Natural extracts elevated drought resistance in Iris tingitana plant

Abstract: A study was carried out for two seasons (2020/21 and 2021/22) to examine the effect of various natural extracts individually or in combination on the drought resistance of Iris tingitana cv. Wedgewood. A mixture of sand and clay (1:1 v/v) was prepared as a growth media. The treatments were (0, 25, and 50 % water drought) with liquid active biostimulants (garlic and seaweed) five times intervals after two weeks from bulb germination. The results revealed that plants at different soil moisture with various biostimulants succeeded in producing flowers of the best quality. Water drought at 25% also increased chlorophyll (a & b) and carotenoids in leaves, while drought at 0% recorded the highest increase in gibberellic acid. At 25% drought, vegetative growth and flower parameters were at their highest levels. Moreover, water drought at 50 % increased abscisic acid (ABA), proline, and catalase. Additionally, increases in vegetative growth, the number of leaves, flower parameters, chlorophyll (a & b), and carotenoids in leaves were noted as a result of applying seaweed extract at a concentration of 10 mL L^-1; however, the best results for gibberellic acid were obtained using the highest concentration of garlic extract (500 mL L^-1). The interactions between treatments indicated the superiority of growing bulbs at 25 % water drought with applying seaweed extracted at 10 mL L^-1 that improved vegetative growth and most of the flower parameters. Meanwhile, treating plants at 25 % water drought with either seaweed at 5 mL L^-1 or garlic extract at 500 mL L^-1 realized the higher chlorophyll (a & b), carotenoids, and gibberellic acid (GA₃) content.