Phytoremediation Strategies for Overcoming Salinity Problems and Use of Halophytes as Companion Plants
In recent years, salinity has become the most important issue in fields, gardens and greenhouses as well. This, of course, has forced us to control saline areas, and therefore, many control mechanisms that have been put forward. Many of them (genetics, biochemical and physical) have not brought the desired success. Since salt is due to irrigation and natural causes, so, alternative control mechanisms should be provided. Recent advancement in this area is to obtain quick results from saline-affected areas without damaging the environment, and add these areas into the arable lands. One of those amelioration procedures is phytoremediation, which is an environmental-friendly green technology that is cost-effective and energetically inexpensive (Shah and Nongkynrih 2007). This procedure is generally performed by using halophytes which are known for their ability to adapt to salinity by altering their energy metabolism (Winicov and Bastola 1997). Adaptation of halophytes to salinity is generally associated with osmotic adjustment that leads to the accumulation of several organic solutes, such as free proline and sugars (Bohnert et al. 1995). Halophyte species (Atriplex spp., Suaeda spp., Salsola spp., Chenopodium spp., Portulaca spp.) could uptake the salt ions through their roots and metabolize or store in leaves (McKell 1994; Grieve and Suarez 1997). Therefore, they have potential to desalinize the salt-affected areas. Due to their biology and physiology, they could possibly be used as companion plants with crop plants. According to Qadir et al. (2002) phytoremediation has two main advantages for the farmers: Firstly, no fnancial outlay to purchase chemical amendments, and secondly, financial or other benefits from the crops grown during the amelioration process.