Search results for "010606 plant biology & botany"
showing 10 items of 1457 documents
Polyamine metabolism during seedling development in rice
1994
The main free amines identified during growth and development of rice seedlings were agmatine, putrescine, spermidine, diaminopropane and tyramine. Amine composition differed according to tissue and stages of development. Conjugated amines were only found in roots. We present evidence that arginine decarboxylase (ADC) regulates putrescine during the development of rice seedlings. When ADC action was blocked by DFMA (α-DL-difluoromethylarginine, a specific irreversible inhibitor of ADC), polyamine titers and seedling development were diminished; when agmatine or putrescine was added, normal polyamine titers and growth were restored. The effects of DFMA were concentration dependent. DFMO (α-D…
Polyamines and related enzymes in rice seeds differing in germination potential
1994
In ungerminated rice seeds, (Japonica rice variety, CV Tapei 309), the content of free amines (putrescine, spermidine, spermine, tyramine) was higher in seed lots having a low germination frequency compared to those with high germination potential. Conversely, amine conjugates (di-feruloylputrescine, di-feruloylspermidine, diferuloyldiaminopropane and feruloyltyramine) decreased with loss of viability. Thus, these compounds appeared to constitute biochemical markers of seed viability. In seeds with high germination potential, conjugates decreased drastically during germination, with an early and rapid increase in free amines (putrescine, spermidine, tyramine). Arginine decarboxylase (ADC) a…
An ecological multi-Level theory of competition for resources used to analyse density-dependence effects in fruit production
2014
International audience; Lescourret and Génard (2003) developed a multi-level theory of competition for resources applied to fruit production, considering that any collection of unit parts (cells or seeds in a fruit, fruits in an infructescence or in a tree...) can form a population and the population is subject to competition, whatever the level of organization. The principles of the theory are that the mass of each unit decreases when the number of units in the population increases and that the total mass of the population increases as the number of units increases until it reaches a maximum, after which it decreases. A three-parameter model based on that theory was used to analyse the lev…
Growth stimulation of seventeen fallow leguminous plants inoculated with Glomus aggregatum in Senegal
2001
Abstract Tropical legumes from fallowed areas in Senegal were inoculated with a tropical strain of Glomus aggregatum to test their relative mycorrhizal dependency in a greenhouse experiment. Twelve species among the seventeen tested showed a significant growth increase when mycorrhizal. Their mycorrhizal dependency varied from 92.7% for Indigofera stenophylla to 26.2% for Prosopis julifora . A significant positive correlation was found between mycorrhizal dependency and root hair length. The results confirm the high mycorrhizal dependency of legumes which are economically very important in the restoration of soil fertility of fallowed areas in the Sahelian and Soudano-Sahelian zones.
Cross-resistance to aryloxyphenoxypropionate and cyclohexanedione herbicides in foxtail millet (Setaria italica)
1997
Abstract Nearly isogenic backcrossed populations of foxtail millet ( Setaria italica (L.) Beauv.), resistant and susceptible to sethoxydim, were used in dose response analysis to seven acetyl-coenzyme A carboxylase inhibiting herbicides, aryloxyphenoxypropionate, and cyclohexanedione. Mortality and fresh and dry weights were recorded at the seedling stage. Results of greenhouse experiments showed that the resistant type was cross-resistant to all tested herbicides. Sethoxydim only was completely safe for the crop while three other herbicides had a moderate effect on the growth of resistant plants at recommended field doses. The last three herbicides had too high a toxicity to be used on mil…
Study of the growth of herbicide-resistant black-grass populations
1991
International audience
Variations in soil-water use by grapevine according to plant water status and soil physical-chemical characteristics - A 3D spatio-temporal analysis.
2016
14 pages; International audience; Understanding plant and soil-water relationships is crucial to optimise agricultural management. In this multidisciplinary work, soil geophysics and plant physiological measurements are coupled and a statistical method is proposed to visualising plant soil-water uptake in space and time. The method is applied in a vineyard context and shows differences in the use of tranpirable soil water by grapevine according to the type of soil and the time of the day (day/night).During two years the water stress experienced by a single Chardonnay/SO4 grapevine clone was monitored both at pre-dawn and midday by leaf water potentials in two field plots exclusively differe…
Statistical modelling and RCS detrending methods provide similar estimates of long-term trend in radial growth of common beech in north-eastern France
2011
International audience; Dendrochronological methods have greatly contributed to the documentation of past long-term trends in forest growth. These methods primarily focus on the high-frequency signals of tree ring chronologies. They require the removal of the ageing trend in tree growth, known as 'standardisation' or 'detrending', as a prerequisite to the estimation of such trends. Because the approach is sequential, it may however absorb part of the low-frequency historical signal. In this study, we investigate the effect of a sequential and a simultaneous estimation of the ageing trend on the chronology of growth. We formerly developed a method to estimate historical changes in growth, in…
Comparative study of the efficiency of buffer zones and harvest discarding on gene flow containment in oilseed rape. A modelling approach
2009
International audience; Oilseed rape (OSR) genes can escape fields in space via pollen and seeds and in time via volunteers resulting from seeds lost before or during oilseed rape harvests. Previous simulation studies and field observations showed that co-existence at the landscape level of contrasting OSR varieties such as genetically modified (GM) and non-GM varieties require costly measures that are difficult to implement, such as isolation distances between OSR fields and stringent volunteer control in all fields and road margins. In the present study, two local strategies, non-GM buffer zones aroundGMfields and discarding the harvest of boundary plants of non-GM fields, were tested in …
Fruit size in relation to competition for resources: A common model shared by two species and several genotypes grown under contrasted carbohydrate l…
2012
International audience; Fruit size is one important criterion of fruit external quality affecting consumer acceptance. The effects of seed number on fruit size in two fleshy fruits, grape and tomato, of different genotypes and grown under distinct carbohydrate availability levels were analyzed with a model. The two-parameter model described within-fruit resource competition and was able to well represent the commonly observed decrease in fresh weight per seed along with the increase in number of seeds, regardless of species, genotypes, and carbohydrate levels that were evaluated in this study. However, carbohydrate levels largely modified the correlation between seed number and fresh weight…