[Seed morphology and effects of sheep rumen digestion on seed germination of 28 Gramineae plants.]

An experiment was undertaken to compare the morphological characteristics of seeds of 28 Gramineae plants which widely distributed in north Xinjiang and to study their digestion in the rumen of sheep. After determining their morphological characteristics including seed length, width, height, seed shape index, 100-seed mass, and seed germination percentage, seeds were put into nylon bags and then placed in the rumen of sheep through a fistula. The bags were removed at different times to determine the morphological characteristics and seed germination rates. The results showed that 23 plant seeds were all elliptic or flat types except for Melica scabrosa, Agrostis ma-tsumurae, Poa bulbosa, Phleum pratense and Triticum aestivum. 100-seed mass of T. aestivum (3.25 g) and Avena sativa (1.69 g) were >1 g, and the 100-seed mass of the other seeds ranged from 0.01-1 g, indicating they were all medium or small type seeds. The color of seed coat was deepened, seed structure was destructed, and the lengths of seed appendages, i.e., awn, lemma and glume were decreased with increasing digestion time. Seed length, width, height, 100-seed mass were decreased with increasing digestion time, but the changes were not significant compared with the non-digested seeds. The seed germination percentages were extremely decreased after sheep rumen digestion. After 6 h of sheep rumen digestion, the germination rates of the seeds of R. kamoji and A. sativa were decreased to 0, and part of the seeds of other 26 plants still had some vigor.