Acclimation to a Change in Light Regime in Seedlings of Six Australian Rainforest Tree Species

1991 ◽  
Vol 39 (6) ◽  
pp. 591 ◽  
Author(s):  
OO Osunkoya ◽  
JE Ash
Keyword(s):  
Light Availability ◽  
Area Ratio ◽  
Light Regime ◽  
Light Environment ◽  
Specific Leaf Weight ◽  
Relative Growth ◽  
Light Regimes ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Acclimation Potential

Acclimation potential of seedlings of six non-pioneer, North Queensland rainforest tree species (Diploglottis diphyllostegia, Flindersia brayleyana, Dysoxylum schgneri, Prunus turnerana, Neisosperma poweri and Castanospora alphandii) were evaluated in three different light regimes. The seedlings were grown from seeds and raised in 37, 10 and 2.5% photosynthetically active radiation (PAR) of full sunlight in a shade house. Plants were harvested at 1, 4, and 15 months after germination. At 4 months, for each species, one-third of the seedlings in each light environment were transferred to each of the two other light environments. The remaining one-third stayed in the same light environment and formed the control. The control seedlings of all species showed a marked response to increasing PAR: relative growth rate (RGR) and total biomass were low in the 2.5% PAR level, increased in the 10% PAR level and were maximal in the 37% PAR level, except for Neisosperma. The seedlings in the 25% PAR level showed a typical shade plant morphology with a high leaf area ratio, low root-shoot ratio and low specific leaf weight. For seedlings of Dysoxylum and Prunus, a change in light regime from 37% PAR to 2.5% PAR resulted in negative relative growth rates. Eleven months after transfer, many growth characteristics still showed significant initial × final light environment interactions, an indication of incomplete adjustment. Acclimation to increasing light availability was faster than acclimation to decreasing light availability. On the basis of biomass allocation patterns (root-shoot ratio, leaf area ratio and specific leaf weight), the six species could not be differentiated under the three light regimes and their dynamics. However, using RGR as a relative measure of carbon economy, it was possible to differentiate the species in their acclimation ability to decreased but not to increased irradiance. It was concluded that, for non-pioneer species, acclimation potential may be more related to physiological than to morphological plasticity.

scholarly journals Acclimation of seedlings of three Mexican tropical rain forest tree species to a change in light availability

1991 ◽  
Vol 7 (1) ◽  
pp. 85-97 ◽  
Author(s):  
J. Popma ◽  
F. Bongers
Keyword(s):  
Growth Rates ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
Light Availability ◽  
Forest Tree ◽  
Gap Dynamics ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Closed Canopy ◽  
Acclimation Potential

ABSTRACTA comparison is made of the light acclimation potential of seedlings of three canopy species of the tropical rain forest of Los Tuxtlas, Mexico: Cordia megalantha, Lonchocarpus guatemalensis, and Omphalea oleifera. These species showed similar growth rates in a range of microhabitats. Gap dynamics were simulated by transferring plants between three environments: beneath a closed canopy, a small gap, and a large gap. Plants of all three species were able to adjust their morphology and growth rates in response to changes in light availability. Growth rates increased when plants were moved to a (larger) gap, and decreased when plants were moved to a more shaded environment. Shade-grown plants were able to acclimate faster to increasing light availability than sun-grown plants to decreasing light availability. Also, plants moved from shady to sunny conditions showed higher relative growth rates than sun control plants, whereas sun-grown plants when moved to the shade showed lower relative growth rates than shade control plants. Species differed in their response to gap dynamics. Omphalea could not acclimate morphologically to shading, but reacted faster than the other species in response to the occurrence of a large gap. Acclimation potential seemed to be related to plasticity in physiological rather than in morphological traits. Suppressed seedlings of all three species performed well in the shade, and were able to acclimate rapidly to gap-conditions.

scholarly journals Utilização de macrófitas aquáticas em substrato para a produção de mudas de moringa

2016 ◽  
Vol 36 (85) ◽  
pp. 25 ◽  
Author(s):  
Walda Monteiro Farias ◽  
Leonaldo Alves de Andrade ◽  
Manoel Bandeira de Albuquerque ◽  
João Rodrigues da Cunha
Keyword(s):  
Water Hyacinth ◽  
Dry Matter ◽  
Aquatic Macrophytes ◽  
Moringa Oleifera ◽  
Water Lettuce ◽  
Relative Growth ◽  
Substrate Composition ◽  
Crown Diameter ◽  
Shoot Ratio ◽  
Root Shoot Ratio

A utilização de macrófitas aquáticas na composição de substratos para produção de mudas de moringa constitui uma alternativa sustentável. Portanto, objetivou-se com esta pesquisa avaliar o desenvolvimento de mudas de moringa, utilizando subtratos com macrófitas aquáticas, e determinar os teores de N, P e K nas mudas. Utilizaram-se diferentes combinações de macrófitas (M), esterco bovino (E) e terra vegetal (TV) para compor os subtratos. O experimento foi conduzido em esquema fatorial 3 × 4, em delineamento em blocos casualizados com quatro repetições. Foram avaliados: alturas das plantas, diâmetro da copa e caule, taxa relativa de crescimento em altura, em diâmetro da copa e do caule, matéria seca da parte aérea e raízes, comprimento de raízes e razão raízes/parte aérea, além dos teores de N, P e K das mudas. As mudas de moringa apresentam crescimento reduzido quando produzidas em substratos constituídos unicamente com taboa. Alface d’água e os substratos compostos por 60% M + 30% E + 10% TV e 70% M + 30% E, proporcionaram melhor nutrição e crescimento das mudas de moringa. O substrato 60M+30E+10TV composto pelo aguapé e taboa promoveram maior aporte de P para as mudas de moringa.Use of aquatic macrophytes in substrate composition to produce moringa The use of aquatic macrophytes in substrate composition to produce seedlings of moringa is a sustainable alternative. Therefore, the objective of this research was to evaluate the development of moringa seedlings using substrates composed with aquatic macrophytes, and to determine concentrations of N, P and K in the seedlings. We used different combinations of weeds (M), manure (E) and topsoil (TV) to compose the substrates. The experiment was conducted in a 3 × 4 factorial in randomized arrangement with four replications. We evaluated plant height, crown diameter and stem, relative growth rate in height, canopy diameter and in stem, dry matter of aerial part and of roots, root length and root/shoot ratio, besides the content of N, P and K in seedlings. Moringa seedlings showed reduced growth when produced in substrates composed only with cattail. Water lettuce and substrates composed of 60% M + 30%E + 10 % TV and 70% M + 30% E, promoted greater nutrition and growth of moringa seedlings. The substrate 60M +30E +10TV composed by water hyacinth and cattail resulted in greater amount of P in moringa seedlings.Index terms: Organic compound;Typha domingensis;Moringa oleifera

scholarly journals Posidonia oceanica molecular adaptation to the light environment

2015 ◽  
Author(s):  
Gabriele Procaccini ◽  
Emanuela Dattolo ◽  
Chiara Lauritano ◽  
Miriam Ruocco ◽  
Lazaro Marin-Guirao
Keyword(s):  
Environmental Changes ◽  
Light Availability ◽  
Posidonia Oceanica ◽  
Light Sensitivity ◽  
Light Environment ◽  
Molecular Adaptation ◽  
Important Species ◽  
Light Regimes ◽  
Seagrass Meadows ◽  
The Impact

Seagrass meadows are among the most productive ecosystems, with Posidonia oceanica being the most important species along the Mediterranean coastline. This species forms extensive mono-specific meadows that are extremely sensitive to medium-high levels of disturbance and are being threatened by fast environmental changes caused by global warming and increasing human activities. The impact can either reflect in higher turbidity along the water column and in increased UV radiation, making the light availability one of the most important factors affecting P. oceanica distribution. Plants developed mechanisms of adaptations at multiple levels to track and cope with fluctuations and changes in the light environment. At molecular level, the modulation of gene expression in response to environmental changes allows plants to optimize the utilization of light energy for growth and to prevent damages due to its excess. To detect the relevant molecular adaptation strategies evolved by P. oceanica and to assess the plasticity showed in the acclimation under different light regimes, we are employing studies both in natural and controlled conditions. Here, we describe the differences in photo acclimation of plants living along the bathymetric cline observed in field and in a common garden experiment in mesocosms, after the exposition to contrasting light regimes. Using a transcriptional approach (both RT -qPCR and RNA-seq) coupled with a physiological one, we are also testing potential divergences existing among populations and individuals related to light sensitivity. These data should supply new insights for the management of seagrasses ecosystems, for the development of most successful transplantation strategies and ultimately for conservation of biodiversity of these precious ecosystems.

scholarly journals Physiological indices and phytomass partition in precocious dwarf cashew clones irrigated with saline waters

2020 ◽  
Vol 11 ◽  
pp. e3196
Author(s):  
Geovani Soares de Lima ◽  
Jailson Batista da Silva ◽  
Lauriane Almeida dos Anjos Soares ◽  
Hans Raj Gheyi ◽  
Reginaldo Gomes Nobre ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Salt Stress ◽  
Leaf Area ◽  
Water Salinity ◽  
Stress Indicators ◽  
Relative Growth ◽  
Physiological Indicators ◽  
Shoot Ratio ◽  
Physiological Indices ◽  
Root Shoot Ratio

This research aimed to evaluate the physiological indices and the accumulation of phytomass in clones of precocious dwarf cashew under salt stress during rootstock formation. The experiment was conducted in greenhouse in the municipality of Pombal-PB. The experimental design was in randomized blocks, and the treatments were organized in a 5 x 3 factorial arrangement, constituting the levels of electrical conductivity of the irrigation water - ECw (0.4 -Control; 1.2; 2.0; 2.8, and 3.6 dS m-1) and the clones of precocious dwarf cashew (Faga 11, Embrapa 51, CCP 76), with three replications and two plants per plot. Water salinity higher than 0.4 dS m-1 resulted in a decrease of the relative growth in plant height, leaf area, and phytomass accumulation in the cashew plant. The cashew clones are sensitive to water salinity from 0.4 dS m-1. Among the physiological indicators, the leaf area ratio, the sclerophylly index, and the root/shoot ratio of the precocious dwarf cashew are highlighted as salt stress indicators. The use of water with 0.4 dS m-1 of electrical conductivity is recommended for the formation of cashew rootstocks.

scholarly journals Root Applications of Gibberellic Acid Enhance Growth of Seven Pelargonium Cultivars

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 555-556 ◽  
Author(s):  
Richard N. Arteca ◽  
Carl D. Schlagnhaufer ◽  
Jeannette M. Arteca
Keyword(s):  
Growth Rate ◽  
Gibberellic Acid ◽  
Root Systems ◽  
Relative Growth ◽  
Unit Leaf ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Wide Range ◽  
Percent Moisture ◽  
Hydroponically Grown

Four concentrations of GA, (0.05, 0.5, 5.0, or 50 mg·liter–1) were applied to the root systems of seven hydroponically grown geranium (Pelargonium × hortorum cv. Empress Irene, Glacier Crimson, Sincerity, Pink Fiat, Sybil Holmes, and Mrs. Parker and P. × domesticum cv. Lavender Grand Slam) cultivars. The relative growth rate of all cultivars tested increased with GA3 treatments. In conjunction with the increase in growth rate, each of the cultivars showed a reduction in the root: shoot ratio and chlorophyll content per unit leaf area with no change in the percent moisture. These Pelargonium cultivars are genetically diverse, showing that GA3 can stimulate growth over a wide range of cultivars. Chemical name used: gibberellic acid (GA3).

Effect of Color Shading-Nets on the Growth and Physiological Characteristics of Chieh-Qua Seedling

2011 ◽  
Vol 366 ◽  
pp. 197-201 ◽  
Author(s):  
Shi Wei Song ◽  
Ling Yan Yi ◽  
Hou Cheng Liu ◽  
Guang Wen Sun ◽  
Ri Yuan Chen
Keyword(s):  
Physiological Characteristics ◽  
Specific Leaf Weight ◽  
Leaf Chlorophyll ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Benincasa Hispida ◽  
Mda Content ◽  
Reduced Light ◽  
Seedling Leaf ◽  
Color Shading

With uncovered net as a control, the effect of color shading-nets (red net, blue net and silver net) and ordinary black net on growth and physiological characteristics of Chieh-qua (Benincasa hispida Cogn.var. chieh-qua How.) seedling were studied. The result showed that, shading-net covering reduced light intensity and temperature, and increased air humidity of the seedling environment, compared with the control. Shading-net covering increased plant height, stem diameter, leaf area and biomass of Chieh-qua seedling, among which covering of blue and silver shading-nets were superior to the others. Root/shoot ratio and strong seedling index were the biggest under blue net treatment, thus it indicated that blue net covering promoted seedling haleness. Specific leaf weight of Chieh-qua seedling was reduced by covering shading-net. In addition to silver net, leaf chlorophyll and carotenoids content were significantly increased by another 3 covering shading-nets. Relative conductivity (RC), malondialdehyde (MDA) content, superoxidase dismutase (SOD) and peroxydase (POD) activity of Chieh-qua seedling leaf were significantly reduced by shading-net covering. This indicated that shading-net covering in seeding nursery alleviated the stress of intensive light and high temperature, and thus increased the integrated seedling quality. Blue shading-net performed the best among all covering shading-nets.

scholarly journals 324 Heat Tolerance Varies with Species, Provenance, and Accession in Fragaria

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 498E-499
Author(s):  
Douglas D. Archbold ◽  
Ann M. Clements
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Plant Growth ◽  
South American ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Whole Plant ◽  
Net Assimilation

Several components of whole-plant growth were compared among accessions of Fragaria chiloensis (FC) and F. virginiana (FV) grown at 23 and 31 °C daytime temperatures. The accessions loosely represented North American (NA) and South American (SA) provenances of FC and Kentucky (KY) and eastern Canadian (CN) provenances of FV. Differences in component values between species and by provenance and accession within species were observed at each temperature. Using the ratio of the component value at 31 °C to that at 23 °C as a basis for comparisons, whole-plant relative growth rate (RGR), leaf net assimilation rate (NAR), root RGR, and root: shoot ratio were reduced relatively more by high temperature in FC than FV, while crown RGR, leaf RGR, and leaves produced per day were not consistently affected by temperature or and did not differed significantly between species. While the SA FC exhibited higher values for nearly all components than the NA FC at both temperatures, both were affected similarly by high temperature. The CN FV exhibited somewhat greater sensitivity to high temperature than the KY FV, with significantly lower leaf NAR, crown RGR, and leaves produced per day in the former group.

Shade Avoidance Influences Stress Tolerance in Maize

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 326-334 ◽  
Author(s):  
Eric R. Page ◽  
Weidong Liu ◽  
Diego Cerrudo ◽  
Elizabeth A. Lee ◽  
Clarence J. Swanton
Keyword(s):  
Abiotic Stress ◽  
Avoidance Response ◽  
Light Quality ◽  
Yield Loss ◽  
Shade Avoidance ◽  
Plant Tolerance ◽  
Relative Growth ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
The Impact

Previous studies have suggested that the reduction in the root/shoot ratio that accompanies the shade avoidance response may reduce the tolerance of individuals to subsequent nutrient or moisture limitations. In this work, we examined the impact of the shade avoidance response on maize seedling growth and development and the response of these plants to a subsequent abiotic stress. Seedlings were grown in a field fertigation system under two light quality environments, ambient and a low red to far-red ratio, which were designed to simulate weed-free and weedy conditions, respectively. This system also enabled the controlled restriction of water and nutrients, which reduced the relative growth rate of the crop and created a secondary stress. Results of this study indicate that, while the shade avoidance response did reduce the root/shoot ratio in maize, this effect did not reduce plant tolerance to subsequent abiotic stress. Rather, the apparent additivity or synergism of shade avoidance and the secondary stressor on yield loss depended on whether the net effect of these two stressors was sufficiently large to shift the population toward the point where reproductive allometry was broken.

scholarly journals Posidonia oceanica molecular adaptation to the light environment

2015 ◽  
Author(s):  
Gabriele Procaccini ◽  
Emanuela Dattolo ◽  
Chiara Lauritano ◽  
Miriam Ruocco ◽  
Lazaro Marin-Guirao
Keyword(s):  
Environmental Changes ◽  
Light Availability ◽  
Posidonia Oceanica ◽  
Light Sensitivity ◽  
Light Environment ◽  
Molecular Adaptation ◽  
Important Species ◽  
Light Regimes ◽  
Seagrass Meadows ◽  
The Impact

Seagrass meadows are among the most productive ecosystems, with Posidonia oceanica being the most important species along the Mediterranean coastline. This species forms extensive mono-specific meadows that are extremely sensitive to medium-high levels of disturbance and are being threatened by fast environmental changes caused by global warming and increasing human activities. The impact can either reflect in higher turbidity along the water column and in increased UV radiation, making the light availability one of the most important factors affecting P. oceanica distribution. Plants developed mechanisms of adaptations at multiple levels to track and cope with fluctuations and changes in the light environment. At molecular level, the modulation of gene expression in response to environmental changes allows plants to optimize the utilization of light energy for growth and to prevent damages due to its excess. To detect the relevant molecular adaptation strategies evolved by P. oceanica and to assess the plasticity showed in the acclimation under different light regimes, we are employing studies both in natural and controlled conditions. Here, we describe the differences in photo acclimation of plants living along the bathymetric cline observed in field and in a common garden experiment in mesocosms, after the exposition to contrasting light regimes. Using a transcriptional approach (both RT -qPCR and RNA-seq) coupled with a physiological one, we are also testing potential divergences existing among populations and individuals related to light sensitivity. These data should supply new insights for the management of seagrasses ecosystems, for the development of most successful transplantation strategies and ultimately for conservation of biodiversity of these precious ecosystems.

Effects of Single-seed Sowing on Root Growth, Root-shoot Ratio, and Yield inPeanut (Arachis hypogacaL.)

2013 ◽  
Vol 39 (12) ◽  
pp. 2228 ◽  
Author(s):  
Ye FENG ◽  
Feng GUO ◽  
Bao-Long LI ◽  
Jing-Jing MENG ◽  
Xin-Guo LI ◽  
...  
Keyword(s):  
Root Growth ◽  
Single Seed ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Seed Sowing
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