Karymorphological and molecular studies on seven species in Polygonoideae (Polygonaceae) in Egypt

Abstract

Seven species in four genera of the Polygonoideae (Polygonaceae) in Egypt were subjected to karyomorphological and molecular studies in order to identify their chromosomal characteristics and investigate their phylogenetical relationships by the conventional staining method and the 5S rDNA PCR. Seed germination after treatment with low temperature stratification and acidification by concentrated H2SO4 was studied. Three rates of germination were obtained in response to the cold stratification and acidification: 1) High in Polygonum equisetiforme, Persicaria lanigera, Pe. lapathifolia and Pe. salicifolia; 2) low in Rumex dentatus; 3) no effect in R. pictus and Emex spinosa. Variation in the chromosome complements number, length and structure were detected for Po. equisetiforme (2n=58; new count); Pe. lanigera (2n=40; new count); Pe. lapathifolia (2n=22); Pe. salicifolia (2n=60); Emex spinosa (2n=18; a new count); Rumex dentatus (2n=40); and R. pictus (2n=18; a new count). Eighteen polymorphic bands of 5S rDNA were used to determine the similarities among the taxa with the similarity coefficient ranging between 0.2 and 0.67.