Vernal Photosynthesis and Nutrient Retranslocation in Dryopteris intermedia

Abstract

The value of preserving wintergreen fronds into the spring by forest understory fern species is unknown. In this study, net photosynthetic rates and nitrogen and phosphorus contents were monitored in a population of Dryopteris intermedia throughout a spring season to explore potential photosynthetic and retranslocational benefits of wintergreen fronds. Net photosynthesis occurred throughout the study indicating a potential for movement of fixed carbon from wintergreen fronds to other parts of the plant. Nitrogen and phosphorus content in the old fronds did not change through spring, thus no evidence for net retranslocation of these nutrients from wintergreen fronds to the rest of the plant was obtained. Maintenance of the wintergreen fronds may simply increase retention time and thus nutrient use efficiency of limiting nutrients. Other possible benefits of wintergreen fronds exist and should be investigated.

Leaf longevity of Oxalis acetosella (Oxalidaceae) in the Catskill Mountains, New York, USA

“…Making use of wintergreen leaves is hypothesized to provide an energy benefit to plants (Chabot and Hicks, 1982;Moore, 1984;Tessier, 2001) by permitting vernal photosynthesis, particularly during warm days (Burkle and Logan, 2003). This leaf habit may also provide a nutrient storage benefit in some species via vernal retranslocation of nutrients from the senescing leaves to the rest of the plant (Moore, 1984).…”

The effect of enhanced nitrogen on aboveground biomass allocation and nutrient resorption in the fern Athyrium distentifolium

“…A. Gray (Tessier 2001), and two winter-deciduous ferns Pteridium aquilinum (L.) Kuhn. (Hunter 1953) and Dennstaedtia punctilobula (Michx.)…”

The relative photosynthetic contribution of old and new fronds of the wintergreen fern Dryopteris carthusiana, Ontario, Canada1

“…According to Tessier (2004), the potential to photosynthesize under high light conditions (by avoiding closed canopies) may be achieved in a number of ways including: spring ephemeral habit (plants which leaf out prior to canopy leaf out and senesce by mid-summer), wintergreen habit (leaves maintained for one full year and replaced in the late-spring), or evergreen habit (maintain leaves year round with leaf longevity exceeding one year) (see also : Landhä usser et al 1997, Tessier 2008; in fact the wintergreen habit has been categorized as a special case of evergreenness (Chabot and Hicks 1982). The latter two strategies are employed by different fern species in the deciduous forests of North America (Tessier 2001). While these strategies make physiological sense in the deciduous forest, where significant high light periods exist in the latespring and autumn, the relative benefit of wintergreen or evergreen habit, when the overstory itself is evergreen, is theoretically less advantageous photosynthetically and generally less common (Uemura 1994).…”

“…Additionally, a handful of studies have evaluated the contribution of overwintered fern leaves to springtime carbon assimilation (Bauer et al 1991, Van Buskirk and Edwards 1995, Noodén and Wagner 1997, Tani and Kudo 2005, Tessier and Bornn 2007 and resource storage (Minoletti and Boerner 1993, Tani and Kudo 2003, but this latter phenomenon is not the case for all wintergreen ferns (Tessier 2001 Uemura (1994) suggests that in the case of plants which have overwintering leaves with low spring photosynthetic rates, the leaves may primarily serve as storage organs providing resources to accelerate the expansion of new leaves in the spring. Given the similarities in photosynthetic parameters we found for old and new fronds of Dryopteris carthusiana, and the significant contribution to overall carbon gain it does not seem that overwintered fronds should be seen as primarily storage organs, rather in our study they were an important source of vernal carbon gain.…”