Réaction géotropique des différents types de racines chez l'hévéa (Hevea brasiliensis)

1996 ◽  
Vol 74 (12) ◽  
pp. 1910-1918 ◽  
Author(s):  
Yannick Le Roux ◽  
Loïc Pagès
Keyword(s):  
Root System ◽  
Hevea Brasiliensis ◽  
Vertical Plane ◽  
Growth Direction ◽  
Vertical Position ◽  
Different Types ◽  
Original Direction ◽  
Growth Development ◽  
Secondary Roots ◽  
Root Observation

To describe the different types of geotropic reactions of hevea (Hevea brasiliensis), young seedlings were cultivated in root observation boxes and submitted to a double gravistimulation (90° rotation of the minirhizotrons in the vertical plane). It was demonstrated that the taproot is a strongly orthogeotropie organ since it resumed rapidly its prestimulation vertical position. Morphological and morphogenetic modifications were associated with the geotropic response: reduced speed of growth coupled with a reduction of the apical diameter as well as an alteration of ramification density in the curving zone and the following one. Early secondary roots showed a somewhat reduced orthogeotropism that was weaker as the growth direction before gravistimulation was more distant from the vertical. Secondary roots of the acropetal sequence were semiplagiotropic, that is only those roots oriented upward after the gravistimulation resumed, more or less, the original direction. Tertiary roots didn't respond to the gravistimulation and therefore were ageotropic. Complementary observations conducted in large laboratory rhizotrons showed that late forming secondary roots were plagiotropic in their younger stages, thereafter loosing most of their sensitivity to gravity. Quaternary roots were ageotropic. On the basis of these data, a geotropic gradient was defined within the hevea root system, where the strongly responding taproot and late secondary roots are opposed to the weakly or nonresponding tertiary and quaternary roots. Functional significations of these differential geotropic reactions in different hevea root types are discussed. Keywords: geotropism, gravistimulation, root system, growth, development, morphogenesis, root observation box, Hevea brasiliensis. [Journal translation]

Modifications expérimentales de la morphogenèse du système racinaire de jeunes semis d'hévéa (Hevea brasiliensis)

2000 ◽  
Vol 78 (11) ◽  
pp. 1460-1468
Author(s):  
Yannick Le Roux ◽  
Loïc Pagès
Keyword(s):  
Root System ◽  
Hevea Brasiliensis ◽  
High Plasticity ◽  
External Diameter ◽  
Active Growth ◽  
Experimental Block ◽  
Tap Root ◽  
Large Growth ◽  
Growth Correlations ◽  
Secondary Roots

Determining factors involved in root polymorphism were studied in young hevea seedlings (Hevea brasiliensis Mull. Arg.) following an experimental block of the tap root in the laboratory, using minirhizotron grown plants. The authors show that this block promotes different morphogenetic modifications in the root system: regrowth of the early secondary roots having the largest external apex, high density of the ramification zone in the taproot apical area, large growth (associated with an important external diameter at the apex), and orthogeotropism of the sequential secondary roots emerging after the treatment in the zone close to the blockage site. The evolution of morphogenetic potentialities of sequential secondary roots following an inhibition of the taproot growth was confirmed using other cultivation set ups, under controlled (aeropinic) or natural (underground observation windows) conditions. Overall results show that the expression of the early morphogenetic potential acquired by the roots can be modulated by the environmental conditions exerting their effect during their development. Notably, the active growth correlations existing between the taproot and the secondary axes confer a high plasticity to the root system which will permit its adaptation to heterogeneous or restricting environments. These correlative influences are discussed in the frame of an hormono-trophic model for the root morphogenetic determinism, essentially based on taproot dominancy.Key words: articial block, growth correlations, root system, morphogenesis, minirhizotron, Hevea brasiliensis.[Journal translation]

scholarly journals Mini-rhizotrons transparents pour l'étude du système racinaire de jeunes plantes. Application à la caractérisation du développement racinaire de jeunes chênes (Quercus robur)

1992 ◽  
Vol 70 (9) ◽  
pp. 1840-1847 ◽  
Author(s):  
Loïc Pages
Keyword(s):  
Root System ◽  
Quercus Robur ◽  
Root Systems ◽  
Transparent Plastic ◽  
Root Morphogenesis ◽  
New Type ◽  
Growth Development ◽  
Architectural Characteristics ◽  
Specific Interests ◽  
Root Observation

A new type of root-observation box is described, which allows continuous observations on entire growing root systems of young plants. Each root-observation box consists of two transparent plastic plates separated by a few millimetres. On the internal face of each plate, a sheet of transparent filter paper is fixed, which allows absorption and distribution of water and nutrients to the root system. The root system can grow between these two plates, the roots growing on either one face or the other. Thus, the entire root system can be observed continuously. It is easy to manipulate it experimentally. The root-observation boxes are placed away from the light into a container. As an example, and to show the suitability of the method, we studied the development of the root system of young oak seedlings (Quercus robur L.). We compared their architectural characteristics with those described by different authors who have used other methods. The specific interests of this new method are emphasized. Key words: root, morphogenesis, rhizotron, root observation box, growth, development, Quercus robur.

Développement et polymorphisme racinaires chez de jeunes semis d'hévéa (Hevea brasiliensis)

1994 ◽  
Vol 72 (7) ◽  
pp. 924-932 ◽  
Author(s):  
Yannick Le Roux ◽  
Loïc Pagès
Keyword(s):  
Root System ◽  
Hevea Brasiliensis ◽  
System Development ◽  
Lateral Roots ◽  
Rubber Tree ◽  
Morphological Plasticity ◽  
Daily Basis ◽  
External Diameter ◽  
First Order ◽  
Root Observation

The major problems (bad anchorage, water stress, and root disease) with the cropping of the rubber tree (Hevea brasiliensis) are related to the architecture of its root system. So, the morphogenetic properties of the various roots that emerge during the development of the young seedlings are described to improve our understanding of the dynamics of root system architecture. In this study, the development of the root system of 12 seedlings grown for 40 days in root observation boxes has been recorded on a daily basis and analysed. Additional observations were also made on plants grown in pots or in the field for a 60-day period. This analysis of the sequential differentiation of the root system allowed us to distinguish five different root types according to their spatial and temporal location at emergence: (i) taproot, (ii) early first-order lateral roots, (iii) acropetal first-order lateral roots, (iv) late first-order lateral roots, (v) second-order lateral roots. Large variations and close relationship were found within the growth and branching characteristics on one hand, and within anatomical characteristics on the other (number of xylem poles, external diameter, and stele diameter). These between-type variations were also observed, to a lesser extent, among roots from the same type. The continuity of these development characteristics, which were shown to be acquired early, led us to characterize a morphogenetic gradient. This gradient is a reference scale to understand the morphological plasticity of the root system growing in other mediums. Key words: root system, development, morphogenesis, anatomy, root observation box, Hevea brasiliensis.

scholarly journals Rooting in the Desert: A Developmental Overview on Desert Plants

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 709
Author(s):  
Gwendolyn K. Kirschner ◽  
Ting Ting Xiao ◽  
Ikram Blilou
Keyword(s):  
Root System ◽  
Developmental Plasticity ◽  
Root System Architecture ◽  
Desert Plants ◽  
Root Cortex ◽  
Date Palms ◽  
Beneficial Impact ◽  
Scarce Water ◽  
Sessile Organisms ◽  
Secondary Roots

Plants, as sessile organisms, have evolved a remarkable developmental plasticity to cope with their changing environment. When growing in hostile desert conditions, plants have to grow and thrive in heat and drought. This review discusses how desert plants have adapted their root system architecture (RSA) to cope with scarce water availability and poor nutrient availability in the desert soil. First, we describe how some species can survive by developing deep tap roots to access the groundwater while others produce shallow roots to exploit the short rain seasons and unpredictable rainfalls. Then, we discuss how desert plants have evolved unique developmental programs like having determinate meristems in the case of cacti while forming a branched and compact root system that allows efficient water uptake during wet periods. The remote germination mechanism in date palms is another example of developmental adaptation to survive in the dry and hot desert surface. Date palms have also designed non-gravitropic secondary roots, termed pneumatophores, to maximize water and nutrient uptake. Next, we highlight the distinct anatomical features developed by desert species in response to drought like narrow vessels, high tissue suberization, and air spaces within the root cortex tissue. Finally, we discuss the beneficial impact of the microbiome in promoting root growth in desert conditions and how these characteristics can be exploited to engineer resilient crops with a greater ability to deal with salinity induced by irrigation and with the increasing drought caused by global warming.

scholarly journals Responses of Primate Caudal Parabrachial Nucleus and Kölliker-Fuse Nucleus Neurons to Whole Body Rotation

2002 ◽  
Vol 88 (6) ◽  
pp. 3175-3193 ◽  
Author(s):  
Carey D. Balaban ◽  
David M. McGee ◽  
Jianxun Zhou ◽  
Charles A. Scudder
Keyword(s):  
Angular Velocity ◽  
Vertical Plane ◽  
Affective Responses ◽  
Macaca Nemestrina ◽  
Whole Body ◽  
Vertical Position ◽  
Limbic Cortex ◽  
Body Rotation ◽  
Spatial Tuning ◽  
Position Sensitive

The caudal aspect of the parabrachial (PBN) and Kölliker-Fuse (KF) nuclei receive vestibular nuclear and visceral afferent information and are connected reciprocally with the spinal cord, hypothalamus, amygdala, and limbic cortex. Hence, they may be important sites of vestibulo-visceral integration, particularly for the development of affective responses to gravitoinertial challenges. Extracellular recordings were made from caudal PBN cells in three alert, adult female Macaca nemestrina through an implanted chamber. Sinusoidal and position trapezoid angular whole body rotation was delivered in yaw, roll, pitch, and vertical semicircular canal planes. Sites were confirmed histologically. Units that responded during rotation were located in lateral and medial PBN and KF caudal to the trochlear nerve at sites that were confirmed anatomically to receive superior vestibular nucleus afferents. Responses to whole-body angular rotation were modeled as a sum of three signals: angular velocity, a leaky integration of angular velocity, and vertical position. All neurons displayed angular velocity and integrated angular velocity sensitivity, but only 60% of the neurons were position-sensitive. These responses to vertical rotation could display symmetric, asymmetric, or fully rectified cosinusoidal spatial tuning about a best orientation in different cells. The spatial properties of velocity and integrated velocity and position responses were independent for all position-sensitive neurons; the angular velocity and integrated angular velocity signals showed independent spatial tuning in the position-insensitive neurons. Individual units showed one of three different orientations of their excitatory axis of velocity rotation sensitivity: vertical-plane-only responses, positive elevation responses (vertical plane plus ipsilateral yaw), and negative elevation axis responses (vertical plane plus negative yaw). The interactions between the velocity and integrated velocity components also produced variations in the temporal pattern of responses as a function of rotation direction. These findings are consistent with the hypothesis that a vestibulorecipient region of the PBN and KF integrates signals from the vestibular nuclei and relay information about changes in whole-body orientation to pathways that produce homeostatic and affective responses.

Differential gene expression in different types of Hevea brasiliensis roots

Plant Science ◽  
2012 ◽  
Vol 183 ◽  
pp. 149-158 ◽  
Author(s):  
Riza-Arief Putranto ◽  
Christine Sanier ◽  
Julie Leclercq ◽  
Cuifang Duan ◽  
Maryannick Rio ◽  
...  
Keyword(s):  
Gene Expression ◽  
Differential Gene Expression ◽  
Hevea Brasiliensis ◽  
Different Types ◽  
Differential Gene

COMPARATIVE DESTRUCTION OF LACTIC STREPTOCOCCUS BACTERIOPHAGES ON VARIOUS SURFACES BY GERMICIDAL AEROSOLS1,2

1964 ◽  
Vol 27 (6) ◽  
pp. 161-165 ◽  
Author(s):  
E. L. Sing ◽  
P. R. Elliker ◽  
W. E. Sandine
Keyword(s):  
Stainless Steel ◽  
Test Chamber ◽  
Quaternary Ammonium Compound ◽  
Vertical Position ◽  
Ammonium Compound ◽  
Complete Inactivation ◽  
Different Types ◽  
Building Surfaces ◽  
Phage Inactivation ◽  
Dichloroisocyanuric Acid

Summary A comparison was made of destruction by various germicidal aerosols of lactic streptococcus bacteriophages on a number of different types of representative building surfaces and stainless steel. With the exception of the stainless steel the surfaces were coated either with enamel or epoxy resin. Surfaces were contaminated by fogging with a phage suspension in a test chamber. After 15 min, germicide was fogged into the chamber and phage recovered from surfaces by scrubbing with inactivator solution. Chlorine compounds as represented by dichloroisocyanuric acid (DCCA) and sodium hypochlorite (NaOCl) were markedly superior to quaternary ammonium compound (QAC) and phosphoric acid wetting agent (PAWA). Porosity of surface greatly influenced rate of phage inactivation. Aerosols appeared to be most effective on surfaces in the horizontal as compared to the vertical position. Complete inactivation of phage was not realized with either QAC or PAWA at all concentrations tested. However, fogging levels of 2000 ppm DCCA and NaOCl attained 100% of destruction of bacteriophage on horizontal building surfaces and 500 to 1000 ppm accomplished this on stainless steel.

The root morphology of Lupinus angustifolius in relation to other Lupinus species

1993 ◽  
Vol 44 (6) ◽  
pp. 1367 ◽  
Author(s):  
JC Clements ◽  
PF White ◽  
BJ Buirchell
Keyword(s):  
Root System ◽  
Lateral Roots ◽  
Poor Performance ◽  
Alkaline Soils ◽  
Poor Growth ◽  
Wide Range ◽  
Proteoid Root ◽  
Primary Lateral ◽  
Secondary Roots ◽  
Coarse Soil

Commercial L. angustifolius cultivation is restricted to acid to neutral coarse-textured soils in Australia. An unsuitable root system may be part of the reason for the poor performance on fine-textured or alkaline soils. As a first step to examine this question plants of 12 annual Lupinus species were grown in a coarse soil with the aim of describing the range of root morphologies within the genus and to compare these to commercial L. angustifolius. A wide range of rooting patterns were observed. The differences in the dominance of the taproot was pronounced between species. The commercial genotype of L. angustifolius occupied an extreme within the range of root morphologies of the species. Roots of L. angustifolius consisted of a dominant taproot and a relatively high number of primary lateral roots but few secondary roots. In contrast, the primary, secondary and tertiary lateral roots of L. pilosus, L. mutabilis, L. atlanticus, L. palaestinus and L. micranthus were more dominant than the taproot. The length and distribution of primary lateral roots along the taproot also varied between species. The number of primary lateral roots fell rapidly with depth in L. angustifolius and L. mutabilis, while the other species had a more even distribution. L. angustifolius had a less extensive root system and relatively thick roots when compared to species such as L. albus and L. mutabilis. L. luteus also had relatively thick roots. The relatively thick roots and less extensive lateral root system in commercial L. angustifolius may partially explain its poor growth on fine-textured soils, where a greater proliferation of finer, lateral roots may be necessary. Proteoid root formation was observed for L. albus, L. cosentinii, L. pilosus, L. palaestinus, L. micranthus, L. digitatus, L. princei and L. atlanticus. They were particularly numerous in L. micranthus and L. albus. The structure of proteoid root clusters varied between species.

scholarly journals РЕАБИЛИТАЦИЯ НЕУХОЖЕННЫХ ЧАЙНЫХ ПЛАНТАЦИЙ И РАЗРАБОТКА ПОСЛЕДУЮЩЕЙ АГРОТЕХНОЛОГИИ НА ПРИМЕРЕ РЕГИОНА ИМЕРЕТИ

2019 ◽  
pp. 7-12
Author(s):  
Копалиани Р. Ш. ◽  
Джинчарадзе Н. И. ◽  
Капанадзе Ш. Ю.
Keyword(s):  
Root System ◽  
The State ◽  
Morphological Features ◽  
Extreme Conditions ◽  
Recent Past ◽  
Different Types ◽  
Tea Plantations ◽  
Long Time ◽  
Massive Scale ◽  
Tea Plants

Tea farming, in the recent past, was one of the leading branches of agriculture in Georgia. Since the 1990s of the last century this very important and leading branch of subtropical agriculture turned out to be bankrupt. On without well-groomed plantations, on a massive scale spread weeds, on the part of which, tea plants have undergone tough competition, it caused the weakness of tea culture function ability, in particular, in tea bushes were disturbed the function of physiological process, mainly the intensity of photosynthesis, increased breathing, etc. This article presents the results of a study of the state of tea plantations, who find themselves in extreme conditions unclean for a long time on the example of one of the tea producing regions of Georgia – Imereti, namely the degree of weed, morphological features of the aerial organs of tea plants, the root system, In this article it is discussed Some aspects of bushes caring process by applying different types of trimming and using the methods of mulching between rows. and also there is presented the development of practical measures for the rehabilitation of tea plantations.

scholarly journals Effect of rootstock on the scion of Hevea brasiliensis through metabolic analysis of latex samples by ¹H NMR

2011 ◽  
Vol 11 (spe) ◽  
pp. 82-88 ◽  
Author(s):  
Eduardo Sanches Pereira do Nascimento ◽  
Clayton Rodrigues de Oliveira ◽  
Paulo de Souza Gonçalves ◽  
Reginaldo Brito da Costa ◽  
Rogério Manoel Biagi Moreno ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hevea Brasiliensis ◽  
Multivariate Data Analysis ◽  
Metabolic Profile ◽  
Metabolomic Analysis ◽  
Pca Analysis ◽  
H Nmr ◽  
Metabolic Analysis ◽  
Different Types ◽  
Grafting Through

In this study, the effect of rootstock on grafting through metabolomic analysis of latex (Hevea brasiliensis) samples was verified by ¹H nuclear magnetic resonance (NMR) and multivariate data analysis. Sixteen metabolites present in the latex cytosol were characterized by NMR. PCA analysis showed that the latex samples of the RR and GR groups can be differentiated. The GR group samples present a metabolic profile similar to the RR group samples, while the RG group is in an intermediate position between RR and GG groups. Sucrose and formate contributed greatly to the separation obtained by PCA, presenting a good correlation between the results. ¹H NMR was an efficient technique to differentiate latex samples from different types of rootstocks and grafting and in the future could be used to predict rubber production by latex analysis.

Sign in / Sign up

Export Citation Format

Share Document