How do plants hedge their bets?
2021-06-01
(Press-News.org) In some environments there is no way for a seed to know for sure when the best time to germinate is.
In spring, cues like light, temperature and water may suggest to seeds that conditions are optimal for germination, but a week later an unpredictable drought or frost could kill the emerging seedlings.
So how does a plant make sure that all of its offspring are not killed at once by an ill-timed environmental stress following germination?
There is evidence that some plant species produce seeds that germinate at different times to hedge their bets against this risk. Many species produce seeds that can enter a dormant state and exist in the soil for several years and some also produce seeds that germinate at different times within a season.
This means that if lethal environmental fluctuations do occur, a fraction of a plant's offspring will survive as seeds, which can go on to germinate at another time.
This variability in germination time can be seen even with genetically identical seeds grown in an identical environment.
In agriculture, the variability in germination time can be a problem when you want to harvest the whole crop at the same time. Instead, farmers have to monitor their crops' maturity, taking measurements from multiple individual plants to estimate when the best time is to harvest.
Scientists at the Sainsbury Laboratory Cambridge University (SLCU) used the model plant, thale cress (Arabidopsis thaliana), to ask: What makes genetically identical seeds germinate at different times?
"We already know that two plant hormones - abscisic acid (ABA) that inhibits germination and gibberellic acid (GA) that promotes germination - interact with each other to control the decision to germinate, but we wanted to know how this interaction creates variability in germination times between seeds", said Dr Katie Abley, researcher at SLCU and joint first author of the research published in eLife.
"By measuring the levels of variability in germination times for hundreds of genetically distinct strains of Arabidopsis, we were able to identify two regions of DNA (genetic loci) that control how variable germination time is. Both loci contain genes that influence how sensitive seeds are to ABA and testing mutants of these genes provided evidence that they regulate variability in germination timing."
Using this new information, the researchers generated a mathematical model of the ABA-GA network to understand how the interactions between ABA and GA could cause a batch of identical seeds to have a range of germination times. They wanted to understand how the network could give rise to different levels of variability in germination time.
"We found that changing ABA sensitivity in the model replicated the experimental germination time distributions that we observed", explained Dr Pau Formosa-Jordan, joint first author and now research group leader at Max Planck Institute for Plant Breeding Research in Cologne, Germany.
"In the model, groups of seeds with higher sensitivity to ABA germinate in a more spread-out way because, upon sowing, each one of these seeds relies on stochastic fluctuations in the ABA-GA network to switch from a non-germination state to a germination state - which is known as a bistable switch behaviour. Yet, seeds with lower sensitivity to ABA more rapidly and synchronously get to the germination state after being sown, without the need for the stochastic fluctuations. Our stochastic model suggests an ABA-GA bistable switch can generate variability in germination times, with the germination time being influenced by stochastic fluctuations in the levels of hormones."
While the researchers expect there to be other genetic and biophysical effects at play that affect variability in germination time, their findings show that this plant trait is genetically controlled and high or low variability in germination times could, therefore, be specifically selected for in crop breeding programmes or to rehabilitate natural areas with highly variable environments.
INFORMATION:
Reference
Katie Abley, Pau Formosa-Jordan, Hugo Tavares, Emily Y. T. Chan, Mana Afsharinafar, Ottoline Leyser, James C. W. Locke (2021) An ABA-GA bistable switch can account for natural variation in the variability of Arabidopsis seed germination time, eLife.
DOI: https://doi.org/10.7554/eLife.59485
Funding
This research was supported by the Gatsby Charitable Foundation.
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-06-01
Research by scientists from University of Southampton (UK) and the Central University of Jharkhand (India) and has shown the first COVID-19 lockdown in India led to an improvement in air quality and a reduction in land surface temperature in major urban areas across the country.
The study found that travel and work restrictions imposed early in the pandemic resulted in a significant environmental improvement, due to an abrupt reduction in industrial activities and a major decrease in the use of land and air transport.
The international team used data from a range of Earth Observation sensors, including those from the European Space Agency's Sentinel-5p and NASA's MODIS sensors, to measure changes in surface temperature and atmospheric ...
2021-06-01
Efforts to contain the novel coronavirus have caused lockdowns and school closures around the world. These efforts and policies have unfortunately cut off many children from valuable resources such as the opportunity for exercise, access to clean water and food, learning, and socialization. Therefore, the effects on mental health and behavior may be found not just in adults but children. However, studies published thus far have been limited to elucidating the mood of middle school and high school students and the conditions for which mood problems occur ...
2021-06-01
Drinking straws are single use plastic products which will be subjected to a Europe-wide sales ban from 2021 onwards. This is stated in EU Directive 2019/904 from 5 June 2019. Consequently, alternative materials have to be established for the production of drinking straws as well as other frequently used products which predominantly were made of plastic so far.
As set out in the EU Framework Regulation for food contact material (Regulation (EC) No. 1935/2004), objects that come into direct contact with food must be safe. The German Federal Institute for Risk Assessment (BfR) has appraised straw, silicone, metal, paper and paper-board, durum wheat, and glass for their suitability to replace plastic ...
2021-06-01
Using a brain-training app helps people eat less junk food and lose weight, new research suggests.
The Food Trainer (FoodT app) trains people to tap on images of healthy foods - but to stop when they see unhealthy snacks, creating an association between these foods and stopping.
The new study, by the universities of Exeter and Helsinki, found that playing the game about once a day for a month led to an average one-point reduction of junk food consumption on an eight-point scale (the scale ranges from four or more items per day, to one or zero items per month).
Overall, people who used the app more also ...
2021-06-01
Parkinson's disease (PD) is a common neurodegenerative disorder caused by the death of dopaminergic neurons in a part of the brain (known as substantia nigra pars compacta), which leads to a deficit of dopamine (DA), one of the main neurotransmitters active in the central nervous system. Symptomatic treatment focuses on increasing the concentration of dopamine into the brain.
However, dopamine is not directly administered, because it is unable to cross the so called blood-brain barrier, which prevents some of the substances circulating in the blood to penetrate into the nervous system. Thus, DA precursor levodopa (L-DOPA) -an amino-acid which participates ...
2021-06-01
Announcing a new article publication for BIO Integration journal. In this article the authors Craig S. Carlson and Michiel Postema, from University of the Witwatersrand, Johannesburg, South Africa and Tampere University, Tampere, Finland discuss deep impact of superficial skin inking: acoustic analysis of underlying tissue.
Skin tattoos are a common decoration, but profound scientific study on whether a skin tattoo alters the acoustic response from superficial tissues, and therefore from underlying tissue, was previously lacking; thus, any quantitative effects were unknown.
This study is the first to investigate the nature of artifacts in ultrasound images, which have been observed to originate from tattooed skin. The work was conducted theoretically and experimentally using ...
2021-06-01
June 1, 2021 -- Researchers at Columbia University Mailman School of Public Health and Universidade Federal de Ciências da Saúde de Porto Alegre, Brazil found that when health workers were trained to promote infant healthy feeding practices to pregnant women their children consumed less fats and carbohydrates at 3 years of age and had lower measures of body fat at the age of 6. The study is the first to show that the roots for obesity start in the first year of life, after mothers stop breastfeeding. The findings are published online in the Journal of Human Nutrition and Dietetics.
"The first year after ...
2021-06-01
Aging is associated with an overall decline in health and increased frailty, and is a major risk factor for multiple chronic diseases. Frailty syndrome, characterized by weakness, fatigue and low physical activity, affects more than 30% of the elderly population. Increasing our understanding of the mechanisms underlying the aging process is a top priority to facilitate the development of interventions that will lead to the preservation of health and improvements on survival and lifespan.
Cumulative evidence suggests that diet and metabolism are key targetable regulators of healthy lifespan. Prof. Haim Cohen, Director of the Sagol Healthy Human Longevity Center at Bar-Ilan University, ...
2021-06-01
This is the main finding of new research involving more than 50,000 participants in 97 samples, published in the prestigious journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).
The findings show that the more extreme choices and decisions of men can be both positive and negative.
"The question of whether men and women make systematically different choices and decisions is one on the most fundamental (and controversial) questions in psychological research," Associate Professor Stefan Volk from the University of Sydney Business School said.
"We found men were much more likely than women to be at the extreme ends of the behavioural spectrum, either acting very ...
2021-06-01
Investigators from Trinity College Dublin, the Irish Mycobacteria Reference Laboratory, St James's Hospital, and the Department of Public Health HSE East believe tuberculosis (TB) care in Irish Prisons should be supported, considering the findings of their study which is published today (Tuesday, 1st June, 2021) in the International Journal of Tuberculosis and Lung Disease.
The study describes an investigation into a large outbreak of tuberculosis which occurred in an Irish prison in 2011. This resulted in 34 people contracting active TB from a single infectious case. The use of Whole Genome Sequencing enabled ...
LAST 30 PRESS RELEASES:
[Press-News.org] How do plants hedge their bets?
