藏羊瘤胃内容物浸泡对11种高寒草甸植物种子萌发的影响

Effects of soaking with Tibetan sheep rumen fluid on the seed germination of 11 plant species on alpine meadow of Qinghai-Tibetan Plateau, China

为明确藏系绵羊对青藏高原高寒草甸植物种子萌发特性的影响,利用藏羊瘤胃内容物对11种青藏高原东北缘常见植物种子浸泡处理12、24、36、48、60和72h后进行萌发试验。结果表明:供试11种高寒草甸植物种子的萌发因藏羊瘤胃内容物处理时间、种皮(果皮)完整性以及植物不同而异。划破种皮的黄花棘豆(Oxytropis ochrocephala)、去除果皮的无脉苔草(Carex enervis)、完整或去除果皮的草玉梅(Anemone rivularis)种子经藏羊瘤胃内容物分别处理12、12、12～36h的发芽率显著高于对照(P<0.05)。藏羊瘤胃内容物处理均显著抑制了破皮和完整的垂穗披碱草(Elymus nutans)、甘肃马先蒿(Pedicularis kansuensis)、醉马草(Achnatherum inebrians)、冷地早熟禾(Poacrymophila)、阴山扁蓿豆(Medicago ruthenia var.inschanica)种子的发芽率。短时间处理对矮生嵩草(Kobresia humilis)、酸模(Rumex acetosa)、西伯利亚蓼(Polygonum sibiricum)种子发芽率无影响而长时间则表现出抑制作用。破皮(划破种皮或去除果皮)种子的萌发响应比完整种子敏感,而完整种子变化趋势则相对平缓。短时间处理提高了去除果皮的草玉梅(12～24h)、无脉苔草(12h)和划破种皮黄花棘豆(12h)种子的发芽指数(P<0.05);随着处理时间的延长,发芽指数呈逐渐减小趋势。藏羊瘤胃内容物浸泡处理对高寒草甸种子萌发有促进、抑制和无影响3种作用,继而潜在影响高寒草甸幼苗的形态建成、种间竞争和群落结构。

To clarify the effects of soaking with Tibetan sheep rumen flmd on the seed germina- tion characteristics of the plants on the alpine meadow of Qinghai-Tibetan Plateau, the seeds of 11 common plant species in the northeastern part of Qinghai-Tibetan Plateau were collected and soaked with the fresh rumen fluid from Tibetan sheep, and a germination test was conducted after the seeds were soaked in the rumen fluid for 12, 24, 36, 48, 60, and 72 h, respectively. The seeds were incubated at 25 ℃ for 8 h and at 15 ~C for 16 h under natural light conditions. The results showed that the seed germination was affected by soaking time, seed coat treatment, and plant species. As compared with the control, the germination percentages of the scarified seeds of Oxytropis ochrocephala, coat-cut seeds of Carex enervis, and coat-cut or intact seeds of Anemone rivularis were increased significantly after soaking for 12 h, 12 h, and 12-36 h, respectively. The germination percentages of both the scarified and the intact seeds of Elymus nutans, Pedicu-laris kansuensis, Achnatherum inebrians, Poa crymophila, and Medicago ruthenia var. inschanica were declined significantly by any exposure to rumen fluid. The seed germination percentages of Kobresia humilis, Rumex acetosa, and Polygonum sibiricum were not affected by short duration treatment, but inhibited with increasing processing time. The germination of scarified seeds was more sensitive to the soaking, as compared to the intact seeds, and the latter was relatively sta- ble. The germination index （GI） of the coat-cut seeds of A. rivularis and O. ochrocephala and of the scarified seeds of C. enervis was increased significantly in short duration treatments of 12-24 h, 12 h, and 12 h, respectively, but decreased gradually with the extension of processing time. It was suggested that the seed germination of the plant species on alpine meadow performed differ- ently （enhanced, inhibited, or not affected） under the treatments of soaking with Tibetan sheep rumen fluid, which might affect the seedling recruitment, interspecific competition, and plant community structure on alpine meadow.