Évaluation de trois contenants pour la production de plants d'espèces feuillues de fortes dimensions

1995 ◽  
Vol 71 (4) ◽  
pp. 459-465 ◽  
Author(s):  
Alain Cogliastro ◽  
Andrée Hallé ◽  
Michel Labrecque ◽  
Stéphane Daigle

Three types of containers of different volumes (Polymos 15, 700 cm3; Polymos 12, 1,000 cm3; Whitcomb®, 3,500 cm3) were tested to produce large hardwood seedlings. Studies of growth and root development of three species, white ash (Fraxinus americana L.), bur oak (Quercus macrocarpa Michx.) and northern red oak (Quercus rubra L.) were used to assess containers after two growing seasons in an unheated plastic shelter. The mean height of seedlings increased with the volume of the containers. The total dry mass of seedlings at 55 cm in height was more important in the larger container; the total root mass and the proportion of secondary roots were higher in the container of greater volume. For the two species of oak, the 3,500 cm3 container produced seedlings with a taproot showing a number of deviations when touching the bottom of the container. White ash, a species with a fibrous root system, showed a higher deviation index in the smaller containers. The openings on the sides of the square-shaped Whitcomb® containers were effective for the air-pruning of secondary lateral roots of species with a taproot and their volume allowed for an important root mass. However, the flat bottom with openings at each of the four corners did not prevent deviation of the primary root. The use of a bottomless square-shaped container with a volume greater than 1,000 cm3 and with adequate lateral openings would optimize the production of large seedlings of hardwood species with taproot. Key words: large containerized seedlings, root development, root deviation, Quercus sp., Fraxinus sp.

1981 ◽  
Vol 11 (4) ◽  
pp. 752-757 ◽  
Author(s):  
William C. Carlson

Controlled-release fertilizers applied to the root zone of 1-0 plug western hemlock (Tsugaheterophylla Raf. Sarg.) at planting stimulated shoot and root growth in the following two growing seasons. The number and diameter of lateral roots was increased by fertilizing, but fertilizing did not alter the shoot–root ratio. The shoot–root ratio did not increase with an increase in seedling size, height, or total weight.


2020 ◽  
Author(s):  
Hardik P. Gala ◽  
Amy Lanctot ◽  
Ken Jean-Baptiste ◽  
Sarah Guiziou ◽  
Jonah C. Chu ◽  
...  

AbstractRoot architecture is a major determinant of fitness, and is under constant modification in response to favorable and unfavorable environmental stimuli. Beyond impacts on the primary root, the environment can alter the position, spacing, density and length of secondary or lateral roots. Lateral root development is among the best-studied examples of plant organogenesis, yet there are still many unanswered questions about its earliest steps. Among the challenges faced in capturing these first molecular events is the fact that this process occurs in a small number of cells with unpredictable timing. Single-cell sequencing methods afford the opportunity to isolate the specific transcriptional changes occurring in cells undergoing this fate transition. Using this approach, we successfully captured the transcriptomes of initiating lateral root primordia, and discovered many previously unreported upregulated genes associated with this process. We developed a method to selectively repress target gene transcription in the xylem pole pericycle cells where lateral roots originate, and demonstrated that expression of several of these targets was required for normal root development. We also discovered novel subpopulations of cells in the pericycle and endodermal cell files that respond to lateral root initiation, highlighting the coordination across cell files required for this fate transition.One sentence summarySingle cell RNA sequencing reveals new molecular details about lateral root initiation, including the transcriptional impacts of the primordia on bordering cells.


Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 265-268 ◽  
Author(s):  
Ghanem S. Hassawy ◽  
K. C. Hamilton

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), IAA (indoleacetic acid), kinetin (6-furfurylamino purine), and their combinations in culture solutions did not affect cotton (Gossypium hirsutumL., var. Deltapine Smooth Leaf) germination but reduced primary root and shoot lengths of seedlings. Trifluralin alone and in combination with IAA or kinetin inhibited lateral root development. When IAA and kinetin were both applied with 5 ppmw trifluralin, lateral roots developed.


2021 ◽  
Vol 43 (2) ◽  
Author(s):  
Fábio Oseias dos Reis Silva ◽  
Moises Zucoloto ◽  
Ana Maria Alves de Souza Ribeiro ◽  
Robson Bonomo ◽  
Fábio Luiz Partelli ◽  
...  

Abstract The aim of this study was to evaluate root development and productivity of ‘Pérola’ pineapple as a function of split N and K fertilization and fertigation management. Four different split nitrogen and potassium fertilizations were evaluated in combination, as well as four different fertigation managements. Root samples were analyzed using the Safira software and surface area, length, root volume per soil volume, root diameter, dry mass, specific surface and specific length were quantified. Average fruit mass and average productivity were also quantified. The different split fertilizations and fertigation management alternatives caused changes in the root system of ‘Pérola’ pineapple. Regarding dry root mass per cm3 of soil, irrigated and fertigated plants split in twenty-seven N applications and four K applications, was 0.106 g.cm3, while irrigated and fertigated plants split in fifty-four N applications and four K applications was 0.523 g.cm3. Regarding productivity and average fruit mass, monthly applications and in four K applications until the ninth month of plant age promote greater increments, while split nitrogen fertilization showed no influence.


HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1824-1829 ◽  
Author(s):  
Gabriele Amoroso ◽  
Piero Frangi ◽  
Riccardo Piatti ◽  
Francesco Ferrini ◽  
Alessio Fini ◽  
...  

This experiment investigated the effect of different container design on growth and root deformation of littleleaf linden (Tilia cordata Mill.) and field elm (Ulmus minor Mill.). The trial was carried out over two growing seasons (2008 to 2009). In April 2008, 1-year-old bare-root seedlings of the two species were potted in three types of 1-L containers: Superoots® Air-Cell™ (The Caledonian Tree Company, Pathhead, UK), Quadro fondo rete (Bamaplast, Massa e Cozzile, Italy), and smooth-sided containers. At the beginning of the second growing season, the same plants were repotted in the following 3-L containers: Superoots® Air-Pot™ (The Caledonian Tree Company), Quadro antispiralizzante (Bamaplast), and smooth-sided containers. At the end of each growing season, a subset of the plants from each container type was harvested to determine shoot and root dry mass and root deformation (by dry weight of root deformed mass relative to the whole root mass). Chlorophyll fluorescence and leaf chlorophyll content were measured during the second growing season. For both species, at the end of first growing season, the poorest root architecture was observed in the smooth-sided containers, whereas Superoots® Air-Cell™ and Quadro fondo rete both reduced the percentage of deformed root mass. At the end of the second growing season, plants of both species grown in Superoots® Air-Pot™ showed less deformed root mass, whereas Quadro antispiralizzante provided good results only in littleleaf linden. A reduction of field elm root biomass and littleleaf linden shoot biomass was observed at the end of the trial in plants grown in Superoots® Air-Pot®. Plants grown in these containers showed less leaf chlorophyll content compared with plants grown in smooth-sided containers at the end of the second year.


2005 ◽  
Vol 18 (6) ◽  
pp. 521-532 ◽  
Author(s):  
Lydia J. Bright ◽  
Yan Liang ◽  
David M. Mitchell ◽  
Jeanne M. Harris

The evolutionary origins of legume root nodules are largely unknown. We have identified a gene,LATD, of the model legume Medicago truncatula, that is required for both nodule and root development, suggesting that these two developmental processes may share a common evolutionary origin. The latd mutant plants initiate nodule formation but do not complete it, resulting in immature, non-nitrogen-fixing nodules. Similarly, lateral roots initiate, but remain shortstumps. The primary root, which initially appears to be wild type, gradually ceases growth and forms an abnormal tipthat resembles that of the mutant lateral roots. Infection by the rhizobial partner, Sinorhizobium meliloti, can occur, although infection is rarely completed. Once inside latd mutant nodules, S. meliloti fails to express rhizobial genes associatedwith the developmental transition from free-living bacterium to endosymbiont, such as bacA and nex38. The infecting rhizobia also fail to express nifH and fix nitrogen. Thus, both plant and bacterial development are blocked in latd mutant roots. Based on the latd mutant phenotype, we propose that the wild-type function of the LATD gene is to maintain root meristems. The strong requirement of both nodules and lateral roots for wild-type LATD gene function supports lateral roots as a possible evolutionary origin for legume nodules.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 685b-685
Author(s):  
Thomas E. Marler ◽  
Haluk M. Discekici

`Red Lady' papaya transplants were planted on a slope with a 30% to 35% grade and grown for 5 months. Excavation was used to determine root distribution on the uphill and downhill sides of the plants. Roots were separated into the taproot system and lateral roots on the uphill and downhill sides. The line intersect method was used to determine length of the lateral roots, and length of the taproot system was measured directly. All roots were dried at 70°C. The taproot system accounted for 2% of the total root length and 66% of the total root mass. Of the 130-m of lateral roots, 71% were located on the downhill side. Similarly, 69% of the dry mass of the lateral root system was located on the downhill side. Primary lateral roots on the uphill side of each plant developed horizontally, but some secondary lateral roots developed against gravity to maintain a portion of the root system close to the surface of the slope. Some of these lateral roots developed at angles of 55° to 60° above the horizontal.


2021 ◽  
Author(s):  
Pierre-Mathieu Pélissier ◽  
Hans Motte ◽  
Tom Beeckman

Abstract Lateral roots are important to forage for nutrients due to their ability to increase the uptake area of a root system. Hence, it comes as no surprise that lateral root formation is affected by nutrients or nutrient starvation, and as such contributes to the root system plasticity. Understanding the molecular mechanisms regulating root adaptation dynamics towards nutrient availability is useful to optimize plant nutrient use efficiency. There is at present a profound, though still evolving, knowledge on lateral root pathways. Here, we aimed to review the intersection with nutrient signaling pathways to give an update on the regulation of lateral root development by nutrients, with a particular focus on nitrogen. Remarkably, it is for most nutrients not clear how lateral root formation is controlled. Only for nitrogen, one of the most dominant nutrients in the control of lateral root formation, the crosstalk with multiple key signals determining lateral root development is clearly shown. In this update, we first present a general overview of the current knowledge of how nutrients affect lateral root formation, followed by a deeper discussion on how nitrogen signaling pathways act on different lateral root-mediating mechanisms for which multiple recent studies yield insights.


1996 ◽  
Vol 36 (7) ◽  
pp. 847 ◽  
Author(s):  
A Costantini ◽  
D Doley ◽  
HB So

The influence of penetration resistance (PR), an easily measured indicator of soil strength, on the growth of Pinus caribaea var. hondurensis radicles and seedlings was investigated. Negative exponential relationships between PR and both radicle and primary root elongation were observed. All root elongation ceased at PR levels of 3.25 MPa. Tip diameters of radicles and primary roots were positively correlated with PR values up to 2.4 MPa, whilst numbers of primary roots, total root lengths and lengths of longest roots were all negatively correlated with PR. Hypocotyl elongation was also reduced by increasing PR, although the reductions occurred at higher PRs than those which inhibited root development. In contrast, primary shoot development was unaffected by PR levels which were sufficient to stop root elongation, but was reduced in soil with a PR of 4.8 MPa. There were significant family x soil type and family x PR interactions for radicle, hypocotyl, primary root and primary shoot development. 1f these interactions are correlated with performance in the field, then they may serve as useful indicators of family suitability to both soil type and high strength soils.


FEBS Letters ◽  
2018 ◽  
Vol 593 (1) ◽  
pp. 97-106 ◽  
Author(s):  
QingKun Dong ◽  
ZhiWei Zhang ◽  
YuTing Liu ◽  
Li‐Zhen Tao ◽  
HuiLi Liu

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