不同诱变处理对苜蓿叶绿素含量及光合作用的影响

为研究60Co-γ射线、紫外线、零磁空间和EMS诱变处理对苜蓿SP1代叶片叶绿素含量及光合作用的影响,筛选最优诱变处理梯度,选育适合高寒地区种植的苜蓿新品系或品种。以‘公农1 号’、‘Wega7F’、‘WL319HQ’、‘敖汉’4 个苜蓿品种试验材料,设置60Co-γ射线150、300、450 Gy射线强度,紫外线30、60、90 min 照射时间,EMS 0.1%、0.2%、0.4%(v/v)溶液浓度,零磁空间处理180 天;测定苜蓿叶片叶绿素a、叶绿素b、叶绿素总量、叶绿素a/b 值以及净光合速率。结果表明,‘公农1 号’450 Gy60Co-γ处理、紫外线处理时间为30 min和0.4%EMS处理下叶绿素a 含量最高,均高于对照3.17 mg/g,但与对照差异不显著,其他处理均低于对照。‘Wega7F’在紫外线60 min 时间处理下,叶绿素b 值明显增加,且显著高于其他处理(P<0.05)。‘公农1 号’在450 Gy 60Co-γ辐射处理下叶绿素含量最高,a/b 比值最小,其他3 个品种在150 Gy处理下叶绿素含量最高,但a/b 比值最小。各苜蓿品种不同诱变处理净光合速率大小依次为：60 min 紫外线处理的‘Wega7F’>零磁空间处理的‘敖汉’>0.4%EMS 处理的‘WL319HQ’>0.4%EMS处理下的‘公农1 号’。150 Gy60Co-γ射线、60 min 紫外线、0.4%浓度EMS处理为苜蓿正向变异处理,有利于筛选有益诱变突变体。     

14个紫花苜蓿品种的引种和生产性能比较评价

为评价不同苜蓿品种的生产性能,筛选能够适应东北地区种植的紫花苜蓿品种,笔者对吉林省东部地区14个国内外紫花苜蓿(Medicago sativa L.)品种播种当年生育期,生长第2年的越冬率及不同茬次的株高、鲜草产量、干草产量、茎叶比等各项农艺性状指标的差异通过灰色关联分析进行比较。结果显示：各品种生育期差异不显著,翌年‘陇中苜蓿’、‘甘农3号’、‘甘农6号’返青较早;‘WL525HQ’、‘WL712’、‘WL656HQ’、‘WL903’越冬率较低且产量及综合评价较低,不适于在吉林省东部地区推广种植;‘WL440HQ’、‘甘农3号’、‘甘农6号’、‘WL168HQ’的越冬率较高且综合评价中表现良好,适合在吉林省东部地区广泛推广种植。     

NaHCO_3胁迫对苜蓿苗期适应性的影响

为了筛选出耐盐碱苜蓿品种,对4个苜蓿品种在不同NaHCO3胁迫下叶片的叶绿素、丙二醛、脯氨酸含量、幼苗存活率进行测定和综合加权分析。结果表明:紫花苜蓿幼苗的生理指标对NaHCO3胁迫的响应存在规律性变化,4种苜蓿叶片的脯氨酸和丙二醛含量随着NaHCO3浓度的升高而增加,叶绿素含量除草原1号外其余品种随着胁迫浓度的增大而降低。4个品种的苜蓿幼苗,在NaHCO3浓度达到200mmol/L时第7天全部致死,4个苜蓿品种的耐NaHCO3由强到弱依次为龙牧803草原1号龙牧806肇东。     

寒区6个紫花苜蓿品种根系中MDA含量及抗氧化酶活性的比较研究

通过测定6个紫花苜蓿品种在高寒地区越冬率及越冬前后丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)3种保护酶活性,比较其越冬前后变化与抗寒性的关系。结果表明,所测各指标变化规律均是随着气温的下降而上升,进入深冬又下降,翌年春季气温回升后,各指标又有所回升;其中MDA含量与越冬率成反比,3种抗氧化酶活性与越冬率成正比。综合各项指标结果表明,公农1号的抗寒性最强,美国品种WL319 HQ抗寒性最弱。     

平欧榛枝条可溶性蛋白及可溶性糖含量与抗寒性关系的研究

为加快山西省平欧榛抗寒育种的进程,深入挖掘平欧榛抗寒资源,为平欧榛生产育种提供理论依据,以 ‘85-28’、‘达维’、‘薄壳红’、‘B-11’、‘玉坠’、‘84-72’、‘魁香’、‘辽榛3号’等生产中主要的8个平欧榛品种（系）成熟1年生枝条为试材,在自然越冬过程中,对其可溶性蛋白、可溶性糖含量进行测定及差异性分析,并结合露地越冬试验,分析与抗寒性的关系。结果表明,在休眠主要低温期,各品种可溶性蛋白及可溶性糖含量均随温度降低呈递增趋势,且抗寒性强的品种较抗寒性弱的增幅大,平欧榛抗寒性与可溶性蛋白及可溶性糖含量呈正相关性。试验各品种（系）抗寒性强弱顺序依次为‘B-11’、‘达维’、‘85-28’、‘84-72’、‘辽榛3号’、‘玉坠’、‘薄壳红’和‘魁香’,与冻害调查结果相吻合。     

四种紫花苜蓿响应缺铁生理反应的比较

铁是植物重要的微量营养元素。为了研究缺铁对抗寒性牧草的生理影响,筛选适合东北地区种植的优良牧草,对‘牧草401’、‘巨人201+Z’、‘金皇后’和‘肇东’苜蓿的缺铁耐受性进行了研究。将四个紫花苜蓿品种分别进行了3d、10d、17d缺铁处理,对其总铁含量、叶绿素含量、丙二醛(MDA)含量和抗氧化物酶活性等指标进行了比较。结果表明:缺铁导致紫花苜蓿的总铁含量和叶绿素含量下降,MDA含量上升,并随处理时间的加长而加剧,抗氧化酶活性则呈先升后降的趋势。与其他3种紫花苜蓿相比,‘肇东’苜蓿表现出较强的缺铁耐受特性,可以作为气候寒冷、土壤铁含量贫瘠区域种植的候选牧草品种。为研究牧草铁胁迫应答分子机制和牧草育种提供了宝贵的理论基础。     

越冬期抗寒性不同冬小麦品种间生理指标的比较

以抗寒性不同的4个冬小麦品种为材料,对其在越冬期间叶鞘内丙二醛、可溶性蛋白和脯氨酸生理指标的含量进行测定,以分析高寒地区冬小麦抗寒性的遗传改良潜力.越冬期间,抗寒性强的品种(系)的丙二醛含量较低,可溶性蛋白含量较高；在低温驯化期抗寒性强的品种脯氨酸含量迅速增加,在越冬期各品种脯氨酸含量均保持较高水平.     

不同低温下核桃枝条抗寒性生理生化指标分析

为了加快山西省核桃抗寒育种的进程,深入挖掘核桃抗寒资源,为核桃生产育种提供理论依据,以山西省主要推广的核桃品种‘礼品1号’、‘礼品2号’、‘中林1号’、‘中林5号’、‘辽核1号’、‘辽核3号’和‘晋龙1号’7个品种为试材,对其被迫休眠期1年生枝条在不同低温条件下的可溶性糖、可溶性蛋白、脯氨酸含量、超氧化物歧化酶(SOD)及过氧化物酶(POD)酶活性等部分抗寒性生理生化进行了测定比较。结果表明：随处理温度的降低,所测指标中可溶性蛋白含量和POD酶活性呈现“降—升—降”的变化。可溶性糖、脯氨酸含量、SOD酶活性的变化幅度不大。‘礼品1号’和‘礼品2号’在可溶性糖、脯氨酸含量变化幅度较大。综合分析各品种抗寒性生理生化指标,可推测其抗寒性强弱顺序：‘礼品2号’最强,‘礼品1号’次之,‘辽核3号’和‘中林5号’抗寒性居中,‘晋龙1号’、‘中林1号’、‘辽核1号’依次降低。     

渗透胁迫下转BADH基因苜蓿组培苗的 抗性响应

用4种不同浓度的聚乙二醇(PEG6000)溶液处理转BADH基因苜蓿SLM01,SLM05株系及其未转基因的受体亲本,14天后测定相关生理指标的变化。结果表明：随着PEG6000浓度的提高,苜蓿叶片中丙二醛（MDA）含量升高,质膜透性增大,但转基因植株的都低于对照;PEG6000处理后渗透调节物质可溶性糖、脯氨酸大量积累,叶绿素含量降低,与受体亲本相比,转基因株系可溶性糖含量的增加幅度较大,脯氨酸积累较少,叶绿素含量下降较慢。以上结果说明转BADH基因苜蓿对PEG造成的渗透胁迫具有较强的抗性。     

苜蓿抗寒突变体生理生化及性状指标分析

为选育在黑龙江省可越冬的理想紫花苜蓿品种。以‘龙牧806’零磁空间诱变处理后二代群体中获得的lm1609、lm1625、lm1704三个抗寒突变体为实验材料,通过测定发芽指标、越冬率、产量特性指标及根系生理生化指标,进行抗寒性能鉴定。3个突变体发芽指数与对照差异不显著;发芽势、简化活力指数lm1609显著高于lm1625、lm1704,分别为82.05%、469.82 (P<0.05);3个突变体的越冬率都显著低于对照组;突变体和对照6月6日起始株高差异不显著,随着植株生长,7月6日和8月6日lm1609、lm1704显著高于lm1625和对照;突变体lm1609、lm1625、lm1704三者鲜草产量差异不显著,但显著高于对照(P<0.05);三个苜蓿突变体植株根系过氧化物酶、超氧化物歧化酶均显著高于对照,并且突变体lm1609POD、SOD最高,分别达到304.85 OD₄₇₀/(min·g)、208.41 U/g (P<0.05)。lm1609突变体具有较高的抗寒特性及产量特性,是为理想的抗寒突变体材料。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Breeding forage grasses for organic conditions

Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions. Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture.     

The performance of double or mixed pollinations with compatible and self-incompatible or incongruous pollen of pear and apple

Summary Six pear and five apple trials were carried out to ascertain the outcome of combinations of compatible pollen (C) with self (S) or incongruous pollen (I) as to the pollination index (PI=seeds/pollinated flower). The PI of the mixture C+I (1:5) was consistently depressed as compared to that of the control C. The results of the double pollinations S/C and I/C were affected by the temperature at pollination; their PI's at <15°C were twice as high as those at >15°C, being well above and below the PI of C in the former and latter case respectively. The opposite was true for the C/S combination, the PI of which increased with the pollination temperature; the PI of C/I did not differ much from the PI of C, irrespective of temperature. The conclusion was reached that the interaction previously and presently found between compatible and self-incompatible pollen also exists to a fair extent between compatible and incongruous pollen. However, in pear neither the mentor nor the pioneer pollen technique proved to aid its hybridization with apple, the formation of self seed was not observed either. In apple the production of apple × pear hybrids was likewise doubtful, but the double pollinations S/C and C/S formed 4–10% self seed.