The Effect of Temperature and Salinity on the Germination of Calligonum comosum L`Her (Polygonaceae) in Two Different Populations in Saudi Arabia

Different degrees of temperature and salinity have been studied to evaluate their effects on the seed germination of Calligonum comosum L`Her grown in two different populations in Saudi Arabia. These two sites have been chosen in Saudi Arabian deserts , one in Nefoud El-Shakika south Onyza city on Najd plateau and the second west El-Dahnaa in the way between El-Riyadh and El-Damam cities, Kingdom of Saudi Arabia. Each of these locations were dominated by Calligonum comosum L`Her beside other species such as Artemisia monosperma, Ephedra elata and Haloxylon ammodendron. These two deserts are completely deferent in their climatic and edaphic factors, since climatic diagrams and soil chemical analyses have been investigated. Twenty plants, with plenty of fruits, from each site have been chosen and collected from each site during April 2003. Germination was in two variables, the number of days to start germinating and the final percentage of germination. The most favorable temperature was 10/20 ºC at seed depth 0.5 cm. and irrigation system every 48 hours 50 ml. dist. water supply. Meanwhile, the seeds in the two locations prefer non-saline media, as the best results obtained at salt concentration 0.0. Whereas the germination start again in Nefoud El-Shakika seeds only at salty media by the concentration of 150 mlmol. Nacl. The results have been discussed according to both differences in climatic and soil characters.