Towards understanding the incidence and evolutionary history of seed recalcitrance: An analytical review

Tolerância à dessecação e armazenamento de sementes de Myrcianthes pungens (O. Berg) D. Legrand (Myrtaceae)

“…A conservação da viabilidade durante o armazenamento das sementes, principalmente com a descoberta de um número cada vez maior de sementes intolerantes à dessecação, denominadas recalcitrantes, tem sido um dos aspectos mais visados nos últimos anos (Linkies et al 2010, Marcos Filho 2015, Barbedo 2018, Barbedo & Santos Junior 2018, Magnani 2018, Lamont et al 2019, Subbiah et al 2019, Wu et al 2019.…”

Seed traits linked to differential survival of plants during the Cretaceous/Paleogene impact winter

“…Interestingly, this mechanism behind recalcitrant seeds (i.e., genetically based transcription factors that regulate abscisic acid inhibition) is widely recognized as being the general cause of seed recalcitrance in most plants included in this study (Farnsworth, 2000), particularly Austrobaileyales (Smiskova et al, 2005) and Laurales (Chen et al, 2020). The study done by Subbiah et al (2019) demonstrated that orthodoxy among these lineages evolved in the cooler, drier climates of the Cenozoic, so it is clear that recalcitrance among lauraceous species is the ancestral condition in this group. It is difficult to assign fossil species to Lauraceae exclusively; that is why most often these species are conservatively assigned to Laurales only (Upchurch, 1995;Pole and Vajda, 2009).…”

“…Most assignments were based on studies conducted by Wyse and Dickie (2017) that used the Kew (Royal Botanic Gardens) Seed Information Database or other contemporary studies to determine the incidence of seed recalcitrance among extant taxa. Subbiah et al (2019) recently studied the evolutionary lability of this trait through geologic time. They found that extant lineages with fossil records that extend into the Cretaceous first evolved this trait independently during Kauffman et al, 1990;Johnson, 2002;Barclay et al, 2003;Johnson et al, 2003;Berry, 2019a Lauraceae (cuticle) 3 Subbiah et al (2019) are supported by contemporary perspectives on the evolution of seed recalcitrance, as the high moisture content of these seeds produced by tropical phanerophytes in megathermal, equable climates with high precipitation/humidity precludes their long-term survival of seeds under drying and freezing conditions (Hong et al, 1997;Wyse and Dickie, 2017).…”

“…Subbiah et al (2019) recently studied the evolutionary lability of this trait through geologic time. They found that extant lineages with fossil records that extend into the Cretaceous first evolved this trait independently during Kauffman et al, 1990;Johnson, 2002;Barclay et al, 2003;Johnson et al, 2003;Berry, 2019a Lauraceae (cuticle) 3 Subbiah et al (2019) are supported by contemporary perspectives on the evolution of seed recalcitrance, as the high moisture content of these seeds produced by tropical phanerophytes in megathermal, equable climates with high precipitation/humidity precludes their long-term survival of seeds under drying and freezing conditions (Hong et al, 1997;Wyse and Dickie, 2017). Laurales, which in this study is regarded as producing recalcitrant seeds, is the only clade included in this study that does not exhibit monomorphism for seed recalcitrance among its extant members (Wyse and Dickie, 2017;Jaganathan et al, 2019).…”

“…This is because aboveground vegetation would have been destroyed by these severe climatic conditions (i.e., total darkness coupled with permafrost conditions) McLoughlin, 2004, 2007;Vajda and Bercovici, 2014), perhaps with a combination of syn-and post-impact wildfires caused by impact ejecta and the subsequent heat-pulse (Morgan et al, 2013). According to Subbiah et al (2019), the vast majority (92%) of plants with recalcitrant seeds are tropical phanerophytes -that is, large trees and shrubs that thrive in megathermal, equable climates with high precipitation/humidity (Huggett, 1998) that first evolved seed recalcitrance in response to global climatic conditions in the Late Cretaceous. To my knowledge, the hypothesis that recalcitrant-seeded plants were among those most affected by the K/Pg impact winter has never been tested.…”