Photoinhibition of seed germination: occurrence, ecology and phylogeny

Abstract

Light conditions provide important information about the best time and place for seedling establishment. Photoinhibition of seed germination (PISG), defined as the partial or complete suppression of germination under white light, has been interpreted as a physiological adaptation to avoid germination at or near the soil surface. This review is the first report of an all-inclusive, fully quantitative analysis of PISG in seed plants. Pertinent data available from the published literature for 301 taxa from 59 families and 27 orders were assessed. The association of PISG with several plant and seed traits allowed us to consider the adaptive significance of PISG in relation to plant life histories and the natural environments. As no gymnosperm has been found to be truly photoinhibited, it seems that PISG is apomorphic to flowering plants (especially monocots). Seeds of most taxa with PISG have a dark colour and intermediate mass, mostly in the range 1 to 27 mg. PISG is absent from humid tropical regions and from cold climates, but it is strongly associated with open, disturbed and dry habitats. An intriguing implication of PISG is the formation of a soil-surface seed bank. Taken together, these results clearly indicate that PISG is a physiological adaptation to avoid germination on the soil surface, where conditions are not suitable for seedling establishment. PISG is probably much more frequent in seed plants than previously thought. Thus, laboratory experiments should be conducted under well-characterized light and dark conditions

Seed germination protocols for six dune species from the Tyrrhenian coast (central Italy)

“…Our results, however, highlighted the ability of P. maritimum seeds to germinate in a wide range of temperatures (5-30°C) both in the dark (53-98%) and in the light (7-98%). Moreover, we observed a strong photoinhibition of seed germination exclusively at 5°C, with seeds weakly photoinhibited at T > 20°C, in accordance with Carta & al. (2017), and with no inhibition at 10-15°C.…”

“…2007). The lowest germination percentages were recorded at 5°C, where strong photoinhibition of seed germination was observed (Carta & al. 2017).…”

Male flowers in Tulipa pumila Moench (Liliaceae) potentially originate from gender diphasy

“…For an estimation of seed viability, we performed germination tests using 100 seeds for each pollination treatment. Seeds without embryos were discarded, whereas fully developed ones were sown on Petri dishes with 1% agar, at 7°C in the dark according to conditions found in the literature (Carta, Skourti, Mattana, Vandelook, & Thanos, ; Van Tuyl & Van Creij, ). Seeds were considered germinated only when the radicle reached 1 mm in length.…”

A research agenda for seed‐trait functional ecology

“…Notwithstanding early recognition of its importance (e.g. Martin, ; Grushvitzky, ), the phylogenetic signal of seed traits such as desiccation tolerance (Wyse & Dickie, ), dormancy (Willis et al ., ), embryoless seeds (Dayrell et al ., ), photo‐inhibition (Carta et al ., ), embryo size (Forbis et al ., ; Vandelook et al ., ) and germination temperature or moisture (Arène et al ., ) has only been recently quantified in such a way as to be accessible for statistical purposes. Indeed, many other seed traits may show correlations with phylogeny, and many more trait–trait relationships are likely to exist as well, for example between germination speed and seed persistence (Saatkamp et al ., ; Kadereit et al ., ).…”