Modeling the Influence of Genetic and Environmental Variation on the Expression of Plant Life Cycles across Landscapes

2015 ◽  
Vol 185 (2) ◽  
pp. 212-227 ◽  
Author(s):  
Liana T. Burghardt ◽  
C. Jessica E. Metcalf ◽  
Amity M. Wilczek ◽  
Johanna Schmitt ◽  
Kathleen Donohue
Keyword(s):  
Environmental Variation ◽  
Life Cycles ◽  
Plant Life

Reproduction in Plant Life Cycles

Biology ◽  
1998 ◽  
pp. 235-253
Author(s):  
Julian Sutton
Keyword(s):  
Life Cycles ◽  
Plant Life

scholarly journals A fish for all seasons: Spatial and temporal variation in patterns of demographic heterogeneity for Retropinna retropinna

2021 ◽  
Author(s):  
◽  
Christopher McDowall
Keyword(s):  
Population Dynamics ◽  
Seasonal Variation ◽  
New Zealand ◽  
Age Structure ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Environmental Variation ◽  
Life Cycles ◽  
Demographic Heterogeneity ◽  
Demographic Attributes

<p>Demographic heterogeneity can have big effects on population dynamics, but for most species we have limited understanding of how and why individuals vary. Variation among individuals is of particular importance for stage-structured populations, and/or where species have ‘complex life-cycles’. This is especially relevant in the case of amphidromous fishes that typically spawn in river mouths and estuaries, develop at sea and return to freshwater to finish development. These fish face strong selection pressures as they negotiate challenges around dispersal and development in order to reproduce successfully. Quantifying variation amongst individual fish can improve understanding of their population dynamics and suggest possible drivers of variation.  I evaluate patterns and sources of variation in demographic attributes of the New Zealand smelt (Retropinna retropinna). R. retropinna is an amphidromous fish that is endemic to New Zealand. While most populations have a sea-going larval stage, a number of landlocked freshwater populations occur, with the largest landlocked population residing in Lake Taupo. Here R. retropinna are presented with a variety of littoral feeding/spawning habitats and environmental conditions that may vary across distinct regions of the lake. In addition, the protracted spawning period for this species in Lake Taupo (occurring over eight months of the year) provides additional scope for seasonal variation to influence demographic attributes of individuals.  I sampled R. retropinna from discrete coastal habitats (beach or river) that were located in the eastern, southern and western regions of the lake. I evaluated patterns of variation in the size-structure, age-structure and morphology of R. retropinna among habitats and/or regions across Lake Taupo. I used otoliths to reconstruct demographic histories (ages, growth rates, hatch dates) of individuals, and used a set of statistical models to infer spatial variation in demographic histories. I found differences in size and age structure between regions, and a temporal effect of hatch date on larval/juvenile growth rates.  In addition, I obtained samples of R. retropinna from a sea-going population at the Hutt river mouth (sampled fish were presumed to be migrating upstream after their development period in Wellington Harbour and/or adjacent coastal environments). While Lake Taupo is large, deep, fresh, oligotrophic and strongly stratified for 8-9 months outside of winter, Wellington Harbour is less than a sixth of the area, shallow, saline, eutrophic and never stratified. These greatly differing environmental conditions led me to expect that these systems’ R. retropinna populations would carry significantly different demographic attributes. I compared the hatching phenology, recruitment age, body morphology, and individual growth histories (reconstructed from otoliths) of R. retropinna sampled from Lake Taupo and Wellington Harbour. I explored the relationships between demographic variation and environmental variation (water temperature, chlorophyll a) for the two systems and found that this additional environmental information could account for much of the seasonal variation in daily otolith increment widths of R. retropinna. My results also suggest that while the two sampled populations likely share similar hatching and spawning phenologies, individuals from Lake Taupo tend to grow more slowly, particularly during winter, and end up smaller than sea-going fish sampled near Wellington. I speculate that these differences reflect variation in food supply (zooplankton may be limited in Lake Taupo over winter).  Overall, my results demonstrate a high degree of variation in morphological and life-history traits within a single species, potentially driven by an interaction between environmental variation and timing of development. My work contributes to a growing body of literature on demographic heterogeneity, and may help to inform the management of landlocked populations of R. retropinna in Lake Taupo.</p>

scholarly journals History and contemporary significance of the Rhynie cherts—our earliest preserved terrestrial ecosystem

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160489 ◽  
Author(s):  
Dianne Edwards ◽  
Paul Kenrick ◽  
Liam Dolan
Keyword(s):  
Terrestrial Ecosystem ◽  
Analytical Techniques ◽  
Land Plant ◽  
Life Cycles ◽  
Systems Science ◽  
Developmental Genetics ◽  
Earth Systems ◽  
Plant Life ◽  
Rhynie Chert ◽  
Tissue Systems

The Rhynie cherts Unit is a 407 million-year old geological site in Scotland that preserves the most ancient known land plant ecosystem, including associated animals, fungi, algae and bacteria. The quality of preservation is astonishing, and the initial description of several plants 100 years ago had a huge impact on botany. Subsequent discoveries provided unparalleled insights into early life on land. These include the earliest records of plant life cycles and fungal symbioses, the nature of soil microorganisms and the diversity of arthropods. Today the Rhynie chert (here including the Rhynie and Windyfield cherts) takes on new relevance, especially in relation to advances in the fields of developmental genetics and Earth systems science. New methods and analytical techniques also contribute to a better understanding of the environment and its organisms. Key discoveries are reviewed, focusing on the geology of the site, the organisms and the palaeoenvironments. The plants and their symbionts are of particular relevance to understanding the early evolution of the plant life cycle and the origins of fundamental organs and tissue systems. The Rhynie chert provides remarkable insights into the structure and interactions of early terrestrial communities, and it has a significant role to play in developing our understanding of their broader impact on Earth systems. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals Completing the cycle: maternal effects as the missing link in plant life histories

2009 ◽  
Vol 364 (1520) ◽  
pp. 1059-1074 ◽  
Author(s):  
Kathleen Donohue
Keyword(s):  
Maternal Effects ◽  
Environmental Effects ◽  
Life Histories ◽  
Life Cycles ◽  
Seed Traits ◽  
Genetic Determination ◽  
Population Growth Rates ◽  
Plant Life ◽  
Maternal Genotype ◽  
Germination Behaviour

Maternal effects on seed traits such as germination are important components of the life histories of plants because they represent the pathway from adult to offspring: the pathway that completes the life cycle. Maternal environmental effects on germination influence basic life-history expression, natural selection on germination, the expression of genetic variation for germination and even the genes involved in germination. Maternal effects on seed traits can even influence generation time and projected population growth rates. Whether these maternal environmental effects are imposed by the maternal genotype, the endosperm genotype or the embryonic genotype, however, is as yet unknown. Patterns of gene expression and protein synthesis in seeds indicate that the maternal genotype has the opportunity to influence its progeny's germination behaviour. Investigation of the phenotypic consequences of maternal environmental effects, regardless of its genetic determination, is relevant for understanding the variation in plant life cycles. Distinguishing the genotype(s) that control them is relevant for predicting the evolutionary trajectories and patterns of selection on progeny phenotypes and the genes underlying them.

How land plant life cycles first evolved

Science ◽  
2017 ◽  
Vol 358 (6370) ◽  
pp. 1538-1539 ◽  
Author(s):  
Paul Kenrick
Keyword(s):  
Land Plant ◽  
Life Cycles ◽  
Plant Life

scholarly journals DELAY OF GERMINATION1 (DOG1) regulates both seed dormancy and flowering time through microRNA pathways

2016 ◽  
Vol 113 (15) ◽  
pp. E2199-E2206 ◽  
Author(s):  
Heqiang Huo ◽  
Shouhui Wei ◽  
Kent J. Bradford
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Life Cycles ◽  
Early Flowering ◽  
Developmental Phase ◽  
Loss Of Function ◽  
Transcript Levels ◽  
Plant Life ◽  
Plant Life Cycle ◽  
Delayed Flowering

Seed germination and flowering, two critical developmental transitions in plant life cycles, are coordinately regulated by genetic and environmental factors to match plant establishment and reproduction to seasonal cues. The DELAY OF GERMINATION1 (DOG1) gene is involved in regulating seed dormancy in response to temperature and has also been associated genetically with pleiotropic flowering phenotypes across diverse Arabidopsis thaliana accessions and locations. Here we show that DOG1 can regulate seed dormancy and flowering times in lettuce (Lactuca sativa, Ls) and Arabidopsis through an influence on levels of microRNAs (miRNAs) miR156 and miR172. In lettuce, suppression of LsDOG1 expression enabled seed germination at high temperature and promoted early flowering in association with reduced miR156 and increased miR172 levels. In Arabidopsis, higher miR156 levels resulting from overexpression of the MIR156 gene enhanced seed dormancy and delayed flowering. These phenotypic effects, as well as conversion of MIR156 transcripts to miR156, were compromised in DOG1 loss-of-function mutant plants, especially in seeds. Overexpression of MIR172 reduced seed dormancy and promoted early flowering in Arabidopsis, and the effect on flowering required functional DOG1. Transcript levels of several genes associated with miRNA processing were consistently lower in dry seeds of Arabidopsis and lettuce when DOG1 was mutated or its expression was reduced; in contrast, transcript levels of these genes were elevated in a DOG1 gain-of-function mutant. Our results reveal a previously unknown linkage between two critical developmental phase transitions in the plant life cycle through a DOG1–miR156–miR172 interaction.

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