Climate drives patterns of seed traits in Quercus species across China

Abstract

Traits enabling seeds to survive post-dispersal desiccation and subsequently germinate are important aspects of plant regeneration for species with desiccation-sensitive seeds. However, how desiccation and germination-related traits co-vary and relate to patterns of climate variation are unknown.We investigated physiological traits related to desiccation and germination of desiccationsensitive seeds from 19 Quercus species, which typically dominate subalpine, subtropical and temperate forests in China.The results demonstrate a strong relationship between climate and seed traits consistent with a hypothesis of minimizing seed death from desiccation. Seeds of subalpine species were most desiccation sensitive and died fastest when dried. These species avoided drought and cold by germinating rapidly. Subtropical and temperate oaks had more variable strategies to minimize the risk of mortality reflecting a continuum between traits that facilitate rapid germination (with the risk of rapid desiccation) and slow germination (and slow desiccation).Across the Quercus species, the relative level of seed desiccation sensitivity, which we predicted to be important for reducing the risk of drying related mortality, was independent of climate. For desiccation-sensitive seeds this suggests a more diverse range of strategies for minimizing desiccation risk than reported previously.

A chromosome-level genome assembly of the Chinese cork oak (Quercus variabilis)

“…Previous studies investigating Q. variabilis have mainly focused on its morphological characteristics (Du et al, 2021;Sun et al, 2021), its responses and adaptations to climate change (Gao et al, 2020;Xia et al, 2022), or its adaptive evolution and introgression, as assessed using whole genome resequencing (Fu et al, 2022). However, to date, no nuclear genomic resources are available for Q. variabilis.…”

The Co-Occurrence of Physiological and Epicotyl Physiological Dormancy in Three Desiccation-Sensitive Castanopsis (Fagaceae) Acorns from China with Specific Reference to the Embryonic Axis Position

“…This suggests that acorns maturing in different environments may show different responses to drying, regardless of the reason. This view is shared by Xia et al [66], who showed that acorns of Quercus from cold regions are more desiccation-sensitive than those from warmer areas. As a common feature across Fagaceae, the maternal environment in which the acorns mature influences their survival during drying.…”

The potential impacts of climate change on ex situ conservation options for recalcitrant-seeded species

“…In terms of seed storage, all oaks studied to date have recalcitrant seeds (Xia et al, 2012(Xia et al, , 2022Royal Botanic Gardens Kew, 2022); consequently, traditional long-term ex situ conservation in seed banks is not possible and thus require cryobiotechnological approaches (Walters et al, 2013;Ballesteros and Pritchard, 2020). Seed embryonic axes (with shoot and root meristems) are the preferred explants for oak cryopreservation as, analogously to conventional seed banking, high genetic diversity can be captured and axes can be grown into full plants with relatively simple micropropagation procedures (Ballesteros and Pritchard, 2020).…”

“…However, this environmentally-modulated response to cryopreservation of the oak seeds may not be shared among all species. For example, another study indicated that seed of subalpine oak species from China were most desiccation sensitive and died faster when dried than subtropical and temperate oak from the same country (Xia et al, 2022), suggesting the opposite trend found for North American and Mediterranean species (Xia et al, 2012;Amimi et al, 2020).…”