Search results for "DORMANCY"

Dormancy and longevity of soil-buried weed seeds : from examples to generalization

2012

EA SPE EcolDur GEAPSI CT3 CT1EA SPE EcolDur GEAPSI CT3 CT1; The main part of the life-cycle of weeds, especially in cultivated fields, is spent as seeds buried in the soil. Longevity and dormancy are two major traits driving weed survival and infestation in the framework of crop rotation and management. Modelling allows inference of these key processes from morpho-anatomical description of the seeds, thus avoiding long-term germination studies of buried seeds over the years. Two new sets of experimental data on two different weeds offer the opportunity to compare actual results to predicted values. This study deals with cornflower (Centaurea cyanus), a winter weed of cereals and oilseed rap…

Effects of environmental factors on seed germination ofAnthyllis barba-jovisL

2008

Abstract The influence of the main environmental factors on seed germination of Anthyllis barba-jovis L. were analysed. This work is part of a broader investigation aimed at the reintroduction of this species on Mount Conero, Ancona (central Italy), where it is at present extinct. The seeds were collected from the Gargano headland (southern Adriatic coast). Experimental analyses were carried out to determine: (i) dormancy levels of seeds collected in successive years, and also collected from the soil seed bank; (ii) effects of usual pre-treatments for overriding the physical dormancy of the seeds; (iii) optimal temperature range for maximum germination; (iv) effects of fire on seed germinat…

"Dormant" secondary metal-alkyl complexes are not omnipresent.

2006

This theoretical study was inspired by the perpetual debate over the so-called “dormancy” of the active sites in propylene polymerization, i.e., a drop in their activity after a regioerror (2,1-insertion), which was reported to occur in many (although not all) catalytic systems. To explore the range of possible situations, we have selected two homogeneous systems of fundamentally different structure: an octahedral system of C 2 symmetry with a tetradentate O N N O ligand and a bridged indenyl catalyst. This choice was not accidental; it is in these two systems where the experimentalists cannot reach a consensus about dormancy. Our density-functional theory calculations explain why in certa…

Seasonal changes of cambial activity in seed plants in relation to climatic zones

2016

Seed dormancy and germination of an endangered coastal plantEryngium maritimum(Apiaceae)

2013

INTRODUCTION Eryngium maritimum L. is a littoral species growing on sand dunes and shingle beaches. Although it is listed among the species widespread in western and southern Europe, overall its population is declining (Van der Maarel & Van der Maarel-Versluys, 1996). The species is included in the Red Data Book of Latvia (Fatare, 2003) and is protected in several other European countries. In northern Europe and in the Baltic Region it grows near the limits of its current area of distribution and therefore is at a greater risk of extinction because in small and isolated populations there is a risk of inbreeding depression. For example, in Eryngium alpinum partial self-incompatibility causes…

Olive embryo in vitro germination potential: Role of explant configuration and embryo structure among cultivars

2014

The in vitro germination of excised embryos can break dormancy rapidly and shorten the time required to produce seedlings, speeding up olive breeding programmes as well as rootstock production. In this study, the in vitro germination potential of four Sicilian olive cultivars was evaluated during two years of experiments, using explants with three different morphological configurations that represent three different degrees of embryo exposure: (1) intact stoneless seeds containing the embryo, the endosperm and the seed coat (Emb+En+SC), (2) seeds without the seed coat (Emb+En) and (3) naked, isolated embryos (seed coat and endosperm both removed: Emb). Differences were found in the germinat…

The role of light in the emergence of weeds: using Camelina microcarpa as an example

2015

When modelling the emergence of weeds, two main factors are considered that condition this process: temperature and soil moisture. Optimum temperature is necessary for metabolic processes that generate energy for growth, while turgor pressure is necessary for root and shoot elongation which eventually leads to seedling emergence from the soil. Most emergence models do not usually consider light as a residual factor, but it could have an important role as it can alter directly or indirectly the dormancy and germination of seeds. In this paper, inclusion of light as an additional factor to photoperiod and radiation in emergence models is explored and compared with the classical hydrothermal t…

Anàlisi de les estratègies germinatives d’espècies halòfiles

2018

En ambients halòfils de clima mediterrani com els localitzats en el litoral sud alacantí, l’ecofisiologia de la germinació és afectada essencialment pel dèficit hídric estacional, les elevades temperatures i les propietats del sòl. En aquest marc d’irregularitat ambiental, s’establí la resposta de germinació integrada en el cicle vital de l’espècie herbàcia halòfita Mesembryanthemum nodiflorum L. per tal d’avançar en el coneixement del funcionament d’aquests ambients salins i així poder abordar futurs programes de conservació vegetal en praderies salines. El protocol de germinació òptim de l’espècie d’estudi s’aconsegueix a un rang tèrmic de 25/10ºC i un fotoperíode de 12/12 h llum/obscurit…

Flagship species of the Pieniny NP. protected ex situ at PAS BGCBDC seed bank at WARSAW-POWSIN

2014

Pieniny Mts. are important biodiversity hotspot in Central Europe. According to Pieniny National Park Long Term Conservation Plan 2000-2020 small, isolated populations of some of Pieniny NP flagship species can become extinct till 2020. That is why their ex situ preservation at seed bank is justified and reasonable as supplement of active and passive in situ conservation measures carried out by National Park staff. PAS Botanical Garden – Center for Biological Diversity Conservation at Warsaw-Powsin has a long tradition of cooperation with Pieniny National Park (S Poland). This article focuses on the actions undertaken during EU funded conservation project: “Ex situ conservation of native, t…