Figure 2. The fully hydrated leaf.
The leaf surfaces.
(2a) The abaxial surface print, showing stomata, elongated epidermal cells and short egg-timer shaped cells (arrow) (bar = 50 m). (2b) SEM micrograph of the lower cell surface with a stoma and egg-timer shaped cells (arrows). No epicuticular waxes are visible (bar = 10 m). (2c) The adaxial surface print with leaf sector protrusions, stoma layers, small egg-timer shaped cells (arrow) and irregularly distributed hairs (double arrow) (bar = 100 m). (2d) SEM micrograph of the upper surface covered with epicuticular waxes (bar = 10 m).
Morphological and ultrastructural aspects of dehydration and rehydration in leaves of Sporobolus stapfianus
by Dalla Vechia F., El Asmar T., Calamassi R., Rascio N., Vazzana C. (1998)
Francesca Dalla Vecchia1, Toufik El Asmar2, Roberto Calamassi3, Nicoletta Rascio1 & Concetta Vazzana2
1 Dipartimento di Biologia, Universita di Padova, Via Trieste 75, I-35121 Padova, Italy;
2 Dipartimento di Agronomia e Produzioni Erbacee, Universita di Firenze, Piazzale delle Cascine 18, I-50144 Firenze, Italy;
3 Dipartimento di Biologia Vegetale, Lab. di Botanica Agraria e Forestale, Universita di Firenze, Piazzale delle Cascine 18, I-50144 Firenze, Italy
In Plant Growth Regulation 24: 219-228 – DOI: 10.1023/A:1005853527769 –
The resurrection species Sporobolus stapfianus Gandoger has been studied by LM, TEM and SEM in order to define the leaf morphology and fine structure and to analyse the cellular changes occurring during the processes of dehydration and rehydration of the plant.
Some characteristics of the fully hydrated leaf and some ultrastructural and physiological events which take place during leaf wilting are discussed in relation to their possible role in plant desiccation-tolerance.
The leaves of S. stapfianus show several characteristics common among xerophytic species. In the resurrection leaf they could play a role in slowing down the drying rate, thus leaving time to activate the mechanisms protecting the cell structures against drought damage.
Actually, the S. stapfianus leaves do not undergo important cellular alterations during dehydration. The chloroplasts, in particular, retain part of their photosynthetic pigments and thylakoid membranes. Upon rewatering leaf recovery is rather fast and the tissue structure and cell organization of the fully hydrated state are already regained after two days.