Two pot experiments were conducted to investigate the effects of the
hydrophylic polymer "hydrosource" (HP) 1% as soil application, vapor gard (VG) 3%
as foliar spray, glycinebetaine (G8) 1.5% as foliar spray, HP+VG, HP+G8 in addition
to the untreated control plants on Gladiolus plants cultivar "White Prosperity' growing
in sandy soil under different irrigation regimes (100%, 80%, 60% and 40% of water
holding capacity, WHC). Growth, flowering character, corm and cormels production,
water use efficiency were investigated. Results revealed that flowering was delayed
as soil moisture level decreased up to 40% (WHC). In addition, plant growth under
severe water stress (60-40% WHC), dry weight of leaves, flowering spike Jength and
weight, flowering spike diameter, number and weight of florates, corm and cormels
weight and water use efficiency were significantly decreased. Using the HP, VG and G8 as individual treatments or in combination
improved the vegetative growth, flowering and corm production. The interaction
between water supply treatments and polymer, VG and GB showed almost significant
effects on the variables studied. These treatments tended to overcome the harmful
effects of water stress and reserved plant growth particularly at low water regimes
(60-40% WHC). The best treatment was recorded at HP+VG or HP+GB combined
treatments at 60% water supply which gave the best growth at low water supply thus
reduces the amount of water required in irrigation as a sequence of improving the
water use efficiency.