Do pH changes in the leaf apoplast contribute to rapid inhibition of leaf elongation rate by water stress? Comparison of stress responses induced by polyethylene glycol and down-regulation of root hydraulic conductivity

2011 ◽  
Vol 34 (8) ◽  
pp. 1258-1266 ◽  
Author(s):  
CHRISTINA EHLERT ◽  
CLAUDE PLASSARD ◽  
SARAH JANE COOKSON ◽  
FRANÇOIS TARDIEU ◽  
THIERRY SIMONNEAU
Keyword(s):  
Polyethylene Glycol ◽  
Water Stress ◽  
Hydraulic Conductivity ◽  
Stress Responses ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Root Hydraulic Conductivity ◽  
Ph Changes ◽  
Leaf Elongation Rate ◽  
Leaf Apoplast

Leaf Elongation Rate in Panicum maximum var. trichoglume Following Removal of Water Stress

1977 ◽  
Vol 4 (2) ◽  
pp. 263 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng
Keyword(s):  
Cell Division ◽  
Water Stress ◽  
Water Potential ◽  
Cell Expansion ◽  
Elongation Rate ◽  
Panicum Maximum ◽  
Leaf Elongation ◽  
Leaf Elongation Rate ◽  
Dark Stress ◽  
Different Levels

Different levels of stress were induced in P. maximum var. trichoglume by withholding water for various periods. Leaf elongation rate was measured during dark stress periods and after rewatering in both the light and the dark. Following rewatering, elongation rates of previously stressed plants exceeded those of controls for periods up to 33 h, during which time elongation rate was more related to previous levels of water stress than to current leaf water potential. In addition, there was a transient burst of elongation when plants were rewatered in the light. It is suggested that the stimulated rates result from expansion of cells which have accumulated during the stress because cell division is less sensitive to water stress than is cell expansion. Despite the stimulated rates of elongation after rewatering, the recovery was incomplete such that the final lengths of stressed leaves were less than those of unstressed plants.

scholarly journals The Singular Molecular Conformation of Humic Acids in Solution Influences Their Ability to Enhance Root Hydraulic Conductivity and Plant Growth

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 3
Author(s):  
Maite Olaetxea ◽  
Veronica Mora ◽  
Roberto Baigorri ◽  
Angel M. Zamarreño ◽  
Jose M. García-Mina
Keyword(s):  
Polyethylene Glycol ◽  
Humic Acid ◽  
Hydraulic Conductivity ◽  
Plant Growth ◽  
Polyacrylic Acid ◽  
Molecular Conformation ◽  
Water Solution ◽  
Biological Effects ◽  
Root Hydraulic Conductivity ◽  
Molecular Systems

Some studies have reported that the capacity of humic substances to improve plant growth is dependent on their ability to increase root hydraulic conductivity. It was proposed that this effect is directly related to the structural conformation in solution of these substances. To study this hypothesis, the effects on root hydraulic conductivity and growth of cucumber plants of a sedimentary humic acid and two polymers—polyacrylic acid and polyethylene glycol—presenting a molecular conformation in water solution different from that of the humic acid have been studied. The results show that whereas the humic acid caused an increase in root hydraulic conductivity and plant growth, both the polyacrylic acid and the polyethylene glycol did not modify plant growth and caused a decrease in root hydraulic conductivity. These results can be explained by the different molecular conformation in water solution of the three molecular systems. The relationships between these biological effects and the molecular conformation of the three molecular systems in water solution are discussed.

scholarly journals Morphogenetic characteristics of three Brachiaria brizantha cultivars submitted to nitrogen fertilization

2013 ◽  
Vol 85 (1) ◽  
pp. 371-377 ◽  
Author(s):  
Marcos F Silva ◽  
Edson M. V Porto ◽  
Dorismar D Alves ◽  
Cláudio M.T Vitor ◽  
Ignacio Aspiazú
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Blade ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Brachiaria Brizantha ◽  
Nitrogen Levels ◽  
Appearance Rate ◽  
Leaf Elongation Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

This study aims to evaluate the morphogenetic characteristics of three cultivars of Brachiaria brizantha subjected to nitrogen fertilization. The design was a randomized block in factorial arrangement 4x3; three cultivars of B. brizantha - Marandu, Piatã, Xaraés and four nitrogen levels - 0, 80, 160 and 240 kg/ha, with three replications. The experimental units consisted of plastic pots filled with 5 dm3 of soil. Thereupon the establishment fertilization, varieties were sowed directly in the pots, leaving, after thinning, five plants per pot. Forty-five days after planting, it was done a standardization cut at 10 cm tall. Nitrogen levels were distributed according to the treatments, divided in three applications. The morphogenetic characteristics were evaluated in three tillers per sampling unit and data were submitted to analysis of variance and regression. For all evaluated characteristics there was no interaction between factors cultivar and nitrogen levels, verifying only the effects of nitrogen on the variables leaf appearance rate and phyllochron. The dose 240 kg/ha of N corresponds to the greater leaf appearance rate. Cultivar Marandu shows the higher leaf blade: pseudostem and ratio of leaf elongation rate and elongation pseudostem, which favors higher forage quality.

scholarly journals MORFOLOGIA FOLIAR DE SORGO SACARINO CULTIVADO EM DIFERENTES ESPAÇAMENTOS ENTRELINHAS E ÉPOCAS DE SEMEADURA

2018 ◽  
Vol 17 (1) ◽  
pp. 63
Author(s):  
ANDRIELI HEDLUND BANDEIRA ◽  
SANDRO LUIS PETTER MEDEIROS ◽  
BEATRIZ MARTI EMYGDIO ◽  
JEAN CECCHIM BIONDO ◽  
LINEU TRINDADE LEAL
Keyword(s):  
Sorghum Bicolor ◽  
Sweet Sorghum ◽  
Block Design ◽  
Shoot Elongation ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Sowing Time ◽  
Leaf Elongation Rate ◽  
Line Spacing ◽  
Sorghum Genotypes

RESUMO - O objetivo deste trabalho foi avaliar as características morfogênicas do colmo principal de genótipos de sorgo sacarino, em diferentes espaçamentos entrelinhas e épocas de semeadura. O experimento foi conduzido em Santa Maria-RS, em delineamento experimental de blocos ao acaso em esquema trifatorial (2x2x3), com dois genótipos de sorgo sacarino (BRS 506 e Fepagro 19), dois espaçamentos entrelinhas (0,50 m e 0,70 m) e três épocas de semeadura (outubro, novembro e dezembro), quatro repetições e dois anos de cultivo. Foram avaliadas a taxa de alongamento das folhas, o número final de folhas no colmo, a taxa de surgimento de folha, filocrono e taxa de elongamento de colmo. As variáveis não apresentaram interação tripla significativa entre genótipo, espaçamento de entrelinhas e época de semeadura. O genótipo BRS 506 apresentou número de folhas acumuladas, taxa de alongamento de folhas nas épocas de semeaduras constante. O atraso na época de semeadura resulta em menor número de folhas acumuladas e taxa de elongação do colmo para o Fepagro 19. O filocrono para o espaçamento entrelinhas 0,70 m é inferior ao de 0,50 m. Os genótipos estudados estão aptos para a produção na região, desde que a semeadura ocorra no mês de outubro. Palavras-chave: alongamento foliar, filocrono, graus-dia, índice Haun, Sorghum bicolor. LEAF MORPHOLOGY OF SWEET SORGHUM CULTIVATED IN DIFFERENT ROW SPACINGS AND SOWING DATES ABSTRACT - The objective of this work was to evaluate the morphogenic characteristics of the main stem of sweet sorghum genotypes in different spacing between lines and sowing times. The experimental was carried out in a randomized complete block design in a trifactorial scheme (2x2x3), with two sweet sorghum (BRS 506 and Fepagro 19), two spacing between lines (0.50 m and 0.70 m) and three sowing seasons (October, November and December), four replications and two years of cultivation. The leaf elongation rate, the final number of leaves in the stem, the leaf appearance rate, phyllochron and shoot elongation rate were evaluated. The variables did not present significant triple interaction between genotype, spacing between rows and sowing time. The genotype BRS 506 presented a number of accumulated leaves, leaf elongation rate at constant sowing times. The delay in sowing seasons results in a lower number of accumulated leaves and the elongation rate of the stem for genotype Fepagro 19. The phyllochron for the 0.70 m line spacing is less than 0.50 m. The genotypes studied are suitable for production in the region, as long as sowing occurs in October.Keywords: leaf elongation, phyllochron, degree-days, Haun index, Sorghum bicolor.

Production of root axes and leaf elongation in perennial ryegrass in relation to dryness of the upper soil layer

1980 ◽  
Vol 95 (3) ◽  
pp. 533-538 ◽  
Author(s):  
A. Troughton
Keyword(s):  
Perennial Ryegrass ◽  
Shoot Growth ◽  
Soil Layer ◽  
Selection Criterion ◽  
Elongation Rate ◽  
Soil Environment ◽  
Leaf Elongation ◽  
Experimental Conditions ◽  
Leaf Elongation Rate ◽  
Subsequent Introduction

SUMMARYDuring a period without rainfall the upper layers of the soil may become dry whilst the lower layers provide sufficient moisture for the plant to continue growing. In experimental conditions simulating such a soil environment, new main root axes ceased to be produced by plants of perennial ryegrass. Shoot growth and leaf elongation rate were little affected during the first 2 weeks of the treatment. The subsequent introduction of moisture round the base of the plant resulted in the rapid production of new root axes and increase in the leaf elongation rate. Although there was considerable intra-varietal genetic variation in the rate of development of new root axes and leaf elongation after wetting it is concluded that this would be of doubtful value as a selection criterion.

scholarly journals GROWTH AND DEVELOPMENT OF MOMBASSA GRASS GROWN IN FULL SUN AND SHADE UNDER NITROGEN LEVELS

2020 ◽  
Vol 28 ◽  
pp. 11-23
Author(s):  
Tiago Barbalho André ◽  
Leonardo Bernardes Taverny de Oliveira ◽  
Antonio Clementino dos Santos
Keyword(s):  
Average Length ◽  
Stem Elongation ◽  
Elongation Rate ◽  
Panicum Maximum ◽  
Leaf Elongation ◽  
Area Index ◽  
Nitrogen Levels ◽  
Leaf Elongation Rate ◽  
Leaf Appearance Rate ◽  
Sun And Shade

The objective of this work was to evaluate the effects promoted by full sun and natural shading (25%) enviroemnts , under the productive components of Panicum maximum cv. Mombasa grown in diferent levels of nitrogen (0, 25, 50, 100 kg ha-1 cycle-1 ). Urea was used as nitrogen source, applied on the surface. This study evaluated the following variables: number of total leaves (NTL), number of green leaves (NGL), number of dead leaves (NDL), leaf lifespan (LLS), sheath length (SL), stem elongation rate (SER), Phyllochron (PHYL), leaf appearance rate (LApR), leaf elongation rate (LElR), leaf senescence rate (LSR), average length of leaf blade (ALLB), leaf area index (LAI) and tiller population density (TPP). The shaded environment provided better conditions for sheath length and leaf elongation rate, however in full sun the tiller density was higher.

Rapid environmental changes that affect leaf water status induce transient surges or pauses in leaf expansion rate.

2000 ◽  
Vol 27 (10) ◽  
pp. 941 ◽  
Author(s):  
John B. Passioura ◽  
Rana Munns
Keyword(s):  
Environmental Changes ◽  
Leaf Growth ◽  
Water Status ◽  
Recovery Phase ◽  
Elongation Rate ◽  
Leaf Water ◽  
Leaf Elongation ◽  
Initial Value ◽  
Leaf Water Status ◽  
Leaf Elongation Rate

We subjected wheat and barley plants to rapid environmental changes, and monitored leaf elongation rates for several hours thereafter. Changes in light, humidity or salinity caused sudden rises (if the leaf water status rose) or falls (if the leaf water status fell) in leaf elongation rate, followed by a recovery phase that lasted 20–60 min. After a step change in light or humidity, the growing leaf eventually resumed its original elongation rate, although the shoot water status, as monitored by leaf thickness, differed markedly. Salinity, on the other hand, produced a persistent change in leaf elongation rate, which settled down to a lower steady rate after the transient response was over. To determine whether the sudden changes in leaf elongation rate were due to changes in leaf water relations, we kept shoots fully hydrated through the environmental changes by automatically pressurising the roots to maintain leaf xylem on the point of bleeding. This annulled the environmental effects on leaf water status, and thereby largely removed the changes in leaf elongation rate. The only exception was at the dark:light transition, when the leaf elongation rate of pressurised plants rose sharply (in contrast to that of unpressurised plants, which fell), then underwent damped oscillations before settling at about its initial value. The sudden excursions of leaf growth in unpressurised plants accompanying the environmental changes were undoubtedly due to changes in leaf water status. The subsequent, generally complete, return of the leaf elongation rate to its initial value within an hour, despite the persistent change in leaf water status, suggests that a control system is operating at a time scale of tens of minutes that eventually overrides, partially or completely, the rapid effects of changes in leaf water status.

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