The origin and anatomy of rhizophores in Vernonia herbacea and V. platensis (Asteraceae) from the Brazilian Cerrado

2005 ◽  
Vol 53 (3) ◽  
pp. 273 ◽  
Author(s):  
Adriana Hissae Hayashi ◽  
Beatriz Appezzato-da-Glória
Keyword(s):  
Root System ◽  
Vegetative Propagation ◽  
Primary Root ◽  
Cotyledonary Node ◽  
Axillary Buds ◽  
Brazilian Cerrado ◽  
Natural Conditions ◽  
Environmental Disturbances

The aim of this work is to study the origin and anatomy of rhizophores in two Asteraceae species from the Brazilian Cerrado: Vernonia herbacea (Vell.) Rusby and V. platensis (Spreng.) Less. In both species, axillary buds from the cotyledonary node give rise to the first rhizophores. As rhizophores develop, these organs branch to form new rhizophores from their axillary buds that constitute a sympodial system of underground branches. Nodes, internodes and axillary buds, protected by cataphylls, are evident in these underground organs. The primary root degenerates and all the root system arises adventitiously from the rhizophores. Under natural conditions, the axillary buds give rise to new rhizophores, but when exposed to the light, these buds develop into aerial stems. When rhizophores are fragmented, each of these structures, which accumulate fructans, are important organs for vegetative propagation mainly in areas subjected to environmental disturbances, such as the Cerrado, where fire and drought frequently occur.

Morphological and developmental investigations of the underground system of Erythroxylum species from Brazilian cerrado

2007 ◽  
Vol 55 (7) ◽  
pp. 749 ◽  
Author(s):  
Alexandre Antonio Alonso ◽  
Silvia Rodrigues Machado
Keyword(s):  
Root System ◽  
Primary Root ◽  
Additional Stress ◽  
Aluminium Content ◽  
Brazilian Cerrado ◽  
Aerial Shoot ◽  
Stage Of Development ◽  
Slow Development ◽  
Shrubby Species ◽  
Underground System

Brazilian cerrado, a neotropical savanna, is characterised by a strongly seasonal climate with distinctive wet and dry seasons, and deep and well drained soils that are acidic and with high aluminium content. Recurrent fires in the dry season place additional stress on the survival of plants, which exhibit an array of strategies of survival. The purpose of this work was to study the underground system of Erythroxylum nanum A.St-Hil. and E. campestre A.St-Hil., two sub-shrubby species, and E. tortuosum Mart., a shrubby species, verifying the possible relationship between the morphology of the underground organs and the resprouting ability of these plants. Anatomical analyses followed the usual techniques of plant anatomy. The cotyledons of the three species were green, foliaceous and photosynthesising. The two sub-shrubby species (Erythroxylum nanum and E. campestre) showed slow development of the aerial shoot system and extensive growth of the primary root in the initial stage of development. E. tortuosum presented the most pronounced development of the aerial system and a poorly developed primary root compared with the sub-shrubby species. The sub-shrubby species occurred in clumps and had underground systems interlinked, consisting of a deep axial primary root system besides soboles in E. nanum and xylopodium in E. campestre. Plants of the E. tortuosum were isolated, highly branched and their underground system consisted of a superficial primary root system. Abundance of reserves and the bud-forming potential of the soboles, xylopodium and roots resulted in production of vigorous branches that are highly valuable in the regeneration of the aerial biomass following fire or seasonal dry in cerrado.

scholarly journals Comprehensive Genome-Wide Association Analysis Reveals the Genetic Basis of Root System Architecture in Soybean

2020 ◽  
Vol 11 ◽  
Author(s):  
Waldiodio Seck ◽  
Davoud Torkamaneh ◽  
François Belzile
Keyword(s):  
Root System ◽  
System Architecture ◽  
Phenotypic Variation ◽  
Genetic Basis ◽  
Genome Wide Association Study ◽  
Primary Root ◽  
Root System Architecture ◽  
Genome Wide Association ◽  
Nucleotide Polymorphisms ◽  
Genome Wide

Increasing the understanding genetic basis of the variability in root system architecture (RSA) is essential to improve resource-use efficiency in agriculture systems and to develop climate-resilient crop cultivars. Roots being underground, their direct observation and detailed characterization are challenging. Here, were characterized twelve RSA-related traits in a panel of 137 early maturing soybean lines (Canadian soybean core collection) using rhizoboxes and two-dimensional imaging. Significant phenotypic variation (P < 0.001) was observed among these lines for different RSA-related traits. This panel was genotyped with 2.18 million genome-wide single-nucleotide polymorphisms (SNPs) using a combination of genotyping-by-sequencing and whole-genome sequencing. A total of 10 quantitative trait locus (QTL) regions were detected for root total length and primary root diameter through a comprehensive genome-wide association study. These QTL regions explained from 15 to 25% of the phenotypic variation and contained two putative candidate genes with homology to genes previously reported to play a role in RSA in other species. These genes can serve to accelerate future efforts aimed to dissect genetic architecture of RSA and breed more resilient varieties.

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.

DEVELOPMENTAL STUDIES ON EUPHORBIA ESULA L.: MORPHOLOGY OF THE ROOT SYSTEM

1963 ◽  
Vol 41 (5) ◽  
pp. 579-589 ◽  
Author(s):  
M. V. S. Raju ◽  
T. A. Steeves ◽  
R. T. Coupland
Keyword(s):  
Root System ◽  
Lateral Roots ◽  
Primary Root ◽  
Cambial Activity ◽  
Euphorbia Esula ◽  
Developmental Studies ◽  
Limited Growth ◽  
Mode Of Reproduction ◽  
Shoot Buds ◽  
Adverse Conditions

The significance of Euphorbia esula L. as a weed is related to its capacity to persist under adverse conditions and to its mode of reproduction. In both these properties, the root system plays an important role. The root system is initially established by seedlings. The seedling has a vigorous primary root with extensive longitudinal growth and considerable cambial activity. Such a root has been designated a "long" root. By contrast, the first lateral roots produced on the primary root have limited growth and no cambial activity. These roots have been termed "short" roots. Thus, the seedling exhibits a "heterorhizic" pattern. Lateral long roots also arise on the primary root of seedlings but their origin is delayed until cambial activity has begun. Such lateral long roots arise much earlier on seedlings growing in denuded areas than on those growing in areas covered by dense vegetation. The mature root system is described in terms of horizontal and vertical long roots, which make up the conspicuous framework of the system, and of the short roots which they produce. Long roots produce shoot-buds and the origin of these structures is delayed until cambial activity has started. Short roots do not give rise to shoot-buds. Cambial activity in long roots appears to be connected with bud production and its absence in short roots probably underlies their inability to produce buds.L'importance de Euphorbia esula L. comme mauvaise herbe est connexé a son capacité de persister dans les situations hostiles et à sa methode de reproduction. Dans ces deux caractéristiques, le système des racines a une signification profunde. Initialement le système des racines s'établit dans le semis. Le semis a une racine primaire très forte avec beaucoup de croissance longitudinale et avec une activité considérable du cambium. Une racine de cette espèce s'appelle une "longue" racine (long root). Par contre, les premières racines latérales que poussent sur la racine primaire ont croissance limité et aucun activité du cambium. Ces racines s'appellent les "courtes" racines (short roots). De cette façon, le semis montre un dessin "heterorhizique" (heterorhizic). Les longues racines latérales ont aussi leur origine sur la racine primaire du semis, mais l'origine est retardé jusqu'au commencement de l'activité du cambium. Les racines de cette espèce apparaissent beaucoup plus tôt sur les semis qui sont situés en terre sans autre végétation, que sur ceux qui sont situés au milieu des autres plantes. Le système adulte des racines se décrit sous forme des longues racines de l'espèce horizontale et verticale, lesquelles constituent la charpente bien visible du système, et des courtes racines que sont produites par les longues racines. Les longues racines produisent les bourgeons, mais l'origine des bourgeons est retardé jusqu'au commencement de l'activité du cambium dans les racines. Les courtes racines ne produisent pas les bourgeons. Il paraît que l'activité du cambium dans les longues racines soit corrélative avec l'initiation des bourgeons et l'absence du cambium dans les courtes racines explique probablement leur incapacité à produire les bourgeons.

Effect of sowing depth and seedling morphology on establishment of grass seedlings on cracking black earths.

1982 ◽  
Vol 4 (2) ◽  
pp. 52 ◽  
Author(s):  
LA Watt ◽  
RDB Whalley
Keyword(s):  
Root System ◽  
Primary Root ◽  
Native Grasses ◽  
Seedling Morphology ◽  
Sowing Depth ◽  
Wide Range ◽  
Shoot To Root Ratio

There is a wide range in the ability of grasses to become established on the cracking black clays of the Inverell district. Some native grasses establish readily on cracking black soils but most of the introduced perennial summer growing grasses are very difficult to establish. This study compared a number of native and introduced grasses in terms of establishment capability, depth of sowing and seedling morphology. In general there was a poor association between establishment capability of a species and the ability of its seedlings to emerge from depth. However, a well developed primary root system and a low shoot to root ratio were generally associated with good establishment capability. The results presented in this paper support the view that a number of seed and seedling features are involved in the progression from a germinating seed through to an established seedling. Species which occupy similar habitats may or may not have similar features.

scholarly journals The Features of Growth of the Primary Root System of Triticum durum Desf. Varieties of the Saratov Breeding

2020 ◽  
Vol 20 (4) ◽  
pp. 433-437
Author(s):  
Eduard G. Hachaturov ◽  
◽  
Valeria V. Korobko ◽  
Keyword(s):  
Growth Rate ◽  
Root System ◽  
Triticum Durum ◽  
Adventitious Roots ◽  
Lower Layer ◽  
Primary Root ◽  
Climatic Chamber ◽  
Main Root ◽  
Shoot Ratio ◽  
Triticum Durum Desf

The objects of the study were plants of 14 varieties of durum wheat Triticum durum Desf. Cultivation was carried out in a climatic chamber at a temperature of 18 ± 1°C under the conditions of a sixteen-hour photoperiod. To study the growth characteristics of the root system of seedlings, the length of the main root and the length of the adventitious roots of the upper and lower tiers were measured; thus, the growth rate of the root system was determined. The cultivars, the seedlings of which are characterized by the longest root system, have been identified – Luch 25, Saratovskaya 59 and Saratovskaya zolotistaya. The varietal characteristics of the growth of the main embryonic root were revealed, the growth rate of which significantly varies among the objects of study. The length of the adventitious roots of the lower layer in plants of the studied varieties ranged from 208 mm (Elizavetinskaya) to 278 mm (Saratovskaya 57 and Annushka); the upper layer – from 105 mm (Nikolasha) to 216 mm (Luch 25). The root-to-shoot ratio was calculated. In 5-day-old seedlings of the studied varieties, this varies from 0,92 to 1,89 rel. units; the degree of variation of the trait is average. In 12-day-old seedlings, the root supply index decreases, amounting to 0,42–1,29 relative units; the degree of variation of the trait is significant (with the exception of variety Luch 25).

scholarly journals Cytokinin functions as an asymmetric and anti-gravitropic signal in lateral roots

2019 ◽  
Author(s):  
Sascha Waidmann ◽  
Michel Ruiz Rosquete ◽  
Maria Schöller ◽  
Heike Lindner ◽  
Therese LaRue ◽  
...  
Keyword(s):  
Root System ◽  
Lateral Root ◽  
Genome Wide Association Study ◽  
Negative Impact ◽  
Lateral Roots ◽  
Primary Root ◽  
Cytokinin Oxidase ◽  
Cytokinin Signaling ◽  
Organ Growth ◽  
A Genome

AbstractDirectional organ growth allows the plant root system to strategically cover its surroundings. Intercellular auxin transport is aligned with the gravity vector in the primary root tips, facilitating downward organ bending at the lower root flank. Here we show that cytokinin signaling functions as a lateral root specific anti-gravitropic component, promoting the radial distribution of the root system. We performed a genome-wide association study and revealed that signal peptide processing of Cytokinin Oxidase 2 (CKX2) affects its enzymatic activity and, thereby, determines the degradation of cytokinins in naturalArabidopsis thalianaaccessions. Cytokinin signaling interferes with growth at the upper lateral root flank and thereby prevents downward bending. Our interdisciplinary approach revealed that two phytohormonal cues at opposite organ flanks counterbalance each other’s negative impact on growth, suppressing organ growth towards gravity and allow for radial expansion of the root system.

scholarly journals The biology of Mercurialis perennis L. polycormones

2014 ◽  
Vol 51 (1) ◽  
pp. 127-148 ◽  
Author(s):  
Krystyna Falińska
Keyword(s):  
Surface Area ◽  
Field Distribution ◽  
Vegetative Propagation ◽  
Random Distribution ◽  
Developmental State ◽  
Developmental Cycle ◽  
Herb Layer ◽  
Natural Conditions ◽  
Geometrical Progression ◽  
Oval Shape

The developmental cycle of <em>Mercurialis perennis</em> L. polycormones lasts about 6 years. Under natural conditions polycormones arise by way of vegetative propagation. Their development and growth depend on the age, size and developmental state of the part of the plant from which the new individual arises. Development of the polycormone is most intensive in the first three years. During that time the young individuals increase their number of above-ground and underground shoots according to geometrical progression. A certain stabilization in growth and spread was observed in the 4th and 5th year of life. At that time the polycormones are of spherical or oval shape and their structure is mono- and polycentric. Their surface area is 0.51-2.0 m<sup>2</sup> and the number of above-ground shoots amounts to 80-200. In the following years the intensity of regeneration decreases. Polycormones developing in garden culture reach their senile phase in the 3rd and 4th year of life, whereas in natural conditions in the 5th and 6th year. Then gradual dying of the oldest parts of the polycormone starts its division into several independent units. The rapid increase of the area occupied by the newly arising individuals leads to obliteration of the boundaries between them. The development of the aggregation-field distribution specific for this species is preceded by random and aggregation-random distribution of the polycormones in the <em>Tilio-Carpinetum</em> herb layer. It is evaluated that compact one-species patches of <em>Mercurialis parennis</em> L. form in forest communities in about 10 years.

scholarly journals Bradyrhizobium japonicum IRAT FA3 alters Arabidopsis thaliana root architecture via regulation of auxin efflux transporters PIN2, PIN3, PIN7 and ABCB19

2021 ◽  
Author(s):  
Mercedes Schroeder ◽  
Melissa Y. Gomez ◽  
Nathan K. McLain ◽  
Emma Gachomo
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Root Development ◽  
Bradyrhizobium Japonicum ◽  
Lateral Root ◽  
Plant Root ◽  
Primary Root ◽  
Efflux Transporters ◽  
Loss Of Function ◽  
Lateral Root Primordia

Beneficial rhizobacteria can stimulate changes in plant root development. While root system growth is mediated by multiple factors, the regulated distribution of the phytohormone auxin within root tissues plays a principal role. Auxin transport facilitators help to generate the auxin gradients and maxima that determine root structure. Here, we show that the plant growth-promoting rhizobacterial strain Bradyrhizobium japonicum IRAT FA3 influences specific auxin efflux transporters to alter Arabidopsis thaliana root morphology. Gene expression profiling of host transcripts in control and B. japonicum-inoculated roots of the wild type A. thaliana accession Col-0 confirmed upregulation of PIN2, PIN3, PIN7 and ABCB19 with B. japonicum and identified genes potentially contributing to a diverse array of auxin-related responses. Co-cultivation of the bacterium with loss-of-function auxin efflux transport mutants revealed that B. japonicum requires PIN3, PIN7 and ABCB19 to increase lateral root development and utilizes PIN2 to reduce primary root length. Accelerated lateral root primordia production due to B. japonicum was not observed in single pin3, pin7 or abcb19 mutants, suggesting independent roles for PIN3, PIN7 and ABCB19 during the plant-microbe interaction. Our work demonstrates B. japonicum’s influence over host transcriptional reprogramming during plant interaction with this beneficial microbe and the subsequent alterations to root system architecture.

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