棉花种子生活力生化(四唑)测定研究

种子生活力的四唑测定是在短期内急需了解种子发芽率或当某些在发芽末期尚有较多的休眠种子时,可应用生活力生化(四唑)染色法快速估测种子生活力.     

浅析种子生活力的四唑测定

实际工作中时常需要在短时间内掌握种子批的生活力状况，如果种子处于休眠状态则难以通过发芽测定得到结果。种子生活力测定可以满足这一要求，四唑测定可以测定出休眠种子样品的生活力百分率。四唑测定法于1942年由德国的莱康教授发明，随着四唑测定技术的发展，ISTA（国际种子检验协会）于1950年成立四唑测定技术委员会。     

浅析种子生活力的四唑测定

在实际工作中时常需要在短时间内掌握种子批的生活力状况,如果此时种子处于休眠状态则难以通过发芽测定得到结果。种子生活力测定可以满足这一要求,四唑测定可以测定出休眠种子样品的生活力。四唑测定法于1942年由德国的莱康教授发明,随着四唑测定技术的发展,ISTA（国际种子检验协会）于1950年成立四唑测定技术委员会。     

濒危植物永瓣藤种子生活力测定研究

永瓣藤为我国东部特有的濒危物种,在系统发育、生态和药用等方面具有重要的意义,因其种子具有休眠特性,常规的发芽试验法很难快速、准确测定其种子生活力。采用四唑染色法,设置不同的TTC质量分数、TTC的pH值、染色时间的正交试验,研究永瓣藤种子的生活力测定条件。结果表明,TTC法能快速有效地测定永瓣藤种子生活力,对生活力测定的影响因子从大到小依次为TTC质量分数、pH值和染色时间,其染色最佳条件是用pH值为7.0,1.0%(w/v)TTC溶液避光染色3 h。     

打破小麦种子休眠的方法

种子休眠通常是指具有生活力的种子在适宜的萌发条件下仍不萌发(发芽)的现象,是植物在长期的系统发育过程中形成的抵抗外界不良环境条件,以保持物种不断发展与进化的生态特性.种子休眠对于植物延续种和物种是十分有利的,但是对于农业生产而言,休眠的种子发芽力降低,会严重地影响田间出苗率.     

3种阔叶树种子生活力四唑法测定研究

本文对山玉兰、厚朴、黄山栾树这3种阔叶树种子生活力四唑测定法进行了研究,探讨各种种子适宜的预处理方法和四唑溶液浓度.结果表明:除黄山栾树种子外,另外2种种子需要全部去除种皮;在25℃测定条件下,测定山玉兰和厚朴种子生活力的最佳处理浓度为0.5%的四唑,黄山栾树用0.1%浓度的四唑;在种子生活力测定时,低质量的种子容易加大实验误差,并对所采用四唑溶液的浓度和种子预处理方法产生影响.     

云木香种子质量检验方法的研究

目的:研究云木香种子质量检测方法,为制定云木香种子检验规程以及种子质量标准提供依据.方法:参考国际植物种子检验规程和中国农作物种子检验规程的方法;结果与结论:采用风选法筛选云木香种子;种子净度为80%～90%;种子质量的测定方法宜选用百粒法;种子水分的测定用低恒温烘干法,烘干时间为4h;用四唑染色法测定种子生活力的最佳条件是种子常温浸泡12 h,TTC溶液浓度为0.5%,染色温度为35℃,染色时间3h;云木香种子发芽最适温度为25℃,不需光照,发芽床选纸上或纸间均可,发芽初次计数时间为置床后第4天,末次计数时间为置床后第8天.     

23种热带及亚热带林木种子生活力的生物化学测定研究

对23种热带及亚热带林木种子用四唑生化测定方法测定了种子生活力,而且在实验室测定了其幼苗成苗率及幼苗性状,确定了前者与后者的相互关系。用四唑染色图型法(TZ图型法)鉴定种子生活力,并结合种子形态、解剖构造进行分析。在上述试验研究的基础上,提出了热带及亚热带树种各类型种子的四唑染色技术要点,确定了种子预处理方法、四唑浓度、染色温度、染色时间,制定了各类树种种子四唑鉴定标准。     

几种小粒蔬菜种子的生活力测定

种子发芽试验是种子质量鉴定项目中重要检测内容，是判定种子质量优劣的重要指标。由于部分作物种子存在休眠、种皮不透气、不透水等影响，往往难以鉴定出种子的真实发芽水平。而种子生活力测定可反映出休眠种子是否具有发芽潜力，具有准确和快速的优点，企业在急需调种和种子样品中休眠种子较多的情况下可采用种子生活力测定方法来预测种子的田间出苗情况。通常，对于大粒作物种子如玉米、棉花等生活力测定技术被广泛采用，技术好掌握，但部分蔬菜种子因籽粒小，内部构造不易辨认，种子的制备和判定存在较多的技术难点。本人根据多年经验，对较难掌握的几种蔬菜种子生活力鉴定方法和判定标准进行阐述，供检验员参考。     

玉米种子生活力与发芽率的回归分析

种子部门在收购、调拨、仓贮、销售和播种前需要了解玉米种子的用价,常规发芽试验需要时间长,因此,有必要探讨一种快速简便的方法。目前,红四唑染色法是国际上应用较广泛的一项种子生活力检验技术。它可以快速检验种子生活力,又不受种子休眠的限制。种子生活力是种子潜在发芽力。在不能或不便进行常规发芽试验时,种子生活力是一项     

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.     

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...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

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...     

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.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.