Trifolium Species Research Articles

Complete genome of the Medicago anthracnose fungus, Colletotrichum destructivum, reveals a mini-chromosome-like region within a core chromosome.

Colletotrichum destructivum (Cd) is a phytopathogenic fungus causing significant economic losses on forage legume crops (Medicago and Trifolium species) worldwide. To gain insights into the genetic basis of fungal virulence and host specificity, we sequenced the genome of an isolate from Medicago sativa using long-read (PacBio) technology. The resulting genome assembly has a total length of 51.7 Mb and comprises ten core chromosomes and two accessory chromosomes, all of which were sequenced from telomere to telomere. A total of 15, 631 gene models were predicted, including genes encoding potentially pathogenicity-related proteins such as candidate-secreted effectors (484), secondary metabolism key enzymes (110) and carbohydrate-active enzymes (619). Synteny analysis revealed extensive structural rearrangements in the genome of Cd relative to the closely related Brassicaceae pathogen, Colletotrichum higginsianum. In addition, a 1.2 Mb species-specific region was detected within the largest core chromosome of Cd that has all the characteristics of fungal accessory chromosomes (transposon-rich, gene-poor, distinct codon usage), providing evidence for exchange between these two genomic compartments. This region was also unique in having undergone extensive intra-chromosomal segmental duplications. Our findings provide insights into the evolution of accessory regions and possible mechanisms for generating genetic diversity in this asexual fungal pathogen.

Study of Trifolium angulatum phytomass in Karcag

Our studies were conducted at the Hungarian University of Agricultural and Life Sciences in Karcag, where in 2023, due to favourable precipitation and temperature conditions, we had the opportunity to study the phytomass yields of a massively reproducing annual Trifolium species in a saline soil condition. Yield measurements (green yield, hay yield, crude protein yield, dry matter yield) showed that in all cases higher yields were measured in the Trifolium angulatum-covered grassland than in the control grassland, and statistical analysis showed a close correlation in all cases. Through our studies, we aimed to provide new data on the specific floristic events in environmentally managed grassland in the Pannonian Basin from a farmer's perspective.

Use of nitrogen-fixing plants to improve planted forest soil fertility and productivity in New Zealand: A review

Background: Planted forests with low fertility soils are likely to require increased inputs of nitrogen (N) to satisfy increasing productivity demands. The use of N fertilisers will become more challenging due to their increasing cost and the risk of unwanted environmental impacts. Nitrogen-fixing plants may provide an alternative option to chemical fertilisers that is not only cheaper but has a lower greenhouse gas footprint. Methods: Information on N-fixing plants was collated from available literature, focusing on species previously associated with planted forests as well as other exotic N-fixing trees and New Zealand native plants not used in commercial planted forests. Results: Benefits to planted forest growth in New Zealand by N-fixing plants have been proven in only a few cases. Lupinus arboreus Sims was used in the 1970s and 1980s to increase N inputs in a planted Pinus radiata D.Don coastal forest, and improved P. radiata productivity was demonstrated. Productivity gains ceased when a blight disease infected the lupin population. Many N-fixing plants have been shown to tolerate low fertility soils and establish in planted forests, but there is limited information on their N contribution to the soil, and whether this N contribution increases P. radiata productivity. Such N-fixing plants include Lotus species, clover (Trifolium species) and weeds such as gorse (Ulex europaeus L.) and broom (Cytisus scoparius (L.) Link), which are commonly found in association with P. radiata forests. New Zealand native N-fixing shrubs may be suitable but there is limited information available describing N-fixation or forestry management for native plant species. Conclusions: Nitrogen-fixing plants are a valuable resource, which when managed properly could be used for enhancing productivity. Issues with pests and disease, and limited knowledge regarding the management of N-fixing species, restricts adoption in planted forests. Well-designed research is needed to assess impacts on whole forest system N cycling as well as selection of appropriate plant species for use in planted forests without unintended consequences such as competition for soil moisture or light. This research needs to be integrated with forest management and delivered as practical options to ensure success.

Assessment of the botanical origin of Saudi Arabian honey samples to identify pollen with chromatographic tools and packing and storage.

The increasing demand for honey purification and authentication necessitates the global utilization of advanced processing tools. Common honey processing techniques, such as chromatography, are commonly used to assess the quality and quantity of valuable honey. In this study, 15 honey samples were authenticated using HPLC and GC-MS chromatographic methods to analyze their pollen spectrum. Various monofloral honey samples were collected, including Acacia, Hypoestes, Lavandula, Tamarix, Trifolium, and Ziziphus species, based on accurate identification by apiarists in 2023 from the Kingdom of Saudi Arabia. Honey analysis revealed the extraction of pollen from 20 different honeybee floral species. Pollen identified from honey samples using advanced chromatographic tools revealed dominant vegetation resources: Ziziphus species (23%), Acacia species (25%), Tamarix species (34%), Lavandula species (26%), Hypoestes species (34%), and Trifolium species (31%). This study uses HPLC to extract phenolic compounds, revealing dominant protocatechuic acid (4.71 mg g-1), and GC-MS to analyze organic compounds in honey pollen. Specifically, 2-dodecanone was detected with a retention time of 7.34 min. The utilization of chromatographic tools in assessing honey samples for pollen identification provides a reliable and efficient method for determining their botanical origins, thereby contributing to the quality control and authentication of honey products.

Do electromagnetic fields used in telecommunications affect wild plant species? A control impact study conducted in the field

Over the last three decades there has been an unprecedented increase in both the coverage of wireless communication networks and the resultant radiofrequency electromagnetic field (RF-EMF) exposure level. There is growing concern that this rapid environmental change may have unexpected consequences for living organisms. Existing research on plants has shown that RF-EMF radiation can affect their growth and development, gene expression and various metabolic activities. However, these findings are largely derived from short-time exposure of crop plants under laboratory conditions. It remains unclear to what extent plants are affected by artificial RF-EMFs in real ecosystems and what potential consequences this could have for ecosystems. This study attempts to assess these long-term effects of RF-EMF exposure on wild plants under controlled experimental field conditions. We investigated the impacts of RF-EMF exposure (866–868 MHz frequency band) from seed germination to maturation for ten common herbaceous plant species over a four-month period. The selected plant species belong to various families and have different functional and morphological traits that might affect a response to the applied RF-EMF.For most of the considered species responses to RF-EMF were undetectable or weak, and where present restricted to a single trait. Only for one species, Trifolium arvense, were effects observed at different plant development stages and for different plant characteristics. In this species RF-EMF stimulated growth and probably influenced leaf heliotropic movements, as indicated by a larger height, larger leaf area and altered leaf orientation one month after germination. However, over the growing season Trifolium arvense plants exposed to RF-EMF entered the phase of senescence earlier, which was manifested through a reduction of green leaf area and an increase in the area of discolored leaf.We conclude that the effects of RF-EMF exposure at environmentally relevant levels can be permanent and irreversible in plants growing in the open natural environment, however, these effects are restricted to specific species. This in turn suggests that future studies should examine whether the effects observed here occur also in more common Trifolium species or other legumes that are a keystone component within European grasslands. Our findings also show that Trifolium arvense could be a candidate indicator of man-made RF-EMFs in the environment.

Classification of Trifolium Seeds by Computer Vision Methods

Traditional machine learning methods have been extensively used in computer vision applications. However, recent improvements in computer technology have changed this trend. The dominance of deep learning methods in the field is observed when state-of-the-art studies are examined. This study employs traditional computer vision methods and deep learning to classify five different types of Trifolium seeds. Trifolium, the leading food for nutritious dairy products, plays an essential role in livestock in some parts of the world. First, an image data set consisting of 1903 images belonging to five different species of Trifolium was created. Descriptive and quantitative morphological features of each species are extracted using image-processing techniques. Then a feature matrix was created using eight different features. After feature selection and transformation, unnecessary and irrelevant features were removed from the data set to build more accurate and robust classification models. Four common and frequently applied classification algorithms created a prediction model in the seed data set. In addition, the same dataset was trained using VGG19, a convolutional neural network. Finally, the performance metrics of each classifier were computed and evaluated. The decision tree has the worst accuracy among the four traditional methods, 92.07%. On the other hand, Artificial Neural Network has the highest accuracy with 94.59%. As expected, VGG19 outperforms all traditional methods with 96.29% accuracy. However, as the results show, traditional methods can also produce results close to the deep learning methods.

A villanypásztor két oldalán

Our studies were carried out in a water buffalo pasture of the Zámolyi basin, in the area of the Csíkvarsai meadow, in the bed of a former lake, which was drained in 2022, then dried up by autumn and it was grazed by domestic water buffalo. The grazed area was surrounded by an electric fence. The vegetation of this part of the area and part of the outside was surveyed on 19 of November. We took 3-3 coenological surveys in both separated areas. Based on the results, there were significant floristic and physiognomic differences in the vegetation. Among the clover species, species with ground-running stems (Trifolium repens and T. fragiferum) were dominant in the grazed area, but in the ungrazed area, there was a coherent plant population of 30-40 cm high, densely located alsike clover (Trifolium hybridum) in the lake bed. In addition, the occurrence of swamp pricklegrass (Crypsis schoenoides) was a floristic new discovery.Due to the loss of water coverage, several Trifolium species have become abundant in the area, which is a result of the germination properties of the species. The thick seed coats were cracked by the loss of the effect of the water coverage on temperature equalisation, and germination could have begun, resulting in a dominant species in the area. During the present study, we have seen a very impressive result of the analysis of the vegetation of the lake bed in autumn aspect in the Zámolyi Basin, which is the result of the impact of water buffalo grazing. The number of species was more significant in the grazed area. Moreover, floristic rarities have been found and as an indicator of grazing, species of different life form types were dominant within the same genus.

Seed Germination and Early Seedling Growth Responses to Drought Stress in Annual Medicago L. and Trifolium L. Forages

Climate change in the Mediterranean-like regions of South Africa has resulted in increased rainfall variability, a delayed start to the wet winter season, and increased occurrences of out-of-season summer rainfall events. These changes in bioclimatic conditions are predicted to become more pronounced and, therefore, could result in poor seedling establishment and false breaks from the soil seed bank, followed by seedling desiccation in annual medic and clover pastures. This study therefore aimed to quantify and compare the responses of three annual Medicago species and five annual Trifolium species to drought stress imposed at the seed germination, seedling establishment, and early seedling growth stages. Three separate controlled trials were conducted. Firstly, the seeds were germinated in seed germination chambers at constant temperatures ranging from 5 to 30 °C, in 5 °C increments, with five osmotic treatments within each temperature, and germination was recorded daily. For the second experiment, seeds were planted at 100, 70, 50, and 30% of the soil’s moisture-holding capacity without subsequent watering, and emergence was recorded daily. For the third experiment, one-month-old seedlings were subjected to two water-limitation periods (15 or 30 days), and their subsequent morphological responses were measured. The results from these experiments indicated that the species differed significantly in their responses to drought, and the best-performing species often differed when drought was imposed at different development stages. Five species—M. polymorpha L., M. truncatula Gaertn., T. alexandrinum L., T. vesiculosum Savi., and T. subterraneum L. ssp. subterraneum—were able to tolerate incidences of drought better than other species and, thus, should be prioritized for further research into the variation in drought tolerance between cultivars within these species.

Morphological and distributional patterns of native and invasive Trifolium (Papilionoideae, Leguminosae) species in southern South America

The ability of a species to colonize new geographical areas is closely related to its morphological response to environmental gradients. Previous studies compared native and alien invasive species in their ability to modify their morphology in reaction to climatic and edaphic factors; however, taxonomically close species have been scarcely analyzed. In this study, morphological variability patterns associated with abiotic factors were evaluated in Trifolium polymorphum, a native species distributed from southern Brazil to northern Patagonia, and Trifolium repens, a species introduced as an important forage crop and naturalized in diverse environments of southern South America. A morphometric study was carried out using herbarium specimens that were then georeferenced to obtain environmental and distributional data. Morphological traits along abiotic and geographical gradients were analyzed, predictive distribution and current and future niches were modelled. Our results showed that leaf morphology of T. repens responds to precipitation and temperature factors, which could explain its invasive behavior in a wide range of environments. Morphological variability of the native T. polymorphum presented a low association with abiotic factors, suggesting possible difficulties in adapting to future environmental changes. Ecological niche modelling analysis showed several overlap areas between species in the current model and a greater expansion of the distribution range of the invasive species in future climate change scenarios.

The Evaluations Of Taxonomic Classifications In The Genus Trifolium L. Based On ITS Sequences

The genus Trifolium L. belonging to family Fabaceae is represented by about 255 species in the world. Two classifications based on the sections or subgenus are commonly used by the researchers in the taxonomically evaluation of the genus Trifolium. However, there are still some confusing and complex situations about the taxonomy of the genus. For this reason, internal transcribed spacer (ITS) regions between rDNA genes in nrDNA were examined for 139 Trifolium taxa with the Maximum Parsimony (MP) method. Furthermore MP tree were evaluated based on two classification used commonly in the genus to provide contributions to taxonomic classification of the Trifolium species and to evaluate phylogenetic relationships of the Trifolium species. Study results support the status of subgenus proposed by new infrageneric classification. Also it can be stated that it is rationale to divide the section Lotoidea into several sections according to phylogenetic relationships of the taxa examined. Finally, this study reveals the importance of sequence information and problems in the barcoding.

Phylogenetic placement of Trifolium kentuckiense (Fabaceae), a new member of the native eastern North American clover clade

In 2013, a new species of clover endemic to Kentucky was described. This species, Trifolium kentuckiense (Fabaceae), has yet to be placed in a phylogeny but is hypothesized to be most closely related to T. reflexum based on morphology. We present phylogenetic evidence from the nuclear (ITS) and plastid genomes (trnL and ndhA introns) that T. kentuckiense is a member of a clade of seven Trifolium species native to eastern North America. Within this clade, T. kentuckiense is strongly placed in a clade with three other annual/biennial Trifolium species (T. bejariense, T. carolinianum, and T. reflexum); it is sister to T. reflexum, although support for this relationship is weak. Our results support previous findings that suggest the ndhA intron is much more variable than the trnL intron in the Eurosid I clade. The ndhA intron contained over twice the number of parsimony informative characters when compared to the trnL intron, though ITS was more variable than either region. We also provide a dichotomous key to native and nonnative members of Trifolium for Kentucky and its surrounding states. We suggest determinations of historic specimens of Trifolium, particularly those identified as T. reflexum, be reassessed to obtain localities that may still support populations of this recently described species. We also provide guidance on when and in what habitats to search for new populations of this extremely rare taxon.

Distribution of some important honey plants visited by honey bees for feeding purposes in Narman (Erzurum, Turkey) natural pasture vegetation

Narman district is located at Eastern Anatolia Region of Turkey. Average altitude is 1650 m, annual total precipitation is about 420 mm. In study area main economic activity is animal husbandry and animal production has made traditional practices, based on rangelands. This study carried out to determine honey plants, frequently visited by honey bees in 20 different locations of Narman. Total 56 plant species were determined and half of these plant species determined as visited plant species by honey bees. Most of honey plant species, determined in locations were wide leafy forbs and some of them were legume species. To determine botanical composition of rangeland vegetation in different locations line intercept method was used. The percentage of all plant species was calculated and each individual honey plant species percentages were determined. Some Alfalfa, Sainfoin, Lotus, Melilotus, Coronilla and Trifolium species were determined in locations. Thymus, Stachys, Centaurea and Campanula species were determined common plant species visited by honey bees.

Selection and characterization of Spanish Trifolium-nodulating rhizobia for pasture inoculation

Identification of elite nitrogen-fixing rhizobia strains is a continuous and never ending effort, since new legume species can be cultivated in different agro systems or are introduced into new areas. This current study reports on the taxonomic affiliation and symbiotic proficiency of nine strains of Trifolium-nodulating rhizobia isolated from different pasture areas in Spain, as well as three Rhizobium leguminosarum bv. trifolii reference strains, on eleven Trifolium species. Based on 16S rRNA gene sequences the strains belonged to the R. leguminosarum species complex. Additional phylogenetic analyses of the housekeeping genes recA, atpD and rpoB showed the strains were closely related to the species R. leguminosarum, R. laguerreae, R. indicum, R. ruizarguesonis or R. acidisoli. In addition, three strains had no clear affiliation and could represent putative new species, although two of the reference strains were positioned close to R. ruizarguesonis. nodC gene phylogeny allowed the discrimination between strains isolated from annual or perennial Trifolium species and placed all of them in the symbiovar trifolii. Neither geographic origin nor host-plant species could be correlated with the taxonomic affiliation of the strains and a high degree of phenotypic diversity was found among this set of strains. The strong interaction of plant species with the rhizobial strains found for biological nitrogen fixation (BNF) was noteworthy, and allowed the identification of rhizobial strains with a maximum proficiency for certain trefoil species. Several strains showed high BNF potential with a wide range of clover species, which made them valuable strains for inoculant manufacturers and they would be particularly useful for inoculation of seed mixtures in natural or cultivated pastures.

Peculiarities herb-bunchgrass steppes of Western Predcaucasia

Relevance. The article presents the materials of the geobotanical examination of the virgin steppes of the Western Predcaucasia. The relevance of the study is due to the modern state of natural grass stand, which is under constant anthropogenic influence.Methods. The research points are located in the southwestern part of the Stavropol Territory and the northeastern part of Karachay-Cherkessia, within the absolute heights of 500–880 m. The description of vegetation and its analysis was carried out on ten accounting sites (10x10 m) according to methods generally accepted in geobotany.Results. It was revealed that in the grass stand the grass familyhas on average 17,5% (its weight fraction is 70–80%). In the formation of grass stand plant associations, the leading role belongs to the dominant sod steppe-grasses: Stipa pulcherrima, Festuca valesiaca, Festuca rupicola, Bothriochloa ischaemum, etc. Legumes (Medicago romanica, Trifolium pratense, Onobrychis arenaria) are the main source of protein for animals, they are diverse and have on average 10,8%, but in weight terms they are inferior to sod steppe-grasses. The flora of the studied steppes is represented by a number of economically valuable plants. These are sod steppe-grasses — the creators of the main feed mass of the steppe. They are also sources of a protein component for animals. But the main source of protein in the steppe grass stands are representatives of the legume family (species Trifolium, Medicago, Onobrychis, etc.). Nectariferous plants (Filipendula vulgaris, Galium ruthenicum, Echium russicum) and drug plants (Adonis vernalis, Glycyrrhiza glabra, Thymus marschallianus, etc.) are found in the steppe. The spectrum of life cycles of the flora is noteworthy. There is a high percentage of perennials — from 66,7 to 97,8%. This fact indicates that the axes of ecological niches are packed relatively tightly by perennials — persistent competitors of annual plants (more often weeds). Until mid-summer the generative stage of development of wild plant species reaches on average 80%. Their gene pool can be recommended for the restoration of low-productive steppe grass stand, as well as for use in selection work.

Growth and Physiological Performance of a Coastal Species Trifolium fragiferum as Affected by a Coexistence with Trifolium repens, NaCl Treatment and Inoculation with Rhizobia.

The aim of the present study was to analyze the growth and physiological performance of two coexisting species, Trifolium fragiferum, and Trifolium repens, under the effect of NaCl and rhizobial symbiosis. Seeds of T. fragiferum and T. repens were collected from populations in the wild, and plants were cultivated in an automated greenhouse, two plants per container. Three basic types of planting were performed: (1) both plants were T. fragiferum (single species), (2) one T. fragiferum and one T. repens (species coexistence), (3) both plants were T. repens (single species). For every basic type, three subtypes were made: (1) non-inoculated, (2) inoculated with rhizobia taken from T. fargiferum, (3) inoculated with rhizobia taken from T. repens. For every subtype, half of the containers were used as control, and half were treated with NaCl. Shoot fresh mass of plants was significantly (p < 0.001) affected by species coexistence, inoculant, and NaCl. Three significant two-way interactions on plant shoot growth were found: between species coexistence and NaCl (p < 0.001), inoculant and species (p < 0.05), and NaCl and species (p < 0.001). A significant three-way interaction between inoculant, NaCl, and species (p < 0.001) indicated different responses of shoot growth of the two species to inoculant type and NaCl. NaCl treatment was an important factor for T. fragiferum, resulting in better growth in conditions of species coexistence, but the positive effect of bacterial inoculant was significantly more pronounced. A decrease in peroxidase activity in leaves was a good indicator of relative NaCl tolerance, while the absence/presence of rhizobial inoculation was reflected by changes in leaf chlorophyll concentration and photochemical activity of photosystem II. It can be concluded that interaction between biotic and abiotic factors affected the outcome of the coexistence of the two Trifolium species. Distribution of T. fragiferum in sea-affected habitats seems to be related to a higher competitive ability with allied species at increased substrate salinity, based on better physiological salinity tolerance.

Co‐occurrence patterns at four spatial scales implicate reproductive processes in shaping community assembly in clovers

Abstract Competition, niche differences and chance all contribute to community assembly; yet, the role of reproductive interactions between species is often less appreciated. Closely related plant species that share floral form, phenology and habitat often interact through pollination. They potentially facilitate pollinator attraction, compete for pollination services and/or exchange pollen. If reproductive processes are important to co‐occurrence, we predicted that fitness costs of heterospecific pollen transfer or pollen limitation should result in lower rates of co‐occurrence among outcrossing congeners. In contrast, selfers, which may be less exposed to heterospecific pollen, and/or less negatively affected by it, should co‐occur more frequently. Flower size is an excellent proxy for mating system in clovers. Using herbarium records and three independent field datasets, we documented co‐occurrence patterns of Trifolium at 1 m2–1 km2 scales in California. Using a randomization procedure to reshuffle matrices of community membership, we generated null hypotheses for the expected composition of large‐ and small‐flowered species in Trifolium communities of different sizes. Across all spatial scales, large‐flowered outcrossers were over‐represented at sites lacking congeners, but under‐represented in communities with multiple congeners. Conversely, small‐flowered selfers often occupied sites with multiple other Trifolium species. Patterns for plant height and leaf size, which are weakly or strongly correlated with flower size, did not explain co‐occurrence patterns as robustly. Regression analysis and model selection corroborated the null model analyses, indicating that the likelihood of co‐occurrence decreased as flower size, and thus reliance on outcrossing, increased. Synthesis. This study suggests that reproductive traits and processes may be significant contributors to community assembly and co‐occurrence in flowering plants.

Molecular Phylogeny of Trifolium L. Section Trifolium with Reference to Chromosome Number and Subsections Delimitation.

The genus Trifolium is one of the largest genera of the legume family Fabaceae with ca. 255 species. The genus is divided into eight sections; the section Trifolium is a major section of the genus, comprising 73 species mainly distributed in the Mediterranean region. We used nuclear ribosomal DNA internal transcribed spacer (ITS) and morphological variation to reconsider the delimitation and phylogenetic relationships of species in the section Trifolium with reference to chromosomal variations. Bayesian analysis of ITS data delimited the species as three clades based on the analysis of ITS sequence and informative indels in combination with morphological variation. The phylogeny of the species by different analyses methods does not support their current delimitation in 17 subsections. The basic chromosome number x = 8 is the number for the genus Trifolium, from which x = 7, 6 and 5 were derived through successive aneuploidy events. With reference to the distribution of these numbers in the species of the section Trifolium, species in clade III and clade II are more evolved than species in clade I.

Variation in Ribosomal DNA in the Genus Trifolium (Fabaceae).

The genus Trifolium L. is characterized by basic chromosome numbers 8, 7, 6, and 5. We conducted a genus-wide study of ribosomal DNA (rDNA) structure variability in diploids and polyploids to gain insight into evolutionary history. We used fluorescent in situ hybridization to newly investigate rDNA variation by number and position in 30 Trifolium species. Evolutionary history among species was examined using 85 available sequences of internal transcribed spacer 1 (ITS1) of 35S rDNA. In diploid species with ancestral basic chromosome number (x = 8), one pair of 5S and 26S rDNA in separate or adjacent positions on a pair of chromosomes was prevalent. Genomes of species with reduced basic chromosome numbers were characterized by increased number of signals determined on one pair of chromosomes or all chromosomes. Increased number of signals was observed also in diploids Trifolium alpestre and Trifolium microcephalum and in polyploids. Sequence alignment revealed ITS1 sequences with mostly single nucleotide polymorphisms, and ITS1 diversity was greater in diploids with reduced basic chromosome numbers compared to diploids with ancestral basic chromosome number (x = 8) and polyploids. Our results suggest the presence of one 5S rDNA site and one 26S rDNA site as an ancestral state.

Contribution to the knowledge of the genetic diversity and taxonomy of some Iranian Trifolium species

Contribution to the knowledge of the genetic diversity and taxonomy of some Iranian Trifolium species

Critical phosphorus requirements of Trifolium species: The importance of root morphology and root acclimation in response to phosphorus stress.

Differences in root morphology and acclimation to low-phosphorus (P) soil were examined among eight legume species from the Trifolium Section Tricocephalum to understand how these root attributes determine P acquisition. Ornithopus sativus was included as a highly P-efficient benchmark species. Plants were grown as microswards in pots with five rates of P supplied in a topsoil layer to mimic uneven P distribution within a field soil profile. Topsoil and subsoil roots were harvested separately to enable measurement of the nutrient-foraging responses. Critical P requirement (lowest P supply for maximum yield) varied over a threefold range, reflecting differences in root morphology and acclimation of nutrient-foraging roots to P stress. Among the species, there was a 3.2-fold range in root length density, a 1.7-fold range in specific root length, and a 2.1-fold range in root hair length. O. sativus had the lowest critical P requirement, displayed a high root length density, the highest specific root length, and the longest root hairs. Acquisition of P from P-deficient soil was facilitated by development of a large root hair cylinder (i.e. a large root-soil interface). This, in turn, was determined by the intrinsic root morphology attributes of each genotype, and the plasticity of its root morphology response to internal P stress. Root acclimation in low-P soil by all species was mostly associated with preferential allocation of mass to nutrient-foraging roots. Only O. sativus and four of the Trifolium species adjusted specific root length beneficially, and only O. sativus increased its root hair length in low-P soil.