A comparison of maturation drying, germination, and desiccation tolerance between developing seeds of Acer pseudoplatanus L. and Acer platanoides L

Abstract

SUMMARYDifferences in maturation drying and desiccation tolerance during seed development were detected between the two contrasting Acer spp., Norway maple (Acer platanoides L.), which shows orthodox seed storage behaviour, and sycamore (A. pseudoplatanus L.), which shows recalcitrant seed storage behaviour. In both species, the onset of germinability (150 d tests at 5 °C) occurred after percentage seed moisture content had begun to decline, but before net loss in seed moisture. The onset of germinability in Norway maple occurred 4 wk before physiological maturity (i.e. 4 wk before the end of the increase in seed dry matter), whereas in sycamore it occurred some ten weeks before physiological maturity when the seeds were only 60 % filled. Seeds of Norway maple were able to tolerate enforced rapid desiccation to 10% moisture content (f. wt) at physiological maturity, when maturationdrying had reduced seed moisture content to 54 %. Between 2 and 4 wk later seed moisture content rapidly declined naturally to 25 %, at which value the fruits were shed. In contrast, a constant rate of maturation-drying was observed in sycamore. The seeds were shed at 58 % moisture content and, in almost all cases, the seeds were intolerant of rapid desiccation to c. 10 % moisture content throughout seed development. A very small proportion of sycamore seeds did survive rapid desiccation when harvested between 6 September and 4 October, but no seeds survived desiccation to 5 % moisture content or below. A comparison of the germination of sycamore seeds harvested on four dates and dried to various moisture contents showed that the seeds tolerated greater desiccation as they matured between 12 July and 20 September, but there was no further change thereafter. The results are therefore compatible with previous classifications of seed storage behaviour in each species, and with the view that the initial decline in seed moisture content stimulates the developmental switch which results in the onset of germinability in both orthodox and recalcitrant seeds.

Cryopreservation changes the DNA methylation of embryonic axes of Quercus robur and Fagus sylvatica seeds during in vitro culture

“…To date, successful freezing in LN 2 has been reported for EAs in recalcitrant seeds of Acer pseudoplatanus (Pukacki and González-Benito et al 2002). Seeds from the suborthodox category are intermediate between the orthodox and recalcitrant categories and show a high sensitivity to low temperatures between 0 and -20°C (Hong and Ellis 1990). Suborthodox seeds fall from the trees highly hydrated because they are not subject to natural dehydration (Berjak and Pammenter 2008).…”

Impacts of warming and changes in precipitation frequency on the regeneration of two Acer species

“…It is thus very likely that these species will be affected differently by climate change. Changes in the soil moisture content might also differently affect the seeds because the seeds of A. platanoides are considered orthodox (desiccation-tolerant), while A. pseudoplatanus' seeds are recalcitrant (desiccation sensitive) (Hong and Ellis, 1990). Also dormancy break might be affected by climate change, as warming may reduce the number of cold days.…”

Conservation Biology for Seven Palm Species from Diverse Genera

“…louisiana when dried. Maturation during drying is also known to improve seed quality traits in some desiccation-tolerant species (Hong and Ellis 1990;Hay and Probert 1995), although this is often a feature of slower desiccation rather than the rapid enforced silica drying used here (Hay and Smith 2003).…”