Search results for "seed"
showing 10 items of 668 documents
Degradation of sexual reproduction in Veronica filiformis after introduction to Europe
2011
Abstract Background Baker’s law predicts that self-incompatible plant species are generally poor colonizers because their mating system requires a high diversity of genetically differentiated individuals and thus self-compatibility should develop after long-distance dispersal. However, cases like the introduction of the self-incompatible Veronica filiformis (Plantaginaceae) to Europe constitute an often overlooked alternative to this rule. This species was introduced from subalpine areas of the Pontic-Caucasian Mountains and colonized many parts of Central and Western Europe in the last century, apparently without producing seeds. To investigate the consequences of the absence of sexual rep…
Doom of the elephant-dependent trees in a Congo tropical forest.
2013
9 pages; International audience; In an evergreen lowland rain forest of the Cuvette Centrale, DR Congo, at the LuiKotale Max-Planck research site, forest elephants (Loxodonta cyclotis) are close to extinction. Between January 2009 and June 2011 we investigated the influence of elephant decline on sustainability of elephant-dispersed tree populations. For this, we explored how trees with the megafaunal syndrome reproduce without seed dispersal by elephants and how does this affect the demography and spatial distribution of these tree species. We studied alternative partners for functional replacement of the elephant. Overall, 18 tree species presenting the megafaunal syndrome were identified…
Phytotoxic Effects of Commercial Eucalyptus citriodora, Lavandula angustifolia, and Pinus sylvestris Essential Oils on Weeds, Crops, and Invasive Spe…
2019
Background: essential oils are well known for their pharmacological effectiveness as well as their repellent, insecticide, and herbicide activities. The emergence of resistant weeds, due to the overuse of synthetic herbicides, makes it necessary to find natural alternatives for weed control. The aim of this study was to evaluate the phytotoxic effects of Eucalyptus citriodora, Lavandula angustifolia, and Pinus sylvestris, three common commercial essential oils, on weeds (Portulaca oleracea, Lolium multiflorum, and Echinochloa crus-galli), food crops (tomato and cucumber), and the invasive species Nicotiana glauca. Methods: to determine herbicidal effects, essential oils were tested at diffe…
Evolutionary ecology of fast seed germination—A case study in Amaranthaceae/Chenopodiaceae
2017
Abstract Germination is a vulnerable and risky step in a plant’s life cycle. Particularly under harsh environmental conditions, where time windows favourable for seedling establishment and survival are short or unpredictable, germination speed might play a highly adaptive role. We investigated the germination speed of 107 Amaranthaceae s.l. at two different temperatures and related the results to various plant and habitat traits taking into account the molecular phylogenetic relatedness of the species sampled. Germination speed is a fast evolving trait in Amaranthaceae s.l. It evolves towards significantly faster optima in C4 and halophyte lineages, albeit for different reasons. While C4 ph…
Fitness of backcross six of hybrids between transgenic oilseed rape (Brassica napus) and wild radish (Raphanus raphanistrum
2002
The process of introgression between a transgenic crop modified for better agronomic characters and a wild relative could lead potentially to increased weediness and adaptation to the environment of the wild species. However, the formation of hybrid and hybrid progeny could be associated with functional imbalance and low fitness, which reduces the risk of gene escape and establishment of the wild species in the field. Our work compares the fitness components of parents and different types of backcross in the sixth generation of hybrids between transgenic oilseed rape (Brassica napus, AACC, 2n = 38) resistant to the herbicide glufosinate and wild radish (Raphanus raphanistrum, RrRr, 2n = 18)…
Fertigation Management and Growth-Promoting Treatments Affect Tomato Transplant Production and Plant Growth after Transplant
2020
Plant biostimulants are of interest as they can stimulate plant growth and increase resource utilization. There is still no information on the use of plant growth-promoters under variable nutritional conditions in the nursery and the effects on tomato seedling growth and plant performance after transplant. This study aimed to evaluate the suitability of gibberellic acid (GA3) or bacterial biostimulant treatments to enhance the growth and quality of greenhouse-grown tomato (Solanum lycopersicum &lsquo
Effect of Bacterial Inoculum and Fertigation Management on Nursery and Field Production of Lettuce Plants
2020
Plant growth-promoting rhizobacteria have been applied to different vegetable crops but there is still no information on the effect of bacterial biostimulant application under variable nutritional level on lettuce seedlings and their performance after transplanting in the field. This study aimed to evaluate the efficacy of a bacterial biostimulant to enhance growth and quality of lettuce seedlings fertigated with increasing nutrient rates and to assess the efficacy of these treatments on lettuce head production. Lettuce seedlings were inoculated with 1.5 g L&minus
Evaluation of some growth regulator effects on encapsulated in vitro-derived microcuttings of three Italian Ficus carica L. genotypes.
2017
In this study, the encapsulation technology based on the calcium alginate coating was applied to some Ficus carica L. genotypes. Uninodal microcuttings (3-4 mm long), excised from in vitro proliferating shoots of three Italian cultivars (‘Bifera’, ‘Palazzo’ and ‘Catalanisca’), were employed. The influence of three different plant growth regulators (PGRs): 6-benzylaminopurine (BAP), meta-topolin (MT) and zeatine (ZEA), added to the artificial endosperm, were evaluated. Particularly, the viability, regrowth and conversion parameters of the synthetic seeds were registered after 60 days from the sowing on a hormone-free medium. Results showed that the cultivars ‘Catalanisca’ and ‘Palazzo’ showe…
A preliminary approach for modelling the effects of cropping systems on the dynamics of broomrape ( Phelipanche ramosa) in interaction with the non-p…
2011
International audience; The current decrease in herbicide use may increase and diversify weed flora in crops as well as companion bioagressors spreading via weeds. Among these bioagressors is Phelipanche ramosa (L.) Pomel, a parastic plant which is very harmful on oilseed rape. The objective of the present work was to develop a new model (called PheraSys) of the effects of cropping systems on parasite dynamics, in interaction with non-parasitic weed hosts. The structure of this first model version was based on models developed for other parasitic plants and on FlorSys which quantifies the effects of cropping systems on non-parasitic weed flora. PheraSys was parametrized with preliminary val…
Time after time: flowering phenology and biotic interactions.
2007
International audience; The role of biotic interactions in shaping plant flowering phenology has long been controversial; plastic responses to the abiotic environment, limited precision of biological clocks and inconsistency of selection pressures have generally been emphasized to explain phenological variation. However, part of this variation is heritable and selection analyses show that biotic interactions can modulate selection on flowering phenology. Our review of the literature indicates that pollinators tend to favour peak or earlier flowering, whereas pre-dispersal seed predators tend to favour off-peak or later flowering. However, effects strongly vary among study systems. To unders…