Allelopathic effects of Viburnum nervosum on seed germination and seedling growth of Abies pindrow Spach.

To understand the process of natural regeneration failure in Abies pindrow forests in western Himalayas, the allelopathic interactions of one under-storey shrub species (Viburnum nervosum D. Don) were studied with keystone species (Abies pindrow Spach). The effects of foliage leachates (0%, 5%, 10%, 15%. 20%) of V. nervosum were investigated on the seed germination, radicle, plumule and seedling growth of A. pindrow. The leachate concentrations inhibited the seed germination, radicle and plumule growth, seedling height and seedling basal diameter of the receptor species. Trans-5-p-coumaroylguinic acid, p-coumaric acid, m-coumaric acid and flavanol were identified as phenolic phytotoxins produced in V. nervosum leaves, which may be responsible for the inhibition of various physiological processes in receptor tree species. Allelopathic interactions of V. nervosum may explain the relative absence of seed germination, poor establishment and growth of seedlings of A. pindrow on the forest floor in these temperate forests. Knowing such tree/under-storey interactions can help the foresters in regenerating these forests by manipulating the silvicultural practices. However, further research is required to identify such other allelopathic interactions in natural habitat of forest tree species in the region.