Semester

Summer

Date of Graduation

2001

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Horticulture

Committee Chair

Rajeev Arora.

Abstract

In this study we established the significance of 25 kDa dehydrin accumulation during cold acclimation (CA) in a wide array of Rhododendron species. These species (24 in total) belong to two diverse subgenera, Hymenanthes and Rhododendron, native to diverse latitudes and altitudes. The dehydrin of interest is highly conserved in Rhododendron genus and was present and up-regulated during CA in all the species studied with one exception---R. brookeanum ---a species adapted to tropics. Some other dehydrins were also found to accumulate in response to cold acclimation in several species, but none of these accumulated consistently. Experimental data show that there is no correlation between the absolute amount of 25 kDa dehydrin and the degree of leaf hardiness in cold acclimated plants. Moreover, a higher number of dehydrin species in a particular genotype does not necessarily translate into more hardy Rhododendron. However, our results suggest that the cold-inducibility of a 25 kDa dehydrin is positively correlated with cold acclimation ability in Rhododendron. (Abstract shortened by UMI.).

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