Light Requirements of Buried Seeds

Nature ◽  
1967 ◽  
Vol 213 (5076) ◽  
pp. 600-601 ◽  
Author(s):  
G. WESSON ◽  
P. F. WAREING
Keyword(s):  
Light Requirements ◽  
Buried Seeds

Role of temperature and light in the germination ecology of buried seeds of weedy species of disturbed forests. I. Lobelia inflata

1992 ◽  
Vol 70 (3) ◽  
pp. 589-592 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seed Banks ◽  
Early Summer ◽  
Light Requirement ◽  
Forest Sites ◽  
Light Requirements ◽  
Lobelia Inflata ◽  
Buried Seeds ◽  
Weedy Species ◽  
Disturbed Forest

Lobelia inflata L. is a weedy species that may be abundant in disturbed forest sites. Temperature and light requirements for germination were determined at 12-h daily thermoperiods of 15:6, 20:10, 25:15, 30:15, and 35:20 °C for seeds exhumed after 0–28 months (September 1987 to February 1990) of burial in soil at near-natural temperatures. At maturity in autumn 1987, 2–15% of the seeds germinated after 15 days incubation at the five thermoperiods in light but 0% germinated in darkness. By January 1988, 68–100% of the seeds germinated in light at all thermoperiods except 15:6 °C. Germination at 20:10, 25:15, and 30:15 °C did not decrease to below 60% during the remainder of the study, and germination at 35:20 °C was less than 60% only four times. Germination at 15:6 °C was erratic with peaks in spring 1988, and in spring to early summer and autumn 1989. Regardless of the season in which seeds were exhumed, they did not germinate in darkness. In a laboratory study, stratification at 5 °C broke dormancy but did not substitute for the light requirement. Seeds of L. inflata have the potential to form long-lived seed banks, and buried seeds can germinate at any time during the growing season if exposed to light. Key words: seed dormancy, seed germination, buried seeds, Lobelia inflata, stratification.

scholarly journals Ecophysiological, morphological, and biochemical traits of free-living Diplosphaera chodatii (Trebouxiophyceae) reveal adaptation to harsh environmental conditions

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Cynthia Medwed ◽  
Andreas Holzinger ◽  
Stefanie Hofer ◽  
Anja Hartmann ◽  
Dirk Michalik ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Botanical Garden ◽  
Tree Bark ◽  
Photon Flux ◽  
Low Light ◽  
Transmission Electron ◽  
Light Requirements ◽  
Adaptive Mechanisms ◽  
Terrestrial Habitats ◽  
Excellent Preservation

AbstractSingle-celled green algae within the Trebouxiophyceae (Chlorophyta) are typical components of terrestrial habitats, which often exhibit harsh environmental conditions for these microorganisms. This study provides a detailed overview of the ecophysiological, biochemical, and ultrastructural traits of an alga living on tree bark. The alga was isolated from a cypress tree in the Botanical Garden of Innsbruck (Austria) and identified by morphology and molecular phylogeny as Diplosphaera chodatii. Transmission electron microscopy after high-pressure freezing (HPF) showed an excellent preservation of the ultrastructure. The cell wall was bilayered with a smooth inner layer and an outer layer of polysaccharides with a fuzzy hair-like appearance that could possibly act as cell-cell adhesion mechanism and hence as a structural precursor supporting biofilm formation together with the mucilage observed occasionally. The photosynthetic-irradiance curves of D. chodatii indicated low light requirements without photoinhibition at high photon flux densities (1580 μmol photons m−2 s−1) supported by growth rate measurements. D. chodatii showed a high desiccation tolerance, as 85% of its initial value was recovered after controlled desiccation at a relative humidity of ~10%. The alga contained the low molecular weight carbohydrates sucrose and sorbitol, which probably act as protective compounds against desiccation. In addition, a new but chemically not elucidated mycosporine-like amino acid was detected with a molecular mass of 332 g mol−1 and an absorption maximum of 324 nm. The presented data provide various traits which contribute to a better understanding of the adaptive mechanisms of D. chodatii to terrestrial habitats.

Unboxing the Buried Seeds of My Belonging

2016 ◽  
Vol 57 (9) ◽  
pp. e153-e156
Author(s):  
Tori Vasquez ◽  
Brenda Sendejo
Keyword(s):  
Buried Seeds

scholarly journals Different levels of shade on population of grasshoppers and its oviposition preference on heliconias

2018 ◽  
Vol 48 (2) ◽  
Author(s):  
Ana Cristina Bittar ◽  
Elen de Lima Aguiar-Menezes ◽  
José Guilherme Marinho Guerra ◽  
Janaína Ribeiro Costa Rouws ◽  
Luiz Augusto de Aguiar ◽  
...  
Keyword(s):  
Block Design ◽  
Oviposition Preference ◽  
Production Parameters ◽  
Lateral Buds ◽  
Randomized Block Design ◽  
Light Requirements ◽  
Four Levels ◽  
Preferred Species ◽  
Different Levels

ABSTRACT: Grasshoppers of the families Acrididae and Romaleidae (Orthoptera) are among the insects that defoliate heliconias and have been gaining status as pests of commercial crops of these plants in Brazil. The objectives of the present study were to identify the grasshopper defoliating heliconias in the municipality of Santo Antônio de Pádua, RJ (Brazil), to evaluate the effect of different levels of shade on the population of this grasshopper and the production parameters of heliconias, and to determine if this grasshopper has an oviposition preference among the heliconias evaluated. The experiment was in a completely randomized block design, in subdivided plots (four levels of shade in the plot, 0%, 30%, 50% and 80%, and four species of Heliconia: H. psittacorum, H. stricta, H. wagneriana and H. psittacorum x H. spathocircinata ‘Golden Torch’ in the subplot), with four replications. The grasshopper was identified as Cornops frenatum frenatum (Acrididae). An increase in shade resulted in a decrease in the number of oviposition holes from the grasshopper and the number of lateral buds. Shade did not influence the number of C. f. frenatum nymphs and adults and the number of flower stems. H. wagneriana was the most preferred species for oviposition by C. f. frenatum. Results suggested using screens to shade heliconia plants can help control C. f. frenatum populations, however, the light requirements of the heliconias should be considered to guarantee productivity.

scholarly journals Photosynthetic light requirements and vertical distribution of macroalgae in newly ice-free areas in Potter Cove, South Shetland Islands, Antarctica

Polar Biology ◽  
2015 ◽  
Vol 39 (1) ◽  
pp. 153-166 ◽  
Author(s):  
D. Deregibus ◽  
M. L. Quartino ◽  
G. L. Campana ◽  
F. R. Momo ◽  
C. Wiencke ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
South Shetland Islands ◽  
Potter Cove ◽  
Shetland Islands ◽  
Light Requirements

Seed mass and light requirements for regeneration in Southeast Asian rain forest

1995 ◽  
Vol 73 (6) ◽  
pp. 817-826 ◽  
Author(s):  
D. J. Metcalfe ◽  
P. J. Grubb
Keyword(s):  
Phylogenetic Analysis ◽  
Rain Forest ◽  
Secondary Forest ◽  
Seed Mass ◽  
Primary Forest ◽  
Secondary Forests ◽  
Light Requirement ◽  
Lowland Rain Forest ◽  
Light Requirements ◽  
Shade Tolerant Species

Seed mass values are given for 140 species of primary lowland rain forest and associated secondary forests in Singapore. Among shade-tolerant species of primary forest there is a trend for a decrease in mean seed mass with tall trees > woody climbers > small trees > shrubs > herbs; the differences between tall trees and small trees or shrubs or herbs, and between herbs and small trees or woody climbers are significant. There are a few light-demanding herbs or shrubs in the primary forest; among small trees, light demanders have significantly lower seed mass values than shade tolerators. In 9 out of 13 comparisons within taxa including both shade tolerants and light demanders the former had appreciably larger seeds than the latter. Two out of 13 comparisons involved very small seeded shade tolerators, and one a notably large-seed light demander. Many shade-tolerant herbs, shrubs, and trees have seed mass values much smaller than those of trees of secondary forest conventionally regarded as small seeded, and exploit moist, litter-free sites, e.g., steep microslopes. The trees of secondary forests on degraded soils do not differ significantly in seed mass from those on nondegraded soils. Key words: seed mass, light requirement, regeneration, tropical rain forest, phylogenetic analysis.

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