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Advisor(s)
Abstract(s)
High relative air humidity (RH>85%) during cultivation is known to reduce
the vase life of cut roses, but the magnitude of such effect is cultivar dependent. The
reasons behind this genotypic variation are not yet known. In this study, the stomatal
density and stomatal responses to two closing stimuli (i.e. desiccation and abscisic
acid (ABA) application) were evaluated using detached fully expanded leaves of two
contrasting rose cultivars in their sensitivity to high RH (‘Frisco’ and ‘Prophyta’)
which were grown at moderate (60%) and high (90%) RH. High RH significantly
increased the stomatal density in both cultivars, but the effect was stronger in the
tolerant cultivar (14% increase for ‘Frisco’, 8% increase for ‘Prophyta’). ‘Frisco’ also
showed a higher stomatal density at moderate RH (53 stomata/mm2) as compared to
the sensitive cultivar (43 stomata/mm2). Moreover, high RH decreased the speed and
the degree to which stomata responded to different closing stimuli in both cultivars,
resulting in higher transpiration rates. This effect was more pronounced in the
sensitive cultivar. It was concluded that the tolerance to high RH during cultivation is
related to more responsive stomata, while the stomatal density is apparently an
irrelevant character. Furthermore, this study showed that the rose guard cell
dimensions are not representative for the pore dimensions.
Description
Keywords
Abscisic acid Desiccation Rosa hybrida Stomatal density Stomatal size Pore Size
Citation
FANOURAKIS, D....[et al] - Cultivar differences in the stomatal characteristics of cut roses grown at high relative humidity. In International Symposium on Postharvest quality of Ornamental plants, 9, Copenhagen, Dinamarca, 11-14 Agosto, 2008 - Proceedings of the 9th International Symposium on Postharvest quality of Ornamental plants. ISHS Acta Horticulturae. ISSN 0567-7572. N.º 847 (2009). p. 251-258