甜玉米(Zea mays L.saccharata Sturt)含糖量与主要农艺性状的相关及通径分析

为选育含糖量高的甜玉米品种,本试验对甜玉米含糖量与主要农艺性状进行相关性分析。结果表明,含糖量与穗长、株高、穗位呈正相关,与单穗重、秃尖长、穗粗、穗行数、行粒数、轴重、轴粗、百粒重、茎粗呈负相关。在实际选择中可以参考这些性状来选择含糖量高的甜玉米。为了更加清楚地了解各主要农艺性状和含糖量之间的直接效应和间接效应,对此进行通径分析,结果表明,各农艺性状对含糖量的通径系数顺序为穗长>株高>轴重>穗位>单穗重>穗粗>茎粗>行粒数>穗行数>百粒重>轴粗>秃尖长>皮渣率。本研究为今后选育含糖量高的甜玉米品种提供了重要的参考依据。     

不同草地早熟禾品种愈伤组织再生体系研究

草地早熟禾(Poa pratensisL.)是一种复杂的多倍体植物且具有兼性无融合生殖方式,建立高效的愈伤组织培养体系是进行基因工程育种的重要环节。本研究利用生产中常用的6个草地早熟禾品种为材料,经愈伤组织诱导后,对其愈伤组织分化及再生体系进行了研究。结果发现,不同草地早熟禾品种的分化再生能力具有明显的差异,不同激素处理组合对草地早熟禾愈伤组织的分化有显著的影响:品种如帝王、超级伊克利、蓝鸟等较易分化和再生,品种如盛宴、布鲁克等则只在特定条件下分化和再生;培养基激素处理组合Ⅴ(2mg/L6-BA+0.1mg/L2,4-D)较适合于所有检测的品种,处理组合Ⅳ(2mg/L6-BA)和Ⅵ(2mg/L6-BA+0.2mg/L2,4-D)对部分品种的分化有较大的促进作用。研究同时评估了2种激素配比(6-BA和2,4-D)对早地早熟禾愈伤分化再生的影响,发现不同草坪草品种对单独使用的6-BA浓度敏感性不同,补加2,4-D后不同品种的分化率也存在明显差异。研究建立的不同草地早熟禾品种的高效再生体系,不仅有利于这些品种的基因工程改造,也为草地早熟禾愈伤组织再生体系研究奠定了重要的理论基础。     

New efforts to overcome apomixis in Poa pratensis L.

Summary By means of a new method, plants of Poa pratensis can be classified rapidly and reliably as to whether they are capable or incapable of parthenogenesis. Parthenogenesis was found to be under strong genetic control, dominant over obligatory fertilization. The selected sexual plants lack all genes/alleles responsible for parthenogenesis, while the polyploid apomictic varieties investigated were heterozygous with one or more dominant alleles. Also dosage effects and/or modifying genes are probably involved. Crosses of sexual individuals with various apomictic varieties resulted in sexual as well as highly apomictic F₁ hyrids. A scheme of recurrent hybridization for breeding of Kentucky bluegrass is proposed.Two other experimental ways to overcome apomixis in Poa pratensis were studied in addition. By application of growth regulators temporary sexuality could not be induced. Attempts of in vitro regeneration of plants from endosperm resulted only in callus and root formation.     

野生草地早熟禾单株移栽法成坪特性初探

通过对单株移栽法建坪的几种野生草地早熟禾成坪初期生长、分蘖和根茎特性进行比较研究，探讨其对成坪特性的影响．旨在为草地早熟禾的建坪及开发利用等提供科学依据。结果表明：不同野生居群在分蘖、地下根茎特性和成坪速度上存在巨大差异。5月底，分蘖数变异范围为47．3-96．7，根茎数变异范围为31．66-41．33条，变异系数高达41．2％；成坪速度与分枝角度之间存在极显著负相关．相关系数为-0．811；坪用价值综合评定中．05P06和05P10表现良好。     

旅游景观早熟禾养护肥应用效果的研究

为研究早熟禾养护肥的实际应用效果。试验以4年生早熟禾为试材,设置纯氮、氮磷、氮磷钾、有机氮4个处理,氮用量均为91.09 kg/hm2,1个对照,3次重复。结果表明：氮磷对提高叶绿素a含量效果最佳,7月份比对照提高33.33%,而有机氮比对照降低2.33%;氮磷处理可以显著提高叶片内叶绿素b含量,9月份比对照提高48.08%,氮磷钾处理提高46.15%;氮磷处理类胡萝卜素含量7、9月显著高于对照,10月比对照提高33.33%,纯氮处理仅提高2.38%;叶片长度氮磷处理6~10均显著高于对照,有机氮处理与对照间无显著差异。综合分析认为,氮磷处理效果最佳,有机氮处理最差。     

Chromosome number and plant morphology in some ecotypes of Poa pratensis L.

Summary In a collection of Poa pratensis the variation in chromosome number and the relation between chromosome number and plant characters were studied. The material was collected at different places in the Netherlands. The number of chromosomes in the population varied from 33 to 92. Plants with 56, 63, 70 and 77 chromosomes were in the majority. The occurrence of different chromosome numbers within almost all investigated plants led to the conclusion that aneusomaty is a rule in Poa pratensis. In the progeny of some plants chromosome numbers were found which were considerably higher than those in the mother plants. It was assumed that this rise in chromosome number was caused by fertilization of aposporous egg cells. No relation could be found between chromosome number and plant characters. A hemiploid plant (39 chromosomes) was marked off from its sibs (77 chromosomes) by a stunted growth and pale leaf colour.     

Evolution and adaptedness in a facultatively apomictic grass, Poa pratensis L.

Summary Facultative apomixis confers great adaptedness and evolutive potential on biotypes belonging to the Poa pratensis L. agamic complex. Pioneering and recent research have dealt with and sometimes elucidated different aspects of apomictic expression, such as cytological mechanisms, distribution patterns, genetic control and environmental effects, in this species. We carried out an investigation on the mode of reproduction expressed in Italian natural populations, cultivars and selected genotypes together with an extensive time (56 years) and space (six countries) review in order to obtain a comprehensive picture of apomixis expression in P. pratensis. Histograms of the estimations were prepared. They showed that, due to breeder and natural selection, both cultivars and natural populations very frequently expressed a high degree of apomixis. Variations in the degree of apomixis across generations, different pollen donors, environments and estimation levels were generally low. It would, therefore, seem that the tenet which holds that apomixis in P. pratensis is strongly influenced by external factors should be reconsidered. Despite the fact that little is known of the genetic, physiological and molecular control underlying apomixis, the overall picture that emerges from our study helps to explain how the balance between sexual and asexual reproduction confers extreme versatility, adaptedness and evolutive capacity on this remarkable grass.     

Callus Production and Plant Regeneration from Mature Embryos of Poa pratensis L.

Plant regeneration from callus cultures may provide a source ot somaclonal variation for the improvement ot the apomictic grass Poa pratensis L. It is first necessary to be able to induce callus and regenerate plants in this species at a high frequency. Variation was observed between 50 cutivars of Poa pratensis for callus induction and plant regeneration. Using the cultivars ‘Merion’ and ‘Victa’, three basal media were tested along with various media additives. Murashige and Skoog's basal medium with 0.2 mg 1^?1 2,4-dichlorophenoxyacetic acid, 0.1 mg 1^?1 6-benzylamanopurine, 100 mg 1^?1 casein hydrolysate and 25 g 1^?1 sucrose is considered to be a good medium for callus growth and plant regeneration. Embryo-like structures were observed in the callus of some cultivars but plant regeneration appeared to be predominantly from shoot meristems on the callus surface. The majority of regenerated shoots were green, but chlorophyll deficient shoots were obtained from media containing coconut milk. Green plantlets could be transferred to soil without difficulty.     

沼液对早熟禾种子萌发及幼苗生长的影响

为研究不同浓度青霉素菌渣厌氧发酵沼液对早熟禾种子萌发和幼苗生长的影响,用不同浓度沼液对早熟禾种子进行催芽和浸种试验。结果表明,采用高浓度沼液催芽和浸种,严重阻碍了早熟禾种子萌发及生长,随着沼液稀释倍数的增加,抑制作用逐渐消除;当沼液稀释100倍进行催芽和浸种为最适浓度,活力指数比对照分别提高了35.38%、39.49%;根长比对照分别提高了42.91%、31.64%;芽长比对照分别提高16.37%、10%。     

青海扁茎早熟禾种子成熟过程中落粒性与生长生理特性的研究

研究了青海扁茎早熟禾(Poa.pratensis var.anceps Gaud.cv.Qinshai)种子成熟过程中落粒率与生长、生理特性间的相关关系.结果表明,青海扁茎早熟采种子落粒率与种子含水量、可溶性糖、电导率问呈极显著的负相关关系,与种子干重、淀粉、TTC、发芽率、发芽指数、活力指数、种苗芽长、盛花期后天数间呈极显著的正相关关系.在青海扁茎早熟禾盛花期后第28天,其种子含水量为35%,发芽率83.33%,发芽指数68.67,活力指数98.36,种苗芽长2.45 cm,电导率346.01μS/cm,ITC含量54.46μg/ml,可溶性糖含量7.27%,淀粉含量14.83%,落粒率为15.89%.种子已经达到生理成熟,此时采收,可获得最佳的种子产量和品质.