Adventive-root development in mature black spruce and balsam fir in the boreal forests of Quebec, Canada

2005 ◽  
Vol 35 (11) ◽  
pp. 2642-2654 ◽  
Author(s):  
C Krause ◽  
H Morin
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Growth Pattern ◽  
Tree Species ◽  
Boreal Forests ◽  
Lateral Root ◽  
Black Spruce ◽  
Lateral Roots ◽  
Balsam Fir ◽  
Root Initiation

Black spruce (Picea mariana (Mill.) BSP) and balsam fir (Abies balsamea (L.) Mill.) are the two main tree species in the boreal forests of Quebec, Canada, and both show adventive-root formation. Little is known about the dynamics of adventive-root initiation and the pattern of length growth. To gain a better understanding of root growth, the root systems of 30 mature black spruce and 30 mature balsam fir were excavated until the root diameter had decreased to 2 cm. Tree ages ranged from 100 to more than 250 years. All trees showed only adventive roots; this was confirmed by dating the root–shoot interface. The youngest lateral roots were located close to ground level, whereas the oldest ones occurred lower in the stump, suggesting a process of renewal for the latter. Reconstruction of the development of the root system revealed a specific root-growth pattern. Adventive roots grew, on average, more than 60% of their total length in the year of initiation, whereas more than 93% of lateral-root elongation was recorded in the first 10 years after adventive roots were initiated. This growth pattern was found to be similar in the two tree species in terms of lateral-root development (p = 0.68). More variability was observed for the ramified adventive roots. However, two patterns emerged. First, around 10% of total elongation was completed in the same year as that of the corresponding lateral roots. Second, several ramified adventive roots were initiated in the same calendar year but delayed by several years relative to lateral adventive root initiation. No significant differences were observed between black spruce and balsam fir (p = 0.1).

scholarly journals A single cell view of the transcriptome during lateral root initiation in Arabidopsis thaliana

2020 ◽  
Author(s):  
Hardik P. Gala ◽  
Amy Lanctot ◽  
Ken Jean-Baptiste ◽  
Sarah Guiziou ◽  
Jonah C. Chu ◽  
...  
Keyword(s):  
Single Cell ◽  
Root Development ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Initiation ◽  
Lateral Root Primordia ◽  
Lateral Root Development ◽  
Lateral Root Initiation ◽  
Molecular Events

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.

Root mapping of three tropical pasture species using 32P

1969 ◽  
Vol 9 (39) ◽  
pp. 445 ◽  
Author(s):  
RA Bray ◽  
JB Hacker ◽  
DE Byth
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Lateral Root ◽  
Sandy Loam ◽  
Lateral Roots ◽  
Root Systems ◽  
Growth Patterns ◽  
Constant Rate ◽  
Initial Root

Root growth patterns of Glycine javanica, Setaria anceps, and Medicago sativa were studied by uptake of 32P from a sandy loam. Placement of isotope was through permanently positioned PVC conduit on a grid over a 90� quadrant of the root system. Detection of radioactivity was in in situ plant material. Lucerne had strong initial root development but was slow to form lateral roots. Glycine and Setaria had quite similar root systems although Setaria had more rapid vertical root development than Glycine. Both these species had strong lateral root systems. When a regression of minimum root length against time was calculated, lateral root growth was shown to be independent of depth and distance from the plant, suggesting that roots behave as if growing from a point source in random directions at a constant rate. This rate was the same for all species. There were also indications of strong vertical root systems in lucerne and Setaria.

Root growth in corn and soybeans: effects of cadmium and lead on lateral root initiation

1978 ◽  
Vol 56 (3) ◽  
pp. 277-281 ◽  
Author(s):  
Carl P. Malone ◽  
Raymond J. Miller ◽  
D. E. Koeppe
Keyword(s):  
Root Growth ◽  
Lateral Root ◽  
Lateral Roots ◽  
Toxic Effects ◽  
Root Initiation ◽  
Inhibitory Effects ◽  
Lateral Root Initiation ◽  
Primary Roots ◽  
Cadmium And Lead

This study examines the previously reported inhibitory effects of Cd on root growth. In hydroponic experiments, 100 μg Cd/ℓ effected a 33% inhibition of lateral root initiation of corn. The growth of corn and soybean primary roots was not reduced at Cd concentrations of 1 mg/ℓ, and the number of lateral root initials in soybeans was not reduced at 2 mg Cd/ℓ. The toxic effects of Cd were ameliorated by additions of Zn or by additions of Fe citrate to nutrient growth solutions. While both Zn and Fe additions did result in increased lateral root initiation, the number of initials was significantly lower than the controls. Lead had no effect on the initiation of soybean lateral roots at a concentration of 100 μg Pb/ℓ. However, 5 mg Pb/ℓ did effect a 21% decrease in corn lateral root initials, but this decrease could not be demonstrated with higher Pb concentrations.

scholarly journals A low-cost aeroponic phenotyping system for storage root development: unravelling the below-ground secrets of cassava (Manihot esculenta)

Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Michael Gomez Selvaraj ◽  
Maria Elker Montoya-P ◽  
John Atanbori ◽  
Andrew P. French ◽  
Tony Pridmore
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Low Cost ◽  
Root Traits ◽  
Suitable Model ◽  
Root Initiation ◽  
Storage Root ◽  
Economic Traits ◽  
Storage Roots ◽  
Storage Root Development

Abstract Background Root and tuber crops are becoming more important for their high source of carbohydrates, next to cereals. Despite their commercial impact, there are significant knowledge gaps about the environmental and inherent regulation of storage root (SR) differentiation, due in part to the innate problems of studying storage roots and the lack of a suitable model system for monitoring storage root growth. The research presented here aimed to develop a reliable, low-cost effective system that enables the study of the factors influencing cassava storage root initiation and development. Results We explored simple, low-cost systems for the study of storage root biology. An aeroponics system described here is ideal for real-time monitoring of storage root development (SRD), and this was further validated using hormone studies. Our aeroponics-based auxin studies revealed that storage root initiation and development are adaptive responses, which are significantly enhanced by the exogenous auxin supply. Field and histological experiments were also conducted to confirm the auxin effect found in the aeroponics system. We also developed a simple digital imaging platform to quantify storage root growth and development traits. Correlation analysis confirmed that image-based estimation can be a surrogate for manual root phenotyping for several key traits. Conclusions The aeroponic system developed from this study is an effective tool for examining the root architecture of cassava during early SRD. The aeroponic system also provided novel insights into storage root formation by activating the auxin-dependent proliferation of secondary xylem parenchyma cells to induce the initial root thickening and bulking. The developed system can be of direct benefit to molecular biologists, breeders, and physiologists, allowing them to screen germplasm for root traits that correlate with improved economic traits.

Lateral root formation and nutrients: nitrogen in the spotlight

2021 ◽  
Author(s):  
Pierre-Mathieu Pélissier ◽  
Hans Motte ◽  
Tom Beeckman
Keyword(s):  
Signaling Pathways ◽  
Root System ◽  
Root Development ◽  
Lateral Root ◽  
Molecular Mechanisms ◽  
Root Formation ◽  
Lateral Roots ◽  
Nutrient Use Efficiency ◽  
Lateral Root Formation ◽  
Lateral Root Development

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.

Formation of lateral root meristems is a two-stage process

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3303-3310 ◽  
Author(s):  
M.J. Laskowski ◽  
M.E. Williams ◽  
H.C. Nusbaum ◽  
I.M. Sussex
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Initial Period ◽  
Subsequent Stage ◽  
Root Initiation ◽  
Root Meristems ◽  
Lateral Root Initiation ◽  
Cell Layers ◽  
Stage Process ◽  
Pericycle Cells

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3–5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.

scholarly journals AT-HOOK MOTIF NUCLEAR LOCALISED PROTEIN 18 as a Novel Modulator of Root System Architecture

2020 ◽  
Author(s):  
Marek Šírl ◽  
Tereza Šnajdrová ◽  
Dolores Gutiérrez-Alanís ◽  
Joseph G. Dubrovsky ◽  
Jean Phillipe Vielle-Calzada ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Apical Meristem ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Initiation ◽  
Lateral Root Initiation

The AT-HOOK MOTIF NUCLEAR LOCALIZED PROTEIN (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 regulates the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from decreased initiation. Overexpression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. Formation of lateral roots is affected during the initiation of LRP and later development. AHL18 regulate root apical meristem activity, lateral root initiation and emergence, which is in accord with localization of its expression.

scholarly journals Splitting in Fire-Killed Trees in the Boreal Forest of Alberta

2003 ◽  
Vol 20 (4) ◽  
pp. 167-174
Author(s):  
Nobutaka Nakamura ◽  
Paul M. Woodard ◽  
Lars Bach
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Black Spruce ◽  
Lodgepole Pine ◽  
White Spruce ◽  
Balsam Fir ◽  
Crown Fire ◽  
In Fire ◽  
Solar Angle

Abstract Tree boles in the boreal forests of Alberta, Canada will split once killed by a stand-replacing crown fire. A total of 1,485 fire-killed trees were sampled, 1 yr after burning, in 23 plots in 14 widely separated stands within a 370,000 ha fire. Sampling occurred in the Upper and Lower Foothills natural subregions. The frequency of splitting varied by species but averaged 41% for all species. The order in the frequency of splitting was balsam fir, black spruce, white spruce and lodgepole pine. The type of splitting (straight, spiral, or multiple) varied by species, as did the position of the split on the tree bole. Aspect or solar angle was not statistically related to the type or occurrence of splitting.

Lateral root initiation in Marsilea quadrifolia. I. Origin and histogenesis of lateral roots

1991 ◽  
Vol 69 (1) ◽  
pp. 123-135 ◽  
Author(s):  
Bai-Ling Lin ◽  
V. Raghavan
Keyword(s):  
Lateral Root ◽  
Single Cells ◽  
Lateral Roots ◽  
Central Axis ◽  
Root Initiation ◽  
Vascular Connection ◽  
Lateral Root Initiation ◽  
Marsilea Quadrifolia ◽  
Lateral Root Primordium ◽  
Root Primordium

In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a fivecelled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types. Key words: lateral root initiation, Marsilea quadrifolia, root histogenesis.

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