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TRANSLOCATION AND TRANSFER OF NUTRIENTS IN VESICULAR‐ARBUSCULAR MYCORRHIZAS
Author(s) -
COOPER KAREN M.,
TINKER P. B.
Publication year - 1981
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1981.tb01728.x
Subject(s) - transpiration , hypha , biology , cytoplasmic streaming , chromosomal translocation , glomus , botany , phosphorus , transpiration stream , chemistry , photosynthesis , cytoplasm , biochemistry , spore , organic chemistry , gene
SUMMARY This paper reports the effects of environmental variables on the movement of phosphate by external hyphae of the mycorrhizal fungus Glomus mosseae , infecting Trifolium repens (white clover), across a barrier in soil‐agar/agar split‐plate cultures. Increasing the transpiration rate of the host increased the total P translocated by the fungus: the maximum rate obtained at full transpiration was 2·3 times that at low transpiration. Temperature also affected P transport, which was at a maximum at 15 to 25°C, but at 5°C only a small amount of P was transported. The maximum P flux in the hyphae, calculated for 20 to 25°C and a moderate host transpiration rate, was 2 × 10 ‐9 mol cm ‐2 s ‐1 . A cytoplasmic streaming inhibitor (cytochalasin B) prevented detectable movement of P across the barrier by the fungus and consequently had inhibited either the uptake or translocation of P by the fungus. Osmotic potentials of 1 or 2 bars in the medium from which 32 P was being absorbed did not appreciably alter the rate of transport of P. The results support the general conclusion that translocation of P in the hyphae occurs normally by protoplasmic streaming but there may also be a‘bulk flow’of hyphal contents under a water potential gradient.