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

Abstract

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 (G s ), decreasing the leaf transpiration rate (T r ) and net photosynthetic rate (P n ). Stomatal density was significantly negatively correlated with both P n and T r but more strongly with T r , 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 P n and T r . Because the negative correlation of stomatal density to T r was stronger than that to P n , leaf WUE i tended to increase.

Leaf physico-chemical and physiological properties of maize (Zea mays L.) populations from different origins

“…The highest leaf stomatal densities were observed on South (S) and North (N) Sahara populations, followed by Dry (D) Spain. The stomatal frequencies determined are within the values reported for other maize cultivars (e.g., Driscoll et al, 2008;Zhao et al, 2015). Some studies analysed the variation of leaf stomatal densities in relation to drought stress, and found increased stomatal densities with water shortage in maize (Zhao et al, 2015), wheat (Triticum aestivum L.) (Quarrie and Jones, 1977), black cottonwood (Populus trichocarpa Torr.…”

The Mitigation Effects of Exogenous Hydrogen Peroxide when Alleviating Seed Germination and Seedling Growth Inhibition on Salinity-Induced Stress in Barley

“…Reductions in counts and sizes of photosynthetic apertures are important indicators that the photosynthesis mechanism is also adversely affected [42,47]. At the same time, it was determined that drought stress reduces the stomata sizes of maize plants, and gas exchange rates decreased in parallel with increasing drought stress [48]. A reduction of stomata sizes under salt stress protects the balance between photosynthesis and carbon intake, and prevents excessive water loss with transpiration [49].…”

Physiological and biochemical changes attenuate the effects of drought on the Cerrado species Vatairea macrocarpa (Benth.) Ducke

“…The high stomatal density observed in plants submitted to 25% fc may have been a strategy to compensate the stomatal closure and then promote homeostasis in gas exchange. Indeed, plants under water deficit present changes in the stomata density and size to improve gas exchange during drought (Zhao et al, 2015). Yang et al (2007) showed positive relation between high stomatal density and WUE.…”