Structure of Populus tremula sample headers in count matrix:

N_barcodeID where:

- N ranges from 1 to 9, and represents a specific tissue section on the array:

	1 = spots under the top left tissue section in the "P_tremula_developing_reproducibility" replicate_1 sample image
	2 = spots under the top right tissue section in the "P_tremula_developing_reproducibility" replicate_1 sample image
	3 = spots under the bottom tissue section in the "P_tremula_developing_reproducibility" replicate_1 sample image
	4 = spots under the top tissue section in the "P_tremula_developing_reproducibility" replicate_2 sample image
	5 = spots under the bottom left tissue section in the "P_tremula_developing_reproducibility" replicate_2 sample image
	6 = spots under the bottom right tissue section in the "P_tremula_developing_reproducibility" replicate_2 sample image
	7 = spots under the tissue section in the "P_tremula_dormant_reproducibility" replicate_1 sample image
	8 = spots under the top tissue section in the "P_tremula_dormant_reproducibility" replicate_2 sample image
	9 = spots under the bottom tissue section in the "P_tremula_dormant_reproducibility" replicate_2 sample image

- barcode_ID corresponds to the barcode sequence in the "1000L3_barcodes.txt" file at https://github.com/SpatialTranscriptomicsResearch/st_pipeline/tree/master/ids. Each barcode ID corresponds to a specific X_Y spot coordinate on the array matrix.