The epiphytic resurrection—or desiccation-tolerant (DT)—fern Pleopeltis polypodioides can survive extreme desiccation and recover physiological activity within hours of rehydration. Yet, how epiphytic DT ferns coordinate between deterioration and recovery of their hydraulic and photosynthetic systems remains poorly understood. We examined the functional status of the leaf vascular system, chlorophyll fluorescence, and photosynthetic rate during desiccation and rehydration of P. polypodioides. Xylem tracheids in the stipe embolized within 3-4 hours during dehydration. When the leaf and rhizome received water, tracheids refilled after approximately 24 hours, which occurred along with dramatic structural changes in the stele. Photosynthetic rate and chlorophyll fluorescence recovered to pre-desiccation values within 12 hours of rehydration, regardless of whether fronds were connected to their rhizome. Our data show that the epiphytic DT fern P. polypodioides can utilize foliar water uptake to rehydrate the leaf mesophyll and recover photosynthesis despite a broken hydraulic connection to the rhizome.

The earliest vascular plants had stems with a central cylindrical strand of water-conducting xylem, which rapidly diversified into more complex shapes. This diversification is understood to coincide with increases in plant body size and branching; however, no selection pressure favoring xylem strand-shape complexity is known. We show that incremental changes in xylem network organization that diverge from the cylindrical ancestral form lead to progressively greater drought resistance by reducing the risk of hydraulic failure. As xylem strand complexity increases, independent pathways for embolism spread become fewer and increasingly concentrated in more centrally located conduits, thus limiting the systemic spread of embolism during drought. Selection by drought may thus explain observed trajectories of xylem strand evolution in the fossil record and the diversity of extant forms.

Premise Water deficit and drought conditions are increasing in intensity, frequency, and duration in the Iberian Peninsula. We observed natural variation in leaf traits across the range of Quercus suber L. (cork oak), an ecologically important species within this region. Stomatal traits (e.g., pore length, maximum aperture) and carbon isotope composition (δ13C) provide an opportunity to examine the integrative effects of drought and dry‐season intensity on leaf development, maximum stomatal conductance, and adaptation to precipitation regimes. Methods Gross leaf traits (e.g., area, thickness), stomatal traits (e.g., pore length, size, aperture), and carbon isotope discrimination were measured in Q. suber leaves, and maximum stomatal conductance to water vapor (gwmax) was calculated. Trees were sampled from nine natural populations across a climate gradient in the Iberian Peninsula, including trees from two genetic lineages. Linear mixed models compared total water deficit to leaf traits, accounting for tree and site as random effects. Results Quercus suber gross leaf morphology remained consistent across the climate gradient, but increasing water deficit was correlated with smaller stomata at the leaf level and low δ13C at the tree level. No traits were significantly different between the two genetic lineages. Conclusions While there were no significant differences in gross leaf morphology across the climate gradient or between the genetic lineages, stomatal traits and δ13C responded to climate, suggesting that Q. suber can inhabit a range of environments in the Iberian Peninsula via micro‐adjustments of the trait that controls water loss into the atmosphere.

The current academic ‘ecosystem’ prioritizes publications and has remained in this stable state despite increasing calls for change. Although writing is a strong determinant of academic success, certain groups may experience publishing barriers that may be amplified by disruptive events like the COVID-19 pandemic. Here we surveyed 342 graduate students and postdoctoral scholars to assess (1) how identity predicted publishing outputs and (2) how the pandemic influenced feelings of writing productivity based on identity. We show that there were differential publication totals across identities. Respondents reported feeling less productive and motivated during the pandemic, despite having more time to write. BIPOC graduate students reported being the most negatively impacted. Since the pandemic disproportionately affected historically excluded groups, we urge the academic ‘ecosystem’ to transition away from an overemphasis on publication outputs and reach a new, more equitable stable state that evaluates accomplishments more holistically.