Theses and Dissertations

Issuing Body

Mississippi State University


Harkess, Richard L.

Committee Member

Bi, Guihong.

Committee Member

Broderick, Shaun.

Committee Member

Cox, Michael S.

Date of Degree


Document Type

Graduate Thesis - Open Access


Plant and Soil Sciences (Horticulture)

Degree Name

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.