凤仙花种子的贮藏和葫发特性研究

通过比较普通开放式贮藏、0～4℃冷冻贮藏和硅胶干燥贮藏条件下的凤仙花种子的活力和细胞膜完整性的变化,发现硅胶干燥贮藏能保持凤仙花种子较高的活力,是一种理想的贮藏方法.     

凤仙花种子的贮藏和萌发特性研究

通过比较普通开放式贮藏、0～4℃冷冻贮藏和硅胶干燥贮藏条件下的凤仙花种子的活力和细胞膜完整性的变化,发现硅胶干燥贮藏能保持凤仙花种子较高的活力,是一种理想的贮藏方法。     

大葱种子超干贮藏遗传完整性的过氧化物同工酶和酯酶同工酶研究

用硅胶干燥法对3种大葱种子进行超干燥处理,得到不同含水量的大葱种子,密封室温中保存1年.1年后进行过氧化物酶和酯酶同功酶分析,结果表明,大葱种子适度干燥后种子遗传完整性保持良好,但种子含水量降至2.0%以下时,大葱种子的耐贮性下降,遗传完整性受到影响.这两种同功酶技术适合用于大葱种子超干燥贮藏的遗传完整性的检测.     

贮藏温度、含水量及干燥方法对黑杨派杨树种子耐贮性的影响

干燥方法、种子含水量、贮藏温度和贮藏时间均对辽宁杨和Ⅰ-72杨种子的发芽率、成苗率、苗高、胚根长度等活力指标有极显著影响.对于杨树种子的贮藏,室内阴干等缓慢脱水的干燥方法较硅胶干燥等快速脱水的方法好,尤以室内阴干Id为最好.低温条件可提高种子的耐贮性,辽宁杨种子温度越低贮藏效果越好,其中以-70℃最好;Ⅰ-72杨种子以4℃的低温贮藏效果最好.在各种贮藏温度条件下,随着贮藏时间的延长,种子的各项活力指标均明显降低.对于杨树种子贮藏而言,贮藏温度比干燥方法和种子含水量更重要.     

超低水分贮藏对几种高油分种子生活力的影响

试验应用氧化钙、氯化钙、硅胶为干燥剂,以不同剂量分别干燥油菜、萝卜、黑芝麻、白芝麻种子,研究超低水分贮藏对高油分种子生活力的影响。结果表明,干燥剂种类和剂量对种子失水速度有明显影响,用氧化钙或氯化钙干燥,种子失水速度较用硅胶干燥为快;干燥剂剂量愈大,种子失水速度愈快。干燥至低水分和超低水分的4种种子在常温下贮藏6～11个月,种子生活力和活力无显著变化;油菜种子水分低至0.2%,萝卜低至0.3%,黑芝麻、白芝麻低至0.6%,均未发现干燥伤害和吸胀损伤。经50℃高温老化14天后,油菜种子水分为0.7%～3.5%、萝卜为0.6%～3.5%,黑芝麻为0.6%～3.5%、白芝麻为0.7%～3.9%,能保持较高的生活力和活力。4种高油分种子耐干性均极强,采用超低水分贮藏可大大延长种子寿命。     

不同贮藏条件和低水分处理对菜豆种子活力的影响

采用不同的温度及相对湿度和低水分处理对菜豆种子进行贮藏,以研究不同贮藏条件下和低水分处理对种子发芽率、活力指数及某些生理生化特性的影响,结果表明,菜豆种子在低温低温及低水分处理条件下贮藏8个月后,仍可保持高的活力,细胞膜能保持较好的完整性,过氧化氢酶、过氧化物酶和酸性磷酸酶的活性较高。而在高温高温条件下贮藏4个月,室温开放贮藏6个月后菜豆种子的发芽率迅速下降,不再适合作种子用。     

超干处理和贮藏对番茄和辣椒种子生活力和活力的影响

试验采用氧化钙为干燥剂对番茄和辣椒种子进行超平处理和贮藏，以研究其对种子生活力和活力的影响。结果表明，番茄种子水分降至3．77％、辣椒种子水分降至3．86％，未发现对种子生活力和活力有明显的影响；对不同含水量的番茄和辣椒种子室温密闭贮今6个月后的调查结果发现，超低水分种子生活力和活力较高，细胞膜能保持较好的完整性，脱氢酶活性和呼吸强度较高。由此可见超干贮藏有利于保持番茄和辣椒种子的生活力和活力。     

不同贮藏条件和低水分处理对菜种子活力的影响

采用不同温度及相对湿度和低水分处理对菜豆种子进行贮藏,以研究不同贮藏条件下和低水分处理对种子发芽率,活力指数及某些生理生化特性的影响,结果表明,菜豆种子在低温低湿及低水分处理条件下贮藏８个月后,仍可保持高的活力,细胞膜能保持较好的完整性,过氧化氢酶过氧化物酶和酸性磷酸酶的活性较高,而在高温高湿条件下贮藏４个月,室温开放贮藏６个月后菜豆种子的发芽率迅速下降,不再适合种子用。     

黄花补血草种子超干保存的研究

在室温条件下采用硅胶干燥法,将黄花补血草种子的含水量降至5％以下。结果表明,在同等老化的条件下,与对照相比较,超干处理的黄花补血草种子发芽率、活力指数保持较高的水平,抗老化能力显著提高。种子含水量不低于3．54％时,超干处理对种子的发芽率、发芽指数和活力指数没有影响。通过对超干种子相对电导率、脱氢酶活性和丙二醛含量的研究表明,适度超干处理对种子细胞膜的完整性没有破坏。试验结果说明,利用超干技术保存黄花补血草种子是可行的。     

超干燥水稻种子贮藏研究

硅胶作干燥剂,超干燥水稻种子（灿,粳）。研究不同干燥方式的干燥速度及对种子生活力的影响。由含水量８．１％￣９．４％干燥至７％、５％、４％、３％,２％后密封贮存于０℃,温室（１５￣３０℃）,４５℃。定期测定种子生活力和活力。结果表明,种子与硅胶重量之比１：１０加风扇干燥速度最快,几种干燥方式对种子生活力没有影响。水稻种子的超干燥临界含水量为３％。经过５年３个月的贮藏后表明,贮于４５℃老化的籼,粳稻种     

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.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

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.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...