Differences in cellular structure regulate stem elongation of alpine and prairie ecotypes of Stellaria longipes grown under two contrasting temperature regimes

Botany ◽  
2009 ◽  
Vol 87 (12) ◽  
pp. 1167-1176 ◽  
Author(s):  
Dang T. Thu Thuy ◽  
Edward C. Yeung ◽  
C. C. Chinnappa
Keyword(s):  
Cell Wall ◽  
Phenolic Compounds ◽  
Cellular Structure ◽  
Stem Elongation ◽  
Cortical Microtubule ◽  
Structural Features ◽  
Wall Thickening ◽  
Microtubule Orientation ◽  
Stellaria Longipes ◽  
Temperature Regimes

The objectives of this study were to explore differences in the structural features of stem elongation in alpine and prairie ecotypes of Stellaria longipes Goldie in response to two contrasting temperature regimes. The two ecotypes were grown under warmer, 28 °C (day) – 22 °C (night), and cooler, 10 °C (day) – 4 °C (night) temperatures, and under the same light irradiance (∼120 µmol·m–2·s–1) and photoperiod (16 h). Temperature exerts a significant effect on the stem elongation of alpine and prairie ecotypes of S. longipes. Significant retardation of growth occurred in plants grown in cooler temperatures (10 °C (day) – 4 °C (night)), while growth was profoundly enhanced when plants were grown under warmer conditions (28 °C (day) – 22 °C (night)). The ecotypes exhibited differential responses to temperature (owing to differences in their cellular structure), particularly in cell length, the timing of cell wall thickening, the deposition of phenolic compounds, and the changes in cortical microtubule orientation.

scholarly journals Inhibition of cell expansion enhances cortical microtubule stability in the root apex of Arabidopsis thaliana

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Expansion ◽  
Cortical Microtubule ◽  
Root Apex ◽  
Cellulose Synthase ◽  
Cellulose Biosynthesis ◽  
Cortical Microtubules ◽  
Wild Type ◽  
Microtubule Stability

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.

scholarly journals Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Amandine Leroy ◽  
Xavier Falourd ◽  
Loïc Foucat ◽  
Valérie Méchin ◽  
Fabienne Guillon ◽  
...  
Keyword(s):  
Cell Wall ◽  
Negative Impact ◽  
Lignin Content ◽  
Structural Features ◽  
Hot Water ◽  
Condensed State ◽  
Structural Factors ◽  
Water Pretreatment ◽  
Hot Water Pretreatment ◽  
The Impact

Abstract Background Biomass recalcitrance is governed by various molecular and structural factors but the interplay between these multiscale factors remains unclear. In this study, hot water pretreatment (HWP) was applied to maize stem internodes to highlight the impact of the ultrastructure of the polymers and their interactions on the accessibility and recalcitrance of the lignocellulosic biomass. The impact of HWP was analysed at different scales, from the polymer ultrastructure or water mobility to the cell wall organisation by combining complementary compositional, spectral and NMR analyses. Results HWP increased the kinetics and yield of saccharification. Chemical characterisation showed that HWP altered cell wall composition with a loss of hemicelluloses (up to 45% in the 40-min HWP) and of ferulic acid cross-linking associated with lignin enrichment. The lignin structure was also altered (up to 35% reduction in β–O–4 bonds), associated with slight depolymerisation/repolymerisation depending on the length of treatment. The increase in $${T}_{1\rho }^{H}$$ T 1 ρ H , $${T}_{HH}$$ T HH and specific surface area (SSA) showed that the cellulose environment was looser after pretreatment. These changes were linked to the increased accessibility of more constrained water to the cellulose in the 5–15 nm pore size range. Conclusion The loss of hemicelluloses and changes in polymer structural features caused by HWP led to reorganisation of the lignocellulose matrix. These modifications increased the SSA and redistributed the water thereby increasing the accessibility of cellulases and enhancing hydrolysis. Interestingly, lignin content did not have a negative impact on enzymatic hydrolysis but a higher lignin condensed state appeared to promote saccharification. The environment and organisation of lignin is thus more important than its concentration in explaining cellulose accessibility. Elucidating the interactions between polymers is the key to understanding LB recalcitrance and to identifying the best severity conditions to optimise HWP in sustainable biorefineries.

scholarly journals Anatomy of the floral, bract, and foliar nectaries of Triumfetta semitriloba (Tiliaceae)

2005 ◽  
Vol 83 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Carlos André Espolador Leitão ◽  
Renata Maria Strozi Alves Meira ◽  
Aristéa Alves Azevedo ◽  
João Marcos de Araújo ◽  
Kellen Lagares Ferreira Silva ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Type A ◽  
Structural Features ◽  
Floral Bract ◽  
Secretory Structures ◽  
Floral Nectary ◽  
Foliar Anatomy ◽  
Weedy Species ◽  
Floral Nectaries

Triumfetta semitriloba Jacq. (Tiliaceae) is a tropical weedy species with floral nectaries and glands located at the margins of the leaves. The objectives of this work were to describe the anatomy of these secretory structures and to analyze their exudates. Sucrose, glucose, and fructose were identified in the product released by these secretory structures, characterizing them as nectaries. The nectaries of T. semitriloba are of a specialized type; a secretory epidermis comprised of pluricellular and multiserial nectariferous trichomes covers a nectariferous parenchyma, vascularized by phloem and xylem. A mass of phenolic compounds occurs in the head cells of the nectariferous trichomes of the foliar and bract nectaries; however, it is absent in trichomes of the floral nectary. The leaf and bract nectaries differed from those from flowers in their length and diameter. Structural features of the nectaries of T. semitriloba are typical of other taxa of the Malvales.Key words: foliar anatomy, histochemistry, Malvales, nectaries, Tiliaceae, Triumfetta semitriloba.

scholarly journals FRA1 modulates cortical microtubule localization of CMU proteins

2019 ◽  
Author(s):  
Anindya Ganguly ◽  
Chuanmei Zhu ◽  
Weizu Chen ◽  
Ram Dixit
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Molecular Mechanisms ◽  
Cortical Microtubule ◽  
Cellulose Synthase ◽  
Lateral Stability ◽  
Cortical Microtubules ◽  
Tail Region ◽  
Opposing Effect ◽  
Growth And Reproduction

ABSTRACTConstruction of the cell wall demands harmonized deposition of cellulose and matrix polysaccharides. Cortical microtubules orient the deposition of cellulose by guiding the trajectory of plasma membrane-embedded cellulose synthase complexes. Vesicles containing matrix polysaccharides are thought to be transported by the FRA1 kinesin to facilitate their secretion along cortical microtubules. The cortical microtubule cytoskeleton thus provides a platform to coordinate the delivery of cellulose and matrix polysaccharides, but the underlying molecular mechanisms remain unknown. Here, we show that the tail region of the FRA1 kinesin physically interacts with CMU proteins which are important for the microtubule-dependent guidance of cellulose synthase complexes. Interaction with CMUs did not affect microtubule binding or motility of the FRA1 kinesin but had an opposing effect on the cortical microtubule localization of CMU1 and CMU2 proteins, thus regulating the lateral stability of cortical microtubules. Phosphorylation of the FRA1 tail region by CKL6 inhibited binding to CMUs and consequently reversed the extent of cortical microtubule decoration by CMU1 and CMU2. Genetic experiments demonstrated the significance of this interaction to the growth and reproduction of Arabidopsis thaliana plants. We propose that modulation of CMU’s microtubule localization by FRA1 provides a mechanism to control the coordinated deposition of cellulose and matrix polysaccharides.

RESPONSE OF PEAS TO ENVIRONMENT: II. EFFECTS OF TEMPERATURE IN CONTROLLED-ENVIRONMENT CABINETS

1966 ◽  
Vol 46 (2) ◽  
pp. 195-203 ◽  
Author(s):  
B. Stanfield ◽  
D. P. Ormrod ◽  
H. F. Fletcher
Keyword(s):  
Plant Development ◽  
Dry Matter ◽  
Accumulation Rate ◽  
Stem Elongation ◽  
Controlled Environment ◽  
Dry Matter Accumulation ◽  
Average Temperature ◽  
Pisum Sativum L ◽  
Temperature Regimes ◽  
Effects Of Temperature

Effects of day/night temperature regimes from 7/4 to 32/24 °C on growth and development of Pisum sativum L. var. Dark Skin Perfection were studied in controlled-environment cabinets. Light intensity was about 1500 foot-candles and the photoperiod was 16 hours. Rate of plant development, in terms of nodes produced per day, increased steadily as the average temperature increased. Rate of stem elongation, however, was most rapid at 21/13 °C; and plant height was greatest at 16/10 °C. On a dry matter accumulation rate basis, vine growth decreased above and below a temperature optimum which shifted from 21/16 to 16/10 °C in the course of plant development. The combination of high day and high night temperatures caused an increase in the number of nodes to the first flower. Tillering was most prolific at the lower temperatures and was absent at 32 °C day temperatures. Pea yield decreased as temperature increased above 16/10 °C, due mainly to a reduction in the number of pods per plant.

Cell wall thickening in two Ulva species in response to heavy metal marine pollution

2020 ◽  
Vol 35 ◽  
pp. 101125 ◽  
Author(s):  
Safia Zeroual ◽  
Salah Eddine El Bakkal ◽  
Mounir Mansori ◽  
Sabine Lhernould ◽  
Céline Faugeron-Girard ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Cell Wall ◽  
Marine Pollution ◽  
Wall Thickening
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