EFFECTS OF DIFFERENT SOURCES OF IRRIGATION WATER ON THE GROWTH OF ZINNIA ELEGANS L. UNDER DROUGHT STRESS

Abstract

The application of deficit irrigation water strategies to floriculture may make a significant contribution to irrigation water conservation. The purpose of this research was to evaluate the effects of different irrigation regimes for Zinnia ‘Solmar Yellow’ plants grown in an open field using different sources of irrigation water. Zinnia plants were grown in a field under three irrigation regimes, corresponding to 100% (control) of field capacity, 75%, and 50% of the irrigation needs. The water used for irrigation was derived from three sources: groundwater, distilled water, and blended water (50% ground-water + 50% distilled-water). In this investigation the vegetative growth, flower yield, pigment characteristics, ion content, leaf water potential, and leaf osmotic potential of plants exposed to these treatments were determined. Under the imposed drought conditions, the irrigation regimes with high or moderate quality water had the following effects: (i) a negative effect on the vegetative growth and flower yield, but a later flowering date; (ii) higher levels of leaf pigments in both distilled water and blended water irrigations at the 100% level; (iii) a decrease in leaf water potential and leaf osmotic potential; and (iv) a decrease in calcium, magnesium, and potassium ion contents but an increase in chloride and sodium ions under distilled water irrigation. In conclusion, irrigation with blended water (50% + 50%) at the 100% and/or 75% levels can be recommended for open field-grown Zinnia ‘Solmar Yellow’ production to enhance host plant tolerance to saline water and decrease the high cost burden of water desalinization.

Keywords

• deficit irrigation
• distilled water
• groundwater
• leaf water relations
• pigment characteristic
• water quality
• water regime