Table 1.

Correlation coefficients from a multiple regression analysis of the transcriptome in epiphytic or apoplastic sites on the transcriptomes of cells exposed to the basal medium and to each of the four environmental stresses in vitro

Stress	Epiphytic sites*				Apoplastic sites*
	Lab A	Lab B	Lab C	Combined dataset	Lab A	Lab B	Lab C	Combined dataset
Osmotic stress	0.40	0.47	0.25	0.42	0.50	0.75	0.42	0.64
Nitrogen limitation	0.34	0.32	0.33	0.36	0.46	0.22	0.41	0.28
Oxidative stress	0	0.02	0.26	0	0	0	0	0
Iron limitation	0.26	0.15	0.10	0.18	0.04	0.04	0.16	0.07

*Multiple regression analysis was performed with the constraints that the coefficients were non-negative and had to sum to one. The transcriptome data were in the form of the transcript abundances weighted with variances using a least-squares approach. Regression analyses were performed separately for the data from each laboratory and for the combined dataset.