Fig. 6.

Suc efflux from source leaves of Arabidopsis sps mutant lines during vegetative growth. Phloem exudates were collected from two mature source leaves (three in the case of spsa1/spsc double mutants) per line after a growth period of 6 weeks under short-day conditions. Suc content in the exudates was determined 1, 2, and 3h after excision. (A) Suc efflux from petioles that were excised 4h before the end of the light period and that were kept under the same light conditions. (B) Suc efflux from petioles during the dark. Leaves were excised immediately at the beginning of the dark period. Data are presented as means ±SD of six individual plants per line. Asterisks indicate a significant difference (*P<0.05; **P<0.001) as analysed by t-test.