共查询到20条相似文献，搜索用时 75 毫秒
1.
高梁同源四倍体及其杂交处的细胞遗传学研究 总被引：2，自引：0，他引：2
对同源四倍体高梁品系和杂交种的细胞学观察发现，其减数分裂的各个时期均有特异性。具体表现在前期Ｉ有３．９４％的ＰＭＣ中存在多个核仁，其中以双核仁形式出现的频率最高；终变期－中期具有不同的染色体构型，可观察到同染色体四种组成形式，后期Ｉ出现大量落后染色体，其中以单价体提前分离造成的染色体落后较为常见，单价染色体落后较少；前期Ⅱ和四分体时期可观察到核外染色体；中期Ⅱ发现有部分染色体不排列于赤道板上；后期 相似文献
2.
3.
4.
陆地棉与澳洲2个野生棉杂种细胞学研究 总被引：7，自引：2，他引：7
本文首次报道了陆地棉×南岱华棉杂种Ｆ１的细胞学研究结果，并与陆地棉Ｘ斯特提棉的杂种进行了对比分析。供分析的细胞数均在７００个以上，中期Ⅰ染色体构型种类占总ＰＭＣ的百分率（构型率）均在７％以下，陆地棉与斯特提棉和南岱华棉杂种Ｆ１的染色体平均构型分别为２１．９７Ⅰ＋７，９７Ⅱ＋０．３５Ⅲ＋０．０１Ⅳ和２０．６２Ⅰ＋８．３７Ⅱ＋０．５２Ⅲ＋０．０２Ⅳ，单一细胞环状二价体、染色体桥和二价体交叉率分别是０．５３与０．４８、７．４４与７．８９和１．０７及１．０６。在２个杂种中均观察到八价体，但为数极少。中期Ⅰ时期二价体和多价体集中于细胞赤道面上，而单价体分散在周围。后期Ⅰ及以后，单价体分布完全随机，形成多个染色体块或片段。四分体形成时期，小孢子数目和大小及形状变异均较大。主要表现在小孢子不是规则的团体，体积大小相差可达２～４倍，单一ＰＭＣ中的数目从ｌ至１３，但其四分体占多数，均在６０％以上。且微核变幅较大，０～６个。经过比较分析，说明两个棉种亲缘关系很近，与陆地棉的种间关系差异也不大。 相似文献
5.
三个棉属种间杂种花粉母细胞减数分裂观察 总被引：2，自引：0，他引：2
对棉属３个种间杂种ＴＭ－１×石系亚１号、ＴＭ－１×辣根棉和ＴＭ－１×瑟伯氏棉花粉母细胞的减数分裂进行了观察。结果表明，３个杂种多数花粉母细胞中期Ⅰ的染色体构型为１３Ⅱ＋１３Ⅰ。二价体联会成环状、棒状或Ｖ型。ＴＭ－１×辣根棉杂种的二价体联会较紧密。杂种除正常的染色体组ＡＡ和ＤＤ联会外，还发生ＡＤ联会及出现多价体。中期Ⅰ单价体大部分分散于赤道板两侧，并较早移向两级。个别二价体也不排列在赤道板上。二价体向两极移动时常形成染色体＂桥＂，使这些染色体移动速度减慢，导致细胞分裂不同步。此外，在第一次分裂和第二次分裂中都能看到落后染色体、远离大多数染色体的零星染色体、孤立的染色体群等现象。后期Ⅱ的花粉母细胞可形成较多的核仁。在四分孢子期，３个种间杂种既产生四分体，也形成二、三、五、六乃至十分体。ＴＭ－１×石系亚１号、×辣根棉、×瑟伯氏棉杂种的四分体数分别为７０．２％、６３．１％和３５．１％。 相似文献
6.
高粱A2 CMS减数分裂染色体行为观察 总被引：2，自引：0，他引：2
高粱（Sorghum bicolor L．Moench）质核互作雄性不育有7种类型，即A1，A2，A3，A4，A5，氏和9E。以A2／B2V4为材料，对赴类型的雄性不育系进行了研究，结果表明：高粱A2V4 CMS花粉母细胞减数分裂染色体行为，在前期Ⅰ至中期Ⅰ无任何异常现象，从后期Ⅰ开始，染色体行为出现各种异常现象，如同源染色体在走向两极时出现滞后或部分不分离；或在后期Ⅱ姐妹染色体不分离造成细胞内染色体多倍化，以致形成两极染色体数目不等；在一个细胞内有几个染色体团或核；三分体及“T”型和直线型排列的四分体。所有这些异常现象最终导致减数分裂不能正常进行，不能发育正常的小孢子，因而造成雄性不育。 相似文献
7.
8.
高粱A2型细胞质雄性不育系小孢子发生的细胞学观察和减数分裂染色体行为分析 总被引：4，自引：0，他引：4
高粱凡型细胞质雄性不育性（CMS）的细胞质来源于IS12662C，A2细胞质杂交种目前已用于生产。本文以A2／B2 V4为材料，对A2CMS小孢子败育过程作了细胞学观察，并对小孢子败育过程中减数分裂的染色体行为作了分析。研究发现，在A2雄性不育系A2V4的花药发育过程中，绒毡层细胞不形成或提前解体；绒毡层细胞畸形化；绒毡层细胞虽发育正常，但小孢子母细胞减数分裂行为异常；这些都导致小孢子退化。A2细胞质雄性不育花粉母细胞减数分裂行为从后期Ⅰ开始出现异常，同源或姊妹染色体向两极分离时滞后或不分裂；染色体多倍化；一个细胞内出现多核和多核仁现象，最终导致小孢子败育。 相似文献
9.
高梁不育系Tx3197A减数分裂中染色体行为 总被引：3，自引：0，他引：3
以Ｔｘ３１９７Ｂ和晋粱５号为对照，对Ｔｘ３１９７Ａ进行了观察。结果发现，减数分裂前期Ⅰ和中期Ⅰ无明显异常。自后期Ⅰ开始，染色体行为出现了多类型的异常现象，导致减数分裂不能正常进行，无法形成花粉粒，从而产生雄性不育。 相似文献
10.
高粱不育系Tx3197A减数分裂中染色体行为 总被引：6，自引：2，他引：6
以Ｔｘ３１９７Ｂ和晋粱５号为对照，对Ｔｘ３１９７Ａ进行了观察。结果发现，减数分裂前期Ⅰ和中期Ⅰ无明显异常。自后期Ⅰ开始，染色体行为出现了多类型的异常现象，导致减数分裂不能正常进行，无法形成花粉粒，从而产生雄性不育。 相似文献
11.
Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts 总被引：7，自引：0，他引：7
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. 相似文献
12.
C. J. Spurr D. A. Fulton P. H. Brown R. J. Clark 《Journal of Agronomy and Crop Science》2002,188(4):275-280
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. 相似文献
13.
Jens Jensen 《Euphytica》1979,28(1):47-56
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. 相似文献
14.
G. H. Kroon 《Euphytica》1994,76(1-2):125-125
Summary
K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes. 相似文献
15.
Hongyan WEI Jian ZHOU Jinguang LU Jingzheng SONG Qiongxi YU Zhihong JIANG 《Medicinal Plant》2019,(6):27-29
[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol... 相似文献
16.
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. 相似文献
17.
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. 相似文献
18.
D. A. Bond G. J. Jellis G. G. Rowland J. Le Guen L. D. Robertson S. A. Khalil L. Li-Juan 《Euphytica》1993,73(1-2):151-166
Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses. 相似文献
19.
Chunli TANG Fengxian ZHAO Hongxia CHEN Jiabao MA Jiangcun WEI Meiyan QIU Zhen XIE 《Medicinal Plant》2019,(6):60-65
[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination... 相似文献
20.
W. Erskine M. Tufail A. Russell M. C. Tyagi M. M. Rahman M. C. Saxena 《Euphytica》1993,73(1-2):127-135
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. 相似文献