Zeaxanthin-independent energy quenching and alternative electron sinks cause a decoupling of the relationship between the photochemical reflectance index (PRI) and photosynthesis in an evergreen conifer during spring

conifer
Monday, November 2, 2015 - 12:41pm

Shhhh! There are spies among us and they are watching ... the secret lives of conifers. A new blockbuster paper by Emmanuelle Fréchette, Chris Wong, Laura Junker and Christine Chang (Ensminger Lab) was just published in Journal of Experimental Botany.  In this paper they examine the invisible lives of the mighty white pine. Unlike deciduous trees, the phenology of photosynthesis in evergreen conifers is invisible to the naked eye, which complicates understanding the effects of global change on the phenology of coniferous forests. Spectral reflectance can help track photosynthetic efficiency during summer, but how accurately can it track the spring activation of photosynthesis?  To find out, Fréchette et al spied on the invisible phenology of pine seedlings using the photochemical reflectance index (PRI) and investigated how it relates to  photosynthetic efficiency, energy utilization and pigment dynamics during spring. PRI mostly closely reflected adjustments of chlorophyll and carotenoid pools  rather than photosynthesis, and they identified mechanisms that prevent the PRI from accurately reflecting photosynthesis during that time of year.

Congratulations on this discovery, Team Ensminger!