scholarly journals Seasonal and Simultaneous Cleistogamy in Rostrate Violets (Viola, subsect. Rostratae, Violaceae)

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2147
Author(s):  
Ali Ammarellou ◽  
Justyna Żabicka ◽  
Aneta Słomka ◽  
Jerzy Bohdanowicz ◽  
Thomas Marcussen ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Basic Research ◽  
Growing Season ◽  
Individual Plant ◽  
Common Phenomenon ◽  
Important Species ◽  
Long Day ◽  
Lateral Branches ◽  
Floral Meristems ◽  
Typical Difference

The special mixed reproductive system, i.e., the ability of an individual plant to develop both open, chasmogamous (CH) flowers adapted to cross-pollination and closed, cleistogamous (CL) flowers with obligate self-pollinating, is a common phenomenon in Viola L. In most sections of Northern Hemisphere violets, cleistogamy is seasonal, and CH and CL flowers develop sequentially in the season. Non-seasonal cleistogamy (simultaneous) is a rare phenomenon in rostrate violets. In the current study, we focused on modification of the CH/CL mating system in V. caspia by environmental conditions, resulting in a gradual switch from temporal cleistogamy, occurring in nature, to simultaneous cleistogamy under greenhouse conditions. V. reichenbachiana with seasonal cleistogamy was the control for V. caspia with the labile seasonal/simultaneous cleistogamy system. In simultaneous cleistogamy, the CH and CL flowers, fruits and seeds developed on an individual plant at the same time on the same branch. The typical difference between CH and CL flowers’ pistils is a straight style ending with a head-like stigma in CH and a curved style in CL adapted to self-pollination. This trait persists in the fruit and seed stages, allowing for easy recognition of fruit of CL and CH flowers in simultaneous cleistogamy. Floral meristems of CH flowers of V. reichenbachiana developed on the rhizome at the end of the growing season under short-day conditions and remained dormant until the following season. The CL floral meristems formed under long-day conditions on elongating lateral branches in the upper leaf axils. The daily temperature influenced the variable CH/CL ratio of V. caspia in nature and greenhouse conditions. Regulation of the CL/CH flower ratio by modifying environmental factors is important for basic research on genetic/epigenetic regulation of cleistogamy and for practical use to produce genetically stable lines of economically important species via CL seeds.

scholarly journals Constraint of soil moisture on CO<sub>2</sub> efflux from tundra lichen, moss, and tussock in Council, Alaska, using a hierarchical Bayesian model

2014 ◽  
Vol 11 (19) ◽  
pp. 5567-5579 ◽  
Author(s):  
Y. Kim ◽  
K. Nishina ◽  
N. Chae ◽  
S. J. Park ◽  
Y. J. Yoon ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Soil Temperature ◽  
Co2 Emission ◽  
Emission Rate ◽  
Growing Season ◽  
The Arctic ◽  
Co2 Efflux ◽  
Growing Seasons ◽  
Tundra Ecosystem

Abstract. The tundra ecosystem is quite vulnerable to drastic climate change in the Arctic, and the quantification of carbon dynamics is of significant importance regarding thawing permafrost, changes to the snow-covered period and snow and shrub community extent, and the decline of sea ice in the Arctic. Here, CO2 efflux measurements using a manual chamber system within a 40 m × 40 m (5 m interval; 81 total points) plot were conducted within dominant tundra vegetation on the Seward Peninsula of Alaska, during the growing seasons of 2011 and 2012, for the assessment of driving parameters of CO2 efflux. We applied a hierarchical Bayesian (HB) model – a function of soil temperature, soil moisture, vegetation type, and thaw depth – to quantify the effects of environmental factors on CO2 efflux and to estimate growing season CO2 emissions. Our results showed that average CO2 efflux in 2011 was 1.4 times higher than in 2012, resulting from the distinct difference in soil moisture between the 2 years. Tussock-dominated CO2 efflux is 1.4 to 2.3 times higher than those measured in lichen and moss communities, revealing tussock as a significant CO2 source in the Arctic, with a wide area distribution on the circumpolar scale. CO2 efflux followed soil temperature nearly exponentially from both the observed data and the posterior medians of the HB model. This reveals that soil temperature regulates the seasonal variation of CO2 efflux and that soil moisture contributes to the interannual variation of CO2 efflux for the two growing seasons in question. Obvious changes in soil moisture during the growing seasons of 2011 and 2012 resulted in an explicit difference between CO2 effluxes – 742 and 539 g CO2 m−2 period−1 for 2011 and 2012, respectively, suggesting the 2012 CO2 emission rate was reduced to 27% (95% credible interval: 17–36%) of the 2011 emission, due to higher soil moisture from severe rain. The estimated growing season CO2 emission rate ranged from 0.86 Mg CO2 in 2012 to 1.20 Mg CO2 in 2011 within a 40 m × 40 m plot, corresponding to 86 and 80% of annual CO2 emission rates within the western Alaska tundra ecosystem, estimated from the temperature dependence of CO2 efflux. Therefore, this HB model can be readily applied to observed CO2 efflux, as it demands only four environmental factors and can also be effective for quantitatively assessing the driving parameters of CO2 efflux.

scholarly journals Growing Season Length as a Key Factor of Cumulative Net Ecosystem Exchange Over the Pine Forest Ecosystems in Europe

2015 ◽  
Vol 29 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Alina Danielewska ◽  
Marek Urbaniak ◽  
Janusz Olejnik
Keyword(s):  
Air Temperature ◽  
Measurement Data ◽  
Growing Season ◽  
Pine Forest ◽  
Pine Forests ◽  
Net Ecosystem Productivity ◽  
Ecosystem Productivity ◽  
Season Length ◽  
Important Species ◽  
Growing Season Length

Abstract The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m-2 y-1 per day of growing season, R2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R2 = 0.47, p = 0.058). The CO2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.

scholarly journals Responses of pea (Pisum sativum L.) to the rising atmospheric concentration of carbon-dioxide

2017 ◽  
pp. 185-188
Author(s):  
András Tamás ◽  
Ágnes Törő ◽  
Tamás Rátonyi ◽  
Endre Harsányi
Keyword(s):  
Carbon Dioxide ◽  
Environmental Factors ◽  
Atmospheric Carbon Dioxide ◽  
Photosynthetic Apparatus ◽  
Carbon Dioxide Concentration ◽  
Growing Season ◽  
Atmospheric Concentration ◽  
Pisum Sativum L ◽  
Key Factor ◽  
Carbon Dioxide Levels

The atmospheric concentration of carbon dioxide increases from decade to decade in increasing pace. In 1957, atmospheric carbon dioxide levels were around 315 ppm, while in 2012 it amounted to 394.49 ppm concentration. In parallel, the global temperature is rising,which is projected to average 1.5–4.5 °C. The carbon dioxide concentration is a key factor – in interaction with the light – affects the plant's photosynthesis. Among the various factors significant interactions prevail: environmental factors affect - the growth and the development of plants, leaf area size and composition, the function of the photosynthetic apparatus, the duration of growing season.

scholarly journals Rainfall in growing season determines the size of an annual-dominated soil seed bank in a desert ecosystem

2020 ◽  
Author(s):  
Ya-Fei Shi ◽  
Zengru Wang ◽  
Bing-Xin Xu ◽  
Jian-Qiang Huo ◽  
Rui Hu ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Growing Season ◽  
Seed Banks ◽  
Desert Ecosystem ◽  
Perennial Herb ◽  
Desert Ecosystems ◽  
Soil Seed Banks

Soil seed banks may offer great potential for restoring and maintaining desert ecosystems that have been degraded by climate change and anthropogenic disturbance. However, few studies have explored the annual dynamics in the composition and relative abundance of these soil seed banks. We conducted a long-term observational study to assess the effects of environmental factors (meteorology and microtopography) and aboveground vegetation on the soil seed bank of the Tengger Desert, China. The desert seed bank was dominated by annual herbs. We found that more rainfall in the growing season increased the number of seeds in the soil seed bank, and that quadrats at relatively higher elevations had fewer seeds. The species composition had more similarity in the seed bank than in the aboveground vegetation, though the seed bank and aboveground vegetation did change synchronously due to the rapid propagation of annuals. Together, our findings suggest that the combined effects of environmental factors and plant life forms determine the species composition and size of soil seed banks in deserts. Thus, if degraded desert ecosystems are left to regenerate naturally, the lack of shrub and perennial herb seeds could crucially limit their restoration. Human intervention and management may have to be applied to enhance the seed abundance of longer-lived lifeforms in degraded deserts.

scholarly journals Variability of pikeperch Sander lucioperca (L. 1758) cohorts in early life history

2019 ◽  
pp. 43
Author(s):  
Petr Blabolil ◽  
Martin Čech ◽  
Tomáš Jůza ◽  
Jiří Peterka
Keyword(s):  
Life History ◽  
Environmental Factors ◽  
Early Life ◽  
Early Life History ◽  
Zooplankton Abundance ◽  
Common Phenomenon ◽  
Sander Lucioperca ◽  
Fish Cohort ◽  
Slow Growing ◽  
Study Development

Year to year fluctuations in 0+ fish cohort strength are a common phenomenon. Many factors can affect cohort strength during the fish's early life period. In this study, development of a 0+ pikeperch Sander lucioperca cohort in the pelagic zone was studied by trawling for 50 days from first larvae hatching, in two consecutive years. In 2007, an abundant S. lucioperca cohort collapsed suddenly soon after hatching. After the incident, slow-growing S. lucioperca prevailed in the catch. In 2008, the catch gradually increased during the whole study period because of prolonged hatching. Environmental factors differed mainly in a slower temperature increase, higher water level and higher zooplankton abundance in 2008 compared to 2007. Our study revealed that a strong 0+ S. lucioperca cohort at the time of hatching might not result in a strong S. lucioperca cohort in general.

Copper nutrition of subterranean clover (Trifolium subterraneum L. cv. Seaton Park). I. Effects of copper supply on growth and development

1981 ◽  
Vol 32 (2) ◽  
pp. 257 ◽  
Author(s):  
DJ Reuter ◽  
AD Robson ◽  
JF Loneragan ◽  
DJ Tranthim-Fryer
Keyword(s):  
Root Growth ◽  
Growth And Development ◽  
Copper Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Growing Season ◽  
Internode Elongation ◽  
Plant Parts ◽  
Lateral Branches

Effects of severe and moderate copper deficiency on the development of leaves and lateral branches, on the distribution of dry weight within the plant, and on seed yield of Seaton Park subterranean clover were assessed as part of three glasshouse experiments. Copper deficiency markedly depressed top and root growth without producing any distinctive symptoms. It retarded phasic development by delaying development of leaves and lateral branches, senescence of plant parts, and flowering: it also depressed the proportion of stem plus petiole in plant tops and decreased internode elongation, pollen fertility and the number of burrs and seeds formed. As a result of its effect in delaying flowering, copper deficiency would depress seed production particularly strongly when low soil water supply shortens the growing season. The need for suitable procedures for diagnosing copper deficiency is emphasized by the lack of specific plant symptoms in this species.

Basic Science in Multiple Sclerosis Research

2016 ◽  
Author(s):  
Wendy Gilmore ◽  
Leslie P. Weiner
Keyword(s):  
Multiple Sclerosis ◽  
Animal Models ◽  
Environmental Factors ◽  
Disease Activity ◽  
Basic Science ◽  
Basic Research ◽  
Multiple Features ◽  
Research Questions ◽  
And Gender

Through the lens of basic science, this chapter provides an overview of research in multiple sclerosis, with a focus on progress and promise in the study of neuropathological and immunological characteristics of the disease and the influence of genetics, environmental factors, and gender. The stage for discussion is set with consideration for the challenges presented by the complexity and heterogeneity inherent in multiple features of the disease. Key research questions are identified and discussed, along with the importance of contributions from advancements in technology and from animal models. The chapter seeks to illuminate the overall goals of basic research, which are to develop new insights into the causes, triggers, and mechanisms of disease activity in multiple sclerosis and to translate them into strategies to prevent, treat, and ultimately cure this enigmatic disease.

Gigantism in tadpoles of the Neogene frogPalaeobatrachus

Paleobiology ◽  
2006 ◽  
Vol 32 (4) ◽  
pp. 666-675 ◽  
Author(s):  
Zbyněk Roček ◽  
Ronald Böttcher ◽  
Richard Wassersug
Keyword(s):  
Thyroid Gland ◽  
Environmental Factors ◽  
Growing Season ◽  
Tropical Species ◽  
Large Size ◽  
Ecological Features ◽  
Pathological Conditions ◽  
Seasonal Ponds ◽  
Pond Size ◽  
Pseudis Paradoxa

We describe three giant palaeobatrachid fossil tadpoles of the genusPalaeobatrachus(Nieuwkoop-Faber [NF] stages 60–64) from the Miocene of Randecker Maar, Germany. The largest was 150 mm at the beginning of metamorphosis (stage 60), whereas the smallest was 100 mm and approaching the end of metamorphosis (stage 64). In contrast, normal palaeobatrachid tadpoles and their pipid relatives, both extinct and extant, rarely exceed 60 mm in length. We review here both ecological and pathological conditions that are conducive to the development of gigantism in tadpoles. Tadpoles that lack a thyroid gland become exceptionally large and arrest development at early hindlimb stages (NF stages 53–56). However, the advanced metamorphic stages of the giantPalaeobatrachustadpoles indicate that they were able to metamorphose, and thus were not athyroid. Environmental factors—pond size and permanence, predators, duration of the growing season—may all contribute to tadpole gigantism in certain extant anuran species. We identify suites of ecological features that distinguish extant anurans with large tadpoles from high-latitude and high-altitude permanent lakes in temperate regions (e.g., certainRanaandTelmatobius) from tropical species, such asPseudis paradoxa, whose tadpoles normally achieve large size in temporary seasonal ponds. The paleoecology of Randecker Maar suggests thatPalaeobatrachustadpoles lived in a permanent semitropical lake, but one with few predators.

The relative importance of environmental factors on the interannual variability of carbon fluxes in the boreal forest

2020 ◽  
Author(s):  
Mariam El-Amine ◽  
Alexandre Roy ◽  
Pierre Legendre ◽  
Oliver Sonnentag
Keyword(s):  
Environmental Factors ◽  
Boreal Forest ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Carbon Sink ◽  
Growing Season ◽  
Carbon Uptake ◽  
Net Ecosystem Productivity ◽  
Ecosystem Productivity ◽  
Environmental Controls

&lt;p&gt;As climate change will cause a more pronounced rise of air temperature in northern high latitudes than in other parts of the world, it is expected that the strength of the boreal forest carbon sink will be altered. To better understand and quantify these changes, we studied the influence of different environmental controls (e.g., air and soil temperatures, soil water content, photosynthetically active radiation, normalized difference vegetation index) on the timing of the start and end of the boreal forest growing season and the net carbon uptake period in Canada. The influence of these factors on the growing season carbon exchanges between the atmosphere and the boreal forest were also evaluated. There is a need to improve the understanding of the role of the length of the growing season and the net carbon uptake period on the strength of the boreal forest carbon sink, as an extension of these periods might not necessarily result in a stronger carbon sink if other environmental factors are not optimal for carbon sequestration or enhance respiration.&lt;/p&gt;&lt;p&gt;Here, we used 31 site-years of observation over three Canadian boreal forest stands: Eastern, Northern and Southern Old Black Spruce in Qu&amp;#233;bec, Manitoba and Saskatchewan, respectively. Redundancy analyses were used to highlight the environmental controls that correlate the most with the annual net ecosystem productivity and the start and end of the growing season and the net carbon uptake period. Preliminary results show that the timing at which the air temperature becomes positive correlates the most strongly with the start of the net carbon uptake period (r = 0.70, p &lt; 0.001) and the start of the growing season (r = 0.55, p &lt; 0.01). Although the increase of the normalized difference vegetation index also correlates with the start of these periods, a thorough examination of this result shows that the latter happens well before the former. No dependency between any environmental control and the end of the net carbon uptake period was identified. Also, the annual net ecosystem productivity is highly correlated with the length of the net carbon uptake period (r = 0.54, p &lt; 0.01). Other environmental controls such as annual precipitations, the mean annual soil temperature or the maximum yearly normalized difference vegetation index have a smaller impact on the annual net ecosystem productivity. By extending the dataset to include forest stands that represent a wider climate and permafrost variability, we will examine the generalizability of these results.&lt;/p&gt;

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