Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2000
Publication Date: N/A
Stomata, plant epidermal pores, have a fundamental role controlling photosynthesis and transpiration, and, hence, water use efficiency, drought sensitivity, and yield. In spite of major advances in understanding plant organogenesis and development via modern techniques, little is known of the specific cellular and molecular processes that underlie formation of stomata. We have used a soybean line expressing a unique branched kampfero triglycoside (K9) to study stomatal development. One of the characters tightly linked with K9 expression is extreme reduction of stomatal density on upper leaf surfaces. We reported earlier that the presence of blue light inhibits stomatal formation and induces K9 accumulation. To understand the relation between blue light, stomatal formation and K9 expression, we asked whether an increase in K9 was obligatorily coupled to altered stomatal formation under the influence of blue light. Plants were raised under high irradiance with or without blue and transferred to the alternate spectral quality at different stages of first trifoliolate leaf development. We clearly showed that blue light affected stomatal development at the guard mother cell stage, about 9 days after emergence. In contrast, flavonoid induction occurred 1-2 days later. Both processes were sensitive to light within narrow developmental windows, but were temporally and causally separate. These results should be important for understanding the molecular basis of blue light regulated gene expression and stomatal formation. Our studies also show that stomatal density is not a fixed morphological feature, but can be rapidly altered over a wide range by suitable environmental cues presented during leaf development.