西葫芦胚囊再生植株倍性鉴定方法研究

利用根尖细胞染色体压片和叶片保卫细胞叶绿体压片方法对西葫芦胚囊再生植株进行了倍性鉴定,结果表明,单倍体、二倍体和四倍体植株叶片表皮保卫细胞叶绿体数的均值分别为(4.15±0.37),(8.05±0.76)和(16.05±0.69),其比例约为1:2:4,说明叶片保卫细胞叶绿体压片方法能有效用于倍性鉴定;单倍体、双单倍体和四倍体叶片表皮保卫细胞的长度分别为(20.31±3.38)μm、(30.80±2.19)μm和(41.78±1.03)μm,其比例约为1:1.5:2,在胚囊再生植株倍性鉴定时也可以参照。     

由小麦×玉米获得的小麦DH系花粉母细胞减数分裂观察

研究了由小麦×玉米远缘杂交获得的小麦双单倍体DH2代花粉母细胞减数分裂过程。结果表明，大多数双单倍体小麦与异源六倍体普通小麦染色体数目相同，这是染色体经秋水仙素成功加倍的结果。同时在少数细胞中观察到了染色体的“块状移动”，在这些“块”中存在少数“染色体落后”现象，这可能是由于在染色体加倍过程中部分细胞染色体数目发生变异造成的。     

不同倍性苎麻的细胞学观察

化学药剂诱导的苎麻孤雌生殖后代植株的染色体数目变化很大, 有单倍体、 混倍体和非整倍体细胞。 在28株孤雌生殖后代植株中, 有6株单倍体细胞超过50%。 秋水仙素诱变株及多倍体杂交后代的染色体数目也呈现多样性, 不同植株甚至同一植株的染色体数目均不一致, 变化在12～84之间。 对不同倍性苎麻植株分生组织的有丝分裂行     

球茎大麦在大麦育种上的应用：Ⅰ.大麦单倍体的诱导与加倍单倍体的 …

以三种栽培大麦品种为母本,三种球茎大麦为父本进行杂交,诱导栽培大麦单倍体,结果杂交成胚率平均为４７．９％。幼胚离体培养成苗率平均为５４．０％。这些胚培苗的根尖细胞染色体数目分别含有７,１４,２１条,不同组合杂交含有的染色体数目不同,所有含有７条染色体的后代,其染色体Ｃ－带带型显示为父本栽培大麦的染色体,表明该后代为栽培大麦单倍体,用滴加０．０４％秋水仙素的Ｋｎｏｐ溶液进行单倍体植株的染色体加倍,结     

药用植物知母染色体核型分析

目的：研究分析知母（Anemarrhena asphodeloides Bge.）染色体核型。方法：采用常规制片方法,并进行显微摄影。结果：知母细胞染色体数目2n=22;核型公式K(2n)=2x=22=16m+6sm。结论：11对染色体中8对为中部着丝点染色体(m),3对为近中部着丝点染色体(sm),未发现非整倍变异和多倍现象,核型不对称上属于为“2B”。     

球茎大麦在大麦育种上的应用——Ⅰ.大麦单倍体的诱导与加倍单倍体的产生

以三种栽培大麦品种为母本,三种球茎大麦为父本进行杂交。诱导栽培大麦单倍体,结果杂交成胚率平均为47.9％,幼胚离体培养成苗率平均为54.0％。这些胚培苗的根尖细胞染色体数目分别含有7,14,21条,不同组合杂交后代含有的染色体数目不同,所有含有7条染色体的后代,其染色体C-带带型显示为父本栽培大麦的染色体,表明该后代为栽培大麦单倍体,用滴加0.04％秋水仙素的Knop溶液进行单倍体植株的染色体加倍,结果加倍率达90％以上,另外,我们还讨论了染色体消失法诱导单倍体的优越性及其机理。     

苜蓿根尖制片技术研究

为了探索苜蓿根尖压片技术方法,为苜蓿染色体制片提供参考依据。试验以苜蓿幼苗的根尖为材料,通过对预处理液、预处理时间、固定时间、染色液及染色时间进行筛选,摸索一套适合苜蓿染色体制片的技术。结果表明：苜蓿制片过程中以8-羟基喹啉为预处理液,预处理2.5 h,用卡诺氏固定液固定20 h,用1 mol/L HCl在60℃条件下解离8 min,用45%的醋酸在室温下软化20 min,以姬姆萨为染液染色3 h,压片效果较好。该研究为苜蓿倍性的直接鉴定提供了方法。     

菜用大黄染色体制片优化及核型分析

以菜用大黄根尖为材料,探讨不同取材时间、预处理溶液、解离时间对菜用大黄根尖染色体制片的影响,并对2个菜用大黄品种RAMB和RO进行了核型分析,以期为菜用大黄的起源、演化及遗传育种提供一定理论依据。结果表明,在上午8：00取材,用冰水混合物预处理24 h,然后在60℃条件下用1 mol/L HCl解离15 min,最后用改良石碳酸品红染色3～5 min,此时染色体制片效果最佳;RAMB和RO的染色体数目均为2n＝44,其核型公式分别为2n＝4x＝44＝36m＋8sm和2n＝4x＝44＝32m＋12sm,核型均为1B型,核型不对称系数分别为57．46％和58．60％,核型对称程度均较高,这表明菜用大黄在进化中处于比较原始类型。     

组织培养中大葱染色体倍性变异的研究

采用大葱茎尖分生组织直接成苗及分化丛生苗、茎盘诱导愈伤组织培养再生植株,通过染色体压片,对大葱愈伤组织及幼苗染色体数目变化进行了研究。结果表明,茎尖分生组织培养的幼苗及丛生苗遗传稳定,其染色体未发生倍性变异,均为2n=16;愈伤组织及其再生苗遗传稳定性较差,愈伤组织染色体数变异率为43.4%,其中单倍体占6.7%、三倍体占2.5%、四倍体占10%、五倍体占4.2%、六倍体占3.3%、七倍体占4.2%、八倍体占3.3%、非整倍体占9.2%;愈伤组织分化苗染色体变异率为11.7%,其中单倍体占6.7%,三倍体占1.7%,四倍体占3.3%。     

生姜染色体观察及核型分析

采用常规压片法获得了分散良好、形态清晰的生姜有丝分裂中期染色体。对其进行体细胞记数及核型分析后表明,生姜的染色体数目为2n=22;全组染色体总长度128.02μm,平均长度5.82μm,最长染色体与最短染色体之比为2.06:1,臂比大于2的染色体占全组染色体的45.5%,因此核型属于2B型,核型公式为2n=2x=22=8m+12sm+2st。     

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.     

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.     

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...     

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.     

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.     

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.     

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.