Tuesday, April 12, 2016

Humid spring days

Posted by Lucy Zipf

March was an important month for me in the Primack lab! With help from lab members, I conducted my first experiment as a graduate student: an investigation of the effect of air humidity on leaf-out times in native and invasive shrubs and trees.

Collecting twigs in Newton, MA

This study was motivated by a recent paper, Laube et al. 2014 (doi: 10.1111/nph.12680), showing that dormant twigs in a high humidity growth chamber leafed out about seven days earlier than dormant twigs in a lower humidity chamber. Could leaf-out in the spring be affected by humidity as well as temperature? We decided to test Laube’s hypothesis.

For our experiment, Richard Primack, Amanda Gallinat and I collected twigs from 15 species, including native and invasive shrubs and native trees from the Boston area. We brought the twigs back to BU, cut the stems, and placed them in cups of water, with help from BU undergraduates Luca Russo, Dillon Travis, Melissa Ruano, and Lucas Stegman! 

Processing twigs in the lab, with Luca Russo and Dillon Travis

Twigs of every species were exposed to each of four humidity treatments: high, medium-high, medium-low, and low. In the course of this experiment we realized that our building is extremely dry – it has the humidity of the Sahara Desert!

A clipping of multiflora rose leafing out in the low humidity treatment

We monitored the twigs daily for leaf-out over the following four weeks. Do twigs leaf out earlier in humid environments? Stay tuned for the results. 

No comments:

Post a Comment