IMPACT OF TEMPERATURE AND SOWING DEPTH ON GERMINATION, GROWTH AND DEVELOPMENT OF THE INVASIVE SPECIES ASCLEPIAS SYRIACA

Abstract

Asclepias syriaca is a perennial species, native to North America. In Romania, being introduced as an ornamental species, in present being found in different habitats (agroecosystems) and on ever wider areas causing damage. Although the basic biological characteristics of Asclepias syriaca are known, its control is a significant problem. As a result, we hypothesized that temperature and sowing depth can be used to reduce the population of Asclepias syriaca. To test this, the seeds were put at 5?C, 27?C, room temperature, after which they were sown at a depth of 0.5 cm and 1 cm respectively, the responses regarding the germination and growth of Asclepias syriaca plants were studied in the laboratory. Following protocol was determined: the length of the roots, the height of the plants and the fresh weight. Asclepias syriaca seeds sown at 1cm depth showed a higher germination percentage compared to those sown at 0.5 cm. The seeds exposed at 27?C were the first to germinate exerting a higher height. Those subjected to the clipping method did not show a stimulation of the germination percentage and the roots and height showed the lowest values. At 5?C the germination percentage is reduced.