Mississippi State University
Harkess, Richard L.
Knight, Patricia R.
Blythe, Eugene K.
Gilliam, Charles H.
Date of Degree
Dissertation - Open Access
Doctor of Philosophy (Ph.D)
College of Agriculture and Life Sciences
Department of Plant and Soil Sciences
Studies were conducted to evaluate the effects of plant health protectants Pageant (pyraclobstrobin + boscalid), Regalia (extract of Reynoutria sachalinensis) and MBI-501 (an anti-transpirant) on drought, heat and cold tolerance. To measure effects on drought tolerance, Pageant, Regalia or MBI-501 were foliar applied to impatiens at four rates (0.0×, 0.5×, 1.0×, and 1.5×) based on the label rates of 0.228 g·L-1 (Pageant), 10 mL·L-1 (Regalia) and 2 mL·L-1 (MBI-501) and to tomato plants at two rates (0.0× and 1.0×) based on the label rates of 0.559 g·L-1 (Pageant), 10 mL·L-1 (Regalia) and 2 mL·L-1 (MBI-501) grown with different target substrate volumetric water contents (TVWC). Pageant applied at the 1.0× rate to well-watered impatiens, had greater shoot dry weight compared to water stressed plants. Regalia application increased root dry weight, leaf chlorophyll content and photosynthetic rate of impatiens and tomato plants. However, results tended to be in the higher TVWC (Pageant and Regalia) to moderately stressed conditions (Regalia). To evaluate heat tolerance in Impatiens walleriana ‘Super Elfin XP White’ (impatiens), Pageant (0.228 g·L-1), Regalia (10 m·L-1) or MBI-501 (2 mL·L-1) were applied prior to the heat event. Photosynthetic rate was less with impatiens exposed to the heat event compared to plants not exposed to the heat event. However, there was no indication Pageant, Regalia or MBI-501 improved heat tolerance. To evaluate heat tolerance in Solanum lycopersicum ‘BHN 640’ (tomato) plants, Regalia was foliar applied at the 1.0× rate at 24 h or 1 h before the heat event. There was no indication Regalia improved heat tolerance. Fragaria ×ananassa ‘Camarosa’ (strawberry) plants were evaluated for chilling tolerance following application of Regalia at the 1.0× rate in a growth chamber. Results indicated no increase in chilling tolerance of strawberry plants compared to plants receiving no Regalia or chilling treatments. Citrus unshiu ‘Owari’ (satsuma) leaves were evaluated for freeze tolerance after application of Regalia at 1.0× (10 mL·L-1) rate in a programmable ultra-low freezer. Results indicated no increased freeze tolerance in satsuma leaves compared to leaves from plants receiving no Regalia or freezing treatment.
Cochran, Diana Renae, "Enhancing Plant Tolerance to Cold, Heat and Drought Through the Use of Selected Plant Health Protectants" (2012). Theses and Dissertations. 1893.