Fig 1.
Sucrose-induced stomatal closure in wheat and watermelon.
Stomatal response to sucrose in A) T. aestivum and B) C. lanatus. This response was assayed by immersing detached leaves for 3 h in artificial apoplastic sap (AS, control) or AS containing 100 mM or 200 mM sorbitol (as an osmotic control) or 100 mM or 200 mM Suc. Data points are means ± SE. [The numbers of independent biological repeats and stomata (n) analyzed for each species are listed in S1 Table.] Different letters indicate a significant difference (Tukey's HSD test, P < 0.05).
Fig 2.
Sucrose-induced stomatal closure in eudicots.
Stomatal response to sucrose in the eudicots A) R. communis, B) P. angulata, C) O. corniculata, D) V. vinifera, E) C. roseus, F) P. hortorum, G) M. azadirachta and H) M. oleifera. This response was assayed by immersing detached leaves for 3 h in artificial apoplastic sap (AS, control) or AS containing 200 mM sorbitol (as an osmotic control) or 200 mM Suc. Data points are means ± SE. [The numbers of independent biological repeats and stomata (n) analyzed for each species are listed in S1 Table.] Different letters indicate a significant difference (Tukey's HSD test, P < 0.05).
Fig 3.
Sucrose-induced stomatal closure in monocots.
Stomatal response to sucrose in the monocots A) Z. mays, B) M. paradisiaca and C) S. bicolor. This response was assayed by immersing detached leaves for 3 h in artificial apoplastic sap (AS, control) or AS containing 200 mM sorbitol (as an osmotic control) or 200 mM Suc. Data points are means ± SE. [The numbers of independent biological repeats and stomata (n) analyzed for each species are listed in S1 Table.] Different letters indicate a significant difference (Tukey's HSD test, P < 0.05).
Fig 4.
Stomatal response to sucrose in symplastic loaders.
Stomatal response to sucrose in the symplastic phloem-loading plants A) C. melo, B) C. pepo and C) O. basilicum. This response was assayed by immersing detached leaves for 3 h in artificial apoplastic sap (AS, control) or AS containing 200 mM sorbitol (as an osmotic control) or 200 mM Suc. Data points are means ± SE. [The numbers of independent biological repeats and stomata (n) analyzed for each species are listed in S1 Table.] Different letters indicate a significant difference (Tukey's HSD test, P < 0.05).
Fig 5.
Sucrose-induced stomatal closure in C4 and CAM plants.
Stomatal response to sucrose was assayed in the C4 eudicots A) A. viridis and B) T. terrestris, the CAM plant C) B. daigremontianum and the C4-CAM plant D) P. oleracea. This response was assayed by immersing detached leaves for 3 h in artificial apoplastic sap (AS, control) or AS containing 200 mM sorbitol (as an osmotic control) or 200 mM Suc. Data points are means ± SE. [The numbers of independent biological repeats and stomata (n) analyzed for each species are listed in S1 Table.] Different letters indicate a significant difference (Tukey's HSD test, P < 0.05).
Fig 6.
Stomatal reactivity to sucrose across evolution and in correlation with minimum water requirements.
(A) Stomatal reactivity to sucrose (relative to sorbitol) in the species tested in our survey. Small circles indicate the mean for each species and big, bold circles indicate the mean value for each group (Eudicots, monocots, symplastic loaders and C4-CAM). Brackets indicate the SE. (B) A negative correlation was observed between the minimum water requirement (mm) and the stomatal reactivity to sucrose (%).