1,721,005 research outputs found
Root architectural and morphological response of Pinus nigra Arn. and Quercus robur L. to nutrient supply and root density in the soil
No full textFine-root dynamics in a Quercus cerris (L.) forest in relation to soil moisture in the Southern Apennines, Italy
No full text
Fine root growth of Quercus pubescens seedlings after drought stress and fire disturbance
No full textPost-fire resprouting is an important process in the Mediterranean climate regions of the world and involves considerable rearrangement of biomass allocation. We have investigated the morphological changes occurring in the fine root portion of Quercus pubescens seedlings growing in controlled conditions
in which fire disturbance is superimposed on drought-stressed plants. We measured the absolute (length, number of apices) and relative (specific root length and root tissue density) morphometric traits of fine
roots, and the biomass and water content of the main plant compartments (leaves, shoot, taproot and
lateral fine roots). Initially, soil drying significantly increased the fine root standing mass and decreased
the specific fine root length irrespective of the fire, but fine root biomass declined after a critical length
of time. Fire significantly decreased the above-ground biomass and its water content notwithstanding the drought stress interruption. On the contrary, time, water supply and fire disturbance factors showed significant interaction effects for the plastic morphological traits, namely, length and number of apices.
In fact, fire reduced and postponed the peak of root growth in terms of the thinnest fine root fraction (0.0–0.5 mm diameter) and number of apices. These findings indicate the advantages of shedding over maintaining the roots under a condition of severe drought. Indeed, shedding makes the overall reduction
of the root system more functional, and induces a partial increase in water particularly in the thicker fraction of the fine roots (0.5–2.0 mm). Shoot removal by fire seems to lessen and prolong the acclimation process to drought, but the decrease in non structural carbohydrate reserves appears to impede the recovery process at least after persistent drought
Effect of drought and fire on root development in Quercus pubescens Willd. and Fraxinus ornus L. seedlings
No full textThis paper casts light on the events taking place in the root system when seedlings of two deciduous woody Mediterranean species, Quercus pubescens Willd. and Fraxinus ornus L., are stressed by drought or fire or both. Stress treatment mimicked the conditions that often Occur in natural Mediterranean ecosystems during dry summers. Allocation of resources to the root system is affected as shown by the fact that taproot biomass decreases under stress conditions only in Fraxinus ornus whereas lateral roots undergo a decrease in length, dry weight. number of apices in both species. An increase in electrolyte leakage from roots of both species during treatments suggests that morphological variations in the root system are associated with damages occurring in root tissue. All the effects observed are reversible if a critical threshold of stress duration is not reached but recovery starts when the aboveground parts are fully replaced. The alteration of a number of root traits suggests that both drought and fire affect root growth and root turnover. Differences in recovery patterns between the two species are observed and attributed to specific tolerances of the root systems. The knowledge of the events taking place at root level might help to understand better the tolerance mechanism to drought or fire characterizing species living in Mediterranean ecosystems
An integrated approach to the characterization of two autochthonous lentil (Lens culinaris) landraces of Molise (South-Central Italy)
No full textVariation of morphological and physiological traits in oak seedlings (Quercus ilex, Quercus trojana, Quercus virgiliana) undergoing to drought and fire treatments: phenotype and functional equilibrium
No full textPioneer and fibrous root seasonal dynamics of Vitis vinifera L. are affected by biochar application to a low fertility soil: A rhizobox approach
No full textThe present work analyzes the impact of biochar-induced modification of soil physico-chemical properties on intra-annual growth dynamics of pioneer and fibrous grapevine roots. A scanner inserted into a buried rhizobox with a transparent side facing the plant root system was used to acquire images of pioneer and fibrous roots of control and biochar-treated plants throughout the vegetative season. Images were analyzed with ImageJ software to measure root traits. Biochar treatment increased soil pH, nutrient concentration, and water content during the driest and warmest period, while bulk density was reduced. Analysis of both pioneer and fibrous root traits highlighted a single peak of growth during the vegetative season. Pioneer roots were thicker and grew faster than fibrous roots, which were longer and more numerous. Amelioration of physico-chemical properties of biochar-amended soil stimulated an earlier root lengthening, and a higher root number at the onset of the season, which resulted in a greater canopy development compared to control plants. Later, in summer, as a consequence of the higher water content of biochar-treated soil, plants modified their root architecture, lowering the number of fibrous roots probably because of the reduced need to exploit soil for water and nutrient uptake
- …
