Lloyd Stark

Biography

The primary theme in my lab is the ecology of vegetative desiccation tolerance in plants. Desiccation tolerance (DT) is the ability of an organism or structure to survive drying out in equilibration with dry air, and among plants is most well developed among the bryophytes. In my lab, various species of mosses are cultured and bred, with experiments on DT normally based on single clonal lines. We are interested in determining the intrinsic ecological strategy of DT employed by a species; this strategy resides along an inducibility gradient, from weakly inducible to nearly constitutive. Experimental topics include the DT of vegetative and reproductive phases, the physiology and timelines of hardening and dehardening phenomena, how different life phases of mosses (shoots, asexual propagules, antheridia, juvenile structures) exhibit variation in response to desiccation stress, and the length of time structures can tolerate continuous desiccation. Specifically, my laboratory is investigating how the three components of desiccation tolerance, (i) the rate of drying, (ii) the duration spent in the dried state, and (iii) the equilibrium relative humidity reached, affect the capacity of a plant to tolerate desiccation. We focus on desert and Mediterranean mosses.

My graduate students are studying (i) the desiccation tolerance in Bryum argenteum life phases and hardening to DT in Physcomitrella and (ii) how the environment within the moss colony compares to the ambient environment, how this potential buffer varies along an elevation gradient in the desert, and including how this phenomenon relates to projected climate change.