Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
An Overview Of The Physiology And Biochemistry Of N Reserves Mobilization In Forage Species, F Le Dily, A Ourry, J Boucaud
An Overview Of The Physiology And Biochemistry Of N Reserves Mobilization In Forage Species, F Le Dily, A Ourry, J Boucaud
IGC Proceedings (1997-2023)
Recent works focusing on the physiological and biochemical events associated to perennial forages sustainability (re-growth after defoliation, winter survival), provided evidence that vegetative storage proteins (VSPs, ca proteins stored in remaining organs and specifically mobilized) were key organic compounds for shoot regrowth. Attempts to elucidate environmental conditions involved in VSPs deposit ability of different species are under progress today. In contrast, mechanisms of spring- or cut-induced proteolysis are investigated at a lesser extend. This contribution is an opportunity to summarize our knowledge of N-reserves mobilization and to set the question of VSPs breakdown regulation.
Intraspecific Competition In Lucerne And Relationships With Reserve Availability, Jean Christophe Avice, Alain Ourry, Gilles Lemaire, Jeffrey J. Volenec, Jean Boucaud
Intraspecific Competition In Lucerne And Relationships With Reserve Availability, Jean Christophe Avice, Alain Ourry, Gilles Lemaire, Jeffrey J. Volenec, Jean Boucaud
IGC Proceedings (1997-2023)
Below-ground reserves are thought to provide an indication of a forage potential for shoot regrowth after defoliation. The aim of this work was to re-evaluate the causal relationships existing between organic reserves (non-structural carbohydrates and N reserves) and shoot regrowth of alfalfa. The variations brought about by cultivar differences (cv Lodi or Europe), length of the previous regrowth period (30 or 45 d), or by intraspecific competition for light within a dense canopy, were studied. Field grown plants were harvested at weekly intervals, and separated as dominant, intermediate and suppressed plants. Shoot regrowth yield was determined and taproot were analyzed …
Effects Of Light Intensity And Defoliation On The Receptiveness For Primary Induction In Festuca Pratensis Huds, Lars T. Havstad
Effects Of Light Intensity And Defoliation On The Receptiveness For Primary Induction In Festuca Pratensis Huds, Lars T. Havstad
IGC Proceedings (1997-2023)
Seedlings of Festuca pratensis Huds. (cv. Salten) were raised at three different light intensities (141, 85 or 28 (mol m-2s-1 ) for 7 weeks after emergence and then either left uncut or defoliated 40 or 80% of total leaf area, before transfer to primary induction (6°C, natural short days) for 12, 15 or 18 weeks. Percentage of heading plants was more affected by the duration of primary induction than by light intensity and defoliation prior to induction. The results lend no support to the existence of a juvenile stage in seedlings of Festuca pratensis. Defoliation had less influence on …
Leaf Anatomy And Ultrastructure Of Poa Ligularis After Defoliation And Water Stress, M G. Klich, R E. Brevedan, S C. Villamil
Leaf Anatomy And Ultrastructure Of Poa Ligularis After Defoliation And Water Stress, M G. Klich, R E. Brevedan, S C. Villamil
IGC Proceedings (1997-2023)
The objective of this study was to determine the effect of defoliation and water stress on leaf anatomy and the mesophyll cell ultrastructure of Poa ligularis. Anatomical differences were detected mainly at epidermal level. Under water stress, leaf roughness was enhanced since the epidermal-cell surface contours became conspicuous. Under defoliation the microscopic roughness decreased as a result of fewer epicuticular wax crystals being formed. Defoliation produced an enhancement of the interlamellar spaces in the irrigated plantís chloroplast. Under no defoliation conditions, chloroplast structure was not affected by water stress. When subjected to water stress, lightly defoliated plants presented chloroplasts …
Root Nitrogen Cycling And Alfalfa Stress Tolerance, J J. Volenec, B C. Joern, L D. Barber, S M. Cunningham, A Ourry
Root Nitrogen Cycling And Alfalfa Stress Tolerance, J J. Volenec, B C. Joern, L D. Barber, S M. Cunningham, A Ourry
IGC Proceedings (1997-2023)
Our hypothesis is that certain root N pools are utilized preferentially during the early shoot regrowth. Our objective was to determine the relative contribution of crown N, root N, and specific root N pools to shoot regrowth after defoliation. We used 15N to follow N into and out of crowns, roots, and specific root N pools, to regrowing shoots after defoliation. The low molecular weight N pool (amino acids, inorganic N,...) acquired 15N rapidly within 2 d of N application. Movement of 15N into the protein-N and insoluble-N pools was delayed initially, but continued until 8 d after N application. …
Effect Of Species Horizontal Distribution On Defoliation Of Ryegrass-Clover Swards Grazed By Sheep, P C. De Faccio Carvalho, F Louault, M Lafarge
Effect Of Species Horizontal Distribution On Defoliation Of Ryegrass-Clover Swards Grazed By Sheep, P C. De Faccio Carvalho, F Louault, M Lafarge
IGC Proceedings (1997-2023)
Defoliation events on labelled white clover (Trifolium repens) growing points or ryegrass (Lolium perenne) tillers were measured during grazing tests by sheep with swards consisting of mixed ryegrass-clover (MIX) or alternate strips of clover and ryegrass (STRIP). Sward surface height was maintained at 6.4 cm by lawnmower cuts in order to obtain a similar surface height for both species. On average, during 13 grazing tests in STRIP and 11 in MIX swards, clover was the more defoliated species : 23.3% of the growing points in STRIP and 26.5% in MIX swards were defoliated compared to 16.2% …
Effects Of Defoliation Frequency On Foraging Selective Behaviour In Pasture With Paspalum Dilatatum, G L. Acosta, A T. Ayala Torales, V A. Deregibus
Effects Of Defoliation Frequency On Foraging Selective Behaviour In Pasture With Paspalum Dilatatum, G L. Acosta, A T. Ayala Torales, V A. Deregibus
IGC Proceedings (1997-2023)
The objective was to assess defoliation effects exerted by sheep grazing on a pasture composed by falaris and dallisgrass, at two phenological stages during spring and summer. A sown pasture of Phalaris aquatica and Paspalum dilatatum were grazed at two phenological stages: stage I (SI), with no more than 5% of reproductive tillers, and stage II (SII), with at least 70% of reproductive tillers. Tillers of both grass species were marked with plastic colour rings along two transects in each plot. Phenological stage of tillers, and the number, age and length of each leaf per tiller were registered. Tiller defoliation …