Observations on the leaf anatomy of Festuca novae‐zelandiae and biochemical responses to a water deficit

Abstract

An examination using scanning electron microscopy, of the leaf anatomy of the New Zealand native tussock grass Festuca novae‐zelandiae, has been undertaken to highlight adaptations implicated in water‐deficit‐stress avoidance. The leaves are curled to form a tight cylinder enclosing a void region which is densely packed with trichomes. This region is continuous with the atmosphere via a narrow leaf margin gap, the aperture of which may be controlled by the relative turgidity of bulliform cells located between vascular ribs. Stomata are located only on the adaxial (inside) surface of the leaf. The leaves are fibrous because of the presence of numerous sclerenchyma (fibre) cells which, in the leaves examined, formed an almost continuous circle of bundles. When subjected to a water deficit, a preferential accumulation (compared on a per dry weight of tissue basis) of the osmoprotectant proline was observed in the leaf base, when compared with the immature or mature laminae. Conversely, the phy‐tohormone abscisic acid accumulated to a greater extent in the immature and mature laminae in comparison with the leaf base.