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 Anatomy of the underground system in Vernonia grandiflora Less. and V. brevifolia Less. (Asteraceae)

2007 ◽  
Vol 50 (6) ◽  
pp. 979-988 ◽  
Author(s):  
Adriana Hissae Hayashi ◽  
Beatriz Appezzato-da-Glória
Keyword(s):  
Environmental Conditions ◽  
Primary Root ◽  
Dry Season ◽  
Herbaceous Species ◽  
Root Structure ◽  
Brazilian Cerrado ◽  
Tuberous Roots ◽  
Cortical Parenchyma ◽  
Underground System

This work dealt with the anatomy of the underground system in Vernonia grandiflora Less. and V. brevifolia Less. (Vernonieae; Asteraceae), two perennial geophytes, to elucidate their ability to sprout in the Brazilian Cerrado conditions. V. grandiflora, a subshrubby species, possessed a thickened underground system constituted by a xylopodium and many tuberous roots. The xylopodium had stem and root structure and its buds were axillary or originated from the cortical parenchyma proliferation. The tuberous roots produced by this organ were adventitious and accumulated inulin-type fructans mainly in the cortical parenchyma. The thickened underground system of V. brevifolia, an herbaceous species, was a tuberous primary root whose buds originated from the proliferated pericycle. The occurrence of these bud-forming underground systems, which stored reserve compounds, enabled these plants to survive throughout unfavourable environmental conditions in the Cerrado, such as dry season and frequent fires in the winter.

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.

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.

Stem Protective Tissue in Erythroxylum Tortuosum (Erythroxylaceae), A Fire Tolerant Species from Cerrado

IAWA Journal ◽  
2008 ◽  
Vol 29 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Alexandre Antonio Alonso ◽  
Silvia Rodrigues Machado
Keyword(s):  
Cell Wall ◽  
Wall Thickening ◽  
Brazilian Cerrado ◽  
Tolerant Species ◽  
Phenolic Substances ◽  
Shrubby Species ◽  
Terminal Buds

The origin and structure are described of the secondary protective tissue in the stem of Erythorxylum tortuosum Mart., a fire tolerant shrubby species common in Brazilian cerrado. The highly tortuous stems are covered with thick bark which is more developed at the base of the stem. After fire in the cerrado, rhytidome fragments of the burned stem flake off, revealing newly formed cork. The first periderm appears near of the terminal buds and is iniated by periclinal divisions in subepidermal cells giving rise to radial rows of cells. The first phellogen is discernible only after the differentiation of the several radial rows of cork cells. Other phellogens have their origin in successively deeper layers of the cortex. The sucessive periderms are discontinuous around the circumference. The collapsed cells with phenolic substances and the accumulated dead cells cause the formation of discontinuous blackish lines, which delimit the sucessive periderms in the rhytidome. The rhytidome contains large quantities of sclereids developed from cell wall thickening of cortex cells. The occurrence of periderm in the young parts of the stem and of rhytidome in the older parts represents pyrophytic characteristics and may explain, in part, the fire tolerance of this species.

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 SEM studies on the leaf indumentum of six Melastomataceae species from Brazilian Cerrado

Rodriguésia ◽  
2011 ◽  
Vol 62 (1) ◽  
pp. 203-212 ◽  
Author(s):  
Camilla Rozindo Dias Milanez ◽  
Silvia Rodrigues Machado
Keyword(s):  
Mixed Type ◽  
Complex Structures ◽  
Brazilian Cerrado ◽  
Stage Of Development ◽  
Different Types ◽  
Young Leaves ◽  
Microscopy Techniques ◽  
First Time ◽  
Scanning Electron ◽  
Glandular Portion

Abstract The wide diversity of their trichomes, which vary from simple unicellular to very complex structures, is a remarkable characteristic in Melastomataceae. This paper characterizes the leaf indumentum of Miconia albicans (Sw.) Triana, M. chamissois Naudin, M. fallax DC., M. ligustroides (DC.) Naudin, Microlepis oleaefolia (DC.) Triana and Rhynchanthera dichotoma DC., typical species from Brazilian cerrado. Samples collected from the median third of young and mature leaf blades were processed following the usual scanning electron microscopy techniques (SEM). We observed ten morphological types of trichomes and four of emergences. With five different types, four of which are reported for the first time, Rhynchanthera dichotoma is the species that presents the most diverse indumenta. A mixed type of trichome formed by a glandular and a branched non-glandular portion called "lateral-gland" was observed in M. ligustroides. Such non-glandular portion presents different degrees of development. A correlation is suggested between the stage of development of the non-glandular portion and the exposition to light of these "lateral gland" on young leaves.

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.

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