Georgia Hernández Corrales: Closely related tropical herbs have similar tolerance to high temperatures

In our newest post Georgia Hernández Corrales—PhD candidate at University of Connecticut, USA—presents her work ‘Evolutionary history constrains heat tolerance of native and exotic tropical Zingiberales’. She discusses the importance of evolutionary history for plant physiology, shares the beauty of tropical forests, and highlights the importance of mentorship for a happy start in research.

About the paper

Lowland forests are one of the warmest ecosystems in the tropics. However, temperatures range from very high in forest gaps and other open areas, to cooler temperatures in forest understories. Our study explored if plants’ heat tolerance is the result of adaptation to the temperature of different habitats, or if heat tolerance is determined by the suite of traits inherited from shared ancestors. If some branches in the tree of life are more tolerant to increasing temperatures, they might be the winners of the survival race against global warming.

Georgia Hernández (lead author) collecting leaves at the field site, la Selva Biological Station (credit: Raquel Castro).

To answer these questions, we selected the “banana-like” plants (order Zingiberales)—a group of charismatic herbs that includes the bananas, heliconias, birds of paradise and gingers. This group is well known in the tropics for its use as a medicinal plant, food, and even as a shampoo.

This study represents a contribution to the understanding of biotic responses to global warming, because it combines plant physiological estimates of heat tolerance with phylogenetic analyses. Plant heat tolerance is a quick and useful method to test the limits of photosynthetic failure and it has gained popularity in recent years.

I think this paper is useful for people in the field of ecophysiology and temperature ecology. Our study also provides a comparison of heat tolerance among exotic and native species at La Selva Biological Station, Costa Rica. We hope that this is just a first attempt to compare exotic species and their capability to tolerate heat damage against local plant species.

About the research

Two main contributions of our study to the broader discipline include that heat tolerance is not constrained by habitat temperatures, but instead determined by evolutionary relationships. We were surprised that the effect of local temperature on heat tolerance was not associated with plants in any of the habitats (open areas, secondary forest and secondary forest). Biodiversity loss by climate change might not be randomly distributed across the tree of life.

An interesting twist in our study is that the focal plant community of our study also includes exotic Zingiberales species. This represented a unique opportunity to test if exotic plants are more tolerant to increasing temperatures than native species at La Selva Biological Station, Costa Rica.

Our results indicate that exotic species can tolerate only marginally higher initial damage to their photosynthetic apparatus than native species. The consequence of such differences for survival and fitness remains unknown but might determine which species will tolerate future temperatures in a warming world.

I think a big question still to be answered is what the role of heat tolerance in sustaining stress is, its relation to survival, and how plants deal with changes in temperature in the short and long run. The next step in my research is to understand how plastic heat tolerance is to temperature increase pertaining to local temperature. I am currently estimating thermal limits for many of these species along an elevational gradient. The results will show how populations respond to changes in temperature and its effect on heat tolerance.

About the research

Georgia Hernández (lead author) collecting leaves of Goeppertia micans (credit: Constantino Hernández Cordero)

I got involved in the field of ecology by working in Dr. Roberto Cordero’s lab (LEFET) as an undergrad at the Universidad Nacional, Costa Rica. In Roberto’s lab, I was introduced to the field of ecophysiology and I learned the methods that are key to my current research. During my undergraduate studies I was amazed by the link between physiological methods at the leaf level with ecological questions and broader ecosystem patterns.

Besides learning about how to conduct research, in Cordero’s lab I learned that science is highly collaborative and creating a great environment for undergrads and grad students to share their ideas is paramount for growth as a researcher. The support from my mentors and other students at the lab were crucial for enabling me to find my own path in the field and continue my studies as a PhD student.

After finishing my undergrad in Costa Rica, I started my PhD at the University of Connecticut, USA, under the advice of Dr. Carlos Robledo-García. Currently, I am working on determining the physiological patterns and demographic mechanisms associated with plant heat tolerance.

Enjoyed the blogpost? Read the research here!

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