Clover Research Articles

Draft genome sequence of subterranean clover, a reference for genus Trifolium.

Clovers (genus Trifolium) are widely cultivated across the world as forage legumes and make a large contribution to livestock feed production and soil improvement. Subterranean clover (T. subterraneum L.) is well suited for genomic and genetic studies as a reference species in the Trifolium genus, because it is an annual with a simple genome structure (autogamous and diploid), unlike the other economically important perennial forage clovers, red clover (T. pratense) and white clover (T. repens). This report represents the first draft genome sequence of subterranean clover. The 471.8 Mb assembled sequence covers 85.4% of the subterranean clover genome and contains 42,706 genes. Eight pseudomolecules of 401.1 Mb in length were constructed, based on a linkage map consisting of 35,341 SNPs. The comparative genomic analysis revealed that different clover chromosomes showed different degrees of conservation with other Papilionoideae species. These results provide a reference for genetic and genomic analyses in the genus Trifolium and new insights into evolutionary divergence in Papilionoideae species.

اثرات تاریخ کاشت، زمان آبیاری و کاربرد گیاهان پوششی بر رشد و عملکرد زعفران (Crocus sativus L.)

به منظور بررسی اثرات زمان‌های کاشت بهاره، تابستانه و پاییزه و نیز مدیریت آبیاری و استفاده از گیاهان پوششی، بر ویژگی‌های رشد و عملکرد گیاه دارویی زعفران (Crocus sativus L.) آزمایشی در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در سال‌های زراعی 89-1388 و 90-1389، به صورت کرت‌های دوبار خرد شده در قالب طرح پایه بلوک‌های کامل تصادفی با سه تکرار اجرا شد. فاکتورهای آزمایشی عبارت بودند از: تاریخ کاشت بهاره، تابستانه و پاییزه زعفران به عنوان فاکتور اصلی (اول خرداد ماه، اول مرداد ماه و اول مهر ماه)، مدیریت آبیاری به عنوان فاکتور فرعی (انجام آبیاری و عدم انجام آبیاری پس از هر تاریخ کاشت) و کاربرد گیاهان همراه در سال دوم آزمایش به عنوان فاکتور فرعی فرعی [شبدر ایرانی (Trifolium resopinatum L.)، خلر (Lathyrus sativus L.) و شاهد]. نتایج نشان داد که با تأخیر در کاشت بنه‌ها از اول خرداد به اول مهر، شاخص‌های کمی زعفران به طور قابل ملاحظه‌ای کاهش پیدا کرد و شدت کاهش در سال دوم آزمایش به مراتب بیشتر بود. بیشترین عملکرد گل در تاریخ کاشت مرداد ماه (به ترتیب 28 و 98 کیلوگرم در هکتار برای سال‌های اول و دوم آزمایش) و کمترین آن در تاریخ کاشت مهر ماه (به ترتیب 18 و 34 کیلوگرم در هکتار برای سال‌های اول و دوم آزمایش) به دست آمد. کاشت زعفران در تاریخ اول مرداد ماه موجب بهبود سرعت گل‌دهی و کاهش نسبی سرعت ظهور برگ گردید. عدم آبیاری پس از کاشت باعث افزایش شاخص‌های کمی زعفران شد؛ به طوری‌که عملکرد گل در تیمار انجام آبیاری پس از کاشت در سال اول نه و در سال دوم 43 کیلوگرم در هکتار و برای تیمار عدم انجام آبیاری در سال‌های اول و دوم به ترتیب 37 و 78 کیلوگرم در هکتار بود. بیشترین تعداد گل در هکتار (480000 گل در هکتار) و نیز بیشترین درصد بنه‌های گل‌دهنده (100 درصد) در سال دوم آزمایش و در تیمار تاریخ کاشت خرداد ماه و عدم انجام آبیاری پس از کاشت به دست آمد. کاربرد گیاهان پوششی به خصوص خلر تا حدودی باعث بهبود ویژگی‌های رشد و عملکرد زعفران گردید؛ به طوری‌که استفاده از این گیاه پوششی، عملکرد گل و کلاله را در مقایسه با شاهد حدود دو درصد افزایش داد. همچنین بیشترین سرعت گل‌دهی و کمترین سرعت ظهور برگ در تیمارهای تاریخ کاشت خرداد ماه، عدم انجام آبیاری پس از کاشت و کاربرد گیاه پوششی خلر مشاهده شد.

Quality Parameters and Antioxidant Activity of Three Clover Species in Relation to the Livestock Diet

Products of metabolism that are directly involved in growth, development and reproduction and also secondary products of metabolism were studied in 16 natural populations of three species of the genus Trifolium (T. repens – four populations, T. alpestre – three populations, T. pannonicum – nine populations), collected from the central Balkans region, i.e. territory of Serbia. Statistical analysis showed the presence of variability in all species of the test material. The best quality of dry matter, estimated by the ratio of crude protein and crude fiber, was achieved in the populations of white clover. In this species, average protein content was 216.4 g kg-1 while the average content of crude fiber was 222.4 g kg-1. The highest average content of total phenols (77.9 mg GA g-1), flavonoids (159.7 mg Ru g-1) and antioxidant activity (70.2 μg ml-1) was measured in populations of T. pannonicum by phytochemical analysis of aerial parts of plants. The content of secondary metabolites and antioxidant activity in other species were extremely low. Populations of T. pannonicum were notable for fodder quality and antioxidant activity: CS091 with 186.2 g kg-1 of crude protein and antioxidant activity of 55 μg ml-1; RA123 with 175.6 g kg-1 of crude protein and a high level of antioxidant activity of 44.8 μg ml-1. It can be concluded that the selection of these populations may lead to creation of different varieties of fodder crops that could give safe animal feed and would be suitable for growing under adverse conditions of mountainous climate.

Replacing synthetic N with clovers or alfalfa in bermudagrass pastures. 1. Herbage mass and pasture carrying capacity

The objective of this study was to evaluate the effects of including alfalfa (ALF, Medicago sativa L.) or a combination of white (Trifolium repens L.) and red (Trifolium pretense L.) clovers (CLVR) inter-seeded into bermudagrass (Cynodon dactylon L. Pers.) on herbage nutritive value compared with monocultures of bermudagrass fertilised with 0 (0N), 56 (56N), or 112 (112N) kg nitrogen (N)/ha over four grazing seasons. In autumn, at the end of the fourth year and in the spring before the fifth grazing season, alfalfa and clover plants were killed and the carryover N benefit of CLVR or ALF was compared with N fertilisation rates during the fifth year. Across years, N fertilisation rate increased herbage mass and carrying capacity linearly; whereas herbage production from CLVR and ALF swards was equivalent to 56N, were greater than 0N and less than 112N. Herbage mass in CLVR and ALF swards was greater than fertilised bermudagrass swards in the spring and did not differ from fertilised bermudagrass in the early summer. In late summer herbage accumulation of CLVR and ALF swards appeared to decrease, limiting the herbage mass in the legume pastures compared with 56N and 112N. Carrying capacity of CLVR and ALF swards was greater than fertilised bermudagrass in the spring and early summer, but did not differ from fertilised swards in the late summer. The N benefit of including legumes in bermudagrass swards can alleviate the reliance on synthetic N fertilisation with little overall effect on pasture carrying capacity.

Replacing synthetic N with clovers or alfalfa in bermudagrass pastures. 3. Performance of growing steers

The objective of this study was to evaluate the performance of steers (n = 590, 263 ± 30.6 kg) grazing alfalfa (ALF, Medicago sativa L.) or a combination of white (Trifolium repens L.) and red (Trifolium pretense L.) clovers (CLVR) inter-seeded into bermudagrass (Cynodon dactylon L. Pers.) pastures compared with fertilisation with 0 (0N), 56 (56N), or 112 (112N) kg nitrogen (N)/ha (n = 4, 0.8-ha pastures per treatment) in north-east Arkansas (USA) over 4 years. The carryover N benefit of CLVR or ALF was compared with N fertilisation rates during the fifth year on performance of growing steers (n = 120; 235 ± 22.6 kg). Average daily gain increased with N application rate and legume pastures were similar to 56N; but liveweight gain per steer grazing legume pastures tended to be greater than 112N. Steer grazing days per hectare and liveweight gain per hectare were greater for ALF and CLVR than bermudagrass monocultures regardless of N fertilisation rate. Steer average daily gain, grazing days per hectare and liveweight gain per hectare for carryover N from legumes did not differ from 56N. These results indicate that replacing synthetic N by inter-seeding legumes into bermudagrass swards has the potential to improve individual animal performance and production per unit area and carryover benefits of legume N may be equivalent to 56 kg N/ha.

Replacing synthetic N with clovers or alfalfa in bermudagrass pastures. 2. Herbage nutritive value for growing beef steers

The objective of this study was to evaluate the effects of including alfalfa (ALF, Medicago sativa L.) or a combination of white (Trifolium repens L.) and red (Trifolium pretense L.) clovers (CLVR) inter-seeded into bermudagrass (Cynodon dactylon L. Pers.) on herbage nutritive value compared with monocultures of bermudagrass fertilised with 0 (0N), 56 (56N), or 112 (112N) kg nitrogen (N)/ha over four grazing seasons. At the end of the fourth year (during the winter), legume plants in ALF and CLVR were killed and the carryover N benefit on bermudagrass nutritive value was evaluated during the fifth year. Pre-grazing herbage of all pastures exceeded the dietary recommendations for growing steers to maintain 0.9 kg/day average daily liveweight gain for crude protein and total digestible nutrients, 118 and 617 g kg/DM, respectively. Post-grazing herbage in ALF was below 600 g/kg total digestible nutrients at all times during the grazing season, post-grazing total digestible nutrients of CLVR was below 600 g/kg during the late summer and autumn. Post-grazing herbage of monoculture bermudagrass pastures fell below 600 g/kg in the middle of summer regardless of N fertilisation. Carryover N benefits of legumes were similar to 112N in the early summer, but were not different than 0N and 56N during the late summer and autumn. Replacing applications of synthetic N in bermudagrass swards with inter-seeding of either clovers or alfalfa produce herbage with equivalent nutritive value to heavily N fertilised monocultures of bermudagrass during the early summer, and similar to moderately N fertilised in the late summer and autumn. The inclusion of legumes in bermudagrass swards can reduce the reliance on synthetic N fertilisation with little overall effect on herbage nutritive quality possibly decreasing environmental impacts of grazing production systems.

Influence of phacoemulsification combined with limbal relaxing incisions for preoperative astigmatism on corneal high-order aberrations

Background phacoemulsification combined with limbal relaxing incision (LRI) is reported to be effective for the management of coexisting cataract astigmatism, but the influence of after phacoemulsification with LRI on corneal high-order aberration is still rarely reported. Objective This study was to evaluate the effect of cataract surgery with LRI for preoperative astigmatism or on corneal high-order aberration. Methods A self-controlled serial cases observational study was designed.A total of 35 cataractous eyes of 35 patients with astigmatism ≥1.0 D before cataract surgery were enrolled in Tianjin Medical University Eye Hospital from August 2014 to April 2015 under the informed consent of patients.LRIs were performed on the eyes during the phacoemulsification and IOL implantation.The uncorrected visual acuity (UCVA), BCVA and optometry were recorded before operation and 1 day, 1 week, 1 month, 3 months after operation.Pentacam was employed to measure the maximal and minimal diopters, astigmatism and high-order aberrations within 3 mm of the anterior corneal surface at above-mentioned time points.All the results were compared among different time points.The optometry outcomes and the anterior corneal surface astigmatism change were analyzed using vector analysis method. Results The UCVA was 0.34±0.22, 0.38±0.25, 0.43±0.27, 0.42±0.28 in 1 day, 1 week, 1 month and 3 months after operation, which was significantly higher than 0.08±0.09 before operation; and the BCVA was 0.54±0.27, 0.64±0.29, 0.67±0.29, 0.71±0.32 in 1 day, 1 week, 1 month and 3 months after operation, showing a significant increase in comparison with 0.22±0.51 before operation(F=54.457, P=0.000; F=62.653, P=0.000). The refractive cylindrical error and corneal astigmatism were significantly decreased after operation in comparison with before operation(F=31.061, P=0.000; F=113.043, P=0.000). High order aberrations (HOA) at postoperative 1 day, 1 week, 1 month, 3 months were all higher than those in preoperation (F=11.189, P=0.000) under the 4 mm pupil diameter.Compared with preoperation, the vertical coma, secondary vertical coma and three leaf clover were significantly increased(all at P 0.05) under the 6 mm pupil diameter. Conclusions Phacoemulsification combined with LRI can reduce the corneal astigmatism effectively and steadily, and the increase of corneal aberrations does not affect visual acuity. Key words: Cataract/surgery; Cataract/complication; Astigmatism/surgery; High order aberration; Limbal relaxing incision

A phytochemical and computational study on flavonoids isolated from Trifolium resupinatum L. and their novel hepatoprotective activity.

Plants from the genus Trifolium have been utilized in the treatment of chronic diseases by many cultures. The aim of this study was to investigate the antioxidant activity of flavonoids isolated from Trifolium resupinatum L. using an in vitro radical scavenging assay and a computational study of the structure-antioxidant activity relationship (SAR). A phytochemical fractionation of the ethanolic extract of T. resupinatum resulted in the isolation of one new flavonoid along with six known flavonoids. The structure of the isolated compounds was elucidated by data obtained from UV, IR, MS, 1D NMR and 2D NMR spectra. The order of antioxidant efficacies of the isolated flavonoids, obtained by DPPH assay, was correlated to that predicted by the computational analysis. To verify the antioxidant potential, the effect of T. resupinatum on oxidative stress, and the expression of the antioxidant enzymes and the redox sensitive nuclear factor erythroid 2-related factor 2 (Nrf2), in a cyclophosphamide-induced hepatotoxicity rat model was investigated. T. resupinatum protected against cyclophosphamide-induced liver injury through attenuation of oxidative stress and inflammation, and up-regulation of Nrf2. Therefore, the present study provides the first clarification of the detailed antioxidant SARs of T. resupinatum flavonoids and points to the involvement of Nrf2 in their hepatoprotective activity.

Karyotype Analysis and Protein Profile for Three Trifolium Species

The aim of the present investigation was cytological and protein comparison among three species within the genus Trifolium. The results revealed, Idiogram of the haploid complements of T. alexandrinum, T. refeigratum and T. repens. Besides T. refeigratum and T. repens have 16 pairs of chromosomes with a pair of satellites located at the end of their short arm in chromosome 16. T. alexandrinum has 8 pairs of chromosomes whose karyotyping formula is 2 nsm (+), 10 nsm (-) + 4 nm. The T. alexandrinum was clustering alone as well as having polymorphic bands that were different from T. refeigratum and T. repens.

Selecting plants with increased total polyphenol oxidases in the genus Trifolium

One of the aims in red clover (Trifolium pratense) breeding is to increase the polyphenol oxidase (PPO) activity, which may effectively reduce protein breakdown in silage and when cattle are fed by fresh clover. We analysed total PPO activity spectrophotometrically and on the level of gene expression using real-time quantitative PCR in single plants derived from an interspecific T. pratense × T. medium hybrid. Experiments were performed for two years and evaluated according to the general linear model with three factors (family, year, and cut). The analysis revealed considerable variability in total PPO activity between individuals and between families. Four families and two individuals with significantly higher PPO activity were selected. Their PPO activity ranged from 3.411 to 3.547 mkatal/min/g and from 4.041 to 5.731 mkatal/min/g, respectively, in comparison with the control variety Amos (2.370 mkatal/min/g). The majority of PPO transcripts were expressed by the two genes PPO1/5 and PPO2. In some genotypes, the PPO5 gene was expressed. Quantitative PCR confirmed the highest activity of PPO genes in seven hybrid plants with higher DNA contents corresponding to 30 chromosomes with 815 013 copies per plant. Our results indicate the suitability of combining two methods for improved selection: initial expression analysis to assess the PPO transcript level indicating gene activity and subsequent enzymatic assay.

Anatomical structure of stems of some species of Trifolium L. in correspondence with the systematics and ecology

The article discusses the results of a comparative study of the anatomy of the stems of 4 Trifolium L. species. Complexes of stem anatomical characteristics which can be applied for species diagnostic are described. Anatomy of T. arvense, T. medium and T. montanum shows xerophytic features aimed on desiccation resistance, manifested in three directions: increased functions of epidermal tissue, enhanced development of mechanical tissues, increased development of water conducting system.

Assessment of Energy Content of Some Tropical Concentrate Feeds of Ruminants using Model of National Research Council - 2001

An experiment was conducted to predict the energy content (TDN- total digestible nutrients, DE- digestible energy and ME- metabolizable energy) of some commonly used tropical concentrate feeds of ruminants using the summative approach model of National Research Council (NRC) 2001, which is based on chemical composition values of feeds rather than the values of digestion trial. Fourteen concentrate feeds (six grains, three oilcakes, two protein meals, three agro-industrial byproducts) were analyzed for their proximate principles, fiber components, neutral detergent insoluble nitrogen (NDIN), acid detergent insoluble nitrogen (ADIN) and the TDN was then calculated. DE and ME contents were estimated from the TDN value. Three types of total mixed rations (TMRs) were prepared comprising 40% concentrate mixture, 40% green fodder (berseem- Trifolium alexandrinum) and 20% wheat straw (Triticum aestivum) on dry matter basis (DMB). These TMRs were fed to three groups of growing Sahiwal calves (average body weight of 173.66±12.54 kg and average age of 12 - 18 months). The predicted TDN values of the TMRs as per NRC (2001) were 60.21, 60.14 and 60.53% of DM, respectively. The TDN values obtained by the results of the digestion trial (61.11, 61.98 and 60.56%) were in conformity with that of in vitro results. Therefore, it was concluded that the TDN based model of NRC (2001) can be successfully implemented to predict the energy density of tropical ruminant feeds. The predicted TDN values of concentrate feeds were also more or less in close proximity of their standard TDN values.

Progress in Simulations with Twisted Mass Fermions at the Physical Point

In this contribution, results from Nf = 2 lattice QCD simulations at one lattice spacing using twisted mass fermions with a clover term at the physical pion mass are presented. The mass splitting between charged and neutral pions (including the disconnected contribution) is shown to be around 20(20) MeV. Further, a first measurement using the clover twisted mass action of the average momentum fraction of the pion is given. Finally, an analysis of pseudoscalar meson masses and decay constants is presented involving linear interpolations in strange and charm quark masses. Matching to meson mass ratios allows the calculation of quark mass ratios: ms=ml = 27:63(13), mc=ml = 339:6(2:2) and mc=ms = 12:29(10). From this mass matching the quantities fK = 153:9(7:5) MeV, fD = 219(11) MeV, fDs = 255(12) MeV and MDs = 1894(93) MeV are determined without the application of finite volume or discretization artefact corrections and with errors dominated by a preliminary estimate of the lattice spacing.

Evolutionary origin of highly repetitive plastid genomes within the clover genus (Trifolium).

BackgroundSome clover species, particularly Trifolium subterraneum, have previously been reported to have highly unusual plastomes, relative to closely related legumes, enlarged with many duplications, gene losses and the presence of DNA unique to Trifolium, which may represent horizontal transfer. In order to pinpoint the evolutionary origin of this phenomenon within the genus Trifolium, we sequenced and assembled the plastomes of eight additional Trifolium species widely sampled from across the genus.ResultsThe Trifolium plastomes fell into two groups: those of Trifolium boissieri, T. strictum and T. glanduliferum (representing subgenus Chronosemium and subg. Trifolium section Paramesus) were tractable, assembled readily and were not unusual in the general context of Fabeae plastomes. The other Trifolium species (“core Trifolium”) proved refractory to assembly mainly because of numerous short duplications. These species form a single clade, which we call the “refractory clade” (comprising subg, Trifolium sections Lupinaster, Trifolium, Trichocephalum, Vesicastrum and Trifoliastrum). The characteristics of the refractory clade are the presence of numerous short duplications and 7-15% longer genomes than the tractable species. Molecular dating estimates that the origin of the most recent common ancestor (MRCA) of the refractory clade is approximately 13.1 million years ago (MYA). This is considerably younger than the estimated MRCA ages of Trifolium (c. 18.6 MYA) and Trifolium subg. Trifolium (16.1 MYA).ConclusionsWe conclude that the unusual repetitive plastome type previously characterized in Trifolium subterraneum had a single origin within Trifolium and is characteristic of most (but not all) species of subgenus Trifolium. It appears that an ancestral plastome within Trifolium underwent an evolutionary change resulting in plastomes that either actively promoted, were permissive to, or were unable to control, duplications within the genome. The precise mechanism of this important change in the mode and tempo of plastome evolution deserves further investigation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-014-0228-6) contains supplementary material, which is available to authorized users.

Effects of contrasting catch crops on nitrogen availability and nitrous oxide emissions in an organic cropping system

Legume-based catch crops (LBCCs) may act as an important source of nitrogen (N) in organic crop rotations because of biological N fixation. However, the potential risk of high nitrous oxide (N2O) emissions needs to be taken into account when including LBCCs in crop rotations. Here, we report the results from a one-year field experiment, which investigated N availability and N2O emissions as affected by three LBCCs, i.e., red clover (CL), red clover–ryegrass mixture (GC) and winter vetch (WV), two non-LBCCs, i.e., perennial ryegrass (GR) and fodder radish (FR), and a control (CO) without catch crops. The effect of two catch crop management strategies was also tested: autumn harvest of the catch crop versus incorporation of whole-crop residues by spring ploughing. LBCCs accumulated 59–67kgNha−1 in their tops, significantly more than those of the non-LBCC, 32–40kgNha−1. Macro-roots accounted for >33% of total N in the catch crops. In accordance with this, LBCCs enhanced the performance of the succeeding unfertilised spring barley, thus obtaining a grain yield of 3.3–4.5Mgha−1 compared to 2.6–3.3Mgha−1 grain yield from non-LBCC and the fallow control treatments. Autumn harvest of catch crops, especially LBCCs, tended to reduce crop yield. The annual N2O emissions were comparable across treatments except for fodder radish, which had the highest N2O emission, and also the highest average yield-scaled N2O emission, at 499gN2O-NMg−1 grain. Although the sampling strategy employed in this study introduces uncertainty about the spatial and temporal variability, differences in seasonal emission patterns among catch crops were captured and harvest of catch crops in late autumn induced significantly higher emissions during winter, but lower emissions after residue incorporation in spring. In comparison with non-LBCC, LBCCs have the potential to partly replace the effect of manure application in organic cropping systems with greater crop production and less environmental footprint with respect to N2O emissions. However, harvest of the catch crops may reduce crop yield unless the harvested N is recycled as fertiliser to the crops in the rotation.

Anthocyanin leaf markings are regulated by a family of R2R3-MYB genes in the genus Trifolium.

Anthocyanin pigments accumulate to form spatially restricted patterns in plants, particularly in flowers, but also occur in vegetative tissues. Spatially restricted anthocyanin leaf markings are poorly characterised in plants, but are common in forage legumes. We hypothesised that the molecular basis for anthocyanin leaf markings in Trifolium spp. is due to the activity of a family of R2R3-MYB genes. R2R3-MYB genes were identified that are associated with the two classic pigmentation loci in T. repens. The R locus patterns 'red leaf', 'red midrib' and 'red fleck' are conditioned by a single MYB gene, RED LEAF. The 'diffuse red leaf' trait is regulated by the RED LEAF DIFFUSE MYB gene. The V locus was identified through mapping two V-linked traits, 'V-broken yellow' (Vby) and 'red leaflet' (Vrl). Two highly similar R2R3-MYB genes, RED V-a and RED V-b, mapped to the V locus and co-segregated with the RED V pigmentation pattern. Functional characterisation of RED LEAF and RED V was performed, confirming their function as anthocyanin regulators and identifying a C-terminal region necessary for transactivation. The mechanisms responsible for generating anthocyanin leaf markings in T. repens provide a valuable system to compare with mechanisms that regulate complex floral pigmentation.

Endopolyploidy Patterns in Organs of Trifolium Species (Fabaceae)

Abstract The pattern of endopolyploidy in the genus Trifolium was studied in mature organs of T. montanum and T. repens at reproductive stage, with comparative data for T. pratense, all from natural populations. Endopolyploidy in root, stem, petiole, leaf, inflorescence stalk, sepal, petal, stamen and carpel was detected by flow cytometry. 2C, 4C and 8C nuclei were found in organs of T. montanum and T. repens, and additionally 16C nuclei in organs of T. repens. The organs of T. montanum and T. repens differed in degree of endopolyploidy based on cycle values calculated from flow cytometry data; it was lowest in leaf and sepal in T. montanum and T. repens, and highest in T. montanum in petal and carpel and in T. repens in petiole and inflorescence stalk. These results are also seen in the two or more peaks of interphase nuclei in the flow cytometry histograms. There were significant correlations between the organs of T. pratense and T. repens as well as substantial differences between Trifolium species in the degree of endopolyploidy. T. pratense showed higher absolute endopolyploidy than T. montanum and T. repens. Principal component analysis showed that individuals of T. repens and T. montanum are more similar to each other than to individuals of T. pratense in degree of endopolyploidy. The observed variation between species might be explained by phylogenetic relationships and genome size differences.

DUAL BEHAVIOUR OF PLANTS AGAINST BACTERIAL QUORUM SENSING: INHIBITION OR EXCITATION

Bacteria use an unique and sophisticated system for regulating diverse physiological processes in function of their population size. This regulatory procedure, called “quorum sensing” (QS), depends on the synthesis and perception between bacteria of small signal molecules such as acyl-homoserine lactones (AHLs). It is now evident that plants can listen to bacterial signals and respond in sophisticated ways to the information. The anti-QS activity of the methanolic extract of 44 plant species was detected through the inhibition of the QS-related violacein pigmentation in Chromobacterium violaceum CV026 in the presence of 5 mgl-1 of C6- homoserin lactone. In addition, the ability of test plants to produce AHL-mimicking compounds that excite QS-related response in CV026 was investigated. The results revealed that the QS inhibition activity was observed in the leaves and stem extracts of tarragon (Artemisia dracunculus), radish (Raphanus sativus) and hollyhock (Althea officinalis), which repress violacein production in CV026. We have also shown that Trifolium repens contains AHL- mimicking molecules that can activate QS function in biosensor bacterium and induce violacein production in CV026. Methanolic extracts were also able to inhibit QS-regulated virulence in Pectobacterium carotovorum subsp. carotovorum on potato tubers. The results suggest that plants have quorum sensing-mimicking signals that could potentially be used for disrupting quorum sensing of associated bacteria thus controlling their infections.

Efficacy of pressurized proximal humerus proximal humeral locking plate fractures

Objective To observe the clinical efficacy of relatively proximal humeral locking compression plate（ LPHP） with the traditional plate for treatment of proximal humeral fractures .Methods The proximal humeral fractures in patients with 58 cases,the patients were divided into two groups ,the treatment group of 32 cases of locking compression plate in the treatment of T plate ,clover plate in the treatment of 26 patients of the control group received traditional.According to the Neer score compared with two groups of patients with postoperative recovery and compli -cations.Results All the 58 patients for 11 ~15 months of follow-up,the treatment group found no fracture ,fracture nonunion,screw and plate humeral head necrosis ,4 cases of shoulder pain was limited;15 cases of excellent score Neer function,good in 12 cases,5 cases,the excellent and good rate was 84.4%.The control group had 3 cases,2 ca-ses of screw loosening of plate fracture ,3 cases of nonunion ,2 cases of humeral head necrosis ,7 cases of shoulder pain limited.6 cases of excellent score Neer function ,good in 9 cases,3 cases,poor in 8 cases,the excellent and good rate was 57.7%.There was significant differences between the two groups （χ2 =5.113,P <0.05） excellent rate. Conclusion LPHP exact treatment of proximal humeral fractures has fewer complications , which can help patients with early rehabilitation exercises . Key words: Bone wires; Fracture fixation,internal; Humerus fractures

Productivity and nitrogen benefits of late-season legume cover crops in organic wheat production

Cicek, H., Entz, M. H., Thiessen Martens, J. R. and Bullock, P. R. 2014. Productivity and nitrogen benefits of late-season legume cover crops in organic wheat production. Can. J. Plant Sci. 94: 771-783. When full-season cover crops are used in stockless organic rotations, cash crop production is compromised. Including winter cereals in rotations can widen the growing season window and create a niche for late-season cover crops. We investigated the establishment and biomass production of relay-cropped red clover (Trifolium pratense L.) and sweet clover (Melilotus officinalis L. ‘Norgold’) and double-cropped cowpea (Vigna unguiculata L. ‘Iron and Clay’), hairy vetch (Vicia villosa L.), lentil (Lens culinaris L. ‘Indianhead’), soybean (Glycine max L. ‘Prudence’), pea (Pisum sativum L. ‘40-10’), and oil seed radish (Raphanus sativus L.) as well as wheat response to these crops under reduced tillage (RT) and conventional tillage (CT) at three locations in Manitoba, Canada. Red clover, sweet clover and pea prod...