Abstract Detail

Pteridology

Blake-Mahmud, Jennifer [1], Sessa, Emily [2], Visger, Clayton [3], Watkins, James [4].

Putting the dry in Dryopteris: transgressive response to drought and temperature stress in allopolyploid ferns.

Polyploidy is a widespread phenomenon in ferns and other land plants. Investigations of the effects of polyploidy usually center on sporophytes, due to their prominence in terrestrial ecosystems. Evidence has shown that allopolyploids often occupy broader ecological niches, have wider geographic distributions, and may display hybrid vigor, relative to their diploid progenitors. The degree to which these themes translate to the gametophytic life stage in ferns is less well understood. Because they lack a cuticle, gametophytes are in equilibrium with their external environment. This means that they may be particularly susceptible to increasing environmental stressors. We investigated the stress physiology of gametophytes from six related Dryopteris species: two tetraploids and their four diploid progenitors. Gametophytes were subjected to three levels of drought and heat stress over three days, and their recovery tracked for 72 hours. We found that in both related triads, gametophytes of the tetraploids withstood heat and drought stress better than their diploid parents, with D. campyloptera and D. celsa exhibiting transgressive phenotypes. In the D. intermedia – D. campyloptera – D. expansa triad, D. intermedia demonstrated the highest sensitivity to stress, which was surprising, given the prevalence of its sporophytes in the northeast forest understory. In the D. golidana – D. celsa – D. ludoviciana triad, drought proved to be the more significant stressor. All six species were able to withstand short periods (24 hours) of high temperature and low humidity stress. The strongest physiological responses arose after two and three days in high-temperature, low-humidity environments, with interactions playing a significant role. Overall, species varied in their stress response; some appeared to avoid temperature and/or drought induced stress, while others were unable to avoid its effects and ranged from sensitive to tolerant in their responses. As a free-living life stage in the alternation of generations, fern gametophytes play an integral role in the establishment and persistence of fern populations worldwide. Understanding how the terrestrial gametophytes of these Dryopteris species withstand complex environmental stress, and how this may be mitigated by ploidal level, is critical in the light of a changing climate.

1 - Colgate University, Biology, 13 Oak Drive, Hamilton, NY, 13346, United States
2 - University Of Florida, Biology, Box 118525, 521A Bartram Hall, Gainesville, FL, 32611, United States
3 - California State University Sacramento, Biological Sciences, 6000 J Street, Sacramento, CA, 95819, United States
4 - Colgate University, 13 Oak Dr, Biology Department 216 Olin Hall, Hamilton, New York, 13346, United States

Keywords:
Dryopteris
polyploidy
abiotic stress
heat stress
Drought
pteridiophytes
gametophytes
allopolyploid
climate change
transgression.

Presentation Type: Oral Paper
Session: PTR1, Pteridology I
Location: /
Date: Monday, July 19th, 2021
Time: 10:00 AM(EDT)
Number: PTR1001
Abstract ID:461
Candidate for Awards:Edgar T. Wherry award