Effects of Scopoletin and Chlorogenic Acid on Stomatal Aperture in Tobacco and Sunflower


Both scopoletin and chlorogenic acid are natural growth inhibitors which have previously been shown to increase in plants under a variety of stress conditions. In order to determine if these inhibitors interfere with stomatal function, tobacco and sunflower seedlings were treated with scopoletin or chlorogenic acid in a nutrient culture. After treatment, daily measurements were made of stomatal apertures by making Duco cement prints from the lower epidermis. It was found that 10-3 M and 5 x 10-4 M treatments of both compounds caused stomatal closure in tobacco within one day after treatment. This closure persisted for several days, but eventually stomata returned to near normal. Stomata of sunflowers treated with 10-3 M and 5 x 10-4 M chlorogenic acid reacted similarly with less extreme effects in the latter group. Both tobacco and sunflower seedlings treated with scopoletin or chlorogenic acid of 10-4 M levels showed an enhancement of stomatal openings. Stomatal reductions induced by 10-3 M and 5 x 10-4 M scopoletin treatments correlate well with growth retardation and photosynthetic reductions previously established in these seedlings. It appears that one mechanism of growth inhibition induced by scopoletin and chlorogenic acid operates through stomatal closure.


Academic Affairs

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stomata, sunflowers, seedlings, industrial plants, cements, transpiration, plant growth regulators, nutrient solutions, photosynthesis

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Journal Title

Bulletin of the Torrey botanical club