Complex Combination of Seed Dormancy and Seedling Development Determine Emergence of Viburnum tinus (Caprifoliaceae)

Abstract

It is concluded that V. tinus does not have epicotyl dormancy. Instead, there is a combination of a weak morphophysiological dormancy and a slow germination process, where different temperatures during an annual cycle favour different development stages. The present study suggests that the first complete seedlings would emerge in the field 1.5 years after fruit maturation in October, i.e. seed dispersal during winter, embryo growth during the first summer, root protrusion and establishment during the second autumn and winter, and cotyledon emergence during the second spring.

Some considerations for adoption of Nikolaeva's formula system into seed dormancy classification

“…Further, depending on temperature regime, including that simulated for the natural habitat of V. tinus, there was about a 6-15 week delay in epicotyl growth in seeds with emerged radicles. Thus, the phenology of germination fits very well that of epicotyl dormancy, as Karlsson et al (2005) acknowledge. Neither radicles nor epicotyls emerged at constant 58C, and cold stratification was not required to break dormancy in epicotyls in seeds with radicles that had emerged at the higher temperature regimes.…”

“…While we agree that seeds of V. tinus do not have deep simple epicotyl MPD, we do not agree that they lack epicotyl dormancy. Thus, based on the results of Karlsson et al (2005), we suggest that seeds of V. tinus have non-deep simple epicotyl MPD, i.e. C 1b B(root)-C 1b (epicotyl).…”

Soil disturbance, vegetation cover and the establishment of the exotic shrub Pyracantha coccinea in southern France

“…In Mediterranean-type ecosystems, post-germination establishment is severely limited by long, dry summer periods, particularly for woody species (Herrera 1992). Dormancy prevents seeds from germinating in the hot, dry season (Schültz 1999) and is a common trait in seeds of many species from mediterranean environments, such as Prunus avium (Oukabli and Mahhou 2007), Virburnum tinus (Karlsson et al 2005) and Ulex parviflorus (Baeza and Vallejo 2006). P. coccinea lacks a marked seed dormancy mechanism, which increases its vulnerability to droughts and may thus hamper its establishment in our study region.…”

Temperature control of seed germination in Fritillaria tubiformis subsp. moggridgei (Liliaceae) a rare endemic of the South-west Alps

“…Timing of seedling emergence is mainly regulated by the dormancy mechanism and germination (radicle emergence) preferences of the seed (Vandelook et al, 2009). However, after the seeds have germinated, there may also be a delay before seedling emergence due to either epicotyl dormancy (Baskin and Baskin, 1998) or a slow rate of growth (Karlsson et al, 2005) Like other species in the Liliaceae (Kondo et al, 2006), the embryos within the seeds of F. tubiformis are underdeveloped at the time of seed dispersal; the embryos need to grow to a critical length within the seed before germination can occur. Such a requirement for embryo growth prior to germination has been called morphological dormancy (Nikolaeva, 1977) and has been reported for species from seven of the nine genera of Liliaceae (Kondo et al, 2006).…”