STORAGE ON MATERNAL PLANTS AFFECTS LIGHT AND TEMPERATURE REQUIREMENTS DURING GERMINATION IN TWO SMALL SEEDED HALOPHYTES IN THE ARABIAN DESERTS

摘要

To compare green and variegated foliage plants namely; Hedera helix, Ardisia pusilla and Scindapsus aureus weretreated under three different light intensities (2, 10 and 20 μmol·m-2·s-1) using florescent lights for three months, andphotosynthetic characteristics and chlorophyll content were measured. IMAGING-PAM chlorophyll fluorescence systemwas used to determine photosynthetic characteristics. The results showed that Fv/Fm (maximal PS-II quantum yield) and Y(II) (effective PS-II quantum yield) values were lower in variegated species compared to those in green species at 2 μmol·m2·s-1 light intensity. Although, Fv/Fm and Y (II) values in variegated S. aureus was lower than variegated H. helix, butvariegated S. aureus survived and Hedera helix plants died after low light treatment. In contrast, Fv/Fm and Y (II) valueswere increased in green and variegated species with increasing the light intensity, except Fv/Fm value for variegated S.aureus which was slightly decreased at 20 μmol·m-2·s-1 light intensity. The ETR (electron transport rate) value was alsolower in both green and variegated species at 2 μmol·m-2·s-1 intensity. ETR values saturated in green and variegated plantswith increasing the light intensity. Higher level of chlorophyll was obtained in green species compared to variegated speciesfor both low and high light intensity treatments. Chlorophyll content in green species decreased at 20 μmol·m-2·s-1 lightintensity, whereas in variegated species, chlorophyll content increased with increasing the light intensities. The results ofchlorophyll fluorescence parameters showed that especially low light intensity created stress condition in variegated foliageplants compared to green plants, and affected the normal growth and development.