Reflectance and Chlorophyll Fluorescence Data from Scots Pine Seedlings during a Long-Term Drought Experiment

This dataset contains hyperspectral reflectance and chlorophyll fluorescence measurements from a long-term drought experiment conducted on Scots pine (Pinus sylvestris L.) seedlings. A total of 810 seedlings were subjected to either drought or irrigation treatments across a 164-day period. The experiment was carried out in a semi-controlled greenhouse environment.

Reflectance data were collected using a HC-900 Series visible hyperspectral scanner (351–898 nm, 480 bands, 1.03 mm² spatial resolution). Here we provide three physiologically relevant days:

Day 29 (pre-stress phase),
Day 88 (peak drought stress),
Day 158 (post-recovery phase).

Fluorescence parameters were collected on days closely aligned with hyperspectral acquisition:

Maximum quantum yield (QY_max) and non-photochemical quenching (NPQ) on days 28, 88, and 154,
Simple fluorescence ratio (SFR_R) on days 32, 88, and 154.

QY_max was calculated as (Fm−Fo)/Fm from dark-adapted measurements.
NPQ was determined using Fm and Fm′ values (NPQ = (Fm−Fm′)/Fm′).
SFR_R was calculated as the ratio of far-red to red fluorescence emission (735 nm / 685 nm) under red light excitation.