Sympatric species of Hibbertia (Dilleniaceae) vary in dormancy break and germination requirements: implications for classifying morphophysiological dormancy in Mediterranean biomes

Abstract

Although the study species are con-generic, sympatric and produce seeds of identical morphology, they possessed different dormancy-break and germination requirements. The physiological component of MPD was non-deep in H. racemosa but varied in the other three species where more deeply dormant seeds required >1 summer to overcome dormancy and, thus, germination was spread over time. Embryos grew during winter, but future studies need to resolve the role of cold versus warm stratification by using constant temperature regimes. To include Mediterranean species with MPD, some modifications to the current seed-dormancy classification system may need consideration: (a) wet/dry conditions for warm stratification and (b) a relatively long period for warm stratification. These outcomes have important implications for improving experimental approaches to resolve the effective use of broadcast seed for ecological restoration.

Overcoming physiological dormancy in seeds of Triodia (Poaceae) to improve restoration in the arid zone

“…Yet, the rate of dormancy loss was species‐specific, and varied amongst florets and seeds. Differences in germination patterns, KAR 1 response, and dormancy breaking treatments amongst con‐generic, sympatric species is consistently observed (Turner et al ; Hidayati et al ) and it is not uncommon to find large variations in dormancy levels between individuals, populations, and collection years within the same species (Andersson & Milberg ; Long et al ). The distinct difference in temperature sensitivity, DAR, and KAR 1 response between florets and seeds in the two populations of T. wiseana , as well as across the remaining Triodia species assessed in this study, highlights this variation and shows that a good understanding of the seed biology and ecology of target species is highly desirable for enhancing restoration outcomes.…”

“…Taken together, these phenomena indicate a widening of environmental conditions that are suitable for germination as dormancy is lost during DAR. In this way, the risks associated with germination and seedling establishment are spread through time (Hidayati et al ), potentially over several growing seasons if seeds after‐ripen in the soil in a similar manner and speed to that observed in laboratory DAR conditions.…”

<i>In Vitro</i> Seed Germination and Embryo Culture in <i>Nothapodytes foetida</i> (Wight) Sleumer

“…Mainly in N. foetida dormancy is due to physical presence of seed coat, physiological condition and presence of phenolic compounds at high extent in seed coat and in such a way results into inhibition of germination resulting in poor germination frequency in vitro (Sharma et al, 2000;Khan 2013). Depending on the plant species and type of dormancy, various methods like scarification, stratification, removal of inhibitors and treatment with growth regulators are used to break dormancy (Baskin and Baskin 1998;Hidayati et al, 2012). Soaking in water prior to sowing is also known to enhance germination percent and rate in different tree species (Bedell 1998).…”

Biodiversity hotspots and Ocbil theory

“…microrefugia and climate change (Cooper et al 2011;Keppel et al 2012;Ashcroft and Gollan 2013;Brendonck et al 2014;Mee and Moore 2014;Barrett and Yates 2015), the evolution of trees (Raven and Andrews 2010;Cramer 2012), clonality (Binks et al 2015), the occurrence of OCBISs (old, climatically buffered, infertile seascapes - Langlois et al (2012), significant gaps in Darwinian evolutionary theory (Hopper and Lambers 2009), old salt lake systems (Bui et al 2014a, b), and evolution of novel aquatic traits (Tuckett et al 2010;Davies and Stewart 2014). Seed biological studies are beginning to explore the relevance of Ocbil theory to their discipline (Tuckett et al 2010;Hidayati et al 2012;Wilman et al 2014;Alvarado et al 2015b;Edwards et al 2015;Ribeiro et al 2015).…”

“…x Four species of Hibbertia (Dilleniaceae) Hidayati et al (2012) x Aust 176 species, exceptionally long-lived seed from SWAFR Merritt et al (2014) x 15 grassland species of Cyperaceae, Poaceae, Velloziaceae, Xyridaceae, and Asteraceae…”