X-ray analysis of seed quality of Eucommia ulmoides Oliv. of different geographical origin

Abstract

The results of X-ray studies of Eucommia ulmoides Oliv. seeds, which are characterized by very deep dormancy, are presented. The experiments were carried out on seeds of different geographic origins: Russia (Kropotkin, North Caucasus) and the Republic of Vietnam (Laitau province). Seeds in the North Caucasus were collected from the surface of the earth in February and therefore underwent natural stratification under the snow cover, while seeds in Laitau province were collected from trees after they matured and stored in a dry, non-stratified state until analysis. The types of identified hidden seed defects are described. The data of individual X-ray characteristics of each investigated seed («parametric passport») are given. Based on the presence of defects, it can be concluded that seeds from the Laityau province should have better sowing qualities compared to seeds from Kropotkin. Differences in the biometric parameters of two-year-old eucommia seedlings of different geographic origin are not significant. However, the germination rate of seeds from Kropotkin is much higher than their Laiteau. This can be explained by the varying degrees of natural readiness of the seeds for sowing. The results of X-ray analysis of stratified seeds of E. ulmoides from Kropotkin coincide with the results of their germination. However, it is not possible to assess the viability of eukomia seeds not subjected to stratification based on the results of determining their good quality by the X-ray method. To obtain the germination of seeds corresponding to the potential of their sowing qualities (according to the performed X-ray analysis) for Eucommia seeds, a long-term (at least 3–4 months) cold stratification is recommended.