Search results for "seedling"
showing 10 items of 110 documents
Evaluating structural and compositional canopy characteristics to predict the light-demand signature of the forest understorey in mixed, semi-natural…
2020
Questions: Light availability at the forest floor affects many forest ecosystem processes, and is often quantified indirectly through easy-to-measure stand characteristics. We investigated how three such characteristics, basal area, canopy cover and canopy closure, were related to each other in structurally complex mixed forests. We also asked how well they can predict the light-demand signature of the forest understorey (estimated as the mean Ellenberg indicator value for light [“EIVLIGHT”] and the proportion of “forest specialists” [“%FS”] within the plots). Furthermore, we asked whether accounting for the shade-casting ability of individual canopy species could improve predictions of EIV…
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
Fine-scale spatial genetic dynamics over the life cycle of the tropical tree Prunus africana
2014
Studying fine-scale spatial genetic patterns across life stages is a powerful approach to identify ecological processes acting within tree populations. We investigated spatial genetic dynamics across five life stages in the insect-pollinated and vertebrate-dispersed tropical tree Prunus africana in Kakamega Forest, Kenya. Using six highly polymorphic microsatellite loci, we assessed genetic diversity and spatial genetic structure (SGS) from seed rain and seedlings, and different sapling stages to adult trees. We found significant SGS in all stages, potentially caused by limited seed dispersal and high recruitment rates in areas with high light availability. SGS decreased from seed and early…
Effect of Short and Long Term Irrigation with Treated Wastewater on Chemical Composition and Herbicidal Activity of Eucalyptus camaldulensis Dehn. Es…
2019
[EN] Water shortage throughout the world, especially in arid regions in the later decades has led to search for alternatives to save potable fresh water. Treated wastewater (TWW) appears to be an opportunity for irrigation. However, it could represent a stress factor for plants, and influence their metabolism, changing their secondary metabolites and, consequently, their biological properties. Eucalyptus camaldulensis essential oil (EO) had been reported to possess phytotoxic activity. The main objective of this work was to compare the chemical composition and herbicidal activity of E. camaldulensis EO obtained from leaves of young plants and old trees irrigated with well water (WW) and TWW…
Volatile unsaturated hydrocarbons emitted by seedlings of Brassica species provide host location cues to Bagrada hilaris
2018
Bagrada hilaris Burmeister, is a stink bug native to Asia and Africa and invasive in the United States, Mexico, and more recently, South America. This species can cause serious damage to various vegetable crops in the genus Brassica, with seedlings being particularly susceptible to B. hilaris feeding activity. In this study, the role of volatile organic compounds (VOCs) emitted by seedlings of three Brassica species on the host preference of B. hilaris was evaluated. In dual choice arena and olfactometer bioassays, adult painted bugs preferred B. oleracea var. botrytis and B. napus over B. carinata. Volatiles from B. oleracea seedlings were collected and bioassayed with B. hilaris adults an…
Seed germination, salt stress tolerance and seedling growth of Opuntia ficus - indica (Cactaceae), invasive species in the Mediterranean Basin
2017
Abstract The present study, focuses on seed germination ecology and seedling growth of Opuntia ficus-indica (Cactaceae), a native species of arid and semi-arid regions of Mexico and invasive in the Mediterranean Basin. Shortly after collecting seeds in December 2014, scarification as well as the intra-specific variability in the responses of germination to light, temperature, salt stress and germination recovery were evaluated among three naturalized populations of this species in the Mediterranean. Moreover, seedling biomass production and the growth rate were measured. The most suitable method of scarification resulted the nail-clippers chipping. For all the populations, the germination t…