scholarly journals Landslides and the Urban Forest

2011 ◽  
Vol 37 (5) ◽  
pp. 213-218
Author(s):  
Robert Loeb ◽  
Samuel King
Keyword(s):  
Root System ◽  
Lateral Root ◽  
Urban Forest ◽  
Basal Area ◽  
Natural Area ◽  
Species Classification ◽  
Slope Steepness ◽  
Tap Root ◽  
Area Survey ◽  
Root Plate

Trees and saplings were felled and killed by rockslides and soil slides formed during the record breaking rains of May 1–2, 2010, in Radnor Lake State Natural Area, Nashville, Tennessee, U.S. The losses were analyzed by species; stem basal area; root plate diameter and depth; percent slope; occurrence in a rockslide or soil slide as well as species classification as a lateral root system species versus tap or heart root system species. The number of stems lost for each species had a distribution similar to the results of the 2009 Natural Area survey but the number of saplings was significantly underrepresented at the landslide sites. Tree deaths were nearly five times greater than saplings lost. Although there were nearly equal numbers of tree and sapling stems classified as possessing a lateral root system versus tap or heart root system, 74% of the sapling losses were from surface root system species. The means for root plate diameter and depth were significantly larger in rockslides than soil slides even though the mean stem basal area did not differ significantly. For both slide types, slope steepness was not correlated with root plate depth, root plate diameter, or stem basal area. Similarly for both root system classi-fications, slope steepness was not significantly correlated except for surface root system trees with root plate depth. Planting tap root system trees reduces the risk of landslide, but advances in the cultivation of taxa, such as hickory (Carya spp.), are needed to assure tap root preservation during transplantation.

Relation between plant size and severity of root rot in subterranean clover

1983 ◽  
Vol 23 (121) ◽  
pp. 126
Author(s):  
MJ Barbetti
Keyword(s):  
Root System ◽  
Western Australia ◽  
Root Rot ◽  
Lateral Root ◽  
Inverse Relationship ◽  
Subterranean Clover ◽  
Plant Size ◽  
Tap Root ◽  
The Relationship

Investigations were carried out in south-western Western Australia in 1977-78 to assess the relationship between dry weights of subterranean clover tops and roots and the severity of root rot. An inverse relationship was established between the severity of rotting of the tap root system and the plant top and the root dry weights. There was no relationship between the severity of root rot of the lateral root system and the plant top and root dry weights.

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.

scholarly journals Morphological Characterization of Root System Architecture in Diverse Tomato Genotypes during Early Growth

2018 ◽  
Vol 19 (12) ◽  
pp. 3888 ◽  
Author(s):  
Aurora Alaguero-Cordovilla ◽  
Francisco Gran-Gómez ◽  
Sergio Tormos-Moltó ◽  
José Pérez-Pérez
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Morphological Plasticity ◽  
Root System Architecture ◽  
Morphological Characterization ◽  
Early Growth ◽  
Soil Conditions ◽  
Wild Tomato Species ◽  
Local Soil

Plant roots exploit morphological plasticity to adapt and respond to different soil environments. We characterized the root system architecture of nine wild tomato species and four cultivated tomato (Solanum lycopersicum L.) varieties during early growth in a controlled environment. Additionally, the root system architecture of six near-isogenic lines from the tomato ‘Micro-Tom’ mutant collection was also studied. These lines were affected in key genes of ethylene, abscisic acid, and anthocyanin pathways. We found extensive differences between the studied lines for a number of meaningful morphological traits, such as lateral root distribution, lateral root length or adventitious root development, which might represent adaptations to local soil conditions during speciation and subsequent domestication. Taken together, our results provide a general quantitative framework for comparing root system architecture in tomato seedlings and other related species.

scholarly journals Root-Plate Characteristics of Common Aspen in Hemiboreal Forests of Latvia: A Case Study

Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 32
Author(s):  
Valters Samariks ◽  
Dace Brizga ◽  
Jeļena Rūba ◽  
Andris Seipulis ◽  
Āris Jansons
Keyword(s):  
Root System ◽  
Complex Structure ◽  
Mineral Soil ◽  
Negative Relationship ◽  
Tree Height ◽  
Belowground Biomass ◽  
Rooting Depth ◽  
Economic Losses ◽  
Coarse Roots ◽  
Root Plate

Climate change will cause winds to strengthen and storms to become more frequent in Northern Europe. Windstorms reduce the financial value of forests by bending, breaking, or uprooting trees, and wind-thrown trees cause additional economic losses. The resistance of trees to wind damage depends on tree species, tree- and stand-scale parameters, and root-soil plate characteristics such as root-plate size, weight, and rooting depth. The root-soil plate is a complex structure whose mechanical strength is dependent on root-plate width and depth, as the root system provides root attachment with soil and structural support. In Latvia, the common aspen (Populus tremula L.) root system has been studied to develop a belowground biomass model, because information about root system characteristics in relation to tree wind resistance is scarce. The aim of this study was to assess the root-plate dimensions of common aspen stands on fertile mineral soil (luvisol). Study material was collected in the central region of Latvia, where pure mature (41–60 years old) common aspen stands were randomly selected, and dominant trees within the stand were chosen. In total, ten sample trees from ten stands were uprooted. The diameter at breast height (DBH) and tree height (H) were measured for each sample tree, and their roots were excavated, divided into groups, washed, measured, and weighed. The highest naturally moist biomass values were observed for coarse roots, and fine root biomass was significantly lower compared to other root groups. All root group biomass values had a strong correlation with the tree DBH. The obtained results show that there is a close, negative relationship between the relative distance from the stem and the relative root-plate depth distribution.

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 Regulation of lateral root development by shoot-sensed far-red light via HY5 is nitrate-dependent and involves the NRT2.1 nitrate transporter

2021 ◽  
Author(s):  
Kasper van Gelderen ◽  
Chiakai Kang ◽  
Peijin Li ◽  
Ronald Pierik
Keyword(s):  
Root Growth ◽  
Root System ◽  
Lateral Root ◽  
Environmental Changes ◽  
Red Light ◽  
Agar Plate ◽  
Nitrate Transporter ◽  
Loss Of Function ◽  
Lateral Root Development ◽  
Nitrate Signaling

AbstractPlants are very effective in responding to environmental changes during competition for light and nutrients. Low Red:Far-Red (low R:FR)-mediated neighbor detection allows plants to compete successfully with other plants for available light. This above-ground signal can also reduce lateral root growth by inhibiting lateral root emergence, a process that might help the plant invest resources in shoot growth. Nitrate is an essential nutrient for plant growth and Arabidopsis thaliana responds to low nitrate conditions by enhancing nutrient uptake and reducing lateral and main root growth. There are indications that low R:FR signaling and low nitrate signaling can affect each other. It is unknown which response is prioritized when low R:FR light- and low nitrate signaling co-occur. We investigated the effect of low nitrate conditions on the low R:FR response of the A. thaliana root system in agar plate media, combined with the application of supplemental Far-Red (FR) light to the shoot. We observed that under low nitrate conditions main and lateral root growth was reduced, but more importantly, that the response of the root system to low R:FR was suppressed. Consistently, a loss-of-function mutant of a nitrate transporter gene NRT2.1 lacked low R:FR-induced lateral root reduction and its root growth was hypersensitive to low nitrate. ELONGATED HYPOCOTYL5 (HY5) plays an important role in the root response to low R:FR and we found that it was less sensitive to low nitrate conditions with regards to lateral root growth. In addition, we found that low R:FR increases NRT2.1 expression and that low nitrate enhances HY5 expression. HY5 also affects NRT2.1 expression, however, it depended on the presence of ammonium in which direction this effect was. Replacing part of the nitrogen source with ammonium also removed the effect of low R:FR on the root system, showing that changes in nitrogen sources can be crucial for root plasticity. Together our results show that nitrate signaling can repress low R:FR responses and that this involves signaling via HY5 and NRT2.1.

scholarly journals New Silvicultural Treatments for Conifer Peri-Urban Forests Having Broadleaves in the Understory - The First Application in the Peri-Urban of Xanthi in Northeastern Greece

2019 ◽  
Vol 10 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Elias Milios ◽  
Kyriaki Kitikidou ◽  
Kalliopi Radoglou
Keyword(s):  
Urban Forest ◽  
Urban Forests ◽  
Basal Area ◽  
Conifer Forests ◽  
Research Hypothesis ◽  
Silvicultural Treatments ◽  
Dead Trees ◽  
Selective Approach ◽  
Conifer Trees ◽  
Cutting Intensity

Background and Purpose: In Greece, forest practice did not develop special silvicultural treatments for planted conifer peri-urban forests where broadleaf trees appear as natural regeneration in the understory. The aims of this study are: a) to analyze the new proposed selective silvicultural treatments for the planted peri-urban forest of Xanthi and for analogous planted conifer forests, where broadleaf trees are naturally established in the understory b) to check the research hypothesis that the new selective silvicultural treatments exhibited higher intensity in terms of the basal area of cut trees, compared to that of traditional treatments in the studied peri-urban forest. Materials and Methods: In the traditional treatments, in the pine overstory cuttings, apart from the dead trees, mainly the malformed, damaged, suppressed and intermediate trees were cut. In the lower stories, the goal of the thinning was the more or less uniform distribution of broadleaf trees. In the proposed selective treatments, the main aim of pine cuttings is to release the broadleaf formations growing in the lower stories, while the treatments of the broadleaf trees will be a form of “positive selection” thinning. Plots were established in areas where the two types of treatments were going to be applied. In each plot, tree measurements and a classification of living trees into crown classes took place. After the application of the treatments the characteristics of cut trees were recorded. Results: In the established plots, before the cuttings (and thinning), total basal area was not statistically significantly different between the two types of treatments. In selective treatments, the basal area of all cut trees was statistically significantly higher than that of the results of traditional treatments. In the broadleaf cut trees there were statistical differences in the ratios of dominant, intermediate and suppressed trees between the two silvicultural approaches. Conclusions: The research hypothesis was verified. The intensity of treatments in terms of the basal area of cut trees was higher in the selective approach, compared to the traditional treatments in the Xanthi peri-urban forest. However, the overstory cutting intensity of the selective treatments depends on the spatial distributions and densities of broadleaved and conifer trees. In the broadleaf trees, the different objectives of the two types of treatments resulted in thinning with different qualitative characteristics. The proposed silvicultural treatments will accelerate the conversion of peri-urban conifer forests having an understory of broadleaf trees into broadleaved forests, or into mixed forests of conifers and broadleaf trees.

Root Morphology and Secretion of two subtropical tree species to NH4+-N and NO3–-N Deposition

2020 ◽  
Author(s):  
Rui Zhang ◽  
Yi Wang ◽  
Zhichun Zhou
Keyword(s):  
Root Growth ◽  
Root System ◽  
Root Morphology ◽  
Tree Species ◽  
Southern China ◽  
N Deposition ◽  
Fibrous Root ◽  
Nitrogen And Phosphorus ◽  
Root Absorption ◽  
Tap Root

Abstract Background: Both NH4+ and NO3– are capable of greatly influencing plants’ growth and biomass. However, the belowground responses of subtropical trees to either NH4+ or NO3– deposition remain poorly understood. Here, we discuss how these two forms of N deposition can affect root development, and experimentally analyzed how they could impact nitrogen and phosphorus absorption in two types (broadleaved with a fibrous root system vs. conifer with a tap root system) of subtropical tree species. Results: In a greenhouse in southern China, 1-year-old S. superba and P. massoniana seedlings grown on P-limited and P-normal soil were treated with NaNO3 and NH4Cl solutions of 0, 80, and 200 kg N ha–1 year–1, corresponding to the control, N80, and N200 groups, respectively. Root phenotype characteristics and metabolism ability were measured after 8 months of growth. The results showed that the root morphology and physiology variables differed significantly between the two species under different N and P treatments. Although S. superba had a larger quantity of roots than P. massoniana, both its root growth rate and root absorption were respectively lower and weaker. N addition differentially affected root growth and activity as follows: (1) NO3–-N80 and NH4+-N80 increased root growth and activity of the two species, but NH4+-N80 led to thicker roots in S. superba; (2) NO3–-N200 and NH4+-N200 had inhibitory effects on the roots of P. massoniana, for which NH4+-N200 led to thinner and longer roots and even the death of some roots; and (3) NH4+-N could promote metabolic activity in thicker roots (> 1.5 mm) and the NO3–-N was found to stimulate activity in thinner roots (0.5–1.5 mm) in the fibrous root system having a larger quantity of roots, namely S. superba. By contrast, NO3–-N and NH4+-N had an opposite influence upon functioning in the tap root system with a slender root, namely P. massoniana. Conclusion: We conclude P. massoniana has a much higher root absorption efficiency; however, nitrogen deposition is more beneficial to the root growth of S. superba.

Temperature Effects on Absorption and Translocation of Trifluralin and Methazole in Peanuts

Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 285-289 ◽  
Author(s):  
K. Hawxby ◽  
E. Basler ◽  
P. W. Santelmann
Keyword(s):  
Temperature Effects ◽  
Lateral Root ◽  
Initial Rate ◽  
Lateral Roots ◽  
Leaf Tissue ◽  
Root Tips ◽  
Plant Parts ◽  
Tap Root ◽  
Rate Of Absorption ◽  
Nutrient Solutions

The absorption and translocation of14C-labeled α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) and 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione methazole from nutrient solutions of various temperatures by(Arachis hypogaeaL. ‘Starr’) seedlings were determined. The accumulation of trifluralin in roots at 24 hr after exposure to trifluralin was greatest at 21 C and decreased at higher temperatures up to 38 C. The amounts of trifluralin translocated and accumulated in hypocotyls, tops, and cotyledons were small but generally increased with temperature. The initial rate of absorption of trifluralin was greater in excised lateral root tips than in tap root tips, but there was a greater accumulation in excised tap roots at 24 hr. The initial rates of absorption were higher for excised lateral roots at high temperatures. Total absorption of trifluralin at equilibrium was not proportional to the initial rates of absorption but was highest at low (21 C) and high (38 C) temperatures for excised lateral roots. The absorption of methazole by roots and translocation to other plant parts increased linearly with temperature, and it tended to accumulate in the mature leaf tissue.

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