1,721,123 research outputs found
FIGURE 2 in New taxa of Hieracium (Asteraceae) from Mount Lesima and adjacent regions (Northern Apennine, Italy)
No full textFIGURE 2. Hieracium lesimanum (isotype, Hb. Gottschlich-75892).Published as part of Gottschlich, Günter & Orsenigo, Simone, 2021, New taxa of Hieracium (Asteraceae) from Mount Lesima and adjacent regions (Northern Apennine, Italy), pp. 39-55 in Phytotaxa 505 (1) on page 44, DOI: 10.11646/phytotaxa.505.1.2, http://zenodo.org/record/542516
FIGURE 8 in New taxa of Hieracium (Asteraceae) from Mount Lesima and adjacent regions (Northern Apennine, Italy)
No full textFIGURE 8. Single capitula of a: H. lesimanum, b: H. scopolii, c: H. scopolioides, d: H. umbrophilum, e: H. lachenalii subsp. zerbanum, f: H. prenanthoides subsp. penicense.Published as part of Gottschlich, Günter & Orsenigo, Simone, 2021, New taxa of Hieracium (Asteraceae) from Mount Lesima and adjacent regions (Northern Apennine, Italy), pp. 39-55 in Phytotaxa 505 (1) on page 52, DOI: 10.11646/phytotaxa.505.1.2, http://zenodo.org/record/542516
Ecophysiology of embryo development and seed germination of the European woodland herbaceous perennial Corydalis cava (L.) Schweigg. & Körte subsp. cava (Fumariaceae)
No full textIn this study we examined the germination ecology with special reference to the temperature requirements for embryo development and germination of Corydalis cava subsp. cava, under both outdoor and laboratory conditions. Corydalis cava is a spring flowering woodland tuberous geophyte widely distributed across Europe. Germination phenology, including embryo development and radicle and cotyledon emergence, was investigated in a population growing in northern Italy. Immediately after harvest, seeds of C. cava were sown both in the laboratory under simulated seasonal temperatures and naturally. Embryos, undifferentiated at the time of seed dispersal, grew during summer and autumn conditions, culminating in radicle emergence in winter, when temperatures fell to ca 5°C. Cotyledon emergence also occurred at ca 5°C, but first emergence was delayed until late winter and early spring. Laboratory experiments showed that high (summer) followed by medium (autumn) and low temperatures (winter) are needed for physiological dormancy loss, embryo development and germination respectively. Unlike seeds of C. cava that germinated in winter, in other Corydalis species radicle emergence occurred in autumn (C. flavula) or did not depend on a period of high summer temperature to break dormancy (C. solida). Our results suggest that subtle differences in dormancy and germination behavior between Corydalis species could be related to differences in their geographical distribution
Marsilea quadrifolia: From Paddy Field Weed to Threatened Species
No full textIn this contribution we illustrate a species on the verge of extinction, commonly known as flagship species of temporary wetland agro-ecosystems. Marsilea quadrifolia L., known also as European water clover, is a leptosporangiate pteridophyte typical of aquatic environments, considered a weed of paddy fields of southern Europe; it grows with a creeping rhizome either in submerged or in emerged condition, experiencing heterophylly. The life cycle is carried out by the alternation of
generations and species reproduction occurs either with vegetative propagation or with sexual reproduction thanks to sporocarps. The species is ubiquitous in many soils at different levels of pH, preferring mesotrophic to eutrophic shallow waters; it can be found either in natural environments such as lakes and small rivers as well as in an agricultural context, such as paddy fields and ditches. M. quadrifolia is native to Eurasia and has a widespread distribution; it spreads also in America, where it is considered an alien species. For this reason, it is classified as “Least Concern” globally according to the IUCN criteria, however, since its distribution is scattered in Europe, it is assessed as “Vulnerable” and listed as threatened with extinction in most European countries. On the other hand, the species is cultivated in aquaria and has been used for centuries
for its ethnobotanical and medicinal properties. Human activities, habitat loss and degradation, excessive water eutrophication, agricultural practices and the presence of alien species are the main threats for the species.
Many efforts have been applied to preserve this species, both through in situ reintroduction as well as ex situ techniques, with cultivation in botanical gardens, in vitro propagation as well as spore cryopreservation. However, despite the few successes of these efforts, it’s reappearance in paddy fields could represent a valid opportunity to combine nature conservation and sustainable agricultural practices, offering new possible income for farmers
Climate warming could shift the timing of seed germination in alpine plants
No full textBackground and AimsDespite the considerable number of studies on the impacts of climate change on alpine plants, there have been few attempts to investigate its effect on regeneration. Recruitment from seeds is a key event in the life-history of plants, affecting their spread and evolution and seasonal changes in climate will inevitably affect recruitment success. Here, an investigation was made of how climate change will affect the timing and the level of germination in eight alpine species of the glacier foreland. MethodsUsing a novel approach which considered the altitudinal variation of temperature as a surrogate for future climate scenarios, seeds were exposed to 12 different cycles of simulated seasonal temperatures in the laboratory, derived from measurements at the soil surface at the study site.Key ResultsUnder present climatic conditions, germination occurred in spring, in all but one species, after seeds had experienced autumn and winter seasons. However, autumn warming resulted in a significant increase in germination in all but two species. In contrast, seed germination was less sensitive to changes in spring and/or winter temperatures, which affected only three species.ConclusionsClimate warming will lead to a shift from spring to autumn emergence but the extent of this change across species will be driven by seed dormancy status. Ungerminated seeds at the end of autumn will be exposed to shorter winter seasons and lower spring temperatures in a future, warmer climate, but these changes will only have a minor impact on germination. The extent to which climate change will be detrimental to regeneration from seed is less likely to be due to a significant negative effect on germination per se, but rather to seedling emergence in seasons that the species are not adapted to experience. Emergence in autumn could have major implications for species currently adapted to emerge in spring
Prediction of climate warming impacts on plant species could be more complex than expected. Evidence from a case study in the Himalaya
No full textMany studies have investigated the possible impact of climate change on the distributions of plant species. In the present study, we test whether the concept of potential distribution is able to effectively predict the impact of climate warming on plant species.
Using spatial simulation models, we related the actual (current species distribution), potential (modelled distribution assuming unlimited dispersal) and predicted (modelled distribution accounting for wind-limited seed dispersal) distributions of two plant species under several warming scenarios in the Sagarmatha National Park (Nepal). We found that the two predicted distributions were, respectively, seven and nine times smaller than the potential ones. Under a +3 8C scenario, both species would likely lose their actual and predicted distributions, while their potential distributions would remain partially safe. Our results emphasize that the predicted distributions of plant species may diverge to a great extent from their potential distributions, particularly in mountain areas, and predictions of species preservation in the face of climate warming based on the potential distributions of plant species are at risk of producing overoptimistic projections.
We conclude that the concept of potential distribution is likely to lead to limited or inefficacious conservation of plant species due to its excessively optimistic projections of species preservation. More robust strategies should utilize concepts such as ‘‘optimal reintroduction’’, which maximizes the benefit–cost ratio of conservation activities by limiting reintroduction efforts to suitable areas that could not otherwise be reached by a species; moreover, such strategies maximize the probability of species establishment by excluding areas that will be endangered under future climate scenarios
Biological flora of Central Europe: Marsilea quadrifolia L
No full textMarsilea quadrifolia L. is a leptosporangiate aquatic fern which has a played key role in the evolutionary history
of plants. It is characterized by heterospory, the ancestral progressive trait that led to the evolution of seeds. The
species has creeping, fleshy, adventitious roots containing multiple rhizomes. From the rhizomes a four-leaf
clover grows above the water level with a long petiole, at the base of which the sporocarps containing spores
are located. Its life cycle is characterized by alternation of generations; reproduction occurs either sexually or by
vegetative propagation. The species grows in wet habitats containing shallow water. In the natural environment
this includes lakes and small rivers; in agricultural areas it can be found in ditches and rice fields. The species can
tolerate nutrient rich waters and because of its phytoremediation properties is capable of partially counteracting
the negative effects induced by a moderate organic enrichment of sediments. It has been harvested for centuries
in Asian countries as both a food source and for ethnobotanical use in Ayurvedic medicine. Supposed medicinal
properties include antibacterial, diuretic, depurative, cytotoxic and antioxidant effects, but these require further
investigation and testing.
M. quadrifolia has a widespread distribution, occurring throughout central-southern Europe and extending
from Eurasia to tropical and temperate areas of eastern Asia and North America, where it is considered a nonnative
species. Despite its wide distribution, in its home range the species is threatened with extinction and
has already been locally extirpated in several European countries. As a result, it is listed as “Vulnerable” in the
European Union Red List due to its scattered distribution and declining population. Habitat loss and degradation,
excessive water eutrophication, and agricultural practices such as the use of herbicides, mechanization and
simplified rotation are the main threats to the species.
As it is listed in Appendix I of the Bern Convention and in Annexes II and IV of Directive 92/43/EEC as a
strictly protected species, in situ and ex situ conservation activities have been conducted in most European
countries. Reintroduction, cultivation in botanical gardens and in vitro propagation are the most commonly
applied conservation methods
Some like it hot and some like it cold, but not too much: Plant responses to climate extremes
No full textCurrent climatic models predict increasing frequency and magnitude of extreme climatic events (ECEs). Ecological studies recognize the importance of these extremes as drivers of plant growth and mortality, as well as drivers of ecological and evolutionary processes. Here we review observational and experimental studies on ECEs on herbaceous plants and shrubs. Extreme events considered were heat waves, drought, advanced or delayed snowmelt, heavy rainfalls, frosts, pulsed watering and flooding. We analysed 39 studies dealing with direct response of plant to ECEs in different ecosystems, with a particular focus on cold ecosystems (alpine and arctic). Although the number of studies increases every year, the understanding of ecological consequences of ECEs is fragmentary. In general, ECEs affected negatively on physiological processes (efficiency of photosystem II, stomatal conductance and leaf water potential), productivity and reproduction, and had consequences on population demography and recruitment several years after ECE. Indeed, the plant responses to ECEs were species specific and depended on the plant life stage and the timing of ECE. In fact, the magnitude of the effect of ECEs decreased over the growing season. Drought had the most severe effect on plants, while heat waves had minor effect if water was available. The overlap of different ECEs had an additive effect (e.g. drought associated to heat-waves). In general, both neutral or positive plant responses were found and acclimation is possible. In some cases, ECEs exert a strong selective pressure on plant species. © 2014 Springer Science+Business Media Dordrecht
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