Application of Inter Simple Sequence Repeat (ISSR) analysis to Detect influence of Drip-Irrigation Methods on Growth and Essential oil of Mentha piperata and Mentha arvensis Plants

The micromorphological characteristics of Opisthopappus taihangensis and Opisthopap-pus longilobus leaves were observed using scan-ning electron microscope and was found that they differ in characteristics and density of glan-dular hairs, size and density of stomata, pattern of anticlinal wall, wax characteristics, size and density of salt vesicles. These differences mainly resulted from the microenvironment heterogene-ity of these two species or different populations. The micromorphological characteristics of the leaves, stomata and salt vesicles could be regard-ed as important classification traits for O. tai-hangensis and O. longilobus. Correlation analysis indicated that there was a significant relationship between morphological characteristics, longitude and latitude. According to principal component analysis, the highest contribution came from the density of glandular hairs. All the 13 populations of Opisthopappus were gathered into two clus-ters based on the microstructural characteristics of their leaves. Three populations of O. longilo-bus were not gathered into a single cluster, but with different populations of O. taihangensis.