† Background and Aims: In mature quinoa (Chenopodium quinoa) seeds, the lasting endosperm forms a micropylar cone covering the radicle. The suspensor cells lie within the centre of the cone. During the final stage of seed development, the cells of the lasting endosperm accumulate protein and lipids while the rest are crushed and disintegrated. Both the suspensor and endosperm die progressi…
† Background and Aims: Intraspecific reproductive differentiation into sexual and apomictic cytotypes of differing ploidy is a common phenomenon. However, mechanisms enabling the maintenance of both reproductive modes and integrity of cytotypes in sympatry are as yet poorly understood. This study examined the association of sexual and apomictic seed formation with ploidy aswell as gene flowt…
† Background and Aims: Physical dormancy (PY)-break in some annual plant species is a two-step process controlled by two different temperature and/or moisture regimes. The thermal time model has been used to quantify PY-break in several species of Fabaceae, but not to describe stepwise PY-break. The primary aims of this study were to quantify the thermal requirement for sensitivity induction…
† Background and Aims: Preservation of cultivar purity creates a particular challenge for plants that are self-incompatible, require insects for cross-pollination, and have easily germinating seeds and vigorously spreading rhizomes. As the fields must be planted with mixed populations, and a balance must be maintained between the cultivars to achieve effective pollination, methods for field …
† Background and Aims: Long-lived underground populations of mycoheterotrophic gametophytes and attached sporophytes at various developmental stages occur in lycophytes. Young underground sporophytes obtain carbon solely from the gametophyte and establish nutritional independence only after reaching the soil surface, which may take several years. This prolonged period of matrotrophy exceeds …
† Background and Aims: Gynodioecy (coexistence of females and hermaphrodites) is a sexual system that occurs in numerous flowering plant lineages. Thus, understanding the features that affect its maintenance has wide importance. Models predict that females must have a seed fitness advantage over hermaphrodites, and this may be achieved via seed quality or quantity. Females in a population o…
† Background and Aims: Trithuria is the sole genus of Hydatellaceae, a family of the early-divergent angiosperm lineage Nymphaeales (water-lilies). In this study different arabinogalactan protein (AGP) epitopes in T. submersa were evaluated in order to understand the diversity of these proteins and their functions in flowering plants. † Methods: Immunolabelling of different AGPs and pe…
† Background and Aims: Physical dormancy (PY) occurs in seeds or fruits of 18 angiosperm families and is caused by awater-impermeable palisade cell layer(s) in seed or fruit coats. Prior to germination, the seed or fruit coat of species with PY must become permeable in order to imbibe water. Breaking of PY involves formation of a small opening(s) (water gap) in a morpho-anatomically speciali…
† Background and Aims: Selective feeding by herbivores, especially at the seedling or juvenile phase, has the potential to change plant traits and ultimately the susceptibility of surviving plants to other enemies. Moreover, since hybridization is important to speciation and can lead to introgression of traits between plant species, differential feeding (herbivore-induced mortality) can infl…
† Background and Aims: Phosphate (Pi) deficiency in soils is a major limiting factor for crop growth worldwide. Plant growth under low Pi conditions correlates with root architectural traits and it may therefore be possible to select these traits for crop improvement. The aim of this study was to characterize root architectural traits, and to test quantitative trait loci (QTL) associated wit…
† Background: Apomixis is an alternative route of plant reproduction that produces individuals genetically identical to the mother plant through seeds. Apomixis is desirable in agriculture, because it guarantees the perpetuation of superior genotypes (i.e. heterotic hybrid seeds) by self-seeding without loss of hybrid vigour. The Paspalum genus, an archetypal model system for mining apomixi…
† Background and Aims: This study examined the adaptive association between seed germination ecology and specialization to either forest or open habitats across a range of evolutionary lineages of seed plants, in order to test the hypotheses that (1) species’ specialization to open vs. shaded habitats is consistently accompanied by specialization in their regeneration niche; and (2) specie…
† Background and Aims: The evolution of seeds together with the mechanisms related to their dispersal into the environment represented a turning point in the evolution of plants. Seeds are produced by gymnosperms and angiosperms but only the latter have an ovary to be transformed into a fruit. Yet some gymnosperms produce fleshy structures attractive to animals, thus behaving like fruits f…
† Background and Aims: Species and hybrids of the genus Miscanthus contain attributes that make them frontrunners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall comp…
† Background and Aims: The coffee genus (Coffea) comprises 124 species, and is indigenous to the Old World Tropics. Due to its immense economic importance, Coffea has been the focus of numerous genetic diversity studies, but despite this effort it remains insufficiently studied. In this study the genetic diversity and genetic structure of Coffea across Africa and the Indian Ocean islands is …
† Background and Aims: Hypericum perforatum (St. John’s wort) is a widespread Eurasian perennial plant species with remarkable variation in its morphology, ploidy and breeding system, which ranges from sex to apomixis. Here, hypotheses on the evolutionary origin of St. John’s wort are tested and contrasted with the subsequent history of interspecific gene flow. † Methods: Extensive…
† Background: Rice is the world’s most important cereal crop and phosphorus (P) and zinc (Zn) deficiency are major constraints to its production. Where fertilizer is applied to overcome these nutritional constraints it comes at substantial cost to farmers and the efficiency of fertilizer use is low. Breeding crops that are efficient at acquiring P and Zn from native soil reserves or ferti…
The 2012 Kansas corn crop suffered through another devastating growing season for most of the state. Unlike the previous year when the northeast and north central areas of the state had too much water during the spring months, all counties in Kansas experienced higher-than-normal temperatures and lack of precipitation during the summer (Figure 1). High temperatures and limited moisture adversel…
Rice research remains an important global undertaking to ensure an adequate food supply for sustainable food security of the poor. Improved technologies for rice productivity growth are critical for achieving food security and reducing poverty in the face of increasing competition for land, labor, and water and the challenges posed by global warming. Millions of poor small farmers grow r…
Abstract. Seed shattering is one of the main traits related with the domestication of cultivated rice and with the invasiveness and persistence of weedy rice. Two independent studies in 2006 have indicated that qSH1 in Japonica and Sh4 in Indica rice are major genes governing this trait. However, a wide variation of seed shattering occurs in weedy rice ecotypes from the same geographic reg…
Abstract. Closure of carpels or angiospermy, a key developmental innovation, has been accomplished through different ontogenic routes among the flowering plants. The mechanism of angiospermy produces structural novelties in the gynoecium, which in turn affects the progamic phase. In this paper, we present the structural details of the gynoecium and functional attributes of the progamic phase …
Abstract. Background and aims: Temperate forests are disjunct in the Northern Hemisphere, having become fragmented from the earlier widespread (Tertiary) boreotropical forest. We asked ‘What are the contemporary patterns of population variation in ecological traits of a Tertiary relict in a macroecological context?’. This issue underpins our understanding of variation in populations oc…
Abstract. Background and aims: Herbaceous–shrubby communities in the Gran Sabana (Great Savanna) Plateau of Venezuela grow under non-zonal conditions. We speculated that this would produce specific patterns of reproductive phenology within these different soil–climate–vegetation associations. Specifically, we tested the hypothesis that the reproductive phenology patterns of four herb…
Abstract. Background: RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen …
Abstract. Recent molecular phylogenetics have indicated that American mayapple (mainly self-incompatible, SI) and Himalayan mayapple, which was considered to be self-compatible (SC), are sister species with disjunct distribution between eastern Asia and eastern North America.We test a hypothesis that the persistence of this early spring flowering herb in the Himalayan region is attributable …
Abstract. Background and aims: Tricyrtis is a genus of monocots with attractive and sophisticated flower shapes and colours, endemic to north-east Asia. There are 18 known species. The highly restricted geographical distribution of the genus is of great interest in terms of both abiotic (continental drift) and biotic (long-distance dispersal) impacts on monocot plant speciation events and …
Abstract. Background and aims: The popular hybrid orchid Vanda Miss Joaquim was made Singapore’s national flower in 1981. It was originally described in the Gardeners’ Chronicle in 1893, as a cross between Vanda hookeriana and Vanda teres. However, no record had been kept as to which parent contributed the pollen. This study was conducted using DNA barcoding techniques to determine the…
Abstract. Background and aims: On the basis of morphological evidence, the species involved in South American Pacific coast harmful algal blooms (HABs) has been traditionally recognized as Alexandrium catenella (Dinophyceae). However, these observations have not been confirmed using evidence based on genomic sequence variability. Our principal objective was to accurately determine the spe…
Abstract. Manilkara multifida is a tropical tree that is endemic to the Atlantic forests of southern Bahia, Brazil. Currently, populations of this species are restricted to fragmented landscapes that are susceptible to anthropogenic disturbances. Considering this issue, and that there is no genetic information available for this endangered species, we developed microsatellite markers for M. mu…
Abstract. Background and aims: Ilex khasiana is a rare and critically endangered holly endemic to the Khasi Hills of Meghalaya, India, and confined to a small number of pocket areas. In addition to conventional methods of propagation, endemic and threatened plants such as this could be more effectively multiplied and conserved using in vitro methods. Such techniques have the additional adv…
Abstract. The plant hormone ethylene regulates growth and development as well as responses to biotic and abiotic stresses. Over the last few decades, key elements involved in ethylene signal transduction have been identified through genetic approaches, these elements defining a pathway that extends from initial ethylene perception at the endoplasmic reticulum to changes in transcriptional reg…
Abstract. Fluorescence in situ hybridization (FISH) is the most direct method for physically mapping DNA sequences on chromosomes. Fluorescence in situ hybridization mapping of meiotic chromosomes during the pachytene stage is an important tool in plant cytogenetics, because it provides high-resolution measurements of physical distances. Fluorescence in situ hybridization mapping of coffee p…
Abstract. Excess water in the form of waterlogged soil or deeper submergence (generically termed ‘flooding’) influences plant growth, survival and species distribution in many natural ecosystems. It also has a negative impact on crop growth and yield since many agricultural species are flooding intolerant. The often devastating effect of flooding on plant performance is related to its in…
Abstract. In spite of the huge economic importance of Aframomum melegueta in the herbal and pharmaceutical industries, its production is limited by lack of planting materials (propagules). The plant also lacks scientific descriptors, which has often led to misidentification with adverse health implications.We thereforeaimed atdeveloping adescriptor list to facilitate the identification of A.…
Abstract. The goal of identifying the genes or even nucleotides underlying quantitative and adaptive traits has been characterized as the ‘QTN programme’ and has recently come under severe criticism. Part of the reason for this criticism is that much of the QTN programme has asserted that finding the genes and nucleotides for adaptive and quantitative traits is a fundamental goal, witho…
Abstract. Background and aims: The botanical classification of Stylosanthes guianensis is controversial, and few studies have used molecular markers to analyse this species. We used microsatellite markers to study the genetic diversity and population structure of S. guianensis and compare our results with the current infraspecific botanical classification. Methodology: A representative…
Abstract. Background and aims: We review evidence for hybridization of Phragmites australis in North America and the implications for the persistence of native P. australis ssp. americanus populations in North America. We also highlight the need for an updated classification system, which takes P. australis intraspecific variation and hybridization into account. Methodology: We reviewe…
Abstract. Background and aims: Light interception is a key factor driving the functioning of wheat–pea intercrops. The sharing of light is related to the canopy structure, which results from the architectural parameters of the mixed species. In the present study, we characterized six contrasting pea genotypes and identified architectural parameters whose range of variability leads to var…
Abstract. Controlled ice nucleation is an important mechanism in cold-hardy plant tissues for avoiding excessive supercooling of the protoplasm, for inducing extracellular freezing and/or for accommodating ice crystals in specific tissues. To understand its nature, it is necessary to characterize the ice nucleation activity (INA), defined as the ability of a tissue to induce heterogeneous ic…
Abstract. Background and aims: Juniperus excelsa is an important woody species in the high mountain ecosystems of the eastern Mediterranean Basin where it constitutes the only coniferous species found at the tree line. The genetic diversity within and among J. excelsa populations of the eastern Mediterranean Basin is studied in the light of their historical fragmentation. Methodology: …
Abstract. Background: Flowering plant seeds originate from a unique double-fertilization event, which involves two sperm cells and two female gametes, the egg cell and the central cell. For many years our knowledge of mechanisms involved in angiosperm fertilization remained minimal. It was obvious that several signals were required to explain how the male gametes are delivered inside the …
Abstract. Rationale: This review comes at a time when in vitro embryo culture techniques are being adopted for the safe exchange and cryo-conservation of coconut germplasm. In due course, laboratory procedures may replace the options that exist among standard commercial nursery germination techniques. These, in their turn, have supplanted traditional methods that are now forgotten or mis…
Abstract. Background and aims: In the last decade, genomic studies using DNA markers have strongly influenced the current phylogeny of angiosperms. Genome size and ploidy level have contributed to this discussion, being considered important characters in biosystematics, ecology and population biology. Despite the recent increase in studies related to genome size evolution and polyploidy i…
Abstract. Background and aims: Anthurium is an important horticultural crop from the family Araceae, order Alismatales, a lineage considered to have diverged from other monocots prior to the cereals. Genome size and its distribution in Anthurium were investigated to gain a basic understanding of genome organization in this large genus and to forge a firm foundation for advancement of mole…
Abstract. Evolutionary chromosome change involves significant variation in DNA amount in diploids and genome downsizing in polyploids. Genome size and karyotype parameters of Hippeastrum species with different ploidy level were analysed. In Hippeastrum, polyploid species show less DNA content per basic genome than diploid species. The rate of variation is lower at higher ploidy levels. All th…
Abstract. Knowledge of the levels and distribution of genetic diversity is important for designing conservation strategies for threatened and endangered species so as to guarantee sustainable survival of populations and to preserve their evolutionary potential. Picconia azorica is a valuable Azorean endemic species recently classified as endangered. To contribute with information useful for t…
Abstract. Napier grass is an important forage crop for dairy production in the tropics; as such, its existing genetic diversity needs to be assessed for conservation. The current study assessed the genetic variation of Napier grass collections from selected regions in Eastern Africa and the International Livestock Research Institute Forage Germplasm-Ethiopia. The diversity of 281 cultivars w…