Dynamics of spatial heterogeneity of stomatal closure in Tradescantia virginiana altered by growth at high relative air humidity

• Published in: Journal of experimental botany Vol. 57; no. 14; pp. 3669 - 3678
• Main Authors: Rezaei Nejad, Abdolhossein, Harbinson, Jeremy, Meeteren, Uulke van
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 2006; Oxford Publishing Limited (England)
• Subjects: abscisic-acid; Agronomy. Soil science and plant productions; Biological and medical sciences; chlorophyll; chlorophyll fluorescence; Chlorophylls; co2; conductance; Dehydration; Desiccation; desiccation (plant physiology); Economic plant physiology; environmental factors; Fluorescence; Fundamental and applied biological sciences. Psychology; Guard cells; Humidity; Imaging; leaf gas-exchange; leaf water potential; Leaves; patchiness; photosynthetic activity; photosystem II; Photosystem II Protein Complex - metabolism; plant adaptation; plant growth; Plant Leaves - growth & development; Plant Leaves - physiology; Plants; PSII efficiency; relative humidity; relative water content; Research Papers; signal-transduction; spatial variation; Stomata; stomatal movement; Tradescantia; Tradescantia - genetics; Tradescantia - growth & development; Tradescantia - physiology; Tradescantia virginiana; Water - metabolism; water content; water potential; Water relations, transpiration, stomata; water stress; Monocotyledones; Growth; Desiccation; Stomata; patchiness; Water potential; Tradescantia virginiana; relative water content; Commelinaceae; Angiospermae; Humidity; Stomatal movement; Water content; PSII efficiency; Spermatophyta
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erl114

The spatial heterogeneity of stomatal closure in response to rapid desiccation of excised well-watered Tradescantia virginiana leaves grown at moderate (55%) or high (90%) relative air humidity (RH) was studied using a chlorophyll fluorescence imaging system under non-photorespiratory conditions. Following rapid desiccation, excised leaves grown at high RH had both a greater heterogeneity and a higher average value of PSII efficiency (ΦPSII) compared with leaves grown at moderate RH. Larger decreases in relative water content resulted in smaller decreases in water potential and ΦPSII of high RH-grown leaves compared with moderate RH-grown leaves. Moreover, the ΦPSII of excised high RH-grown leaves decreased less with decreasing water potential, implying that the stomata of high RH-grown leaves are less sensitive to decreases in leaf water potential compared with moderate RH-grown leaves. After desiccation, some non-closing stomata were distributed around the main vein in high RH-grown leaves. Direct measurements of stomatal aperture showed 77% stomatal closure in the margins after 2 h desiccation compared with 40% closure of stomata in the main-vein areas in high RH-grown leaves. Faster closure of stomata in leaf margins compared with main-vein areas of leaves grown at high RH was related to substantially lower relative water content in these areas of the leaves.