Responses of stomata to environmental factors-experiments with isolated epidermal strips of Polypodium vulgare

Abstract

Stomatal responses in isolated epidermis strips of the fern Polypodium vulgare to humidity and temperature were investigated. Movements were observed under a microscope, the epidermis being mounted in a climatized chamber above a water table, the gap between tissue and water being similar to that between epidermis and mesophyll in the intact leaf. Stomatal aperture increases as the water vapor deficit is decreased. The relationship is approximately linear until full aperture is reached. The speed of stomatal movement depends on the magnitude of the change in saturation deficit. Temperature also exerts a strong influence on stomatal aperture. Low temperature causes closure. Maximal opening occurs between about 20° C and 28° C. Higher temperature leads to a slight reduction in aperture. The temperature range corresponding to maximum apertures depends on the temperature that prevailed during cultivation of the plants. The data are used to construct three-dimensional graphs showing stomatal behavior under the simultaneous influence of temperature and humidity for plants of different precultivation. The possible mechanisms that lead to the observed stomatal reactions are discussed.

International research on cassava photosynthesis, productivity, eco-physiology, and responses to environmental stresses in the tropics

“…Numerous more recent reports showed that several herbaceous and woody plant species tended to close their stomata in response to dry air whether within a plant community or in attached leaves or isolated epidermal strips (e.g. , Lange et al 1971, Schulze et al 1972, Aston 1976, Hall and Hoffman 1976, Rawson et al 1977, Sheriff and Kaye 1977, Lösch 1977, 1979, Lösch and Schenk 1978, Tibbitts 1979, Ludlow and Ibaraki 1979, Lösch and Tenhunen 1981, Farquhar et al 1980, Jarvis 1980, Tazaki et al 1980, Hall and Schulze 1980, Bunce 1981, Leverenz 1981, Fanjul and Jones 1982, Meinzer 1982, Kaufmann 1982, Schulze and Hall 1982, Gollan et al 1985, Körner 1985, Körner and Bannister 1985, Schulze 1986, Jarvis and McNaughton 1986, Ward and Bunce 1986, Bongi et al 1987, Hirasawa et al 1988, Pettigrew et al 1990, Held 1991, Kappen and Haeger 1991, Tinoco-Ojanguren and Pearcy 1993. This apparently widespread phenomenon indicated the need for further detailed studies, and for its inclusion in plant community/environment ecosystem models (Jarvis and McNaughton 1986).…”

How do stomata respond to water status?

“…The biphasic WWR/RWR response is observed in angiosperms following any hydraulic perturbation, including a change in evaporative demand (Mott et al ., ), source water potential (Comstock & Mencuccini, ), hydraulic conductance (Saliendra et al ., ) or leaf excision (Powles et al ., ). An exception is seedless plants, which appear to lack a WWR and exhibit only a rapid RWR (Lange et al ., ; Lösch, , ; Brodribb & McAdam, ). The duration of the WWR varies widely across taxa, from c .…”

Evolution of the Stomatal Regulation of Plant Water Content

“…Such a linkage means that guard cells lose turgor as leaf water potential declines, passively closing the pore and dramatically reducing evaporation ). This extremely simple means of stomatal closure in response to declining leaf water status requires no metabolic input or complex signaling intermediates and is well described in lycophytes and ferns (Lange et al, 1971;Lösch, 1977Lösch, , 1979Brodribb and McAdam, 2011;Martins et al, 2016). Stomatal responses to changes in vapor pressure deficit (or the humidity of the air) are thus highly predictable in these early vascular plants based on a passive model that links leaf turgor with guard cell turgor Martins et al, 2016).…”