Effects of animals rumen juice on seed germination of Vicia angustifolia with different seed size

To help understand the effects of grazing on seed germination characteristics of Vicia angustifolia L., we conducted a laboratory germination experiment of V. angustifolia L., which is a main companion species of Leguminosae family in alpine grassland of the Qinghai-Tibetan Plateau, using Yak and Tibetan sheep rumen juices along three seed size categories. Results show that Yak and Tibetan sheep rumen juices significantly restrained germination of seeds for three size categories, decreased seed germination percentage, germination index and prolonged first and mean germination times. Meanwhile, the medium-size seeds presented the maximum geminated percentage, and the larger seeds germinated better than the smaller seeds. Additionally, there were significant interaction effects between rumen juice and seed size on seed germination of V. angustifolia . Our results suggest that grazing pressure of animal feed present have significant negatively effects on seed germination for V. angustifolia with different seed size in alpine area of the Qinghai-Tibetan Plateau. Key words : Vicia angustifolia, rumen juice, seed mass, germination, herbivory.