Date of Award
Master of Science
Guava (Psidium guajava L.) is a tropical, woody perennial with nutritious fruit. It exceeds most tropical and subtropical fruit plants in adaptability and productivity. This thesis focused on the physiology of freezing tolerance and cold acclimation in guava. Freezing tolerance tests, growth and leaf relative water content measurements, anthocyanin content analyses, and protein analyses were performed on nonacclimated and cold-acclimated leaves of guava cultivars Lucknow-49 and Ruby y Supreme. The freezing tolerance of nonacclimated leaves were -2.3 yC and 2.7 yC, and enhanced to -4.2 yC and -4.6 yC after cold acclimation for `Lucknow-49' and `Ruby y Supreme', respectively. Growth and leaf relative water content reduced, while anthocyanins accumulated in guava during cold acclimation. Protein analyses which were performed after cold acclimation and drought stress by electrophoresis and immunoblots revealed that three proteins (69, 23.5, and 17.4 kDa) accumulated in response to low temperatures, and three proteins (78, 17.4, and 16 kDa) accumulated in response to drought stress. One common 17.4 kDa dehydrin accumulated in response to cold and drought stresses. In summary, we indicated that guava possesses some freezing tolerance, and also is able to cold acclimated. Diverse mechanisms are used by guava to tolerate freezing stress. Cold acclimation in guava appears to involve complex physiological and biochemical changes, and also overlapping responses with drought stress.
Hao, Wei, "Freezing tolerance and cold acclimation in guava (Psidium guajava L.)" (2008). Graduate Theses and Dissertations. 11179.