Effects of Salicylic acid on Growth of Sour Orange ( Citrus aurantium) Seedling under Saline Water Irrigation

Abstract

An experiment was conducted at Hilla Agricultural secondary school in Abo-Gharaq – Babylon Governorate in a woody lath house by using 6 months old of sour orange ( Citrus aurantium L.) seedlings which grown in plastic pots filled with river soil. The aim of this experiment is to study the effects of spraying vegetative canopy with salicylic acid at a concentrations of (0, 100 and 200 mg.L-1 ) for 4 times with month interval using salinity Irrigation water with three different levels of salinity(1, 2 and 4 ds.m-1 ) for four months, to assess the effects of treatments and their interactions on seedlings tolerance to salinity. For this reason plant growth parameters (height of seedling , leaf area , fresh and dry weights of vegetative and roots) were measured .Results showed that increasing the levels of irrigation water salinity to 4 ds.m-1 significantly decreased all vegetative growth characteristics. Meanwhile, spraying with 200 mg.L-1 salicylic acid caused an increase in height of seedling , leaf area , fresh and dry weight of vegetative and roots. From the interaction between the water irrigation salinity and salicylic acid, the results indicated that seedlings spraying with 200 mg.L-1 salicylic acid irrigated with 2 ds.m-1 water salinity significantly increased the height of seedling and vegetative dry weight, while spraying with 200 mg.L-1 salicylic acid irrigated with 1 ds.m-1 water salinity significantly increased leaf area, vegetative fresh and root dry weights seedling compared with seedling spraying with 0 mg.L-1 salicylic acid irrigated with 4 ds.m-1 water salinity.