Evaluation of Chlorophyll Content and Fluorescence Parameters as Indicators of Drought Tolerance in Barley

Drought is a major abiotic stress that severely affects food production worldwide. Agronomic and physiological traits associated with drought tolerance are suitable indicators for selection of drought tolerance genotypes to reduce the impact of water deficit on crop yield in breeding program. The objective of this study was to identify indicators related to drought tolerance through analysis of photosynthetic traits in barley （Hordeum vulgare L.）. These traits included chlorophyll content, initial fluorescence （Fo）, maximum primary yield of photochemistry of photosystem Ⅱ （Fv /Fo） and maximum quantum yield of photosystem Ⅱ （Fv/Fm）. Four genotypes （Tadmor, Arta, Morocco9-75 and WI2291） variable in drought tolerance were used to investigate the correlation between these traits and drought tolerance. The results reflected that all of these traits were affected negatively in the four genotypes at different levels of post-anthesis drought stress, but the decrease in drought tolerant genotypes was much less than that of drought sensitive genotypes. The results further revealed that the components of the photosynthetic apparatus could be damaged significantly in drought sensitive genotypes, while drought tolerant genotypes were relatively less affected. On the other hand, the values of chlorophyll content, Fo, Fv/Fo and Fv/Fm in drought tolerance genotypes were significantly higher than those in drought sensitive genotypes under drought stress. It was concluded that chlorophyll content, Fo, Fv/Fo and Fv/Fm could be considered as reliable indicators in screening barley germplasm for drought tolerance.

Alleviation of Al Toxicity in Barley by Addition of Calcium

The potential mechanism by which Ca alleviates Al toxicity was investigated in barley seedlings. It was found that 100 Al-alone treatment inhibited barley plant growth and thereby reduced shoot height and root length, and dry weights of root, shoot and leaf; promoted Al accumulation but inhibited Ca absorption in plant tissues; and induced an increase in the activities of superoxide dismutase （SOD）, catalase （CAT）, and peroxidase （POD） and in the level of lipid peroxidation （MDA content） in leaves. Except for the increase in Ca concentration in plant tissues, treatment with 0.5 mM Ca in the absence of Al had less effect on the above-mentioned parameters, compared with the control. Addition of Ca efficiently reduced Al toxicity, which is reflected by the promotion of plant growth, reduction in Al concentration and MDA content, increase in Ca concentration and in SOD, POD, and CAT activities compared with the Al-alone-treatment; with increase in Ca level （3.0 raM）, the ameliorative effect became more dominant. This indicated that the alleviation of aluminum toxicity in barley seedlings with Ca supplementation could be associated with less absorption of Al and the enhancement of the protective ability of the cell because of increased activity of the antioxidative enzyme.

Effects of Waterlogging on Photosynthesis and Antioxidant Enzyme Activities of Six Barley Genotypes with Different Waterlogging Tolerance

A field experiment was carried out to study genotypic difference in the effect of waterlogging on photosynthesis, chlorophyll content and antioxidative enzyme activities in barley. Waterlogging caused a rapid decline in net photosynthetic rate (Pn) and stomatal conductance (gs), and little change in chlorophyll content during early days of the treatment. A dramatic increase in malondialdehyde (MDA) content, superoxide dismutase (SOD) and peroxidase (POD) in waterlogged plants in the early days of the experiment was found, indicating the occurrence of oxidative stress in barley plants exposed to waterlogging. There was a highly significant difference in the changed extent of all these parameters among genotypes. Franklin and Yongjiahong Liuleng Damai, which were relatively sensitive to waterlogging in terms of growth, photosynthesis and chlorophyll content, accumulated much more MDA than the other two relatively tolerant genotypes (93-3143 and QS). After removal of waterlogging, the genotypic difference became much greater in recovering of these examined parameters. Yongjiahong Liuleng Damai showed higher recovery, while Franklin only recovered to 50% of the control at the 14 day after waterlogging removal. It may be concluded that it is the difference in anti-oxidative stress caused by waterlogging that account for the major difference in photosynthesis among barley genotypes.

Genotypic and Environmental Variations of Arabinoxylan Content and Endoxylanase Activity in Barley Grains

Arabinoxylan （AX） content in barley grains is an important quality determinant when barley is used as raw material of malt or beer production. The cultivar and environmental variations of total arabinoxylan （TAX）, water extractable arabinoxylan （WEAX） and endoxylanase activity （EA） were investigated using eight barley cultivars growing at seven locations with diverse environmental conditions. The results showed that both barley cultivar and location significantly affected the TAX, WEAX and EA levels, but the variations of TAX content and EA were mainly attributed to cultivar, while the impact of location on WEAX content was greater than that of cultivar. Correlation analysis indicated that TAX was significantly correlated to WUAX.

Genotypic Difference in Plant Growth and Mineral Composition in Barley Under Aluminum Stress

Four barley genotypes (Tiantaiyangdamai, Xiyin2, Mimaill4 and Tai94-Ce6) were exposed to 0, 50, 100, and 150μM of Al-containing solution with pH 4.5, to determine the differences in growth inhibition , Al concentration and accumulation and mineral composition among genotypes. The results showed that Mimaill4 and Tai94-Ce6 had significantly higher Al concentration and accumulation than Tiantaiyangdami and Xiyin2, especially in roots, and the growth traits including root and shoot dry weights, shoot height, root length and tillers per plant were more inhibited in the former two genotypes. Al treatments caused a significant reduction of N, P, K, Ca, Mg and Mn content in both roots and shoots, of Cu in shoots; and a significant increase in Fe and Zn content in both roots and shoots, of Cu in roots. The changed rates of mineral content caused by Al treatments, in terms of the content in 150μM Al divided by the content in the control, differed significantly among four genotypes. Two Al-sensitive genotypes, Mimaill4 and Tai94-Ce6 had much greater changes in mineral content than other two Al-tolerant genotypes Tiantaiyangdamai and Xiyin2 when subjected to Al stress in comparison with the control. It is indicated that the Al-tolerant genotype is characterized by less uptake and accumulation of Al in roots and smaller disorders in mineral metabolism and ion homeostasis.

Variation of Grain and Malt Qualities in Barley as Affected by Cultivars and Environments

Inferior and unstable quality of malt barley in China has limited its wide use in malting and brewing industries. In this research, eight two-rowed barley cultivars were planted at 7 locations with different ecological conditions in southern China, to investigate the cultivar and environmental effect on grain and malt qualities. The results showed that grain protein content differed dramatically among locations, but there were no significant differences among cultivars. For four malt qualities including diastatic power, wort viscosity, Kolbach index and malt extract, significant differences were found among cultivars and locations, except for diastatic power among cultivars. Coefficients of variance(CV)caused by location were greater than those caused by cultivar for each quality parameter, especially for diastatic power and Kolbach index, indicating the predominant influence of environment on malt quality. The analysis showed that grain protein content was positively related to diastatic power and wort viscosity, and negatively to malt extract. Kolbach index was positively related to malt extract, and negatively to diastatic power and wort viscosity. Diastatic power showed positive and negative correlation with wort viscosity and malt extract, respectively.

Cultivar and Environmental Effects on p-glucanase Activity in Both Barley Grain and Malt and Its Function in β-glucan Degradation

Eight two-rowed barley cultivars were grown at seven locations in the southern winter-barley zone of China. Mean grainβ-glucanase activity ranged from 39.89 U kg-1 for Suyin2 to 49.75 U kg-1 for Xi-umai3 in 8 cultivars grown at 7 locations, and from 38. 74 U kg-1 in Zhengzhou to 57. 96 U kg-1 in Putian among 7 locations on an average of all cultivars. Correspondingly, mean malt β-glucanase activity of 8 cultivars ranged from 313.33 U kg-1 for ZAU3 to 489. 89 U kg-1 for Daner Barley, and of 7 locations from 330.40 U kg-1 in Yancheng to 418. 24 U kg-1 in Putian. There were significant differences among cultivars and locations in maltβ-glucanase activities. The locations showed much larger variation in maltβ-glucanase activities than cultivars. The reduction of total β-glucan content after malting varied in both cultivars and locations, with a mean of 78.31%. The analysis of correlations showed that maltβ-glucan content was significantly positively and negatively correlated with grain β-glucan content and malt β-glucanase activity, respectively, and malt β-glucanase activity was significantly positively correlated with grain β-glucanase activity.

The influence of drought stress on malt quality traits of the wild and cultivated barleys

As a major abiotic stress,drought causes instability and deterioration of malt barley quality.There is distinct difference among barley cultivars in the responses of the main malt quality traits to drought stress.In the previous study,we identified some Tibetan wild barley accessions with relatively less change of malt quality traits under drought.In this study,we examined the impact of drought stress during grain filling stage on grain weight and several important malt quality traits,including total protein content,β-glucan content,limit dextrinase activity,β-amylase activity,and protein fractions in four barley genotypes(two Tibetan wild accessions and two cultivars).Drought treatment reduced grain weight,β-glucan content,and increased total protein content,β-amylase activity.These changes differed among barley genotypes and treatments,and are closely associated with grain filling process and kernel weight.All the results indicated Tibetan wild barley had great potential for developing drought tolerant barley cultivars.Relatively stable kernel weight or filling process under water stress should be highlighted in malt barley breeding in order to reduce the effect of water stress on malt barley quality.

Relationship of Grain Fructan Content to Degree of Polymerisation in Different Barleys

Fructans are important in the survival of plants and also valuable for humans as potentially health promoting food ingredients. In this study fructan content and composition were determined in grains of 20 barley breeding lines and cultivars with a wide variation in chemical composition, morphology and country of origin, grown at one site in Chile. There was significant genotypic variation in grain fructan content ranging from 0.9% to 4.2% of grain dry weight. Fructan degree of polymerisation (DP) was analysed using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Changes in the distribution of different chain lengths and the pattern of structures of fructan were detected with increasing amount of fructan in the different barleys. A positive correlation was found between fructan content and the relative amount of long chain fructan (DP > 9) (r = 0.54, p = 0.021). Our results provide a basis for selecting promising barley lines and cultivars for further research on fructan in barley breeding with the aim to produce healthy food products.

Assessing the product quality and biological activities of barley(Hordeum vulgare L.)grasses at different harvest times

Barley(Hordeum vulgare L.)grasses(BG)have attracted considerable interest due to their multiple physiological activities and health benefits.In this paper,eight BG at four different growth stages were collected:seedling,tillering,stem elongation,and heading,and their product qualities and biological activities were examined and studied.Results demonstrated that harvest time obviously influenced proximate composition,surface color,and amino acid profile.Z21 and Z23 harvested at the seedling and early tillering stages,respectively,had higher total phenolic content(TPC)and total flavonoid content(TFC)than the other BG.Moreover,Z21 and Z23 possessed better DPPH radical-scavenging ability,antioxidant capacity,andα-glucosidase inhibitory activity,which were positively correlated with TPC,TFC,and protein and total amino acid contents.Our findings suggested that the early tillering stages were the preferable harvest times for BG with good product quality and biological properties.

NaCl胁迫对青稞种子萌发及幼苗生长的影响

以西藏自治区5个青稞(Hordeum vulgare L. var. nudum Hook. f.)品种为试验材料,研究不同NaCl浓度对青稞种子萌发及幼苗生长的影响,并且对不同青稞品种耐盐性进行评价分析。结果表明,NaCl浓度为0.1%时对青稞萌发及幼苗生长具有一定的促进作用;当浓度增至0.5%时,种子的发芽势、发芽率、活力指数以及幼苗的根长、芽长、根鲜重均显著下降;当浓度为1.0%时,隆子黑青稞与苟芝紫青稞已丧失发芽能力。总体来看,5个青稞品种中,喜拉22耐盐性最好,其次是藏青320、藏青2000、苟芝紫青稞,隆子黑青稞耐盐性最弱。

2,4-表芸苔素内酯浸种对干旱胁迫下大麦种子萌发及幼苗生理特性的影响

【目的】研究不同浓度芸苔素内酯溶液对干旱胁迫下大麦种子萌发及幼苗生长的影响,分析芸苔素内酯溶液的最佳浸种浓度。【方法】以新啤6号大麦种子为材料,采用不同浓度(0、5、25、50、100、200μg/L)芸苔素内酯溶液浸种后,在蒸馏水(CK)或23%聚乙二醇溶液中进行纸上发芽试验。统计发芽率、发芽势、发芽指数以及根和芽的干、鲜重,测定分析不同浓度芸苔素内酯溶液浸种对干旱胁迫下大麦芽和根中相对含水量、电导率、丙二醛、脯氨酸、可溶性糖含量以及抗氧化酶活性的影响。【结果】干旱胁迫显著抑制大麦种子的萌发和幼苗生长。与仅干旱胁迫处理相比,5、25μg/L芸苔素内酯溶液处理可使大麦种子发芽率、发芽势和发芽指数分别提高34.23%、65.74%、25.80%和45.45%、31.82%、47.70%。与仅干旱胁迫相比,25μg/L芸苔素内酯处理使根和芽中的可溶性糖含量分别增加7.86%和12.53%,使根和芽中的游离脯氨酸含量分别增加35.06%和20.63%。25μg/L芸苔素内酯处理可使根和芽中的过氧化氢酶、过氧化物酶以及超氧化物歧化酶活性均有所提高。【结论】适宜浓度的芸苔素内酯溶液浸种可提高干旱胁迫下大麦根和芽中的渗透调节物质含量和抗氧化酶活性,促进大麦种子萌发和幼苗生长,且以25μg/L芸苔素内酯处理的效果最为明显。

GREEN PLANT REGENERATION FROM PROTO PLASTS OF BARLEY (Hordeum vulgate L.)

Barley is the world’s fourth leading cereal in acreage planted, after wheat, rice and corn. Nevertheless, whilst plant regenerations from protoplast cultures of rice, corn and wheat were realized one after another during the past few years, only albinos were regenerated sporadically from barley protoplasts. The present note reports that a group of complete green plants has been obtained from protoplasts isolated from cell suspension cultures in barley.

大麦单倍体细胞水平与植株水平耐低氮性的关系

为了确定大麦籽粒产量和苗期耐低氮能力与小孢子培养阶段的氮胁迫下愈伤组织产量之间是否存在一致性,以2份大麦基因型为供试材料,进行了以下3项研究:(1)培养基中水解干酪素和谷氨酰胺使用量对小孢子培养愈伤组织产量的影响;(2)营养液中NH4NO3不同添加量对大麦苗期生长量的影响;(3)盆栽时正常施氮与不施氮处理对大麦单株产量的影响。结果表明,培养基中氮含量的下降明显降低小孢子培养愈伤组织产量,2份基因型的降幅存在明显的差异;营养液中氮使用量的下降明显降低植株高度、主根长度和植株及根干重,2份基因型之间的降幅也存在明显的差异;盆栽时不施氮处理的大麦有效穗和单株产量低于正常施氮的对照,2份基因型间有差异。氮素胁迫下,2份基因型小孢子培养愈伤组织产量的相对值与苗期植株高度、茎叶干重、主根长度和根干重的相对值以及单株产量的相对值存在一致性,说明供试基因型小孢子水平与植株水平的耐低氮性存在相关性。

萌发温度及品种对青稞种子萌发和幼苗生长的影响

以黑、白、墨绿和花4个青稞品种为试验材料,研究温度对青稞种子萌发特性和幼苗生长的影响,分析了不同温度下不同青稞品种种子萌发特性的差异。结果表明,各样品的发芽势、发芽率和发芽指数指标均在10～25℃范围内随着温度的升高而升高,在25℃时达到最大值;30℃时青稞种子萌发指标均呈小幅下降。同时,青稞幼苗的生长情况和生物量也是在25℃时达到最佳。因此,青稞种子萌发和幼苗生长的最适温度较低,为25℃。对于不同品种,在同一处理温度下,种子萌发指标和幼苗生长、生物量指标的高低顺序为黑青稞>墨绿青稞>花青稞>白青稞。由于低温影响种子的萌发进程和幼苗生长,因此在实际生产中对低萌发率、生长迟缓的种子要特别注意选择适宜的播种期。

大麦幼苗叶片表皮蜡质组分及含量对外源ABA的响应及其对表皮透性的影响

为了探究ABA对大麦幼苗叶片表皮蜡质组分和含量的化学调控作用及表皮蜡质对叶片保水性的影响,采用外源ABA喷施大麦幼苗,研究大麦幼苗叶片表皮蜡质组分和含量对外源ABA的响应及其对表皮透性的影响。结果表明,ABA处理可提高大麦幼苗叶片的表皮蜡质含量,且在高浓度处理下蜡质含量增加较多。抗旱品种的蜡质总含量高于干旱敏感品种,但高浓度处理下,干旱敏感品种的蜡质增加幅度高于抗旱品种,说明ABA对干旱敏感品种的处理效果较好。气相色谱质谱联用分析表明,大麦幼苗表皮蜡质的成分主要为醇类、酸类、醛类、酮类、烷类、酚类和酯类,其中醇类和酸类为其主要成分,分别占蜡质总量的20.60%和16.02%。ABA处理可使抗旱品种Z027S078T蜡质组分中的烷类、醇类、酚类以及干旱敏感品种的醇类含量降低,其它组分含量增加。抗旱品种Z027S078T在低浓度ABA处理下,醛类增加量最多,达到了44.30%,高浓度处理下酮类和酸类增加量较多,分别达到了106.89%和104.85%;干旱敏感品种垦啤6号在10和100μmol·L-1ABA处理下均酯类和酮类的增加幅度较高,说明抗旱品种中的醛类、酮类、酸类和干旱敏感品种中的酯类、酮类是大麦幼苗叶片表皮蜡质对外源ABA响应的关键。表皮蜡质总量较多的抗旱品种Z027S078T较干旱敏感品种垦啤6号有相对较高的相对含水量和较低的表皮透性,表明表皮蜡质在降低蒸腾提高植物保水性方面具有积极的作用。

氯酸盐处理对不同大麦地方品种苗期性状的影响

为了建立基于氯酸盐的大麦氮高效筛选体系,探究氯酸盐处理对大麦幼苗的影响,并鉴定出对氯酸盐反应有差异的大麦种质材料,用于将来的大麦氮高效分子机理研究和育种。以18个上海地方品种和3个主栽品种为供试材料,在人工气候室进行水培试验,分别设置2 mmol/L KNO_(3)(CK)和2 mmol/L KClO_(3)处理,处理4 d后,测定大麦幼苗的苗高、根长、地上部和根干质量。结果表明:氯酸盐对大麦苗期生长有明显的抑制作用,特别是苗高和干质量。方差分析表明,所有性状在氯酸盐处理和正常培养(对照)下都呈极显著差异,并且处理和品种间,所有性状也均存在极显著的互作。不同指标的变异系数表明,不管是氯酸盐处理还是正常供氮条件下,根长和干质量的变异系数相对较大,而苗高的变异系数相对较小。相关性分析也表明,这些形态学指标在2种条件下都呈正相关关系。基于苗高和地上部干质量的氯酸盐敏感度对供试材料的区分总体上相似,但也有区别。苗高和地上部干质量对氯酸盐的反应可以作为筛选大麦氮高效的指标,并且基于苗高和地上部干质量的氯酸盐敏感度都认为,B104、B002、B053、B092和B068在对氯酸盐最敏感的6个品种里,说明这5个大麦品种氮素利用率可能比较高,而B016、B006和B008则都在对氯酸盐最不敏感的6个品种里面,说明这3个大麦品种氮素利用率可能比较低。

不同醇溶液对青稞种子萌发及生长的影响

为促进青稞(Hordeum vulgare var. coeleste L.)种子的活力和幼苗产量,研究了不同醇溶液(1%的甲醇、乙醇、丙醇、正丁醇)对青稞种子萌发及幼苗生长的影响。结果表明,与对照相比,1%不同醇溶液处理对青稞种子萌发和幼苗生长具有明显影响。1%甲醇对青稞种子的萌发和幼苗生长均起促进作用,其发芽率、发芽势、发芽指数分别比对照组高1.11、1.11个百分点和1.12,幼苗叶绿素a、叶绿素b、总叶绿素分别比对照组高0.013 7、0.000 4、0.000 7 mg/g,以及幼苗的苗高、根长分别比对照组高2.15、3.51 cm;1%乙醇溶液也对种子萌发有明显促进作用,且效果优于1%甲醇溶液,其发芽率、发芽势、发芽指数分别比对照组高4.44、5.56个百分点和6.86,但1%乙醇溶液抑制青稞幼苗的生长;1%丙醇、1%正丁醇溶液则对青稞种子的萌发及幼苗生长都起不同程度的抑制作用,1%正丁醇溶液抑制程度最强。研究表明,1%甲醇溶液对青稞种子的萌发及幼苗生长均起到促进作用。

30份大麦种质资源的苗期抗旱性鉴定及抗旱指标筛选

在西北内陆地区,干旱是影响大麦生长发育的重要非生物胁迫因素,鉴定大麦资源的抗旱性,确定抗旱指标,筛选抗旱种质,培育抗旱品种具有重要意义。以30份大麦种质为材料,设置正常供水和反复干旱胁迫2个处理,在旱棚内进行盆栽试验,测定干旱对株高、根长、叶长、地上部鲜重、根鲜重、地上部干重、根干重和总干重的影响;采用抗旱性度量值(D值)、综合抗旱系数(CDC值)、加权抗旱系数(WDC)、频次分析、相关分析、主成分分析、灰色关联度分析、隶属函数分析、聚类分析和逐步回归分析相结合的方法,对其进行苗期抗旱性鉴定及抗旱指标筛选。结果显示干旱胁迫对各指标均有极显著影响。频次分析表明,各指标对干旱胁迫反应的敏感程度依次为根长、根干重、总干重、地上部鲜重、地上干重、叶长、根鲜重和株高;相关分析表明,总干重与根干重、地上部干重、叶长和根长呈极显著正相关,与地上部鲜重呈显著正相关,与株高和根鲜重呈不显著正相关;主成分分析表明,4个主成分可代表大麦种质资源抗旱性83.583%的原始数据信息量。基于D值、CDC值和WDC值的供试大麦种质抗旱性排序相近。灰色关联度分析表明,各指标DC值与D值间的关联度大小依次为株高、地上部干重、总干重、叶长、地上部鲜重、根长、根干重、根鲜重,与各指标DC值与WDC值关联度大小排序基本吻合。根据D值进行聚类分析,可将供试大麦种质划分为5个抗旱级别,其中1级2份、2级13份、3级6份、4级7份、5级2份。除根鲜重、地上部干重、根干重和总干重外,其余指标的隶属函数值、CDC值、D值和WDC值均随抗旱级别的升高而增大。逐步回归分析表明,与D值密切相关的指标有株高和总干重。苗期抗旱性强的大麦种质资源材料有西藏25和NEVADA,可作为大麦抗旱育种、抗旱机理及干旱调控缓解机制研究的材料。株高和总干重可作为评价大麦种质资源苗期抗旱性鉴定的性状指标。

大麦抗蠕孢叶斑病遗传资源鉴定及主要抗病类型分析

大麦蠕孢叶斑病是由兼性寄生麦根腐平脐蠕孢菌(Bipolaris sorokiniana)引起的重要叶部病害,在世界大麦种植区域均有发生,尤其在气候温暖湿润地区最具破坏性,能造成严重的产量损失,也是我国东北春麦区目前首要真菌流行病害。蠕孢叶斑病主要在大麦生育中后期流行为害,种植抗病品种是防治该病害最经济有效的措施。本研究利用2个来自东北麦区强致病力优势菌株Z 12028和Z 15525对350份大麦种质资源进行苗期和成株期接种鉴定,仅1份材料2013F61903苗期高抗Z12028菌株,未发现对叶斑病免疫的材料。针对2个强致病力菌株,从中获得9份全生育期抗病材料,即ZDM00009、ZDM00013、ZDM00094、ZDM08888、ZDM01414、ND14049、ND B112、Newdale和垦啤麦9号;ZDM00074、Bowman、Stander等14份材料(4.3%)仅在苗期抗病,成株期却感病;72份材料(28.3%)属于成株抗病类型。对Z 12028和Z 15525菌株具有成株抗性的品种所占比例分别为28.1%和29.5%。因此,抗蠕孢叶斑病的大麦种质资源中保留成株抗性的材料明显多于全生育期抗性类型。本研究结果能为发掘大麦抗叶斑病新基因提供重要抗源材料。