黄土性土壤固化对黑麦草生长和根系活力的影响

采用盆栽试验,研究了安塞黄绵土不同容重、不同固化剂(路邦EN-1固化剂)掺量对黑麦草生长和根系活力的影响.结果表明:黄绵土容重在1.2～1.4 9·cm-3范围内,随土壤容重的增加,黑麦草叶绿素含量、根系活力、根冠比、根生物量和植株生物量均降低;各土壤容重条件下,黑麦草叶绿素含量、根系活力、根冠比、根生物量和植株生物量均高于对照,且随着固化剂掺量的增加均呈先增加后降低的趋势.土壤容重和固化剂掺量交互作用对根生物量和总生物量的影响均显著(P＜0.05).总体来看,土壤容重1.3 g·cm-3、固化剂掺量0.15％处理下,各指标值均最高.     

Efficacy of Selective Gametocides on Lolium perenne L.

The efficacy of six chemicals as selective male gametocideson perennial ryegrass plants was studied by making use of agenetic marker technique. In a preliminary screening experimenteach of the chemicals was used in five concentrations and infive treatments at several stages of development at or nearear emergence. Promising treatments from within this experimentwere assessed in more detail subsequently. In most treatmentsfemale fertility was impaired more than male fertility. In thetreatments in which the desired effect was found, i.e. malefertility was depressed appreciably more than female fertility,the differential gametocidal selectivity of the chemicals couldnot be considered distinct enough to merit application on afield scale.     

Genetic control of androgenetic response in Lolium perenne L.

In a study of androgenesis in 90 Norwegian genotypes of perennial ryegrass (Lolium perenne L.), heritabilities ranged from h _b ² =0.46 to 0.80. Very high or completely positive genotypic correlations were found between most characters of androgenetic response (e.g. embryo-like structures per 100 anthers, plants per 100 embryo-like structures, albino plants per 100 anthers, green plants per 100 anthers). Three genotypes, 2 Norwegian (7-5 and 9-5) and 1 Danish (245), which had significantly different androgenetic responses were selected to study the genetic control of the processes. Genotypes 7-5 and 9-5 were highly embryogenie, 7–5 and 245 were relatively high producers of green plants, while 9-5 was unable to produce green plants. The six possible reciprocal crosses between these three genotypes were made, and 10 or 11 F₁ plants from each cross were used for anther culture experiments. The cross 7-5 x 245 showed average superiority over both parents for total plant regeneration and green plant production, results not previously reported. The phenotypic correlations estimated among progenies from the crosses ranged from r=-0.99^*** to 0.81^***. These considerable changes, relative to the results of the screening experiment, are most likely the result of changed allele frequencies caused by the strong selection of parents in these crosses, and a relatively simple genetical control. This is also inferred from the large transgressive segregation observed.Abbreviations ANT anthers - ELS embryo-like structures - ALB albino plants - GRP green plants - DH doubled haploid plants     

The genetic control of incompatibility in Lolium perenne L.

An examination of the incompatibility mechanism of Lolium perenne using the pollen stigma reaction has revealed that no precise one or two locus system is operative in this species.     

黑麦草内生真菌感染状况的检测及定量分析

选取内生真菌特异性引物,成功建立了利用PCR技术对黑麦草中内生真菌感染状况的检测和定量分析方法。此检测方法的准确性高于常规乳酸-苯胺蓝染色法。利用实时荧光PCR定量分析的结果表明：不同植株之间内生真菌含量差异较大,而同株植物相同龄级分蘖之间内生真菌含量无显著差异。由此可见内生真菌的含量不仅与植物种以及品种有关,也与植物的基因型密切相关。     

Nitrogen uptake and root morphological responses of defoliated Lolium perenne (L.) to a heterogeneous nitrogen supply

Lolium perenne L. (c.v. Magella) plants were grown under three nutrient treatments for six weeks and then defoliated to test the hypothesis that for their regrowth they could acquire N equally well irrespective of N distribution. Two different N levels were applied; uniform level 1 N (U1), uniform level 2 (U2) and heterogeneous level 2 (H2). A system where the nutrient patch could be applied without barriers to root growth was adopted. A single defoliation to 4 cm height resulted in a reduction in tillering, biomass increment and N uptake at 3 weeks after defoliation. Root growth was reduced by defoliation under all N treatments. Defoliation was found to reduce the proportion of N in the shoots which was derived from root uptake from 7 to 14 days. At 21 days this effect was significant for the plants with a heterogeneously distributed supply only. By the end of the regrowth period, the undefoliated plants from H2 had a shoot biomass and N content equal to that of plants receiving the same total N but supplied homogeneously (U2). However, defoliation reduced the ability of the plant to acquire N from the patch. No preferential root growth was measured into the N-rich patch, but an increased root diameter within the patch was found. Root diameter was reduced by defoliation, coinciding with a reduction in concentration of N in the root tissue. As a result of the increased sink strength of the growing leaves after defoliation, the roots may become a source of carbon and also nitrogen. These responses to an N-rich patch under defoliation could alter a plant's competitive balance in a mixed sward. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of sheath tube length on leaf development in perennial ryegrass (Lolium perenne L.)

Position in and contribution of leaf laminae to the canopy of forage grasses are important both in determining herbage growth rates and intake rate by grazing animals. These canopy characteristics are controlled by the way dry matter is apportioned between sheath and lamina in growing leaves. The objective of this work was to determine how the development of individual leaves is affected by altering the effective length of the psuedostem tube, on the assumption that the light environment within the tube varied. The development of a leaf from initiation at the apex to maturity was followed by successive destructive dissections of tillers. Vertical incisions were made in the pseudostem of each tiller to three different depths. The three treatments imposed were — no incision (control), moderate and severe incision of the sheath length. Destructive harvests of tillers followed 3, 6, 12 and 24 days after imposition of treatments. Incision resulted in the length of the monitored leaf being reduced significantly at all harvests, and differentiation of the sheath beginning earlier. The length reduction reflected a reduction in both cell size and cell number and the effects were evident at the earliest harvest. The data support the theory that leaf size and timing of onset of sheath development are influenced by the environment of the developing leaf. The present results indicate that sheath tube length affects leaf development and suggests that the effects are substantially explained by a direct light effect on the location and depth of the elongation zone.     

Bioactivity of a pentapeptide isolated from corn gluten hydrolysate on Lolium perenne L.

Corn gluten hydrolysate (CGH) has been observed to inhibit root formation of germinating grass seeds and has the potential for use as a natural herbicide. Five dipeptides have been isolated from the aqueous solution of CGH and proved to have greater root-inhibiting activity than the crude extract of CGH. The objective of this study was to isolate and identify other biologically active compounds from CGH with herbicidal properties. A perennial ryegrass (Lolium perenne L.) Petri dish bioassay was used to test for the bioactivity. A pentapeptide, Leu-Ser-Pro-Ala-Gln, was isolated from CGH by using Sephadex G-15 gel filtration and two-step C18 reversed phase high performance liquid chromatography procedures. The compound suppressed growth of both the root and the shoot of germinating perennial ryegrass. It required 0.5 mg/mL of the pentapeptide to inhibit 50% of root length in the perennial ryegrass bioassay, and this compound is more active than any of the five dipeptides isolated previously from CGH.Abbreviations CGM corn gluten meal - CGH corn gluten hydrolysate - HPLC high performance liquid chromatography - RP reversed phase - MeOH methanol - AUFS absorbance units of full scale - Rt retention time - TFA trifluoroacetic acid - PTH phenylthiohydantoin - ANOVA analysis of variance     

The typification of Lolium perenne L. and Loliutn temulentum L. (Poaceae)

LOOS, B. P. & JARVIS, C. E., 1992. The typification of Lolium perenne and Lolium temulentum (Poaceae). The typification of the Linnaean species Lolium perenne and Lolium temulentum has been studied. Lolium perenne is typified by material in LINN, as proposed by Terrell, but it has been necessary to select a lectotype for L. temulentum , and material in the Burser herbarium (UPS) has been chosen for this purpose. The study shows that although Linnaeus used awns as a diagnostic character to distinguish the two species, he was aware of the intraspecific variability in this character.     

Effects of soil mechanical impedance on root and shoot growth of Lolium perenne L., Agrostis capillaris and Trifolium repens L.

A method was used for applying a uniform mechanical impedanceto plant roots using sand packed at different bulk densitieswith depth within each growth cylinder. In a growth experiment,replicate cylinders were packed with sand to give the followingmechanical impedances: 0.25 MPa penetration resistance (negligibleimpedance), 1.40 MPa (moderate impedance) and 2.30 MPa (severeimpedance). Seedlings of Lolium perenne L., Trifolium repensL. and Agrostis capillaris were grown for 23 d in each impedancetreatment and effects on both roots and shoots were studied.Severe mechanical impedance affected both root and shoot growthrates for all three species resulting in smaller leaves andshorter roots. For the grasses, the root-to-shoot ratio at harvestwas the same for all the treatments, but a delay in the initiationof both shoots and roots was observed in the severe mechanicalimpedance treatment. The results are discussed in relation tothe possibility that roots penetrating the impeding treatmentsmay have caused signalling that kept shoot and root growth insynchrony. Differences observed in the response to mechanicalimpedance of T. repens compared to the other two species maybe a function of differences in the physiology between mono-and dicotyledonous species. Key words: Mechanical impedance, Lolium perenne, Trifolium repens, roots, shoots     

Detection of brassinosteroids in pollen of Lolium perenne L. by immunocytochemistry

Bioactive brassinosteroids have been localized in developing and mature pollen of anhydrously fixed rye-grass (Lolium perenne) by immunocytochemistry using polyclonal antibodies to castasterone generated in rabbits. Tricellular pollen fixed by freeze-substitution was also labelled in the starch granules. Study of the developmental sequence of the pollen through the microsporocyte, microspore, bicellular and tricellular stages showed that the brassinosteroids were increasingly sequestered in starch granules as the amyloplasts matured, supporting the view that these are storage organelles for these potent plant growth promoters. In bicellular pollen, heavy labelling was seen in the zone within 0.5 m of the starch granule, where stromal tissue remains. Thus, the stroma may be the site of synthesis of these compounds. During aqueous fixation, the brassinosteroids leached from the starch granules of tricellular pollen, indicating that they would be quickly available after imbibition to influence the physiology of germinating pollen. The results from high-performance liquid chromatography of dansylaminophenylboronates from partially purified extracts of freshly dehisced tricellular pollen of rye-grass showed 25-methylcastasterone may be a minor component, together with two unknown peaks. No specific binding of brassinolide to any soluble proteins extracted from tricellular rye-grass pollen was observed using the antibodies in gel electrophoresis or enzyme-linked immunosorbent assays.Abbreviations HPLC high-performance liquid chromatography - R_t retention time - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis We thank the Australian Research Council for support, the N.S.W. Department of Agriculture for rice seed, Professor K. Mori and the Zen-Noh Corporation for authentic brassinosteroid samples, Dr. I. Hudson for statistical advice, Dr. A. Bacic and Ms. I. Bonig for helpful discussion, and J.M.S. thanks Professor R.B. Knox for laboratory facilities.     

黑麦草(Lolium perenne L.)内生真菌的检测、分离及鉴定

从多年生黑麦草(LoliumperenneL.)5个品种———SR4000、Pinnacle、Topgun、CalypsoⅡ、Justus中分离出61个菌株。次培养后,所得形态稳定的菌株可分为4个形态群,依据其形态特征及APPCR的结果,确定其中的57个分离菌株为Neotyphodiumlolii。     

The Pattern of Abortion of Developing Seeds in Lolium perenne L.

The pattern of seed abortion was followed in each floret offour centrally positioned spikelets in inflorescences of L.perenne from field plots given zero ( –F) or 150 kg Nh^–1 ( + F). There was severe lodging prior to anthesisin the +F plots and control inflorescences were compared withthose held in an erect position and with others reduced to fourcentral spikelets. In the - F plots there was only very limitedlodging and erect control inflorescences were compared withthose reduced to four central spikelets. Observations were madeover a 3-week period and the pattern of seed abortion was verysimilar in all of the treatments. Approximately half of thedeveloping seeds in each spikelet were lost by abortion andthere was a similar degree of loss from all florets. The numberof abortions increased greatly with time and approx. one-thirdwere of ovaries and two-thirds were of seeds at a very earlystage of development (1–2 mm in length and without chlorophyllformation). The effect of nitrogen fertilizer was to increaseboth the number of florets per spikelet and the mean weightper seed. The results are discussed in terms of the availabilityof resources to sustain seed development and growth; it is concludedthat the high degree of abortion may be due to genetic defectsassociated with outbreeding rather than with a shortage of nutritionalfactors     

Field performance of cell-suspension-derived Lolium perenne L. regenerants and their progenies

 Two sets of plants (Lb and Lc), regenerated from different single-genotype-derived embryogenic suspension cultures of Lolium perenne cv Citadel, were evaluated for agronomic traits in a modified polycross design in the field. Seed from the primary regenerated plants was harvested to evaluate morphological and phenological traits of corresponding progenies in a replicated field experiment. When compared to seed-grown plants of the same cultivar, primary regenerants of the Lb set showed a significant delay in ear emergence and a more-erect growth habit, while primary regenerants from the Lc set showed a significantly higher seed yield. However, progenies of regenerated plants did not differ from those of seed-grown plants. Embryogenic suspension cells of L. perenne have the potential for producing fertile, well-performing, material which can be integrated into breeding programs. Received: 3 November 1997 / Accepted: 25 November 1997     

The Growth and Survival of Severely-shaded Tillers in Lolium perenne L.

The effect of shading a single tiller to below its compensationpoint for a period of 5 weeks in vegetative plants of Loliumperenne L. cv. S23, was studied in two different experimentseach employing two light regimes, one of which was common toboth experiments. In the first experiment tillers in the axils of the first leafwere shaded three weeks from appearance at both 40 and 70 Wm^–2. None of the shaded tillers died and they continuedto produce new leaves and increase in dry weight but at a reducedrate. In the second experiment, tillers with one emerged leafin any leaf axil position were shaded at 70 W m^–2 andin a treatment in which light was reduced to 13 W m^–2after initial growth at 70 W m^–2. As in the first experimentall shaded tillers survived at 70 W m^–2 but in the 70 13 W m^–2 transfer regime all shaded tillers died. In the second experiment shaded tillers in both light regimeswere supplied with ¹⁴C-assimilate by translocation from theremainder of the plant but in the 70 13 W m^–2 the initialsupport was withdrawn within 5 weeks of shading. The results are discussed in terms of the physiological relationshipsbetween the tillers of the grass plant. Lolium perenne L., growth of tillers, survival of tillers, effect of light     

Water Use Characteristics of Dactylis glomerata L., Lolium perenne L. and L. multiflorum Lam. Plants

Cocksfoot (Dactylis glomerata L.). perennial ryegrass (Loliumperenne L.) and Italian ryegrass (L. multiflorum Lam.) plantswere grown on deep (75–95 cm) columns of soil in glasshousesand growth rooms with and without irrigation. The species inwhich growth declined least rapidly after water had been withheldwere those which transpired most slowly. During early establishmentin the glasshouse cocksfoot transpired least because of slowroot growth. In the growth room, when root systems were deeperand denser, perennial ryegrass transpired least because of lowleaf water conductance. Results are discussed in relation to(a) drought resistance in the three species; (b) breeding forincreased drought resistance through modifying root distributionand leaf water conductance; and (c) the use of isolated soilcolumns in water relations studies. Dactylis glomerata L., Lolium perenne L., Lolium multiflorum Lam., cocksfoot, perennial ryegrass, Italian ryegrass, transpiration, roots, leaf water conductance     

Development and mapping of a public reference set of SSR markers in Lolium perenne L.

We report on the characterization and mapping of 76 simple sequence repeat (SSR) markers for Lolium perenne. These markers are publicly available or obtained either from genomic libraries enriched for SSR motifs or L. perenne expressed sequence tag (EST) clones. Four L. perenne mapping populations were used to map the SSR markers. A consensus linkage map of the four mapping populations containing 65 of the SSR markers is presented, together with primer information and a quality score indicating the usefulness of the SSR marker in different populations. The SSR markers identified all seven L. perenne linkage groups.     

Endophyte transmission via seeds of Lolium perenne L.: immunodetection of fungal antigens

We traced the presence and distribution of Neotyphodium lolii within developing inflorescences and embryos of perennial ryegrass (Lolium perenne L.), cultivar "Grassland Nui," by in situ immunolocalization of fungal proteins. Evidence is presented that the fungus penetrates through the rachilla at the base of the ovary, and localizes in a very precise and specific manner in the ovular nucellus, but never enters the embryo sac or the integuments. Young embryos do not contain mycelium, but as they mature the hyphae penetrate through the scutellum from a neighboring "infection layer"-a remnant of nucellus heavily colonized by the fungus-that is readily visible as a discrete area directly adjoining the base of embryo cavity. Our observations document that N. lolii is transmitted to the embryo exclusively via sporophytic maternal tissue.