Response of stomatal density and bound gas exchange in leaves of maize to soil water deficit

• Published in: Acta physiologiae plantarum Vol. 37; no. 1
• Main Authors: Zhao, Wensai, Sun, Yonglin, Kjelgren, Roger, Liu, Xiping
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-01-2015; Springer Berlin Heidelberg
• Subjects: Agriculture; Biomedical and Life Sciences; corn; correlation; drought; gas exchange; leaves; Life Sciences; Original Paper; photosynthesis; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; seedlings; soil water; soil water content; soil water deficit; stomata; stomatal conductance; stomatal movement; water use efficiency; Maize; Drought; Stomatal density; Photosynthetic parameters
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-014-1704-8

Stomatal behavior in response to drought has been the focus of intensive research, but less attention has been paid to stomatal density. In this study, 5-week-old maize seedlings were exposed to different soil water contents. Stomatal density and size as well as leaf gas exchange were investigated after 2-, 4- and 6-week of treatment, which corresponded to the jointing, trumpeting, and filling stages of maize development. Results showed that new stomata were generated continually during leaf growth. Reduced soil water content significantly stimulated stomatal generation, resulting in a significant increase in stomatal density but a decrease in stomatal size and aperture. Independent of soil water conditions, stomatal density and length in the trumpeting and filling stages were greater than in the jointing stage. Irrespective of growth stage, severe water deficit significantly reduced stomatal conductance (Gₛ), decreasing the leaf transpiration rate (Tᵣ) and net photosynthetic rate (Pₙ). Stomatal density was significantly negatively correlated with both Pₙand Tᵣbut more strongly with Tᵣ, so the leaf instantaneous water use efficiency (WUE ᵢ ) correlated positively with stomatal density. In conclusion, drought led to a significant increase in stomatal density and a reduction in stomatal size and aperture, resulting in decreased Pₙand Tᵣ. Because the negative correlation of stomatal density to Tᵣwas stronger than that to Pₙ, leaf WUE ᵢ tended to increase.