Biomass allocation in Aster acuminatus: variation within and among populations over 5 years

1985 ◽  
Vol 63 (11) ◽  
pp. 2035-2043 ◽  
Author(s):  
Jeffrey W. Ashmun ◽  
Robert L. Brown ◽  
Louis F. Pitelka
Keyword(s):  
Biomass Allocation ◽  
Clonal Growth ◽  
Standing Crop ◽  
Light Availability ◽  
Light Level ◽  
Light Regimes ◽  
Wide Range ◽  
Role Of Light ◽  
Growth And Allocation

Patterns of biomass allocation were analyzed over a 5-year period for 15 patches of the forest herb, Aster acuminatus Michx., on Kent Island, New Brunswick. The patches were distributed over a wide range of understory light regimes but otherwise occupied similar environments. In every year, light level was positively correlated with mean ramet size, ramet density, and plot standing crop (grams per square metre). This suggests that the patches were at or near their light-determined carrying capacities. There was significant variation in patterns of biomass allocation among plots in every year. This variation was always correlated with plot standing crop. In general, as standing crop increased, mean relative allocation to stems, flowers, and clonal growth increased, while allocation to leaves and rhizomes decreased. Patterns of allocation varied significantly between years for those plots sampled more than once, yet among-plot relationships with standing crop were maintained. Both thinning and shading of natural patches had pronounced effects on growth and allocation. Thinning resulted in larger plants and greater relative allocation to flowers and clonal growth, compared to controls. Shading resulted in generally opposite patterns. This study documents the important role of light availability, working directly and through intraspecific competition, in determining patterns of growth and biomass allocation in A. acuminatus.

scholarly journals Interacting Effects of Light and Temperature on Sporulation of Peronospora tabacina on Tobacco Leaves

1976 ◽  
Vol 29 (3) ◽  
pp. 281 ◽  
Author(s):  
YigaI Cohen
Keyword(s):  
Light Level ◽  
Inhibitory Effect ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Present System ◽  
Tobacco Leaves ◽  
Spore Yield ◽  
Role Of Light ◽  
Effect Of Light

The interacting effects of light and temperature on spore formation of P. tabacina on tobacco leaves were investigated. The following points indicated that an enzymic build-up of an antisporulant during a wet light period and its enzymic decay over a dry dark period may explain the inhibitory effect of light upon sporulation, and its reversal by darkness. (1) Fluorescent blue light of relatively low photon flux density (3 �7 /lE m - 2 S -1) inhibited sporulation by 99 % at 20oe. (2) Light level and temperature during the sporulation period determined spore yield of the pathogen: at high temperatures (in the range 8-24�C) sporulation was inhibited at low light level, whilst no inhibition occurred at much higher light levels at low temperatures. (3) Preceding dry dark treatments given at 200e considerably diminished the inhibitory effect of light, but not if given at 100e. (4) The diffusion of an inhibitory compound from irradiated to unirradiated areas of detached leaves was demonstrated. (5) The continuing photosynthetic activity of the host in the light at 20oe, and the lack of sucrose following dark periods at lOoe, were not associated with the inhibitory effect of light. The similarity between the role of light in the present system and the role of light in activation and decay of phenylalanine ammonia-lyase is discussed.

Light and nutrient effects on growth and allocation of Inga vera (Leguminosae), a successional tree of Puerto Rico

2006 ◽  
Vol 36 (5) ◽  
pp. 1121-1128 ◽  
Author(s):  
Randall W Myster
Keyword(s):  
Biomass Allocation ◽  
Mycorrhizal Fungi ◽  
Light Availability ◽  
Arbuscular Mycorrhizal ◽  
Growth Responses ◽  
Light Levels ◽  
Nutrient Effects ◽  
Below Ground ◽  
High Degree ◽  
Growth And Allocation

With the aim of acquiring a better understanding of ecological growth and biomass allocation of Neo tropical trees, I inoculated Inga vera Willd. (Leguminosae) plants from cuttings with Rhizobium spp. and arbuscular mycorrhizal fungi and grew them in a greenhouse for 8 months under varying light (L), phosphorus (P), and nitrogen (N) treatments. I obtained the following results: (1) L, P × N, and L × P × N treatments affected every response variable, but most increases occurred under full light; that is, light levels influenced growth of Inga vera to a greater extent than did P and N additions by themselves; (2) response variables showed a high degree of similarity in regard to which combination of treatment levels had the greatest positive response (full light – low N – high P) and which combination led to other significant increases (full light – low N – no P, full light – high N – no P); and (3) percent AM colonization was affected mainly by light, not P levels. I conclude that growth responses of Inga vera are primarily controlled by light availability, which can interact with nutrient addition to affect biomass allocation to both above- and below-ground structures.

scholarly journals The role of light in the adaptation of Thymus praecox Opiz subsp. praecox for diverse habitat conditions

2020 ◽  
Vol 48 (3) ◽  
pp. 1194-1209
Author(s):  
Beata BARABASZ-KRASNY ◽  
Katarzyna MOŻDŻEŃ ◽  
Anna SOŁTYS-LELEK ◽  
Ingrid TURISOVÁ
Keyword(s):  
Chlorophyll A ◽  
Cell Membranes ◽  
Physiological Activity ◽  
Light Availability ◽  
Dry Mass ◽  
Habitat Conditions ◽  
Partial Shade ◽  
Chlorophyll A And B ◽  
Role Of Light

The light decides about the course and efficiency of photochemical processes, being an important component of the surrounding environment shaping the plant composition in specific conditions. Thymus praecox subsp. praecox belongs to endangered taxa due to preferences for open habitats, which as a result of natural succession are exposed to overgrowth and shading with forest-scrub vegetation. In this study, an attempt was made to check the physiological activity of creeping thyme in changing environmental conditions prevailing on isolated stands in the Ojców National Park (Southern Poland). The increase in fresh and dry mass and the percentage of water in plants were determined, the content of chlorophyll a and b was measured, the intensity of chlorophyll a fluorescence was examined and the degree of electrolytes leakage through cell membranes was checked. The main aim was to determining the optimal habitat conditions for this taxon, which could help protect it. Based on the conducted research it was found, among others higher mass increase in plants from a sunny stand. Regardless of the measurement period, an increase in chlorophyll a and b content and a higher degree of cell membranes destabilisation in plants from a partially shaded stand was observed. The obtained results show, that T. praecox subsp. praecox characterises small habitat flexibility - even partial shade is not a convenient habitat for it. To optimal development, this subspecies requires conditions with high light availability. Creeping thyme is a heliophilic and thermophilic taxa and the sunny stands are optimal for it.

Assessing the role of light availability in the regeneration of Araucaria angustifolia (Araucariaceae)

2002 ◽  
Vol 50 (6) ◽  
pp. 741 ◽  
Author(s):  
L. S. Duarte ◽  
L. R. Dillenburg ◽  
L. M. G. Rosa
Keyword(s):  
Forest Succession ◽  
Light Availability ◽  
Canopy Cover ◽  
Native Forest ◽  
Araucaria Angustifolia ◽  
Light Conditions ◽  
Area Index ◽  
Species Tolerance ◽  
Role Of Light

The role of Brazilian pine (Araucaria angustifolia) in the process of forest succession is a topic of increasing controversy. While some authors consider the species to be pioneer, others consider it to be a climax species in relict temperate forests. We designed a field experiment to assess the role of light availability on the regeneration of A. angustifolia. The following three forests, with contrasting patterns of the species regeneration, were selected at a National Forest in southern Brazil: a Pinus plantation, an Araucaria plantation and a native araucarian forest. We analysed the population structure of Brazilian pine, the vegetation architecture, the light regime experienced by seedlings and the height growth of seedlings and sprouts. Brazilian pine colonisation and regeneration were observed in the Pinus and Araucaria plantations, respectively. No seedlings were found in the native forest. The greatest foliage area index and canopy cover were found in the native forest and the smallest in the Pinus plantation. In spite of the architectural differences, the native forest and the Araucaria plantation had similar light conditions and they both had lower levels of irradiances than the Pinus plantation. Seedlings and sprouts of Brazilian pine were found to occupy spots in the Araucaria plantation with canopy cover greater than the average forest conditions. Considering the similarity of understorey light conditions between the Araucaria plantation and the native forest (where no regeneration was taking place), we concluded that light availability was not limiting the regeneration of the species. Tolerance to shading and other aspects of the species indicate that Brazilian pine is not strictly heliophyllous and pioneer and is able to be established in the forest understorey.

scholarly journals The Role of Light during Phlox drummondii Hook. Seed Germination

HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 786-788
Author(s):  
William J. Carpenter ◽  
Eric R. Ostmark ◽  
John A. Cornell
Keyword(s):  
Seed Germination ◽  
Light Level ◽  
Total Darkness ◽  
Regression Equations ◽  
Continuous Darkness ◽  
Light Duration ◽  
Radicle Emergence ◽  
Phlox Drummondii ◽  
Role Of Light

The role of light on phlox germination and radicle emergence was studied. Neither light level nor duration affected total germination (G) percentages, which ranged from 93%. to 98%. Increasing light level and lengthening light duration delayed achieving 50% of final germination (T50) and increased the span in days between 10% and 90% germination (T90 - T10). Increasing light duration from 0 to 24 hours during germination at 0.15 μmol·s-1·m-2 progressively increased T50 from 3.5 to 7.1 days and T90 - T10 from 2.6 to 13.1 days. Similarly, lengthening light duration from 0 to 24 hours at 1.5 μmol·s-1·m-2 light increased T50 from 3.7 to 10.8 days and T90 - T10 from 2.8 to 13.4 days, whereas 15 μmol·s -1·m-2 increased T50 from 3.9 to 21.9 days and T90 - T10 from 2.9 to 29.2 days. Increasing the number of days in darkness from 0 to 6 decreased T50 from 14.8 to 4.3 days and T90 - T10 from 20.2 to 3.5 days. Increasing the number of days in light from O to 6 increased T50 from 4.0 to 8.9 days and T90 - T10 from 3.8 to 8.2 days. Estimated rates of decline or increase in T50 and T90 - T10 with each added day in darkness or light were measured by fitting regression equations. Seeds germinated in continuous darkness or in 24 or 48 hours of light followed by total darkness had similar G, T50, and T90 - T10. The results indicate that initial phlox seed germination was not affected by light, but that light inhibited radicle extension in later germination stages.

The Problem of Identifying and Modeling the Relationship between Monetary Factor and Inflation in the Russian Economy

2008 ◽  
pp. 61-76
Author(s):  
A. Porshakov ◽  
A. Ponomarenko
Keyword(s):  
Money Supply ◽  
Money Demand ◽  
Russian Economy ◽  
Long Run ◽  
Complex Approach ◽  
Wide Range ◽  
Long Time ◽  
The Relationship ◽  
Supply Side Factors

The role of monetary factor in generating inflationary processes in Russia has stimulated various debates in social and scientific circles for a relatively long time. The authors show that identification of the specificity of relationship between money and inflation requires a complex approach based on statistical modeling and involving a wide range of indicators relevant for the price changes in the economy. As a result a model of inflation for Russia implying the decomposition of inflation dynamics into demand-side and supply-side factors is suggested. The main conclusion drawn is that during the recent years the volume of inflationary pressures in the Russian economy has been determined by the deviation of money supply from money demand, rather than by money supply alone. At the same time, monetary factor has a long-run spread over time impact on inflation.

Introduction: Emotion, History and the Arts

2018 ◽  
Vol 7 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Erin Sullivan ◽  
Marie Louise Herzfeld-Schild
Keyword(s):  
Historical Change ◽  
Carson Mccullers ◽  
Emotional Life ◽  
Review Section ◽  
The Arts ◽  
Wide Range ◽  
War Correspondents ◽  
History Of ◽  
Johan Huizinga

This introduction surveys the rise of the history of emotions as a field and the role of the arts in such developments. Reflecting on the foundational role of the arts in the early emotion-oriented histories of Johan Huizinga and Jacob Burkhardt, as well as the concerns about methodological impressionism that have sometimes arisen in response to such studies, the introduction considers how intensive engagements with the arts can open up new insights into past emotions while still being historically and theoretically rigorous. Drawing on a wide range of emotionally charged art works from different times and places—including the novels of Carson McCullers and Harriet Beecher-Stowe, the private poetry of neo-Confucian Chinese civil servants, the photojournalism of twentieth-century war correspondents, and music from Igor Stravinsky to the Beatles—the introduction proposes five ways in which art in all its forms contributes to emotional life and consequently to emotional histories: first, by incubating deep emotional experiences that contribute to formations of identity; second, by acting as a place for the expression of private or deviant emotions; third, by functioning as a barometer of wider cultural and attitudinal change; fourth, by serving as an engine of momentous historical change; and fifth, by working as a tool for emotional connection across communities, both within specific time periods but also across them. The introduction finishes by outlining how the special issue's five articles and review section address each of these categories, while also illustrating new methodological possibilities for the field.

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