Occurrence, structure, and function of short cells in maize leaf epidermis.

Short cells are specialised epidermal cells of grasses and they include cork and silica cells. The time of occurrence, distribution, and number of short cells differ among plants or tissues of the same plant. The present study aimed to assess the occurrence, structure, and function of short cells in the epidermis of maize (Zea mays L.) leaves from cultivar "Zhengdan 958″ under field and potted experimental conditions. Results showed that short cells occurred synchronously in multiple maize leaves. Few short cells occurred at the base of the fifth leaf; most were found at the middle and base of the sixth leaf, and throughout the seventh leaf. The accumulation of K+ and H2 O2 in cork cells changed periodically with stomatal opening and closure, which was consistent with the accumulation of K+ and H2 O2 in subsidiary cells; whereas no accumulation was observed in silica cells. Moreover, photosynthetic parameters and stomatal aperture were significantly higher in leaves containing short cells than in those without them in the same parts of different leaves or in different leaves at the same leaf position. Accumulation of K+ and H2 O2 in cork cells increased with increasing water stress. In conclusion, short cells not only improved leaf mechanical support and photosynthetic performance, and maize drought resistance, but they also participated in stomatal regulation.