Abstract Detail

Ecology

Borer, Catherine [1], Dunn, Michael [2], Christensen, Magdalen [2], Harnage, Katherine [2].

Calcium availability and cycling in understory shrubs.

Flowering dogwood (Cornus florida L.) is a charismatic understory species that can enhance soil calcium availability through its comparatively high foliar Ca content and rapid rate of leaf litter decomposition. In previous work, using sequential extractions of tree foliage, we demonstrated that this ecological Ca pumping by flowering dogwood is related to the very high proportion of labile Ca maintained in the leaves of this species. This is in contrast to many other tree species, which sequester and crystalize a substantial proportion of their foliar Ca in a physiologically unavailable form. Ecological Ca availability is important because Ca is an essential macronutrient in plants and is a key component of many cellular structures and physiological processes. It acts as an essential intracellular second messenger that helps plants sense and respond to a wide array of environmental signals.
Flowering dogwood is being threatened by the fungal disease dogwood anthracnose (Discula destructiva), which is spreading through the range of this species. Because of its key role in Ca cycling, the decline of flowering dogwood may alter ecosystem-level Ca dynamics. In order to evaluate the possible effect of the decline of flowering dogwood on forest Ca cycling, we have assessed Ca partitioning in the foliage of a range of common understory species to determine whether they may retain Ca in a labile form and enhance calcium cycling in forests, in a similar way to flowering dogwood. We used sequential extractions to evaluate the chemical partitioning of calcium in leaves from six individuals of seven species (four native and three invasive) that are commonly found on the campus of Berry College, in northwest Georgia, USA. Species included flowering dogwood, Eastern redbud (Cercis canadensis), American holly (Ilex opaca), Muscadine (Vitis rotundifolia), Chinese privet (Ligustrum sinense), Chinese holly (Ilex cornuta), and Leatherleaf mahonia (Mahonia bealei). Although flowering dogwood retains significantly more labile calcium in its foliage than other species, we found a wide range of labile calcium in the foliage of the species that we evaluated in this study. This suggests that forest Ca cycling may be slowed as dogwoods decline. Seasonally deciduous species, such as Eastern redbud and Chinese privet retained significantly more labile foliar calcium, in comparison with evergreen species, such as the hollies and mahonia.

1 - Berry College, Biology, P.O. Box 490430, Mount Berry, GA, 30149, United States
2 - Berry College, Biology, Mount Berry, GA, 30149, USA

Keywords:
Flowering dogwood
Calcium cycling
Mineral Nutrient
Cornus florida.

Presentation Type: Poster
Session: P, Ecology
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC023
Abstract ID:838
Candidate for Awards:None