Allelopathic Tolerance and Physiological Response of Three Excellent Forages to the Root Extract of Euphorbia jolkinii

Purpose To study the allelopathic tolerance and physiological response of three excellent forages to the root extract of Euphorbia jolkinii, and to provide a basis for the selection of excellent grass species for reseeding and management of degraded mountain meadows in northwest Yunnan.

Methods The root extract of E. jolkinii was used as donor material, and three excellent forages (including Lolium perenne, Arundinella hookeri and Trifolium repens) suitable for reseeding and management of mountain meadows in northwest Yunnan were used as recipient materials, the evaluation of allelopathic tolerance to E. jolkinii root extract and their physiological responses were carried out.

Results The root extract of E. jolkinii showed significant allelopathic inhibitory effects on the seedlings growth, root vitality, the content of chlorophyll a, chlorophyll b and carotenoid, and the synthesis of gibberellin, zeatin, salicylic acid and jasmonic acid of three forages. The allelopathic tolerance of T. repens was strongest, followed by L. perenne, and the lowest in A. hookeri. Moreover, the inhibitory effect increased with the increase of mass concentration of extract. To resist allelopathic stress, the recipient plants increased soluble sugar and malondialdehyde content, antioxidant enzyme activity and abscisic acid biosynthesis to resist the adverse environment, enhancing its own resistance.

Conclusion The allelopathic effect of E. jolkinii is strong. In the mountain meadows with low and medium coverage of E. jolkinii, it is recommended to use the allelopathic tolerant species such as T. repens and L. perenne for reseeding and management.