%;萌芽期抗旱性两者均达极强抗旱性标准;茎叶干物质显著分别增加了12.33%和11.42%;根干重显著分别增加了19.13%和13.00%;叶片相对含水率分别提高了23.53%和37.78%;穗粒数显著分别提高了22.36%和17.30%;产量显著分别增加了38.48%和20.78%。     

耐大豆疫霉根腐病QTL定位的研究

利用1200个RAPD随机引物和341对SSR引物对Conrad×OX760的重组自交系(RIL)F2:6群体的耐大豆疫霉根腐病基因进行QTL定位。试验设两个地点、两个年限,在MLG D1b+W和MLG M连锁群上检测到3个QTL,即QP-1(OPL18-800bp)、QP-2(OPN03-600bp)和QP-3(Satt536和Satt463)。每个QTL对病害损失率的贡献率从13.34%到22.31%不等。QP-1和QP-2经多重QTL分析(Mapmaker/QTL1.1)对两年(2000年和2001年)两点(Wood-slee和Werver)平均病害损失率的贡献率合计达44.5%,QP-3对2001年Woodslee试验点的病害损失率的贡献率为15.2%,QP-1对2000年Woodslee试验点的病害损失率的贡献率为21.55%,对2000年Wever试验点的病害损失率的贡献率16.71%,及对两年两点平均病害损失率的贡献率为22.31%。在大多数生态环境下能稳定的、再次被检测出的QTL,可以作为育种工作中的重点选择指标,用以指导耐大豆疫霉根腐病品种的分子辅助选育。     

铝胁迫对花生不同基因型生长发育的影响

盆栽花生铝胁迫试验表明,铝对花生形态发育和产量性状均有较大的影响,花生不同基因型耐铝毒害具显著差异。根系性状是评价花生受害程度和耐铝毒潜能的重要指标。高产和低产材料中都存在耐铝毒基因型。     

小麦转录因子基因TaNF-YB2;1表达特征及遗传转化对植株抵御干旱和盐分逆境能力的影响

NF-YB型转录因子在介导植物抵御非生物逆境中发挥着重要作用。为揭示小麦该家族成员Ta NF-YB2;1在干旱和盐分逆境下的表达特征及超表达Ta NF-YB2;1对植株抵御上述逆境能力的影响。利用半定量RT-PCR技术,研究Ta NF-YB2;1的表达特征,采用农杆菌介导的遗传转化技术,建立了超表达Ta NF-YB2;1的转基因烟草植株。结果表明,Ta NF-YB2;1 c DNA全长序列为958 bp,编码163个氨基酸残基。在24 h PEG模拟干旱和盐分处理条件下,Ta NF-YB2;1的转录本数量明显上调。正常培养下,与野生型植株相比,转基因植株的生长和干物质积累量未发生改变;但在干旱和盐分处理下,转基因株系植株的生长较野生型植株明显改善,表现为植株个体体积增大,单株干物质积累量增多。因此,Ta NF-YB2;1的表达受到干旱和盐分逆境的明显诱导,通过对干旱和盐分逆境应答,该基因在介导植株抵御上述环境逆境中发挥着重要功能。     

不同南瓜品种种子发芽耐盐性的研究

以中国南瓜、西洋南瓜、福瓜3个南瓜品种种子为试验材料，进行种子发芽耐盐性研究，测其种子发芽率、发芽指数、活力指数、苗长以及POD比活力，比较这些指标间的差异显著性，评价不同品种间发芽耐盐性的差别。结果表明：中国南瓜的发芽耐盐性最强，其次为福瓜，西洋南瓜最弱。     

Bacterial salt tolerance is unrelated to soil salinity across an arid agroecosystem salinity gradient

In arid and semi-arid ecosystems, salinization is a major threat to the productivity of agricultural land. While the influence of other physical and chemical environmental factors on decomposer microorganisms have been intensively studied in soil, the influence of salinity has been less exhaustively assessed. We investigated the influence of soil salinity on soil bacterial communities in soils covering a range of salt levels. We assessed tolerance of the bacterial communities from Libyan agricultural soils forming a salinity gradient to salt (NaCl), by extracting bacterial communities and instantaneously monitoring the concentration-response to added NaCl with the Leucine incorporation technique for bacterial growth. To maximise our ability to detect differences in bacterial salt tolerance between the soils, we also repeated the assessment of bacterial growth tolerance after one month incubation with 1 or 2% added organic matter additions to stimulate microbial growth levels. We could establish clear concentration-response relationships between bacterial growth and soil salinity, demonstrating an accurate assessment of bacterial tolerance. The in situ soil salinity in the studied soils ranged between 0.64 and 2.73 mM Na (electrical conductivities of 0.74-4.12 mS cm⁻¹; cation exchange capacities of 20-37 mmol_c kg⁻¹) and the bacterial tolerance indicated by the concentration inhibiting 50% of the bacterial growth (EC₅₀) varied between 30 and 100 mM Na or between electrical conductivities of 3.0 and 10.7 mS cm⁻¹. There was no relationship between in situ soil salinity and the salt tolerance of the soil bacterial communities. Our results suggest that soil salinity was not a decisive factor for bacterial growth, and thus for structuring the decomposer community, in the studied soils.     

Detection of tolerance of barley cultivars to infection by powdery mildew (Erysiphe graminis f.sp. hordei)

Summary Barley genotypes representing a wide range of resistance expressions and origins, from major resistance genes in modern cultivars to field resistances in landraces, were assessed for tolerance to disease under glasshouse and field conditions. A few genotypes were picked out as showing less yield loss than would be expected from the level of mildew infection. Genotypes showing more than the expected yield loss were also found. The potential use of tolerance as a breeding character is discussed.     

不同品种对水稻铅汞耐性和富集能力的影响

选取2种类型水稻土(黄泥土和红泥土)和9个水稻品种,通过温室盆栽试验,研究Pb(250 mg/kg)、Hg(0.6 mg/kg)污染条件下,水稻品种对水稻Pb、Hg耐性和富集能力的影响。结果表明,Pb污染处理显著降低了水稻产量,在红泥土和黄泥土中,水稻产量的降低幅度分别为3.6%~29.8%和2.3%~16.9%;Hg污染处理下,水稻产量略有下降,但差异不显著。不同品种水稻对Pb、Hg污染的耐性和富集能力差异显著。在Pb污染处理下,宁粳1号产量降幅较小,耐性较高;天协6号产量降幅较大,耐性较低;在Hg污染处理下,宁粳1号耐性较高,浙1500耐性较低。在2种类型水稻土中,特三矮2号稻米Pb的富集系数较高,对Pb污染较敏感;浙1500稻米Hg的富集系数较高,对Hg污染较敏感;宁粳1号稻米Pb、Hg的富集系数均较低,对Pb、Hg污染均不敏感。水稻品种、土壤类型和污染类型对水稻Pb、Hg耐性的影响不同,3个因子的相对贡献率分别为36.5%、18.3%和27.1%。