PHOTOSYNTHETIC RESPONSE, BIOMASS DISTRIBUTION AND WATER STATUS CHANGES IN RHAMNUS ALATERNUS PLANTS DURING DROUGHT

Rhamnus alaternus is used as an ornamental plant in Mediterranean regions.
The objective of this research was to analyse the ability of R. alaternus to overcome water stress in terms of adjusting its physiology and morphology.
For this, potted plants were grown in a greenhouse and subjected to water stress by reducing irrigation water by 50% compared with the control (irrigated to container capacity). The water stress produced the smallest plants at the end of the experiment.
After ten months of drought, the leaf area, leaf number, total dry biomass and height had decreased, although the root/shoot ratio and succulence were not affected.
Total root length decreased with water stress, a reduction observed for all sizes of root.
Biomass distribution in the different parts of the plant (root, shoot and leaf) was similar in both treatments.
An improvement in water use efficiency was seen in water deficit plants.
Throughout the experiment, leaf color, chlorophyll, fluorescence (F_v/F_m) and ion leakage (membrane damage) were not affected by deficit treatment.
Water stress lowered the predawn and midday leaf water potentials, although the decrease in the latter parameter was more affected by the climatic conditions.
It is concluded that water deficit leads to morphological changes in this species as an adaptation to Mediterranean conditions.

XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Advances in Ornamentals, Landscape and Urban Horticulture

S. Álvarez, M. Castillo, J.R. Acosta, A. Navarro, M.J. Sánchez-Blanco

water deficit, ornamental, evergreen, gas exchange, osmotic adjustment, water use efficiency, growth

https://doi.org/10.17660/ActaHortic.2012.937.104