Identification of drought-tolerant woody perennials using chlorophyll fluorescence

The purpose of this research was to determine whether chlorophyll fluorescence values obtained from excised leaves of woody plants subjected to dehydration in vitro provided a measurable indicator of whole-plant performance following drought in situ and to gain a greater understanding of alterations in leaf photosynthetic properties between species. [UMN]

"The purpose of this research was to determine whether chlorophyll fluorescence values obtained from excised leaves of woody plants subjected to dehydration in vitro provided a measurable indicator of whole-plant performance following drought in situ and to gain a greater understanding of alterations in leaf photosynthetic properties between species. Based on reductions in photochemical efficiency, as measured by chlorophyll fluorescence, of detached leaves of 30 woody plants in vitro following 24 hours of dehydration, plants were ranked in order of tolerance. Five species identified as drought tolerant, intermediate, and sensitive were subjected to 70 days of drought under glasshouse conditions. Based on mortality rates at day 70, drought tolerance followed the same order as that obtained in vitro. In addition, reductions in chlorophyll fluorescence parameters and photosynthetic rates of whole plants mirrored tolerance ranking in vitro (i.e., rates declined most rapidly in species identified as dehydration sensitive and least in species identified as drought tolerant). Alteration to leaf chlorophyll fluorescence parameters in the test species highlighted a number of previously unreported effects on the leaf photosynthetic apparatus in response to drought. Results strongly indicate that screening of detached leaf material in vitro using chlorophyll fluorescence can provide a means of gauging the drought tolerance of plants with limited whole-plant experimentation." [Abstract]