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Description
The ability of a plant to cope with abiotic stress plays an important role in its survival
reproduction. Accelerated global warming has become a major abiotic stress and can negatively
impact the stability of plant population dynamics as well as agricultural productivity. Sexual
dimorphisms often displayed by dioecious species in their sexual features and sometimes in their
vegetative traits or structures (not related to sexual reproduction), can cause contrasting outcome
for thermotolerance in them. This can lead to biased population sex ratios. Currently, little is
known about the causes and mechanisms of plant population sex ratio biases[1], especially in
bryophytes (non-vascular plants).
Bryophytes are excellent candidates to study the sexual dimorphism under heat stress
because of their small size, simple structure, and ease of clonal reproduction. Additionally, as
early diversifying groups, comparative studies with other plant tax offer insights into the
evolution of thermotolerance. Here, I use Marchantia inflexa as the study organism, which has
unisexual individuals from the island of Trinidad, the republic of Trinidad and Tobago. This
tropical liverwort is an ideal candidate to study heat tolerance variations across populations as
they typically grow along moist, forested streams, and warm and drier roadsides [2].
Previous studies on M. inflexa revealed a sexual dimorphism in the basal
thermotolerance where male vegetative thallus (undifferentiated thallus) recovered faster
compared to female vegetative thallus from a brief heat stress [unpublished data]. However, each
life stage plays a different role and that could affect how they respond to stressors. I hypothesize
that differentiated vegetative thallus with sex structures would recover differently when
subjected to a heat stress based on their reproductive allocation and based on the stress level of
the habitat they grew.
Plants for this proposed study will be collected from previously studied sites in
Trinidad including four stream and three road populations. From each population 15 each male
and female undifferentiated and differentiated (with young sex structures) thallus tips will be
collected (~1 com long). Thalli will be taken to the research station, and the initial chlorophyll
fluorescence will be measured, which is a measure of the quantum efficiency of photosystem II
(Fv/Fm). Then the thallus tips will be heat stressed at 55C for 45 minutes and their recovery
Fv/Fm will be measured at four time points (right after, 24 hours after, 5 days after and 10 days
after). I predict that male differentiated thallus tips will recover faster compared to female
differentiated thallus, due to higher female investment in reproduction. And based on the habitat
I would predict further variations in male and female differentiated thallus. The results from this
study will contribute to the knowledge on how different life stages of M. inflexa respond and
recover from thermotolerance.
Status | Active |
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Effective start/end date | 6/10/24 → 6/9/25 |
Funding
- Sigma XI Scientific Research Society Inc: $987.00
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