2.8 | Leaf chemical and morphological traits
For each treatment four leaflets—one from each of three leaves, of
similar age and sun exposure as the leaves used for gas-exchange
measurements—were collected prior to the switch in conditions, and
three more at the end of the experiment. Leaf area was measured with an
LI-3100C leaf area meter (LI-COR), and leaves were dried at 70°C and
weighed to determine leaf mass per area (LMA). Leaf nitrogen (N) content
was measured using a Thermo Flash EA1112 analyzer (Waltham, MA, USA). To
determine stomatal density epidermal impressions were taken with the
nail varnish method from three leaves per treatment. T. rosea is
hypostomatous, so only stomatal impressions of the abaxial sides—three
per leaf—were counted.