Horticultural ecophysiology of Tasmanian native pepper
Tasmannia lanceolata is currently wild harvested on a small scale predominantly to extract polygodial from leaves. The consistency of extract yield and quality by orchard production of selected clones could significantly increase its use. Early attempts at small scale orchard establishment had mixed results, the reasons for which were not clear. The effect of climate on plant ecophysiology, growth and extract yield were investigated in both glasshouse and field trials. Light, temperature and wind were manipulated under controlled conditions. High light levels (800 µmol m-2 s-1, compared to 600 and 400) and temperatures up to 20°C positively affected photosynthetic rate. At 25°C, photosynthetic rate significantly declined and stomatal conductance significantly increased. Under controlled wind conditions, photosynthetic rate declined at higher wind speeds, while stomatal conductance increased and plant water potential became more negative at higher wind speeds for plants at a constant temperature (20°C). In field trials, plants sheltered in tree guards with 50% shade had higher growth rates over an extended period than unsheltered plants. Improved growth did not negatively affect quality and overall quantity of polygodial was greatly increased. The results demonstrate that understanding the ecophysiology of native species is critical to ensuring the development of successful horticultural production systems and site selections.
Wilson, M.D., Menary, R.C. and Close, D.C. (2018). Horticultural ecophysiology of Tasmanian native pepper. Acta Hortic. 1228, 385-390
Tasmannia lanceolata, climatic conditions, temperature, wind speed, tree guards