Fatemeh Rabizadeh

Abstract

The climate and soil characteristics of a given region play an important role in the endemism of plants. There are few studies on gypsophytes species vegetation in gypseous desert areas of Iran. Ecological adaptation in ecosystems such as gypsophytes species plant communities in Semnan province leads to the biodiversity of endemic plants. The genus Moltkia Lehmann consists of 7 species, belonging to the Boraginoideae family and the Lithospermeae tribe. Three species named M. caerulea, M. gypsaceae, and M. longiflora are listed in the flora Iranica. M. gypsaceae was first collected and named by Rishinger from the gypseous areas of Semnan. Studies have shown that M. gypsaceae is an independent species. In this paper, western parts of Semnan with an area of 28000 ha were studied as the main habitat of M. gypsace. Gypsum soils are widely distributed in certain areas in the western and northwestern parts of Semnan. Spearman’s rank correlation coefficient between descriptive variables was studied by ordination analysis on this species. M. gypsaceae was found in gypsum areas of Semnan with a frequency of 63% and high frequency at altitudes of 1230 to 1980 m above sea level. M. gypsaceae was found only in gypsum soils with endemic and gypsophytes species of Semnan, especially Astragalus fridae, but it does not exist in calcareous and salty communities. Studies on the adaptation of this species showed that this species like other gypsophytes species prefers gypsum and elevation and avoids magnesium and sodium. In the anatomical slices of different organs of M. gypsaceae, calcium sulfate crystals are well observed. M. gypsaceae has obvious and long trichomes with gypsum crystals. These features somehow show the plaster outflow pathway from calcium sulfate crystals called Cystolith, which is stored in its Lithocyste cells.