高粱种质材料幼苗期耐盐碱性评价

采用Hoagland营养液砂培法,以NaCl和Na2CO3组成的混合盐碱对高粱幼苗进行胁迫处理,建立高粱幼苗期耐盐碱评价方法,并评价了66份高粱种质材料的耐盐碱性.结果表明:盐浓度在8.0～12.5 g·L-1时,高粱耐盐碱品种‘TS-185’与盐碱敏感品种‘Tx-622B’在幼苗期的耐盐碱性差异明显,表明进行高粱幼苗期耐盐碱性评价时适宜的盐浓度范围为8.0～12.5 g· L-1.在10.0和12.5 g·L-12个盐浓度下,66份高粱种质材料的相对存活率、相对地上部鲜质量和相对株高的差异均达显著水平,表明不同品种的耐盐碱性不同.其中,‘三尺三’为高度耐盐碱品种,‘MN-2735’等16个品种为耐盐碱品种,‘EARLY HONEY’等32个品种为中等耐盐碱品种,‘Tx-622B’等16个品种为盐碱敏感品种,‘MN-4588’为高度盐碱敏感品种.苏丹草类型高粱一般具有较高的耐盐碱性,而保持系对盐碱较为敏感.     

Haplotype analysis of QTLs attributed to salinity tolerance in wheat (Triticum aestivum)

A diverse collection of wheat germplasm, consisting of 100 bread wheat lines with varying levels of salinity tolerance were evaluated based on incomplete block design (lattice) with two replications in field conditions. Plant material was screened for salinity tolerance under normal and saline field conditions. Subsequently in order to assess the haplotype diversity of QTLs attributed to salinity tolerance in wheat (Triticum aestivum), a collection of 30 extremes tolerant and sensitive genotypes among them were selected for genotyping on the basis of morphological, physiological and phenological traits. Genotyping was done using microsatellite markers which had been detected as the flanking regions of large effect QTLs attributed to salinity tolerance on chromosomes 2A, 4D and 3B. Combined analysis of saline and normal conditions revealed that genotypes showed highly significant responses. Association analysis of SSR markers with traits, showed markers Xcfa2121b, Xgwm10 and Xgwm296 on chromosome 2A and markers Xgwm194 and xgwm624 for chromosome 4D, had significant association with most of measured traits. Haplotype diversity analysis showed markers Xgwm10, Xgwm445, Xbarc353.2, Xgwm312, Xgwm515 and Xwmc296 on chromosome 2A as well as markers Xwmc326 and Xgwm345, Xbarc48.4 on chromosomes 3B and 4D were identified as the best markers attributed to salinity tolerance and they can be informative markers for improvement of salinity tolerance through marker-assisted selection programs.     

Screening of local/exotic accessions of lentil (Lens culinaris Medic.) for salt tolerance at two growth stages

Screening of available local/exotic germplasm of a crop for salinity tolerance is of considerable value for the economic utilization of salt-affected soils of arid and semi-arid regions.The response of 133 lentil (Lens culinaris Medic.) accessions, to NaCl at the germination and seedling stage, was examined. A great amount of variation of NaCl tolerance in lentil was observed at both the growth stages but, in general, there was no consistent relationship between tolerance assessed at germination or at the seedling stage. In the NaCl treatment five accessions, ILL 5845, ILL 6451, ILL 6788, ILL 6793, and ILL 6796 produced significantly greater fresh and dry plant biomass in both absolute and relative terms than the others, but these accessions performed as well as other intermediate or low biomass producing accessions in total germination percentage and rate of germination. In view of the existence of the great amount of variability of tolerance to NaCl among lentil varieties improvement in NaCl tolerance in this species is possible.     

Analysis of genomic region spanning <Emphasis Type="Italic">Saltol</Emphasis> using SSR markers in rice genotypes showing differential seedlings stage salt tolerance

Micro satellite markers located in the Saltol QTL of 5 Mb region (10.4–15.6 Mb) in chromosome 1 confering seedling stage salt tolerance were used to evaluate 94 rice genotypes. Out of 21, eight SSR markers at Saltol region of Chromosome were found polymorphic. Based on the phenotypic screening, 94 genotypes were grouped as highly tolerant (20), tolerant (18) moderately tolerant (32), sensitive (19) and highly sensitive (5). The marker RM3412 appears to be diagnostic of salinity tolerance and associate to salinity tolerance at seedling stage as it is closely linked to SKC gene. Based on Saltol markers study, CSR 31, CSR 38, CSR 41, CSR 32, Wild 11, CSR 18, Azgo, Pant Dhan 4, Trichi 1, CSR 10 and IR64426-4B-11-1 could not be identified as tolerant genotypes though had expressed tolerant to highly tolerant phenotype to salinity stress at seedling stage, suggesting that QTLs other than Saltol might be controlling their salinity tolerance. It is suggested that these genotypes could serve as potentially novel germplasm and could be exploited for the development of new breeding lines with high level of salinity tolerance by pyramiding of the Saltol and other QTLs.     

Emergence and seedling growth of soybean cultivars and maturity groups under salinity

Soybean is an important agricultural crop and has, among its genotypes, a relatively wide variation in salt tolerance. As measured by vegetative growth and yield, however, the achievement or failure of a high emergence ratio and seedling establishment in saline soils can have significant economic implications in areas where soil salinity is a potential problem for soybean. This study was conducted to determine the effects of salinity, variety and maturation rate on soybean emergence and seedling growth. Included in the study were the variety ‘Manokin’; four near-isogenic sibling lines of the variety ‘Lee’ belonging to maturity groups IV, V, VI and VII; and the variety ‘Essex’ and two of its near-isogenic related lines representing maturity groups V, VI and VII, respectively. Field plots were salinized with sodium chloride and calcium chloride salts prior to planting. The soybeans were irrigated with furrow irrigation which redistributed the salts towards the tail ends of the field plots. Elevated soil salinity near the tail ends of the field significantly reduced soybean emergence rate, shoot height and root length. No significant reduction was found for emergence or seedling growth of variety ‘Manokin’ when the electrical conductivity of soil solution extract (ECe) was less than 3 dS m⁻¹. Soybean emergence and seedling growth was significantly reduced when soil ECe reached about 11 dS m⁻¹. Maturity groups V and VII of variety ‘Lee’ or V and VI of ‘Essex’ appeared to be more sensitive to salinity stress than other maturity groups. Salt tolerance of different genotypes and maturity groups should be considered, among other limiting factors, in minimizing salinity effects on soybean growth. This revised version was published online in June 2006 with corrections to the Cover Date.     

The response of lucerne (Medicago sativa L.) to sodium sulphate and chloride salinity

Sodium and sulphate-dominated salinity is a serious environmental problem occurring in soils and groundwater in many parts of the world. The effect of Na2SO4 and NaCl, at electrical conductivity levels ranging from 2 to 17 dS m-1, on the growth and tissue ion concentrations of 16 lines of lucerne (Medicago sativa L.) was examined in the greenhouse over a 2 month period. Averaged across all lines, plants grown at 17 dS m-1 produced 66% of the dry matter of plants grown at 2 dS m-1. However there were significant differences among lines in relative salt tolerance (as defined by the slope of the reduction in dry matter) versus electrical conductivity. Dry matter production was negatively correlated with shoot concentrations of Na+, Cl- and S2- and generally lines that were more tolerant to salinity had lower concentrations of those ions in the shoots. We conclude that lucerne is moderately tolerant to Na2SO4 -predominated salinity, and that the degree of intraspecific variation that exists within this species will allow more tolerant lines to be selected for establishment in conditions where sulphate salinity is a problem.Collaborator     

Molecular profiling in relation to drought tolerance in advance breeding lines of rice using microsatellite markers

Using agro-morphological characters and microsatellite markers, advance breeding lines of rice were discriminated for their ability to tolerate drought stress at reproductive stage. Experimental materials consisting of 17 advance breeding lines and a check were evaluated in randomized block design with three replications under irrigated condition and drought condition created under rainout shelter during three consecutive years. An analysis of variance revealed significant differences among the genotypes for all the ten agro-morphological characters evaluated under both the conditions across the years. Principal component analysis showed the relative importance of root length, number of tillers per plant, number of grains per panicle, harvest index and grain yield per plant among agro-morphological characters and stress tolerance level, stress susceptibility index, stress tolerance index and drought tolerance efficiency among drought tolerance indices as the important classification variables. Relative mean performance in respect of grain yield as well as drought tolerance indices reflected remarkably greater degree of drought tolerance in 11 advance breeding lines and the check, discriminating them from remaining entries under evaluation. Utilizing a panel of 32 microsatellite primers, selective amplification of targeted genomic regions revealed that the primers RM 72, RM 163, RM 212, RM 225, RM 231, RM 302, RM 327, RM 518, RM 521, RM 555, RM 1349, RM 3549 and RM 5443 were highly informative with greater gene diversity and discrimination ability. Hierarchical cluster analysis based on molecular profiles discriminated the entries into five genotypic groups and drought tolerant entries were accommodated into three distinct groups with remarkably greater efficiency (85.7%). Principal coordinate analysis based two dimensional plots of microsatellites dependent genetic profiles displayed a very close correspondence with the genotypic clustering pattern revealed from a perusal of dendrogram. Sequential exclusion of primers in cluster analysis led to identification of RM 212, RM 231, RM 324, RM 431, RM 521, RM 3549 and RM 6374 as the most useful primers for discrimination of drought tolerant and susceptible lines of rice. Molecular profiling based on these markers can be utilized as efficient tools for discrimination and identification of drought tolerant lines.

     

Mapping salinity tolerance during Arabidopsis thaliana germination and seedling growth

To characterize and dissect genetic variation for salinity tolerance, we assessed variation in salinity tolerance during germination and seedling growth for a worldwide sample of Arabidopsis thaliana accessions. By combining QTL mapping, association mapping and expression data, we identified genomic regions involved in salinity response. Among the worldwide sample, we found germination ability within a moderately saline environment (150 mM NaCl) varied considerable, from >90% among the most tolerant lines to complete inability to germinate among the most susceptible. Our results also demonstrated wide variation in salinity tolerance within A. thaliana RIL populations and identified multiple genomic regions that contribute to this variation. These regions contain known candidate genes, but at least four of the regions contain loci not yet associated with salinity tolerance response phenotypes. Our observations suggest A. thaliana natural variation may be an underutilized resource for investigating salinity stress response.     

水稻新种质资源的耐盐性鉴定评价

用0.5%的NaCl溶液作灌溉水,对2000-2002年江苏省水稻区域试验参试品系和近年引进的部分水稻种质资源进行苗期耐盐性鉴定.结果表明:株高矮化是苗期盐胁迫的一种形态特征;耐盐性鉴定易受环境影响;就整体而言,籼稻种质资源的苗期耐盐性好于粳稻;综合2年结果,籼156和64608两种质资源的苗期耐盐性较强.     

以色列野生二粒小麦(Triticum dicoccoides)耐盐性鉴定

采用水培法对从以色列引进的分属8个自然群体的93份野生二粒小麦进行了耐盐性初步鉴定.结果表明:①供试材料中仅有高耐盐材料3份,耐盐材料7份 ,耐盐性较好的材料仅占参试材料总数的10.7%;②8个自然群体的野生二粒小麦的耐盐性存在较大差异,其中3号群体耐盐性明显高于其他群体,说明来自Tabigha地区的野生二粒小麦具有丰富的耐盐基因源;③将经过鉴定的耐盐性较好的野生二粒小麦与普通小麦中的耐盐品种进行比较研究发现,以色列耐盐性较好的野生二粒小麦的耐盐性不如普通小麦中的茶淀红和SW10两个耐盐品种.     

陆地棉萌发至三叶期不同生育阶段耐盐特性

摘要：土壤盐渍化是一个世界性的资源问题和生态问题,盐分胁迫几乎会影响棉花所有重要的生命活动, 造成棉花的减产或其他不利影响。本试验通过对14个品棉花种（系）的萌发期耐盐性、芽期耐盐性以及两个耐盐性不同的品种（系）三叶期的耐盐性,对棉花不同时期的耐盐特性进行了研究,结果表明：棉花在不同生育阶段耐盐能力是不同的,棉花盐敏感时间是在萌发出苗期。随着生育期的延长,棉花的耐盐性是逐步提高的,进行耐盐性鉴定的最佳时期在是萌发出苗期。在三叶期,随着盐分浓度的提高,棉花苗受伤害程度逐渐增加,盐敏感性品种受伤害大于耐盐品种,在同样盐浓度胁迫条件下,耐盐性不同的品种各部分受到的伤害不同,耐盐品种（系）中棉所35受伤害程度由高到低依次为：真叶>上胚轴>子叶;盐敏感品种（系）Tamcot CAB-CS受伤害程度由高到低依次为：真叶> 子叶>上胚轴。     

Responses of photosynthesis, chlorophyll fluorescence and ROS-scavenging systems to salt stress during seedling and reproductive stages in rice

BACKGROUND AND AIMS: Salinity is a widespread soil problem limiting productivity of cereal crops worldwide. Rice is particularly sensitive to salt stress during the seedling stage, with consequent poor crop establishment, as well as during reproduction where salinity can severely disrupt grain formation and yield. Tolerance at the seedling stage is weakly associated with tolerance during reproduction. Physiological responses to salinity were evaluated for contrasting genotypes, during the seedling and reproductive stages. METHODS: Three rice genotypes differing in their tolerance of salinity were evaluated in a set of greenhouse experiments under salt stress during both seedling stage and reproduction. KEY RESULTS: Photosynthetic CO2 fixation, stomatal conductance (gs) and transpiration decreased substantially because of salt stress, but with greater reduction in the sensitive cultivar IR29. The tolerant lines IR651 and IR632 had more responsive stomata that tended to close faster during the first few hours of stress, followed by partial recovery after a brief period of acclimation. However, in the sensitive line, gs continued to decrease for longer duration and with no recovery afterward. Chlorophyll fluorescence measurements revealed that non-photochemical quenching increased, whereas the electron transport rate decreased under salt stress. Salt-tolerant cultivars exhibited much lower lipid peroxidation, maintained elevated levels of reduced ascorbic acid and showed increased activities of the enzymes involved in the reactive oxygen scavenging system during both developmental stages. CONCLUSIONS: Upregulation of the anti-oxidant system appears to play a role in salt tolerance of rice, with tolerant genotypes also maintaining relatively higher photosynthetic function; during both the vegetative and reproductive stages.     

Salinity tolerance of japonica and indica rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) at the seedling stage

In order to identify the degree of salinity tolerance of the indica and japonica rice groups, 10 varieties were tested under saline and non-saline conditions. Twelve-day-old seedlings were grown in normal culture solution, then initially salinized at an electrical conductivity (EC) of 6 dS/m for 4 days, and finally salinized at an EC of 12 dS/m for the next 14 days. The growth parameters, and Na and K absorption in the shoot were measured to characterize the tolerance level of the two rice groups. Reduction in all growth parameters of tolerant varieties was significantly lower in indica varieties than in japonica varieties. Tolerant indica varieties were good Na excluders, absorbed high amounts of K, and maintained a low Na/K ratio in the shoot. Tolerant japonica varieties also absorbed less Na but were not as good excluders as indica varieties. Shoot K concentration alone did not show any relationship to salinity tolerance. These results indicate that, for all parameters measured, the tolerance level of indica was higher than that of japonica.     

组培条件下不同番茄品种及砧木自交系幼苗期硝酸盐耐性的比较

采用组培的方法,对15个番茄普通栽培品种的幼苗进行系列浓度Ca(NO₃)₂胁迫处理,10 d后调查不同品种单株幼苗的生长情况和盐害程度。结果表明,15个供试品种幼苗期硝酸盐耐性存在显著差异。上海903、苏红2003、阳光906、大禹中蔬4号、三星L402、番茄大红、中蔬4号、宝大903、霞粉、毛粉 802为硝酸盐敏感品种;早丰番茄、江蔬14号、宝粉和三星906为中等耐硝酸盐品种;日本大粉皇后为耐硝酸盐品种。同时对7个番茄砧木自交系（TR-1、TR-2、TR-3、TR-4、TR-5、TR-7、TR-8）进行了幼苗期高浓度Ca(NO₃)₂的耐盐分析。结果表明,砧木自交系的平均侧根数均显著高于同浓度下供试的普通番茄栽培品种,盐胁迫指数均显著低于普通栽培品种,具有较强的耐盐性;其中TR-8耐盐性最强。     

Diversity analysis of selected rice landraces from West Bengal and their linked molecular markers for salinity tolerance

Study of genetic diversity in crop plants is essential for the selection of appropriate germplasm for crop improvement. As salinity posses a serious environmental challenge to rice production globally and especially in India, it is imperative that the study of large collections of germplasms be undertaken to search for salt tolerant stocks. In the present study, 64 indica germplasms were collected from different agro-climatic zones of West Bengal, India, from the Himalayan foothills in the northern part down to the southern saline belt of the state keeping in view the soil characteristics and other edaphic factors prevailing in the region. Salt tolerance parameters were used to screen the large set of germplasms in terms of root-shoot length, fresh-dry weight, chlorophyll content, Na+/K+ ratio and germination potential in presence of salt. Standard evaluation score or SES was calculated to find out tolerant to sensitive cultivar. Twenty-one SSR markers, some associated with the Saltol QTL and others being candidate gene based SSR (cgSSR) were used to study the polymorphism of collected germplasm. A wide diversity was detected among the collected germplasms at the phenotypic as well as molecular level. Of the 21 SSR markers, 15 markers were found to be polymorphic with 88 alleles. Based on phenotypic and biochemical results, 21 genotypes were identified as salinity tolerant, whereas 40 genotypes turned out to be salt susceptible. The present study shows that apart from the established salt tolerant lines, several other landraces like Bonkanta, Morisal, Ghiosh, Patni may be the source of salt tolerant donor in future breeding programs.     

花生品种耐盐性指标筛选与综合评价

采用盆栽试验,设置不同盐胁迫浓度,通过萌发至幼苗期的出苗速度、植株形态和生物量等指标对200个花生品种(系)进行耐盐性评价.结果表明: 随盐胁迫浓度的增加,花生出苗时间延长,对植株形态建成抑制加重,物质积累减少.鉴定花生品种耐盐性强弱的适宜盐胁迫浓度为0.30%~0.45%.采用隶属函数值法将10个指标归结为平均隶属函数值,根据不同胁迫浓度下各指标与平均隶属函数值之间的相关性大小,植株鲜质量、地上部鲜质量、地下部鲜质量、地下部干质量、株高和主茎高均较大,可作为首选指标,植株干质量、地上部干质量、主根长和出苗速率均较小,可作为辅助指标综合判断品种的耐盐能力.200个品种(系)在不同盐胁迫浓度下均可分成高度耐盐型、耐盐型、盐敏感型和高度盐敏感型4组.随盐胁迫强度加大,耐盐品种数量下降,而盐敏感品种数量上升.部分品种在低、中、高盐胁迫强度下表现出统一性(均耐盐或均敏感);部分品种存在差异性,即低胁迫强度下表现耐盐性而在高胁迫强度下表现盐敏感性.     

Growth and mineral nutrition of six rapid-cycling Brassica species in response to seawater salinity

The growth of six rapid-cycling lines of Brassica species, B. napus, B. campestris, B. nigra, B. juncea, B. oleracea and B. carinata was inhibited by seawater salinity. Based on the change in dry matter reduction relative to the control at varying concentrations of salts (4, 8 and 12 dS m^-1), the relative salt tolerance of these species was evaluated. B. napus and B. carinata were the most tolerant and most sensitive species, respectively, while the other four species were moderately tolerant. The influence of seawater on the concentrations of 12 elements including macronutrients and micronutrients in the shoots of these Brassica plants was characterized to determine the relationship between nutritional disturbance and relative salt tolerance. It was found that seawater salinity had a significant effect on the concentrations of Ca, Mg, K, Cl, Na and total N in the shoots of these plants but only the change in Ca concentration was significantly related to the relative salt tolerance of these six rapid-cycling Brassica species according to a rank analysis of the data. This finding indicates that Ca may play a regulatory role in the responses of Brassica species to saline conditions.     

Improving salinity tolerance in crop plants: a biotechnological view

Salinity limits the production capabilities of agricultural soils in large areas of the world. Both breeding and screening germplasm for salt tolerance encounter the following limitations: (a) different phenotypic responses of plants at different growth stages, (b) different physiological mechanisms, (c) complicated genotype × environment interactions, and (d) variability of the salt-affected field in its chemical and physical soil composition. Plant molecular and physiological traits provide the bases for efficient germplasm screening procedures through traditional breeding, molecular breeding, and transgenic approaches. However, the quantitative nature of salinity stress tolerance and the problems associated with developing appropriate and replicable testing environments make it difficult to distinguish salt-tolerant lines from sensitive lines. In order to develop more efficient screening procedures for germplasm evaluation and improvement of salt tolerance, implementation of a rapid and reliable screening procedure is essential. Field selection for salinity tolerance is a laborious task; therefore, plant breeders are seeking reliable ways to assess the salt tolerance of plant germplasm. Salt tolerance in several plant species may operate at the cellular level, and glycophytes are believed to have special cellular mechanisms for salt tolerance. Ion exclusion, ion sequestration, osmotic adjustment, macromolecule protection, and membrane transport system adaptation to saline environments are important strategies that may confer salt tolerance to plants. Cell and tissue culture techniques have been used to obtain salt tolerant plants employing two in vitro culture approaches. The first approach is selection of mutant cell lines from cultured cells and plant regeneration from such cells (somaclones). In vitro screening of plant germplasm for salt tolerance is the second approach, and a successful employment of this method in durum wheat is presented here. Doubled haploid lines derived from pollen culture of F₁ hybrids of salt-tolerant parents are promising tools to further improve salt tolerance of plant cultivars. Enhancement of resistance against both hyper-osmotic stress and ion toxicity may also be achieved via molecular breeding of salt-tolerant plants using either molecular markers or genetic engineering.