Uptake And Partitioning Of P-32 And Zn-65 By White Clover As Affected By Eleven Isolates Of Mycorrhizal Fungi

We compared the effect of eleven mycorrhizal fungi populations (Glomus spp.) from two different climatic regions (Iran vs. Switzerland) on the uptake and partitioning of P-32 and Zn-65 by white clover (Trifolium repens L. var. Milkanova). Fungi significantly differed in the colonization of roots with hyphae, vesicles or arbuscules and in their effect on the uptake of (32)p or Zn-65 by white clover. Fungi also differed in their effects on the percentages of (32)p or Zn-65 transported to the plant tops. There was no relationship between the uptake of (32) P and that of Zn-65 in plants colonized by different fungi. Isolates Z7 and Q12 (from Iran) were superior to Swiss isolates for their effect on the uptake of zinc (Zn) by white clover. Among the Swiss isolates, that from Langwiese and Hausweid resulted in the highest and lowest partitioning of both P-32 and Zn-65 to the plant tops, respectively. We conclude that the effectiveness of vesicular arbuscular mycorrhizae in uptake of phosphorus (P) and Zn may be nutrient specific and that some fungal isolates may also affect the relative partitioning of P and Zn between plant roots and tops.