Enhancement of drought tolerance in salvia coccinea plants by irradiation with gamma and laser pre-treatments

الملخص EN

Gamma- and laser-irradiated seeds were grown under drought stress conditions to evaluate the irradiation effects on growth, flowering and some physiological traits of Salvia coccinea plants grown in pots.

Pre-sowing gammairradiation at 5, 10, 15, 20 and 25 k.rad or laser irradiation (He-Ne) for 5, 10, 15 and 20 min.

exposure time were applied.

Soil moisture levels were imposed by irrigating the plants with 100 (control), 80, 60 and 40% of field capacity (F.C.).

Results indicated that laser-irradiation was less effective than gamma-irradiation on drought stress.

Plants grown under high water stress (40 and 60% F.C.) resulted in significant decreases in all vegetative growth and flowering parameters tested.

The decrease in plant growth and flowering quality induced by water deficit was associated with a reduction in leaf relative water content and increases in total phenols, proline and abscisic acid contents in plants.

Under water stress, there were significant changes in the activities of the defensive enzymatic system in leaves.

The activities of peroxidase and catalase in irradiated plants with gamma or laser were higher at 60% F.C.

than in other water stress treatments.

In general, it can be concluded that initiated resistance of Salvia coccinea plants under drought stress are enhanced after pre-sowing seed irradiation with gamma at 15-25 k.rad followed by laser for 10 min.

exposure time.

The most effective combination was gamma-radiation (15-25 k.rad) plus soil moisture content at 80% F.C.

This combined treatment protects plants from the deleterious effects of drought.

It can tolerate soil water deficit and consume less irrigation water by 30%.