玉米花粉超低温长期保存后其后代的染色体观察

玉米自交系郑１１４２的花粉在－１９６℃保存１～２年后，田间授粉于原自交系郑１１４２，获得的后代植株，其花粉母细胞减数分裂时染色体数目和结构均属正常     

不同萌发率胡杨种子萌发前后同工酶动态变化分析

对不同萌发率的胡杨种子萌发前后酯酶同工酶、过氧化物酶同工酶和超氧化物歧化酶同工酶电泳谱带的动态变化进行分析.研究表明:对于吸胀的种子,过氧化物酶同工酶没有表达;酯酶同工酶得到表达,且萌发率中等的种子表达最高;超氧化物歧化酶同工酶也得到表达,但萌发率高的种子几乎没有表达;对于干种子,酯酶同工酶没有表达,过氧化物酶同工酶得到表达,且萌发率中等的种子表达最高;超氧化物歧化酶同工酶得到充分的表达.     

洋槐种子脱氢酶过氧化物酶及同工酶研究

种子贮存过程中生活力下降,常伴随着细胞质膜的损伤,严重时使种子失去萌发能力或出现畸形苗和死苗。而过氧化物酶作为保护质膜不受过氧化物的破坏已有研究报导,故过氧化物酶的延缓种子老化作用是值得注意的。本文以洋槐种子为材料,测试正常种子萌发过程中过氧化物酶及同工酶的变化;老化种子电导率、脱氢酶、过氧化物酶及同工酶的关系。     

用等电聚焦法对茄子种子几种同工酶的研究

通过等电聚焦电泳方法对茄子种子进行同工酶分析，发现酯酶和过氧化物酶同工酶酶谱在父本、母本及杂交一代之间有一定的差别，而且这种差别有一定的时间局限性。而酸性磷酸酶的同工酶酶说在茄子的亲本和杂交一代间没有差别。由于茄子种子同工酶酶谱有一定的差别，因此可以利用这种差别来进行种子纯度检验。     

用等电聚焦法对茄子种几种同工酶的研究

通过等电聚焦电泳方法对子种子进行同工酶分析，发现酯酶和过氧化物酶同工酶酶谱在父本，母亲一及杂交一代之间有一定的差别，而且这种差别有一定的时间局限性。而酸性磷酸酶的同式酶酶说在子的亲本和杂交一代间没有差别。由于茄子种子同工酶酶谱有一定的差别，因此可以利用这种差别来进行种子纯度检测。     

秋水仙素处理对益母草种子生理生化的影响

研究了秋水仙素处理对益母草种子生物生化变化的影响。方法：以益母草种子为材料，观察了不同程度秋水仙素处理后，酯酶同工酶、过氧化物酶同工酶、发芽、生长情况等的变化。结果：与对照相比，发现各种程度秋水仙素处理的益母草种子，过氧化物酶同工酶带无明显变化；用0．05％－0．5％浓度秋水仙素分别处理益母草种子，酯酶同工酶谱带有增多的现象；并且用不同浓度秋水仙素处理12h后，发现用0．2％浓度处理的种子生长较好。结论：说明一定程度秋水仙素处理就改变益母草种子中酶数量；用0．2％浓度的秋水仙素处理最有利于提高益母草的产量。     

杂交玉米自交系防杂保纯措施

1原原种套袋繁殖 1．1种子来源 原原种套袋繁殖的种子，应是选育单位或育种家保存的亲本自交系种子，或在原种繁殖区选择的具有原自交系典型性状的优良单穗。     

匍匐翦股颖新品系酯酶和过氧化物酶同工酶研究

通过垂直平板聚丙烯酰胺浓度梯度凝胶电泳,分析了匍匐翦股颖(粤选1号、新品系2号、3号、4号)和原品种匍匐翦股颖Penncross的酯酶、过氧化物酶同工酶。结果表明：新品系的酯酶同工酶、过氧化物酶同工酶酶谱具有原品种Penncross全部或大多数酶带,出现数量不等的Penncross所没有的新酶带,也出现酶带的减少,另外,新品系的POD同工酶活性明显比Penncross强。     

西瓜同工酶及可溶性蛋白分析

对京欣一号西瓜的亲本及杂种一代的几种同工酶系统及可溶性蛋白进行了分析。结果表明，在种子萌发过程中，过氧化物酶、酯酶和可溶性蛋白随发育阶段或营养状况的改变而改变；而在相同萌发时期，过氧物酶工酶、酯酶同工酶、过氧化氢酶同工酶和淀粉酶同工酶在亲本及杂种间未见差异，杂种的可溶性蛋白图谱表现与母本相同，而与父本有差异。此外，对６个品种的西瓜、非洲西瓜和瓠瓜的分析结果表明，非洲西瓜和瓠瓜的过氧化物酶酶谱、酯酶     

不同剂量~(60)Co-γ射线对小麦、水稻幼苗生长的影响

用10—30KR剂量~(60)CO—γ射线处理小麦中引15、St和水稻沪B干种子、幼苗生长期胚根、子叶发育受到明显抑制.对幼苗生长的影响后期(萌发5天后)比早期(开始萌发至萌发第5天)明显,芽鞘的发育对γ射线不敏感.过氧化物酶同工酶的分析结果表明,发育受抑的小麦St、水稻沪B胚根中各增加1—2条负极酶带;发育受抑的小麦中引15、St、水稻沪B子叶中,过氧化物酶同工酶没有产生变化,而从外部形态特征上看没有变化的中引15芽鞘中比对照多2条正极带.上述结果表明,经r射线照射后,植物外部形态特征的变化与内部过氧化物酶同工酶的变化并不完全相关.     

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.