Lacking chloroplasts in guard cells of crumpled leaf attenuates stomatal opening: both guard cell chloroplasts and mesophyll contribute to guard cell ATP levels |
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Authors: | SHU‐WEI WANG YING LI XIAO‐LU ZHANG HAI‐QIANG YANG XUE‐FEI HAN ZHAO‐HUI LIU ZHONG‐LIN SHANG TOMOYA ASANO YASUSHI YOSHIOKA CHUN‐GUANG ZHANG YU‐LING CHEN |
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Institution: | 1. Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, , Shijiazhuang, 050024 China;2. School of Basic Medical Sciences, Chengde Medical College, , Chengde, 067000 China;3. Advanced Science Research Center, Kanazawa University, , Kanazawa, Ishikawa, 920‐0934 Japan;4. Division of Biological Science, Graduate School of Science, Nagoya University, , Nagoya, Aichi, 464‐8602 Japan |
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Abstract: | Controversies regarding the function of guard cell chloroplasts and the contribution of mesophyll in stomatal movements have persisted for several decades. Here, by comparing the stomatal opening of guard cells with (crl‐ch) or without chloroplasts (crl‐no ch) in one epidermis of crl (crumpled leaf) mutant in Arabidopsis, we showed that stomatal apertures of crl‐no ch were approximately 65–70% those of crl‐ch and approximately 50–60% those of wild type. The weakened stomatal opening in crl‐no ch could be partially restored by imposing lower extracellular pH. Correspondingly, the external pH changes and K+ accumulations following fusicoccin (FC) treatment were greatly reduced in the guard cells of crl‐no ch compared with crl‐ch and wild type. Determination of the relative ATP levels in individual cells showed that crl‐no ch guard cells contained considerably lower levels of ATP than did crl‐ch and wild type after 2 h of white light illumination. In addition, guard cell ATP levels were lower in the epidermis than in leaves, which is consistent with the observed weaker stomatal opening response to white light in the epidermis than in leaves. These results provide evidence that both guard cell chloroplasts and mesophyll contribute to the ATP source for H+ extrusion by guard cells. |
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Keywords: | Arabidopsis mesophyll cells white light |
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