Extrafloral nectary plants not only occur in natural areas but also in urban parks. These areas are prone to edge effects, and plants face different microenvironmental conditions. We investigated the spatial variation of ant–plant interactions in an urban park, and we examined if plants with ants would show lower herbivory levels and if it depended on habitat type (interior or edges). Seedlings of Inga laurina were set in 200-m long transects (which covered both the west and east edges, and the interior) in an urban park and then experimentally assigned to be either ant-present or ant-excluded plants. Leaf herbivory was investigated throughout the wet season and was influenced by the interaction effect between ants and habitat type. Ants decreased the herbivory on the west edge, but on the east edge results were the opposite. The east edge had higher temperature and sunlight exposure in comparison to the other sites and was assumed to disrupt the stability of ant–plant interactions. In the interior of the fragment, herbivory depended on ant presence/absence and on the location of plants along the transect. Our study highlights how the outcomes of ant–plant interactions are spatially conditioned and affected by different types of habitats.

The seeds of most Australian acacias have pronounced physical dormancy (PY). While fire and hot water (HW) treatments cause the lens to ‘pop’ almost instantaneously, for many Acacia species the increase in germination percentage can be gradual. If PY is broken instantly by HW treatment, why is germination often an extended process? Control and HW treatments were performed on seeds of 48 species of Acacia. Seeds were placed on a moist substrate and imbibition was assessed by frequently weighing individual seeds. In the two soft-seeded species all control seeds were fully imbibed within 6–24 h, while in hard-seeded species very few control seeds imbibed over several weeks. In 10 species over 50% of the HW-treated seeds imbibed within 30 h, but mostly the percentage of imbibed seeds gradually increased over several weeks. Some seeds in a replicate would imbibe early, while others would remain unimbibed for many days or weeks then, remarkably, become fully imbibed in less than 24 h. While HW treatment broke PY almost instantaneously, it appeared that in many Acacia species some other part of the testa slowed water from reaching the embryo. This process of having staggered imbibition may be a way of ensuring not all seeds in a population germinate after small rain events. Thus it appears the lens acts as a ‘fire gauge’ while some other part of the seed coat acts as a ‘rain gauge’.

A new combination in Vachellia is published for Acacia pennivenia. A summation of the current state of knowledge of this Socotran endemic species is presented, including a morphological description, a distribution map and an updated conservation assessment. Colour photographs and a black-and-white line drawing are presented.

Systemic uptake of organic compounds from roots to leaves follows a Gaussian distribution in relation to the lipophilicity, as measured by the log Kow. Quantification of compound uptake with different lipophilicities, and applied as a seed treatment that diffuses through the seed coat into the embryo during imbibition, has not been reported. The aim of this investigation was to quantify the uptake of non-ionic compounds into seeds of soybean and corn. A series of fluorescent piperonyl amides were synthesized and a novel combinatorial pharmacodynamic technique was developed that provided a range of compounds from log Kow 0.02 to 5.7. Seeds were treated with a mixture of amides, imbibed and compounds chemically extracted and quantified by high-performance liquid chromatography using a fluorescence detector. The maximum uptake efficiency of the applied amide mixture from whole soybean and corn seeds was 67% at log Kow 2.9, and 43% at log Kow 3.4, respectively. The critical partition coefficient for uptake for both species was <4.2 log Kow. Seeds were dissected and separated as soybean embryo and testa, and corn internal tissues (embryo + endosperm) or seed covering layers (pericarp + testa), and >75% of the amides were found in the soybean embryo or corn internal tissues compared with the covering layers at log Kow <4.2. The distribution of amides showed that the corn seed covering layer had similar hydrophilic/lipophilic properties as internal tissues, while soybean tissues had different hydrophilic/lipophilic properties. Collectively, the Gaussian uptake pattern for systemic uptake into plants was not found for either seed species.

Differences in fruit morphology among or within species might indicate differences in other regenerative traits, such as seed dormancy and germination. In species with physical dormancy (PY), environmental conditions are suggested to be responsible for dormancy break in field. Seeds of Vachellia caven have PY. This species exhibits two fruit morphs highly represented in Córdoba forests, Argentina: one is dehiscent and the other is indehiscent. In this study we performed a burial experiment with the aim to determine if the differences in V. caven fruit morphology were related to different patterns of PY break of their seeds in field conditions. We related these patterns to (1) environmental conditions that could influence the loss of PY, and (2) histological features of the lens zone. Seeds of both morphs exhibited dormancy break within 14 months of the start of the experiment, but with different patterns. The dehiscent morph showed an abrupt percentage of seeds that broke dormancy 14 months after the beginning of the experiment, probably after undergoing environmental changes similar to those suggested by the two-stage softening model. The indehiscent morph showed a gradual increase in seeds that broke dormancy, not clearly related to any of the environmental variables studied. No differences in seed coat structure of the lens zone were observed between morphs. The existence of both morphs could confer the species with higher possibilities of establishing and coping with environmental heterogeneity. Those characteristics contribute to the understanding of the success of this species in open and disturbed environments.

Seed of 41 accessions of Crotalaria representing 35 species were analyzed for the concentration of total pyrrolizidine alkaloids (PAs) and for oral toxicity to 1-week-old chicks. All accessions were assayed for the presence of monocrotaline and spectabiline by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). High concentrations of PA were found in the seed of Crotalaria spectabilis Roth # CVTSP (3.85%), C. retusa L. (2.69%), C. alata Leveille (1.60%), C. quinquefolia L. (1.19%), and C. argyrolobioides Bak. (1.01%). The seed of Crotalaria argyrolobioides produced toxic signs but no deaths when fed at 10 mg/g of body weight, whereas the seed of the other four species were 100% lethal when fed to chicks in one dose at 2 to 6 mg/g of body weight. Seed of other species contained less than 0.6% PA and were nontoxic to chicks fed one dose at 10 mg/g of body weight. Monocrotaline was identified in 17 accessions and spectabiline in 7. No species contained both monocrotaline and spectabiline.

The effect of herbicides on the concentration of miserotoxin, the toxic compound in Wasatch milkvetch [Astragalus miser var. oblongifolius (Rydb.) Cronq. # ASAMO], was investigated. Eight herbicides or herbicide combinations were applied to Wasatch milkvetch in June 1985 and 1986. The concentration of miserotoxin was determined weekly for 4 weeks after treatments. All treatments in both years significantly reduced the miserotoxin concentration when compared to the controls, except for the 0.6 kg ae/ha rate of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) in 1986. Wasatch milkvetch treated with triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} at 1.7 and 2.2 kg ae/ha desiccated rapidly and had consistently low concentrations of miserotoxin 4 weeks after treatment.

Leaflets of 1690 species of Old World and South American Astragalus collected from herbaria at Kew, England; Edinburgh, Scotland; Munich, Germany; and Vienna, Austria were analyzed qualitatively for toxic aliphatic nitro compounds. The catabolites of nitro compounds found in species of Astragalus (nitro-bearing), 3-nitro-1-propanol and 3-nitropropionic acid, are especially toxic to cattle and sheep. A total of 190 of 1624 (12%) Old World species, 30 of 66 (45%) South American species, and a single species of one Astragalus subgenus were positive for nitro compounds. Most Old World species that contained aliphatic nitro compounds were collected in the Middle East and the Union of Soviet Socialist Republics. Nitro compounds were detected in specimens of eight species collected between 1822 and 1836. The nitro-bearing species were chemotaxonomically related and grouped within taxonomic sections. The presence of two or three nitro-bearing species within a section indicated that other species within the same section might also be nitro-bearing.

A tandem mass spectrometric procedure was developed to detect sesbanimide A and its isomers in plant materials. Analysis of seed extracts from 10 Sesbania species using this procedure readily detected sesbanimides in Drummond rattlebush, rattlebush, and bagpod sesbania. The toxic sesbanimides were not detected in hemp sesbania or in other species with no known history of animal toxicity.

Five broadleaf crops, alfalfa, peanut, soybean, tobacco, and tomato, were tested for their susceptibility to three broomrape species, branched, Egyptian and crenate, in the greenhouse. All five crop species were parasitized by one or more broomrape species. Peanut plants were most susceptible and soybean plants were least susceptible to parasitism by broomrape. Egyptian and branched broomrapes had a wider host range affecting plants in both the Solanaceae and Fabaceae. Crenate broomrape mainly infected plants belonging to Fabaceae, except for the few attachments to tomato and tobacco. Apparently, this is the first report on parasitism of peanut plants by branched broomrape and that of peanut and alfalfa plants by crenate broomrape. Parasitism of soybean plants by any of the broomrape species also was observed for the first time in these experiments. These results indicate that broomrapes, although not a major problem on any of the crops in the United States, could parasitize several major broadleaf crops should the parasite become established.

Physical dormancy of Robinia pseudoacacia seeds makes it a challenge for scientists and forest managers to obtain a homogeneous germination for larger seed samples. Water imbibition of the seeds can be achieved through manual piercing of the seed coat, but this method remains time consuming and heterogeneous. We tested several ecologically friendly methods to break seed dormancy, including manual pin puncture, water soaking, oven dry-heating (two temperatures) and sanding. Sanding was performed using an automatic grinder to control shaking duration (three durations) and get a homogeneous scraping of the coat. All methods, except dry-heating, resulted in successful dormancy breaking; water soaking was the least efficient method, attaining 57% germination. Sanding proved to be as efficient as puncturing (97%) but long duration sanding (10 or 15 min) could damage cotyledons, which would impede further development of the plant. Short-time sanding (5 min) proved to be the best method to reach high total germination and healthy (undamaged cotyledon) seedlings, and was successfully applied to 500 seeds. The reference puncture method and the automatic sanding were also tested on seeds of nine Fabaceae species and proved to be efficient for some species. Automated sanding can thus be used as a standard to break physical dormancy of black locust or other Fabaceae seeds to allow further comparative studies of plant populations or genotypes.

Information from a field perspective on temperature thresholds related to physical dormancy (PY) alleviation and seed resistance to high temperatures of fire is crucial to disentangle fire- and non-fire-related germination cues. We investigated seed germination and survival of four leguminous species from a frequently burned open Neotropical savanna in Central Brazil. Three field experiments were conducted according to seed location in/on the soil: (1) fire effects on exposed seeds; (2) fire effects on buried seeds; and (3) effects of temperature fluctuations on exposed seeds in gaps and shaded microsites in vegetation. After field treatments, seeds were tested for germination in the laboratory, together with the control (non-treated seeds). Fire effects on exposed seeds decreased viability in all species. However, germination of buried Mimosa leiocephala seeds was enhanced by fire in an increased fuel load treatment, in which we doubled the amount of above-ground biomass. Germination of two species (M. leiocephala and Harpalyce brasiliana) was enhanced with temperature fluctuation in gaps, but this condition also decreased seed viability. Our main conclusions are: (1) most seeds died when exposed directly to fire; (2) PY could be alleviated during hotter fires when seeds were buried in the soil; and (3) daily temperature fluctuations in gaps also broke PY of seeds on the soil surface, so many seeds could be recruited or die before being incorporated into the soil seed banks. Thus seed dormancy-break and germination of legumes from Cerrado open savannas seem to be driven by both fire and temperature fluctuations.

In fire-prone ecosystems, many species regenerate after fire from persistent soil seed banks. Species with physically dormant (PY) seeds have dormancy broken by fire-related heat. The magnitude of post-fire recruitment, to predict response to varying fire severity, is commonly estimated by testing dormancy-breaking temperature thresholds of fresh PY seeds. However, seeds spend years in the soil during the inter-fire period, and determining whether dormancy-breaking thresholds change over time is essential to accurately predict population persistence. Germination of four south-eastern Australian PY species from the Fabaceae family (Acacia linifolia, Aotus ericoides, Bossiaea heterophylla and Viminaria juncea) were studied. Dormancy-breaking temperature thresholds vary inter-specifically and the species represented either high or low dormancy-breaking threshold classes. Freshly collected seeds, and seeds that had been buried in the field or stored in dry laboratory conditions for 6 and 18 months were subjected to a fire-related range of heat treatments (40–100°C). Seed ageing increased germination response to heat treatments, effectively lowering the dormancy-breaking thresholds of three species. The fourth species, A. linifolia, initially had a relatively large non-dormant fraction which was lost as seeds aged, with older seeds then displaying PY broadly similar to the other study species. Patterns of threshold decay were species-specific, with the thresholds and viability of low-threshold species declining more rapidly than high-threshold species. The non-dormant fraction did not increase over time for any of our study species. Instead of increasing their non-dormant fraction, as is common in other vegetation types, these fire-prone PY species displayed a change of dormancy-breaking temperature thresholds. This is an important distinction, as maintaining dormancy during the inter-fire period is essential for population persistence. While changes in sensitivity to dormancy-breaking treatments have previously been reported as seeds age, our study provides the first test of changes to temperature thresholds, which increases the range of germination response from the seed bank under varying fire severity.

Legume consumption plays a pivotal role in the prevention and treatment of the metabolic syndrome (MetS). This systematic review aimed to highlight the beneficial effects of legume interventions for the prevention and/or improvement of parameters related to the MetS and the implicated metabolic pathways so far reported. The methodology involved a search in four electronic databases (Medline, Web of Science, Scopus, Cochrane Library) from January 2007 to December 2014, considering as descriptors ‘Metabolic Syndrome’ and ‘Fabaceae’ and adequately adjusting the equation in each one of them. In total, forty-one studies were finally included. The majority of the studies described a regulating effect on glucose and lipid metabolism due to legume administration, whereas effects on blood pressure and renal parameters are not fully described. Regarding the metabolic pathways involved, they include the up-regulation of genes related to β-oxidation and acetyl-CoA degradation and the down-regulation of glycolytic and lipogenesis genes, as well as those associated with the acetyl-CoA synthesis. The ameliorating effects of legume consumption on the alterations associated with the MetS are clearly reported and coincide with changes in the expression of protein and genes involved in lipid and glucose metabolism. More research needs to be conducted including more legume species that are highly consumed as part of a healthy dietary pattern.

A clear understanding of the mechanisms involved in releasing seed dormancy is important for effective plant conservation and regeneration of desert species. The dormancy types and dormancy release mechanisms of 19 Fabaceae species from four cold deserts in Xinjiang province, China, were studied. An imbibition experiment was performed to determine the presence or absence of physical dormancy. Other treatments included mechanical scarification, sulphuric acid scarification and simulation of summer temperatures typically encountered in the field. High summer temperature treatments included a maximum soil temperature of 80°C, 65°C and 40°C, conducted under dry and wet conditions. The results showed that all the species had orthodox seeds. Caragana korshinskii, Caragana intermedia, Caragana microphylla and Onobrychis taneitica seeds were not dormant. Glycyrrhiza uralensis, Ammodendron bifolium, Vicia costata and Eremosparton songoricum seeds had combinational dormancy (PY+PD) whereas the other 11 species had physical dormancy. The mechanical scarification and sulphuric acid scarification treatments were significant to break dormancy (>80%). Melilotus suaveolens and Oxytropis sp. seeds were temperature-insensitive. Sophora alopecuroides, S. salsula, E. songoricum, A. bifolium and Cassia tora seeds were wet-heat sensitive. Glycyrrhiza glabra seeds were dry-heat sensitive, while those of Halimodendron halodendron and Astragalus lehmannianus were sensitive to both dry and wet heat. Although high temperatures, typical of summer, promoted the breaking of physical dormancy, the proportion of seeds of which dormancy was broken differed among species. These differences were indicative of the conditions in which the species are found naturally. Species may have different adaptations that promote favourable regeneration. Given suitable temperature and moisture conditions similar to those in their natural environment, most species were capable of regeneration.

A synopsis of the native and naturalised species of Senna (Leguminosae: Caesalpinioideae) in the Arabian Peninsula is provided. Nine species are recognised. A key to the species is presented. For each species the accepted name with selected synonymy is given, followed by a diagnostic morphological description, the geographical distribution, details of habitat preference, and citation of specimens studied. Preliminary regional conservation assessments are given for all species.

This study analysed the anatomical structure of the seed coats, identified the location of water uptake and evaluated the effects of alternating temperatures and heat treatment on the breaking of physical dormancy of two species of Fabaceae (Caesalpinioideae), Cassia leptophylla and Senna macranthera, from the Atlantic forest of Brazil. The seed coats of both species consisted of a cuticle (extra-hilar region) or remaining funicle region (hilar region), subcuticular layer, palisade layer with lignin, osteosclereids, sclerified parenchyma and white cells. The palisade layer was formed by elongated macrosclereids with a light line of callose. In thermally scarified seeds of C. leptophylla, water entered through the micropylar canal, and in S. macranthera the water entered through the lens. Alternating temperatures that ranged from 15 to 30°C did not break physical dormancy of either species; however, exposure to 50°C broke seed hardcoatedness, allowing the entrance of water in both species.

Physical dormancy refers to seeds that are water impermeable. Within the Fabaceae, the structure associated with the breaking of dormancy is usually the lens. This study verified the role of the lens in physical dormancy of seeds of Schizolobium parahyba, a gap species of Fabaceae from the Atlantic Forest of Brazil. The lens in S. parahyba seeds appeared as a subtle depression near the hilum and opposite the micropyle. After treatment of the seeds with hot water, the lens detached from the coat. Blocking water from contacting the lens inhibited water absorption in hot-water-treated seeds. High constant (30°C) and alternating (20/30°C) temperatures promoted the breaking of physical dormancy and germination in non-scarified seeds. Maximum percentage of germination occurred earlier for seeds incubated at 20/30°C than for those incubated at 30°C. Seeds with a blocked lens did not germinate at alternating or high temperatures. This study suggests that alternating temperatures are probably the cause of physical dormancy break of seeds of S. parahyba in gaps in the forest.

Mature seeds of many legume species are normally characterized by water-impermeable seed coats, a form of physical dormancy. However, observations have suggested that the incidence of mature but permeable (non-dormant) seeds is sometimes substantial. Yet, the ecological processes associated with this non-dormancy have received little attention by plant ecologists. In white clover (Trifolium repens), we therefore studied: (1) the occurrence of initially permeable seeds in wild populations; (2) the relative performance of non-dormant and dormant seeds in plant establishment and reproduction in a field-sown experiment; and (3) the extent to which the trait is affected by humidity and plant genotype in a greenhouse experiment. No less than 35% of all viable seeds from the wild populations proved to be water permeable at maturity. The proportion of permeable seeds within inflorescences ranged from 0 to 100%. In the field-sown experiment, autumn-germinated non-dormant seeds had almost equally good chances of establishing as spring-germinated dormant seeds. Due to a marked head start in growth, the former yielded more flowers (and thus seeds) in the first flowering season. However, the greenhouse experiment proved that variation in the proportion of permeable seed between inflorescences represented a plastic response to humidity conditions during seed ripening, rather than variation among clones (broad-sense heritability ≤ 0.025). Thus the trait is not easily subject to selection.

Plant viruses pose a threat to the acquisition, maintenance and distribution of lupin germplasm (genus Lupinus, family Fabaceae). The availability of sufficient quantities of healthy and virus-free seeds from maintained lupin collections is mandatory for conducting lupin research. The objective of this research was to determine which lupin species were potentially infected with potyviruses (presumably seed-borne) upon germination in the greenhouse. The procedure for screening lupin seedlings in the greenhouse for potyviruses incorporated enzyme-linked immunosorbent assay followed by elimination or segregation of infected seedlings from the population before transplantation into the field plots for regeneration and accession characterization. None of the accessions in this evaluation had been tested previously for virus. From 2002 to 2005, 15 perennial (30 accessions) and 6 annual lupin species (213 accessions) were evaluated on site at the Western Regional Plant Introduction Station in Pullman, WA, USA. While none of the greenhouse perennial seedlings tested positive for potyvirus, seedlings in three annual species (Lupinus albus, Lupinus angustifolius and Lupinus luteus) were infected by potyviruses, presumably by seed transmission. Future testing may focus on the annual species, thus saving limited germplasm maintenance resources.