oa Propagation of potential native plants for urban landscape in Gulf countries

Gulf Countries have an arid/hyper arid climate with little precipitation, a low groundwater recharge rate and no reliable, perennial surface water resources. The total consumption of ground water resources in these countries exceeds with times its natural recharge capacity. However, urbanization expansion and the need for green landscapes in most of the Gulf cities increase the demand on the irrigation water. This puts great stress on the limited water resources in the Gulf Countries. One way for the sustainable use of the limited water resources is through the use of native desert plants in landscaping the cities. Native plants are those that have evolved naturally under the harsh environmental conditions of the GCC countries. They can tolerate very high temperatures, drought (water deficit) and high salinity. Native plants provide a beautiful, hardy, drought resistant, low maintenance landscape while benefiting the environment. Besides that they are adapted to the local climate, geography and hydrology and should require little or no fertilizers and water for growth and maintenance, given that native plants have adapted and evolved to local conditions over thousands of years. In addition, the beauty of native wildflowers and grasses creates a sense of place. The native plants increase our connection to nature and provide a beautiful place to relax. Native plants are also resistant to most kinds of local insects and resistant to most pathogens. Consequently, using native plants would reduce the use of the hazardous chemicals and hence save the environment in a sustainable way. In the present study, we screened more than 100 plants native to the GCC region to select the most potential in landscaping. Plants are selected based on their appearance, texture and tolerances to drought and salinity, fit as ornamental plants. Priorities are given for species that have wide ecological amplitudes. These species can tolerate wide range of environmental (especially soil factors) and hence would be more successful under new conditions in of the urban environment. The main challenge facing the use of native plants in landscaping is the great dormancy in their seeds, which results in very low germination rate. In addition, there is a lack of propagation information for most of the native desert plants used in the urban landscaping. Our results showed that large number of studied plants have little dormancy and can germinate in a wide condition of temperatures and light. However, many other potential plants have very deep dormancy. Treatments with different growth regulators, such gibberellic acid, kinetin and thiourea and fusicoccin are currently in progress to break physiological dormancy. Other treatments, such as sulfuric acid, are also carried out to break physical seed coat dormancy. In addition, seeds are stored under different conditions to break the morphological dormancy.