Mississippi State University
Harkess, Richard L.
Cox, Michael S.
Date of Degree
Graduate Thesis - Open Access
Plant and Soil Sciences (Horticulture)
Master of Science (M.S.)
College of Agriculture and Life Sciences
Department of Plant and Soil Sciences
Pelargonium peltatum, ivy geranium, experiences foliar bleaching at temperatures exceeding 30° C. Contessa™ Red (heat tolerant) and Temprano™ Lavender (heat susceptible) were compared. Established plants underwent temperature treatments of 15/20° C or 25/30° C night/day with moisture treatments of 80% or 30% substrate volumetric water content (VWC). Photosynthesis, leaf greenness and growth data were collected at days 0, 7 and 11. No differences in photosynthetic rate nor a decrease in greenness in developed leaves occured in either cultivar due to high temperature or drought. Contessa™ Red had overall greater growth and leaf greenness than Temprano™ Lavender. Greenness and growth increased similarly for both cultivars at 80% VWC. Any decrease in foliar bleaching due to drought was likely due to a decrease in growth. A second study using Temprano™ Lavender indicated foliar bleaching occurs in newly emerging, developing leaves.
Horton, Anna McLaurin, "Heat Stress Inhibits Chloroplast Development in Ivy Geranium" (2018). Theses and Dissertations. 2476.