Adaptation of Plants to Saline Conditions in Arid Regions

Abstract

Saline regions are widespread throughout the deserts of the Middle East. In addition to other factors, this is mainly related to the geographical location of the region. It is bordered on several sides by large bodies of saline water, including the Mediterranean Sea, the Red Sea, the Indian Ocean, the Arabian Sea, the Gulf of Oman and the Arabian (Persian) Gulf. The presence of saline water bodies along the shores of the countries in the region creates vast areas of coastal salt marshes. In addition, there are extensive areas occupied by inland saline tracts. The area of salt-affected land is increasing in the region as a result of anthropogenic factors. It is significant that the Arabs, from time immemorial, have used the Arabic term sabkha (pl. sebakh) for these saline regions. They described them as being salty and more or less waterlogged in some cases. Only a few plants can grow under the conditions prevailing in the sebakh. Though Pallas (Schrader 1809) gave the name “halophyte” to such plants early in the nineteenth century, more than 15 centuries ago, the Arabs gave them the name hamdh, which denotes plants with salts in their bodies and growing in sebakh. Arabic lexicographers give various specifications for this group of plants, including: salty plants, plants with a sour taste, succulent plants that ooze water when punctured, plants with a disagreeable smell, plants used for washing clothes, utensils and the hands, plants that do not flower in spring but flourish during summer. These characteristics coincide with those assigned to halophytes as defined by modern scientists. It is even more interesting to know that the Arabs give examples of these hamdh plants as follows: rimth (Haloxylon and Hammada spp.), girm or shurah (Avicennia marina, Fig. 61), soweid (Suaeda sp.), shnan (Seidlitzia rosmarinus, Fig. 62) ikrish (Aeluropus lagopoides, Fig. 63), etc. The Arabs differentiate between hamdh plants and the kholla, which are the sweet plants, i. e. they do not contain much salt compared to hamdh plants, which are loaded with salt. Evidently, one can easily correlate these two terms — hamdh and kholla — with halophytes and glycophytes, respectively.