临界点干燥对杏花粉形态的影响

本文采用临界点干燥法和自然干燥法干燥了７个杏品种（种）的花粉，并进行了电镜扫描。经对比分析认为：无论花粉大小，还是花粉壁构造特征，同基因型的花粉以临界点干燥法干燥的花粉较自然干燥法干燥的花粉变异小；临界点干燥法能观察到自然干燥法观察不到的花粉三顶距、萌发孔等特征。进行孢粉学研究，临界点干燥法优于自然干燥法。     

试管中甘薯块根的形成

对桐庐林场板栗园内的６４年板栗无性系或品种的叶、叶脉、枝条皮孔、枝条颜色、雄花序、雌花以及２０个品种花粉的萌发器、形状和纹饰进行了观察分析，发现各品种之间叶形、叶厚、被毛程度、枝条皮孔数、枝条颜色有一定的差异；花粉极面观形状基本一致，但花粉萌发沟孔深度、花偻赤道面形状及花粉粒大小均有一定程度的差异。     

耐冬山茶孢粉学研究

对耐冬山茶花粉形态进行比较研究，可以为探索山茶属植物的演化、系统分类以及耐冬山茶的品种分类提供孢粉学依据。通过用扫描电镜对耐冬山茶18个品种及3个南方山茶品种的花粉形态进行观察分析，结果如下：耐冬山茶花粉粒为腰鼓形或长球形，极面观为近三角形或三裂圆形，具三孔沟，从表面看内孔不显著。外壁两层，外层厚于内层。花粉粒表面纹饰大多为蠕虫状，亦有拟蠕虫状或拟网状。脊间或网纹间具穿孔和穴，有的脊上有较明显横向波状纹，穿孔和穴的形态及数量品种间有差异。花粉粒形态可以做为耐冬山茶品种分类的依据之一，耐冬山茶和南方山茶品种花粉形态存在较大的差异。 关键词：耐冬山茶；花粉；品种     

铁筷子花粉育性与形态比较研究

利用花粉离体萌发法探索适合铁筷子花粉离体萌发的培养基,测定并比较了供试铁筷子花粉的生活力;利用Hitachi TM3000型扫描电子显微镜对铁筷子花粉粒进行形态观察。结果表明:0.5%琼脂+10%蔗糖+30 mg/L硼酸+30 mg/L氯化钙是最适宜铁筷子花粉萌发的离体培养基,野生铁筷子花粉育性明显强于园艺品种。铁筷子花粉粒为长球形,具3条萌发沟,等间距环状分布,属于N_3P_4C_5型花粉,极面观为三裂圆形或近三瓣形,同时在花粉粒大小、邻孔脊宽、单位面积穿孔数和外壁纹饰上存在显著差异,主成分分析和聚类分析均能很好地区分野生铁筷子与园艺品种。花粉粒的形态特征和花粉育性可为铁筷子种和品种间鉴别和杂交育种提供重要依据。     

10个八仙花品种花粉粒形态扫描电镜观察

利用电镜扫描观察10个八仙花品种的花粉粒,根据花粉粒的形状、长短轴比、萌发沟特征、纹饰特征、极面特征等分析八仙花不同品种间以及孕性花粉粒形态特征的差异性.结果 表明,八仙花可孕花的花粉粒均为长球体,除了'无尽夏'和'奥塔克萨'不孕花花粉粒为超长球体外,其他也为长球体,均具3条萌发沟,沟长裂至两极,属于N3P4C5型花粉;花粉粒极面形状有差异,'无尽夏'、'奥塔克萨'、'蒙娜丽莎'、'头花'和'初恋'极面观为三裂圆形,其他品种极面观为钝三角形;不同品种花粉粒的萌发沟长度与萌发沟脊面宽也存在差异,仅'玫红妈妈'不同孕性花粉粒具有显著性差异.外壁纹饰均为孔穴状,其孔穴大小、形状以及分布特征不同,但是同一品种的不同孕性花粉粒形态特征并无差异.综上所述,花粉粒的外壁纹饰可作为八仙花品种鉴定的依据之一,但是不能作为花粉孕性的鉴别依据.     

普通小麦雄性不育系及其保持系花粉形态的扫描电镜观察

利用扫描电镜观察了4种细胞质类型普通小麦(T. aestivum)雄性不育系及其保持系共16个材料的花粉形态,结果表明:不同细胞质类型雄性不育系之间的花粉粒形状及花粉粒表面纹饰有一定的差异,但花粉粒的大小、花粉粒萌发孔特征与不育细胞质类型无相关关系。不育系与其保持系在花粉粒形状、花粉粒表面纹饰方面也存在着明显的差异。     

观赏海棠不同品种花粉形态扫描电镜观察

海棠花粉特性的研究,对于品种改良与育种操作、基因保存等具有非常重要的意义。本研究利用扫描电镜观察20种观赏海棠的花粉形态特征,测定各品种花粉粒的孔穴大小及密度、条脊宽、条脊距、极轴长以及赤道轴长。结果表明,20个海棠品种的花粉形状为长球形或超长球形,侧面观为长椭圆形,极面观为三角形,属于N3P4C5型花粉。花粉外壁均具有条脊,且不同品种花粉的条脊宽、条脊距、孔穴大小等有显著的形态差异。通过聚类分析,在相似距离为15时,20个海棠品种分为四大类群。本研究将为海棠品种鉴定及系统分类提供孢粉学依据。     

滇Ⅰ型粳稻不育系花粉败育状况分类研究

对供试的114个滇I型粳稻不育系花粉镜检，结果表明：滇I型不育系的大部分材料中均有染败花粉粒，但染败花粉粒所占比率因保持系来源的不同而有差异。其中有23份材料的花粉粒全部为圆败和碘败，这些材料以圈败花粉粒所占的比率较大，圆败花粉率占50％以上的有16份，占无染败花粉材料的69．56％，滇I型不育系中未发现全部为碘败花粉的材料。用败育程度较高(花粉粒全部为圆败和碘败)的不育系材料分别与南29和南34测交，杂交组合育性均可恢复，南29和南34对败育程度较高的滇I型不育系仍具有恢复力。     

抽穗开花期不同高温处理对水稻开花习性和结实率的影响

为了探明高温胁迫对水稻的伤害机理,利用人工气候箱在水稻抽穗开花期对2个耐热性不同早稻品种进行不同高温处理,研究高温胁迫对水稻开花习性和结实率的影响。结果表明,随着胁迫温度的升高,日开花数减少,日开花峰值降低,开颖角度减小,花粉粒直径增大,花药开裂、花粉活力、柱头活力下降,结实率降低。相关分析表明,2个品种的结实率与花粉活力、花药开裂系数、柱头活力之间均呈显著正相关（R=0.9733*,0.9768*和0.9270*）。水稻抽穗开花期受高温的危害存在品种间差异,相同高温胁迫下,耐热品种996受高温的伤害小于热敏感品种4628。     

澳洲坚果花粉保存及生活力测定

为研究澳洲坚果花粉最佳保存方法,为人工授粉提高产量及杂交育种亲本组合提供理论依据,以澳洲坚果品种D的花粉为材料,采用自然干燥,干燥皿干燥,40 ℃烘箱干燥3种干燥方式,分别干燥2 h,6 h,10 h,24 h,并在低温（4 ℃）条件下保存5 d、10 d、15 d、20 d、25 d、30 d,以琼脂培养法测定花粉萌发率。结果表明：自然干燥和干燥皿干燥方式下花粉萌发率差异不显著,但两者均极显著高于40 ℃烘箱干燥方式下的花粉萌发率;自然干燥下4个干燥时间在保存了20 d内的花粉萌发力均能用于人工授粉;干燥皿干燥2 h、6 h保存20 d内的花粉萌发率均在15%以上,可以在生产中应用;40 ℃烘箱干燥方式处理下,所有干燥时间和保存时间的花粉萌发力均在15%以下,对于人工授粉没有价值;在低温（4 ℃）保存下,澳洲坚果花粉萌发率以自然干燥方式下干燥2 h保存5 d最佳,为42.24%;但是综合考虑外界环境调控的容易程度,在生产中选择干燥皿干燥方式为最佳。     

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.