Geoperception in primary and lateral roots of Phaseolus vulgaris (Fabaceae). III. A model to explain the differential georesponsiveness of primary and lateral roots

1985 ◽  
Vol 63 (1) ◽  
pp. 21-24 ◽  
Author(s):  
J. Steven Ransom ◽  
Randy Moore
Keyword(s):  
Phaseolus Vulgaris ◽  
Concentration Gradient ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Growth Inhibitors ◽  
Gravitropic Response ◽  
Primary Roots ◽  
Primary And Lateral Roots

Half-tipped primary and lateral roots of Phaseolus vulgaris bend toward the side of the root on which the intact half tip remains. Therefore, tips of lateral and primary roots produce growth effectors capable of inducing gravicurvature. The asymmetrical placement of a tip of a lateral root onto a detipped primary root results in the root bending toward the side of the root onto which the tip was placed. That is, the lesser graviresponsiveness of lateral roots as compared with primary roots is not due to the inability of their caps to produce growth inhibitors. The more pronounced graviresponsiveness of primary roots is positively correlated with the presence of columella tissues that are 3.8 times longer, 1.7 times wider, and 10.5 times more voluminous than the columellas of lateral roots. We propose that the lack of graviresponsiveness exhibited by lateral roots is due to the facts that they (i) produce smaller amounts of the inhibitor than primary (i.e., strongly graviresponsive) roots and (ii) are unable to redistribute the inhibitor so as to be able to create a concentration gradient sufficient to induce a pronounced gravitropic response.

scholarly journals Impact of soil compaction heterogeneity and moisture on maize (Zea mays L.) root and shoot development

2008 ◽  
Vol 54 (No. 12) ◽  
pp. 509-519 ◽  
Author(s):  
B. Konôpka ◽  
L. Pagès ◽  
C. Doussan
Keyword(s):  
Zea Mays ◽  
Soil Moisture ◽  
Soil Compaction ◽  
Statistical Tests ◽  
Lateral Roots ◽  
Primary Root ◽  
Leaf Biomass ◽  
Fine Soil ◽  
Primary Roots ◽  
Primary And Lateral Roots

Soil compaction heterogeneity and water content are supposed to be decisive factors influencing plant growth. Our experiment focused on simulation of two soil moisture levels (0.16 and 0.19 g/g) plus two levels of clod proportion (30 and 60% volume) and their effects on root and leaf variables of maize (<I>Zea mays</I> L.). We studied number of primary and lateral roots as well as primary root length at the particular soil depths. Statistical tests showed that the decrease rate of the number of roots versus depth was significantly affected by the two studied factors (<I>P</I> < 0.01). Soil moisture and clod occurrence, interactively, affected leaf biomass (<I>P</I> = 0.02). Presence of clods modified root morphological features. Particularly, the diameter of primary roots in the clods was significantly higher than of those grown in fine soil (<I>P</I> < 0.01). For primary roots, which penetrated clods, branching density decreased considerably for the root segments located just after the clods (<I>P</I> = 0.01). Regarding their avoidance to clods and tortuosity, large differences were found between primary roots grown in the contrasting soil environments.

Geoperception in primary and lateral roots of Phaseolus vulgaris (Fabaceae). II. Intracellular distribution of organelles in columella cells

1984 ◽  
Vol 62 (5) ◽  
pp. 1090-1094 ◽  
Author(s):  
J. Steven Ransom ◽  
Randy Moore
Keyword(s):  
Phaseolus Vulgaris ◽  
Lateral Roots ◽  
Relative Volume ◽  
Precise Location ◽  
Primary Roots ◽  
Columella Cells ◽  
Primary And Lateral Roots ◽  
Cellular Components

A morphometric analysis of the ultrastructures of columella cells in primary and lateral roots of Phaseolus vulgaris was performed to determine the precise location of cellular components in these cells. Roots were fixed in situ to preserve the in vivo ultrastructure of the cells. All cellular components in columella cells of both types of roots were distributed asymmetrically. The nucleus and vacuome were located primarily in the middle third of both types of columella cells. Dictyosomes, mitochondria, and amyloplasts were most abundant in the lower third of the columella cells in both types of roots. The distribution of amyloplasts was the most asymmetrical of all cellular components examined, with the lower third of the columella cells containing approximately 90% of the relative volume of amyloplasts in both types of roots. The distribution of cellular components in columella cells of primary roots was not significantly different from that of columella cells of lateral roots. These results indicate that differences in georesponsiveness of primary and lateral roots of P. vulgaris are probably due to factors other than the ultrastructures of their individual columella cells.

scholarly journals P-Protein-Producing Cells of the Primary Root of Vicia Faba

1969 ◽  
Vol 22 (6) ◽  
pp. 1573 ◽  
Author(s):  
SY Zee
Keyword(s):  
Phaseolus Vulgaris ◽  
Vicia Faba ◽  
Lateral Roots ◽  
Primary Root ◽  
P Protein ◽  
Primary Roots ◽  
Cambial Cells

Newcomb (1967) reported the occurrence of P-protein in the differentiating pro cambial cells which border the protophloem elements in the main and lateral roots of Phaseolus vulgaris. Similar cells, found in the primary roots of seedlings of V icia faba, are described here.

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.

Effect of organic pollutant treatment on the growth of pea and maize seedlings

2012 ◽  
Vol 7 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Marie Kummerová ◽  
Štěpán Zezulka ◽  
Lucie Váňová ◽  
Helena Fišerová
Keyword(s):  
Zea Mays ◽  
Seed Germination ◽  
Lateral Roots ◽  
Organic Pollutant ◽  
Primary Root ◽  
Dry Weight ◽  
Considerable Effect ◽  
Maize Seedlings ◽  
Polycyclic Aromatic ◽  
Primary And Lateral Roots

AbstractThis study confirmed the considerable effect of polycyclic aromatic hydrocarbon fluoranthene (FLT; 0.01, 0.1, 1, 4 and 7 mg/l) exposure on the germination of seeds, growth and root morphology of seedlings in Zea mays and Pisum sativum. Seed germination was significantly inhibited at FLT≥0.01 mg/l in maize and at ≥1 mg/l in pea. The amount of released ethylene after 3 days of germination was significantly increased in both species at FLT≥0.1 mg/l. After 7 days of seedling cultivation a significant decrease in the dry weight of roots and shoots occurred in maize at FLT≥0.1 mg/l while in pea similar effect was observed at ≥1 mg/l. The total length of primary and lateral roots was significantly reduced by FLT≥1 mg/l in maize and by 4 and 7 mg/l in pea. The length of the non-branched part of the primary root was significantly reduced by FLT≥0.1 mg/l in maize and ≥0.01 mg/l in pea. In both species the number of lateral roots was significantly increased at FLT≤1 mg/l and inhibited at concentrations of 4 and 7 mg/l. Fluoranthene content in roots and shoots of both species positively correlated with the FLT treatment.

scholarly journals Expression Studies on AUX1-like Genes in Medicago truncatula Suggest That Auxin Is Required at Two Steps in Early Nodule Development

2001 ◽  
Vol 14 (3) ◽  
pp. 267-277 ◽  
Author(s):  
Françoise de Billy ◽  
Cathy Grosjean ◽  
Sean May ◽  
Malcolm Bennett ◽  
Julie V. Cullimore
Keyword(s):  
Medicago Truncatula ◽  
Lateral Root ◽  
Sequence Similarity ◽  
Lateral Roots ◽  
Peripheral Region ◽  
Nodule Development ◽  
Central Position ◽  
Root Tips ◽  
High Sequence Similarity ◽  
Primary Roots

Medicago truncatula contains a family of at least five genes related to AUX1 of Arabidopsis thaliana (termed MtLAX genes for Medicago truncatula-like AUX1 genes). The high sequence similarity between the encoded proteins and AUX1 implies that the MtLAX genes encode auxin import carriers. The MtLAX genes are expressed in roots and other organs, suggesting that they play pleiotropic roles related to auxin uptake. In primary roots, the MtLAX genes are expressed preferentially in the root tips, particularly in the provascular bundles and root caps. During lateral root and nodule development, the genes are expressed in the primordia, particularly in cells that were probably derived from the pericycle. At slightly later stages, the genes are expressed in the regions of the developing organs where the vasculature arises (central position for lateral roots and peripheral region for nodules). These results are consistent with MtLAX being involved in local auxin transport and suggest that auxin is required at two common stages of lateral root and nodule development: development of the primordia and differentiation of the vasculature.

GERMINATION, GROWTH AND DEVELOPMENT OF COMMON MILKWEED

1978 ◽  
Vol 58 (2) ◽  
pp. 493-498 ◽  
Author(s):  
PRASANTA C. BHOWMIK
Keyword(s):  
Lateral Roots ◽  
Seedling Emergence ◽  
Primary Root ◽  
Germination Percentage ◽  
Asclepias Syriaca ◽  
Seed Collection ◽  
Primary Roots ◽  
Number Of Leaves ◽  
Primary Root Length ◽  
Storage Temperatures

Germination percentage of common milkweed (Asclepias syriaca L.) seeds was low 1 mo after seed collection. Seed dormancy decreased with time at storage temperatures of −12°, 5° or 21 °C. After 11 months of storage, seeds stored at 21 °C had 15–18% higher germination compared to the seeds stored at −12° and 5 °C. The best seedling emergence was obtained at a temperature of 27 °C when seeds were planted at a depth of 0.5 or 1 cm. Seedling emergence was better in muck or sandy soil than in clay soil. Seedlings developed slowly up to 30 days after emergence at 15 °C under an 8-, 12- or 16-h photoperiod. High temperatures (27 °C) stimulated seedling growth under each photoperiod. Taller seedlings with more leaves, longer primary roots, more lateral roots and adventitious root buds grew at 27 °C as compared to 15° or 21 °C. Increasing the photoperiod from 8 to 16 h increased plant height and number of leaves but not primary root length.

scholarly journals Early development and gravitropic response of lateral roots in Arabidopsis thaliana

2012 ◽  
Vol 367 (1595) ◽  
pp. 1509-1516 ◽  
Author(s):  
S. Guyomarc'h ◽  
S. Léran ◽  
M. Auzon-Cape ◽  
F. Perrine-Walker ◽  
M. Lucas ◽  
...  
Keyword(s):  
Lateral Root ◽  
Developmental Plasticity ◽  
Lateral Roots ◽  
Expression Patterns ◽  
Primary Root ◽  
Root System Architecture ◽  
Specific Response ◽  
Root Induction ◽  
Root Gravitropism ◽  
Auxin Transporter

Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observations, we showed that gravitropism was acquired slowly after emergence. Using a lateral root induction system, we studied the kinetics for the appearance of statoliths, phloem connections and auxin transporter gene expression patterns. We found that statoliths could not be detected until 1 day after emergence, whereas the gravitropic curvature of the lateral root started earlier. Auxin transporters modulate auxin distribution in primary root gravitropism. We found differences regarding PIN3 and AUX1 expression patterns between the lateral root and the primary root apices. Especially PIN3, which is involved in primary root gravitropism, was not expressed in the lateral root columella. Our work revealed new developmental transitions occurring in lateral roots after emergence, and auxin transporter expression patterns that might explain the specific response of lateral roots to gravity.

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