Light-microscopic images of shoot apices display the meristem with two or three surrounding foliage leaf bases (Fig. 1).
The foliage leaf bases around the meristem dome were initially observed to be well oxygenated (~95 μM O2), but immersion in PVS3 solution during dehydration caused sudden, dramatic decline in O2 level around the foliage leaf bases (~0.85 μM) (Fig. 3).
When apices were immersed in cryoprotectant solution, the well-oxygenated peripheral regions (foliage leaf bases) became likewise hypoxic within a few minutes, probably resulting from strongly restricted gaseous diffusion.
The O2 level immediately declined to 20%% atmospheric saturation (~50 μM or 4 kPa oxygen) when the microsensor penetrated the foliage leaf bases, whereas a sharp decrease was detected at meristem region (Fig. 1).
The LAI-2000, that obtains measurements of effective LAI (Le: LAI retrieved assuming random foliage distribution) based on gap fraction at five view angles, is designed to work under diffuse light conditions.
The main signals observed for the foliage are Cu (copper based green/blue pigment), Ca (yellow lake substrate) and Pb, Sn (lead tin yellow) for the garland paintings and an addition of Ni, Co, K signals, elements associated with smalt, a blue cobalt potash glass pigment [22], for the other paintings (see Additional file 1).
Based on canopy foliage temperature and sap flow data, we considered A. pseudoplatanus the most drought sensitive species followed by F. sylvatica, T. platyphyllos and P. avium and the two ring-porous species F. excelsior and Q. petraea being clearly the least sensitive ones.
Thus, comparison of N content across years required an LMA adjustment from whole leaf to leaf disc (LMAdisk = 0.9635 LMAtotal) + 0.7013 (mg cm−2); n = 28; R = 0.66; based on 2008 foliage).
The interactive map is based on reports from "foliage ambassadors" -- basically anyone who signs up to send in e-mail updates.
