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.