Laurel wilt, caused by Raffaelea tauricola. has been responsible for extensive losses of redbay (Persea borbonia) in South Carolina and Georgia since 2003. Symptoms of the di.sease have been noted in other species of the Lauraceae such as the federally endangered pondberry (Lindera melissifolia) and the threatened pondspice (Litsea aeslivitlis). Pondberry and pondspice seedlings were inoculated with R. tatiricota from redbay. and both species proved highly susceptible to laurel wilt. Field assessments found substantial mortality of pondberry and pondspice, but in many cases the losses were not attributable to laurel wilt. R. lauricola was isolated from only 4 of 29 symptomatic pondberry plants at one site, but the fungus was not recovered from three plants at another site. R. lauricola was isolated from one of two symptomatic pondspice plants at one site, and from five of 11 plants at another site, but not from any plant at a third site. Insect bore holes, similar to those produced by Xyleborus glahratus (the vector of laurel wilt), were found in some pondberry and pondspice stems, but adults were not found. Damage caused by Xylosandrus cotnpaclus was found in pondberry stems, but this ambrosia beetle does not appear to be a vector of R. lauricola. Xyleboriniis .ut.xeseni adults were found in a dying pondspice with laurel wilt, and R. lauricola was recovered from two of three adults. Isolates of R. lauricola frotn pondberry. pondspice. and X. sa.xe.'ieni had rDNA sequences that were identical to previously characterized isolates, and inoculation tests confirmed that they were pathogenic to redbay. Because pondberry and pondspice tend to be shrubby plants with small stem diameters, these species may not be frequently attacked by X. glabratus unless in close proximity to larger diameter redbay.

A micropropagation protocol using shoot cultures is described for Lindera melissifolia, a federally listed endangered shrub endemic to the southeastern United States. Stock plants were harvested from native L. melissifolia populations growing in the lower Mississippi Alluvial Valley. In vitro proliferation was on woody plant medium supplemented with 1 μm zeatin. After 6 weeks, zeatin level was increased to 5 μm. Treatment of micropropagated shoots with a liquid auxin (2 indole-3-butyric acid : 1 1-naphthalenacetic acid) resulted in a low mean rooting percentage (≤44%) compared with rooting in the absence of auxins and on a pure peat medium ex vitro, which increased rooting to ≥80%. Time to rooting was 8 weeks. Plants were acclimatized for 2 weeks, then potted in a 2 peat : 1 perlite medium supplemented with superphosphate, 10N–10P–10K, and Milorganite. Micropropagated L. melissifolia stecklings have been successfully outplanted in both controlled and field studies at the Center for Bottomland Hardwoods Research (Stoneville, Miss.).

Bottomland hardwood ecosystems, important for their unique functions and values, have experienced considerable degradation since European settlement through deforestation, development, and drainage. Currently, considerable effort is underway to restore ecological functions on degraded bottomland sites. Restoration requires a better understanding of the biological components, especially plants, and their interactions with other biotic and abiotic components of the ecosystem. Previous experimental approaches have focused on the effects of stress on floodplain plant species in controlled, small-scale studies or large, uncontrolled ecosystem-scale studies. We describe a facility, named the Flooding Research Facility (FRF), where hydrologic regimes can be manipulated to study ecophysiology of floodplain species. Key features of the FRF include the ability to establish experiments on a scale larger than would be possible in a greenhouse, but small enough to control key abiotic variables, such as flood frequency, duration, and light availability on native bottomland soil. Design of the FRF allows for random and replicated treatment applications. Additionally, we provide an example of ongoing research on the effects of flooding and light availability on pondberry (Lindera melissifolia), a federally endangered shrub found in the southeastern United States.

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