耐盐水稻种质资源的筛选

用0.8% NaCl溶液和国际水稻所水稻耐盐性9级评价方法对前人选留的38份水稻耐盐种质资源(用0.5%NaCl盐土筛选)进行了重复筛选,以期获得极端耐盐水稻种质资源.同时研究了不同盐浓度对水稻发芽率的影响.结果表明:高浓度盐溶液显著抑制水稻种子的发芽率,但品种间有较大差异;筛选出苗期极端耐盐品种6份,其中1级1份,2级4份,3级1份;极端耐盐水稻品种苗高的增长受高浓度盐溶液抑制,但品种间差异不显著;而盐溶液对极端耐盐水稻品种出叶速率的影响因品种而异.     

盐胁迫下不同来源粳稻选育品种的主要农艺性状鉴定分析

以选自30个国家的402份粳稻选育品种作为试验材料,分析了自然条件和盐胁迫下不同来源粳稻选育品种主要农艺性状的表型差异和聚类特点。结果表明,盐胁迫下各个国家品种的主要农艺性状有明显的差异,主要表现在抽穗期明显推迟,秆长和穗长明显缩短,穗粒数和有效穗数明显减少,结实率和千粒重明显降低。在盐胁迫下共筛选出了18份具有较强的耐盐性的材料。对主要农艺性状和聚类结果的分析表明,各个国家间粳稻选育品种耐盐性和聚类结果与各国家所处地理位置、纬度和气候条件有一定的相关性。     

实时荧光定量PCR检测RSV胁迫下抗病、感病水稻中与脱落酸相关基因的差异表达

采用实时荧光定量PCR方法测定了水稻条纹病毒(Rice stripe virus,RSV)胁迫下抗性不同品种水稻中与脱落酸相关基因的mRNA转录水平变化.结果表明:感病品种武育梗3号中WGPI、OsGASA2、Polcalcin、OsCBIA、Myb和OsCIPK15基因表达水平均上调,上调比率分别为4.96、5.17、2.01、5.17、12.04和7.84.而抗病品系KT 95-418中,OsGASA2和OsCIPK15基因表达水平下调,下调比率分别为1/5.40和1/2.08;Polcalcin和Myb基因表达水平上调,上调比率分别为4.20和3.86;WGPI和OsCBIA表达量变化不明显.这些结果表明,RSV胁迫能诱导脱落酸相关基因表达量的变化,并且在抗病、感病水稻品种中的表达特征不同,从而提示植物激素脱落酸可能调控了RSV胁迫条件下相关基因的表达.     

Establishment of Salt Stress Tolerant Rice Plants Through Step Up NaCl Treatment In Vitro

Establishment of salt tolerant rice plants was examined by single step or step up NaCl treatments of shoot bud clumps in vitro, and variation among in vitro salt tolerant plants were examined by rapid amplified polymorphic DNA (RAPD). Shoot bud clumps were necrotic, stubbed or dead when subjected to single step treatment with 1.5 or 2.0 % NaCl. Conversely all the clumps could grow vigorously when subjected to step up salt treatment with 0.5, 1.0, 1.5 and 2.0 % NaCl at 3 week intervals and 2 % NaCl tolerant plants were established. RAPD revealed shoot bud clumps with and without different NaCl treatments, seedlings from field and grown in vitro, and regenerants from callus were genetically close to one another. Conversely, callus cultures were genetically isolated. Growth under different salt stress conditions was not correlated with the genetic variation, suggesting that 2.0 % NaCl tolerant plants might not result from genetic mutation but were due to adaptation of plants by step up NaCl treatment in vitro.     

Molecular Biological Identification of a Rice Salt Tolerant Line

A rice salt tolerant line No.170 was obtained from EMS treated anther culture of japonica variety and selected under salinity stress. The salt tolerance trait has been stably inherited through nine generations. In order to characterize this mutant line in molecular biological respects, 130 RFLP genetic markers along 12 pairs of chromosomes based on McCouch’s. rice RFLP linkage map were used to assay polymorphism between the mutant line and its original variety, was shown that allelic differences were found at two linked loci RG711 and RG4 on chromosome 7. Besides, proteins of roots and leaves between the mutant and the control plants were compared by means of two dimensional polyacrylamide gel electrophoresis. The comparison showed that some new proteins appeared in the salt tolerant plant under salinity-stress condition, which might be produced by salt inducible genes.     

水稻盐胁迫相关内含子microRNA的表达及其生物发生机制

内含子microRNA是一类位于编码基因内含子区域的非编码小RNA。目前,动物内含子microRNA研究报道较多,而关于植物体内含子microRNA的功能及其生物发生机制报道较少。本研究通过高通量测序技术,结合生物信息学方法,发现在盐胁迫条件下水稻幼苗中共85个内含子microRNAs表达,其中差异表达的有24个。预测到的51个靶基因的功能分析,主要涉及抗氧化途径、植物激素信号转导途径及功能基因表达调控途径。此外,根据宿主基因的表达情况推测,共30个内含子microRNAs具有独立表达的功能。通过分析内含子microRNA前体DNA片段上游1 kb序列中的启动子核心元件,初步验证其具有独立表达的能力。因此,推测水稻幼苗在盐胁迫条件下,部分内含子microRNA独立于宿主基因表达,并参与水稻盐胁迫下的自我防御机制。     

He-Ne激光对盐胁迫下水稻幼苗抗氧化活性的影响

为减轻盐胁迫对植物造成的伤害,本研究采用He-Ne激光对盐胁迫下的水稻进行辐照处理,选用水稻9311作为对照、耐盐海稻86作为研究对象,以0.5%的氯化钠进行盐胁迫,He-Ne激光(辐照计量5 m W·mm-2,波长632.8 nm)进行照射。设置了对照组(CK),盐胁迫组、盐胁迫和激光复合处理组(分别为L、BL组),进行了水稻抗氧化活性方面的研究。结果表明:与对照组(CK)比较,He-Ne激光对水稻的盐胁迫有一定的缓解作用,其中对水稻9311的作用最明显,表现为激光处理提高了水稻幼苗中过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性和减缓了丙二醛(MDA)含量的增速;同时也说明新选育的海稻86耐盐性高于水稻9311。因此,一定剂量的He-Ne激光可以提高了水稻的耐盐性,这为抗盐胁迫及耐盐植物的育种提供了途径和理论依据。     

不同耐盐性花生品种对NaCl胁迫的光合和抗逆生理响应特征

以较耐盐花生品种‘花育25’、‘鲁花12’和盐敏感品种‘海花1’、‘花育20’为材料,采用盆栽试验,设置0、1.0、2.0、3.0 g/kg土壤NaCl胁迫浓度梯度,测定其净光合速率、表观量子效率、气孔导度等光合特性,以及抗氧化酶活性和渗透调节物质含量等指标,明确NaCl胁迫条件下不同耐盐性花生品种光合和生理生化特性的适应特征。结果表明：(1)NaCl胁迫明显抑制各品种花生叶片光合作用,净光合速率随盐胁迫浓度的升高呈明显降低的趋势。(2)各品种花生叶片净光合速率均先随光照强度的增强而升高,当光强达到一定数值时趋于平稳;光补偿点和光饱点因品种和盐胁迫浓度差异较大,较高的盐胁迫浓度使叶片光补偿点升高,盐敏感品种的光饱和点降低。(3)盐胁迫条件下,各品种叶片表观量子效率和最大净光合速率均随盐胁迫强度的增加呈显著降低趋势,盐敏感品种利用弱光的能力在低盐胁迫下强于耐盐品种,其最大净光合速率在较高盐胁迫浓度(3.0 g/kg)下明显低于耐盐品种,但两类品种的叶片表观量子效率降幅相近(78.65%~88.00%)。(4)在NaCl胁迫下,耐盐品种叶片自由水含量显著高于盐敏感品种;在2.0～3.0 g/kg NaCl胁迫下,耐盐品种叶片SOD、CAT、POD活性和MDA含量的升降幅度均低于盐敏感品种;耐盐品种在NaCl浓度低于2.0 g/kg时的抗氧化能力明显高于盐敏感品种。研究发现,盐胁迫下花生品种抗盐耐逆的主要生理响应特征是提高光补偿点和最大净光合速率,增强叶片持水能力和物质代谢能力,以及提升抗氧化和渗透调节能力。     

盐胁迫下不同水稻种质形态指标与耐盐性的相关分析

选用中国、韩国和国际水稻研究所(IRRI)不同耐盐能力的籼、粳、爪哇稻16份为材料进行芽期和苗期试验。随着NaCl浓度增加,种子开始发芽的时间推迟、发芽过程延长、发芽率降低;品种的发芽率能有效地指示其芽期耐盐能力。NaCl浓度对许多苗期形态指标有显影响,其中叶片盐害指数能反映品种的苗期耐盐能力;随着NaCl处理时间的增长,叶片盐害指数与NaCl浓度间的相关性越来越大。同一品种在芽期的耐盐能力和苗期表现不一致,两的相关系数很低。     

NaCl胁迫下不同番茄品种萌芽期耐盐性评价

为了对不同品种番茄的耐盐性进行筛选,对39个番茄品种种子萌发期的耐盐性进行鉴定,对番茄种子发芽率、发芽势、发芽指数、胚根度下胚轴长度等耐盐性指标进行分析,并分析了各番茄品种萌芽期的鲜重及干重百分率等.39个番茄品种中,表现最好的是LA2711和贵妃,在100 mmol L-1的NaCl盐溶液胁迫下两者的相对发芽率、发芽势、发芽指数、胚根以及下胚轴的生长速度等各项生理指标都明显强于其他的番茄品种,物质积累量较其他品种也有较突出的表现,番茄大红合作903、湘蔬一号(早抗一号)、红玉、东农709、中杂102、中杂8号、中粉王98-20、强丰、丽春、羞女、绿金蓝樱桃番茄为较耐盐的番茄品种.湘蔬六号(C90-6)、冀番系列番茄、金棚三号、早丰番茄、西安早红、佳粉15号、红秀霞光(东农711)、月光(东农708)、红霞、欧宝(美国红)、中杂105、日本樱桃番茄、粉红帅一号、白果强丰、东方红一号、毛粉802为耐盐力弱的番茄品种,其它品种为最不耐盐的品种.不同番茄品种之间的耐盐性差异较大,在番茄种子萌芽期可对其耐盐性进行快速鉴定.     

mRNA差别显示技术研究进展及其在水稻中的应用

随着基因组计划的顺利实施,大量的生物信息被解析,分离和鉴定差异表达基因已成为分子生物学研究的热点.mRNA差别显示技术(DDRT-PCR)是目前有效筛选、分离差异表达基因的方法之一.就DDRT-PCR的基本原理、存在的问题及相应的改进方法作了简要概述.阐明了该技术在水稻生长发育、杂种优势、抗逆性基因研究中的应用、取得的成绩,最后对该技术在水稻突变体及抗药性上的应用前景做了有益探讨.     

Differential Responses of Two Wheat Varieties Differing in Salt Tolerance to the Combined Stress of Mn and Salinity

The effect of Mn and NaCl on growth, mineral nutrients and antioxidative enzymes in two tetroploid wheat genotypes differing in salt tolerance was investigated in this study. 100 mM NaCl and Mn stress significantly inhibited plant growth, photosynthesis and Ca uptake, while stimulated ROS accumulation, MDA and proline content in wheat plants, Mn stress also increased SOD, APX, GR and DHAR activities. Durum wheat (AS780) was less affected by 100 mM NaCl and Mn stress than emmer wheat (AS847) due to more proline production, higher antioxidative enzymes activities and less-affected mineral nutrients. Application of 10 mM NaCl to Mn-stressed durum wheat alleviated Mn-induced damage by reducing Mn accumulation and translocation, while promoting proline accumulation and SOD, APX and GR activities. Irrespective of NaCl level, the combined stress of Mn and NaCl caused more severe oxidative stress, result in further reduction of photosynthetic rate and plant growth in emmer wheat as compared to Mn stress alone. The additively negative effects of NaCl and Mn stress on growth of emmer wheat results from reduced SOD and APX activities as well as Ca, Cu and Fe accumulation in both shoots and roots. These results suggest that salt-tolerant durum wheat is superior to emmer in adapting to Mn stress and the combined stress of salinity and Mn.

     

Comparison of Membrane Pluidity of Seedling Mitochondria of Chilling Sensitive and Chilling Tolerant Rice

The membrane fluidity of seedling mitochondria of chilling-sensitive rice and that of chilling-tolerant rice were compared by using spin labeled stearic acid: 5, 12 16-NS and fluorescent probe DPH. From the ESR spectra using 5-NS as a spin labeled probe it clearly showed that the calculated order parameter (S) of seedling mitochondria of chilling-sensitive rice Qiu Guang was obviously higher than that of chilling-resistant rice Ji Geng 44. Similar results were obtained when seedling'mitochondria of another species of chilling sensitive Zao Jin were compared with those of chilling tolerant rice Ji Geng 60. Moreover, the difference of order parameters between Ji Geng 44 and Ji Geng 60 was quite small, but both of them are obviously lower than those of chilling-sensitive rice Qiu Guang or Zao Jin. The results using spin labeled probe 12-NS, 16-NS clearly showed that the relative correlation times (τc) of seedling mitochondria of chilling-sensitive rice Qiu Guang or Zao Jin was markedly higher than that of the chilling tolerant rice Ji Geng 44 or Ji Geng 60. A comparison of membrane fluidity of seedling mitochondria of chilling-sensitive and chilling-resistant rice using fluorescent probe DPH was also carried out. Similar results were obtained and showed that the fluidity of mitochondrial membrane of chilling resistant rice seedling was obviously higher than that of the chilling-sensitive ones. Thus, it seemed that the fluidity of mitochondrial membrane might be used as a biophysical test for screening chilling tolerance of rice at seedling stage.     

盐胁迫下镧对水稻幼苗生长的保护效应

通过液培实验,研究水稻幼苗在盐胁迫下,镧对水稻幼苗的保护作用。结果表明：水稻幼苗植株在≤1．5％的盐浓度的盐胁迫下,10mg·L^-1镧能提高幼苗植株超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性;降低幼苗植株脂质过氧化产物丙二醛（MDA）的含量和脯氨酸（Pro）的含量;减小质膜透性;提高叶片叶绿素含量和叶绿素a／b的比值;增强根系的活力,进而促进水稻幼苗的生长。10mg·L^-1镧对盐胁迫的缓解作用与盐浓度有关,随着盐浓度增大,镧的缓解作用将逐渐消失。分析表明,在≤1．0％和≥0．5％的盐浓度胁迫下,镧对水稻幼苗的生长存在更有效的防御机制,能够促进水稻幼苗的生长代谢。     

差异显示技术研究NaHCO3 胁迫下星星草基因表达

用差异显示技术研究NaHCO3胁迫下星星草(Puccinellia tenuiflora)基因的表达。经Reverse Northern检测, 获得了7个差异表达的基因片段。其中, 6个为胁迫后诱导表达, 1个为胁迫后抑制表达。序列同源性分析表明, 胁迫诱导表达的6个基因片段中, 1个与钙依赖性蛋白激酶(CDPKs)基因同源性较高,其余5个可能为新序列, 胁迫后抑制表达的基因片段与假定的adaptor蛋白基因同源性较高。本研究为进一步研究星星草的抗盐机理奠定了基础。     

差异显示技术研究NaHCO3胁迫下星星草基因表达

用差异显示技术研究NaHCO3胁迫下星星草(Puccinellia tenuiflora)基因的表达.经Reverse Northern检测,获得了7个差异表达的基因片段.其中,6个为胁迫后诱导表达,1个为胁迫后抑制表达.序列同源性分析表明,胁迫诱导表达的6个基因片段中,1个与钙依赖性蛋白激酶(CDPKs)基因同源性较高,其余5个可能为新序列,胁迫后抑制表达的基因片段与假定的adaptor蛋白基因同源性较高.本研究为进一步研究星星草的抗盐机理奠定了基础.     

差异显示技术研究NaHCO_3胁迫下星星草基因表达

用差异显示技术研究NaHCO3胁迫下星星草(Puccinelliatenuiflora)基因的表达。经ReverseNorth-ern检测,获得了7个差异表达的基因片段。其中,6个为胁迫后诱导表达,1个为胁迫后抑制表达。序列同源性分析表明,胁迫诱导表达的6个基因片段中,1个与钙依赖性蛋白激酶(CDPKs)基因同源性较高,其余5个可能为新序列,胁迫后抑制表达的基因片段与假定的adaptor蛋白基因同源性较高。本研究为进一步研究星星草的抗盐机理奠定了基础。     

Linkage Disequilibrium in Salt Tolerant Genotypes of Rice (Oryza sativa L)

Genome wide linkage disequilibrium (LD) was investigated in a set of 32 genotypes representing salt tolerant improved varieties and landraces and six salt sensitive genotypes of rice with 64 microsatellite markers to identify the genomic regions that are associated with salt tolerance in rice. Out of 64 markers analyzed, 36% SSR pairs exhibited significant LD at 0.05. A few regions were identified as targets of selection in 10 chromosomes with high r ² values. The model-based groups from Bayesian clustering analysis are largely consistent with known pedigrees of the lines. The increased percentage of association of SSR loci in the improved varieties indicated the role of selection in linkage disequilibrium especially for salt tolerance. LD was extended as far as 100 cM in the present study. Most of the markers (43.8%) with significant LD values were observed in the genomic regions of reported QTL for salt tolerance in rice.     

不同低温胁迫下粳稻耐冷种质的孕穗期耐冷性比较

为粳稻孕穗期耐冷标准品种的建立和耐冷遗传育种研究提供优异基因资源,利用人工低温气候室,采用15℃、17℃、19℃3种胁迫温度,4d和6d两种胁迫时间,3×2交互式设计的方法,对来自黑龙江、吉林、辽宁和云南的12份粳稻种质进行了孕穗期耐冷性强度的研究。结果表明,随着低温胁迫的增强,各水稻品种的平均空壳率都随之增加;在15℃/6d胁迫下,供试品种平均空壳率的方差和变异系数达到最大,该胁迫强度可被选用于孕穗期强耐冷种质的筛选。依据15℃/6d胁迫下供试品种平均空壳率的方差分析及多重比较结果,空育131和龙稻3号具有极强的孕穗期耐冷性。不同地区可根据参试品种在本试验中的耐冷表现,并结合当地水稻种植区的光温条件选择相应的耐冷标准品种。