M. Giovannetti et al., Microchambers and video-enhanced light microscopy for monitoring cellular events in living hyphae of arbuscular mycorrhizal fungi, PLANT SOIL, 226(2), 2000, pp. 153-159
Mycelial elongation and protoplasmic flow rate in vitro were monitored for
germinated spores of Gigaspora rosea and Glomus caledonium respectively, gr
owing on membranes in microchambers, by using a combination of time-lapse a
nd video-enhanced light microscopy and image analysis. The microchambers al
lowed continuous observation of living mycelium over a period of several ho
urs during which protoplasm flow and bidirectional movements of cellular or
ganelles and particles were monitored in individual hyphae. Growth rate of
G. rosea hyphae, calculated 8 days after germination, was 2.64 mum/min. Pro
toplasmic flow rate, measured on the basis of the movement of particles, ra
nged from 2.98 to 4.27 mum/s in living hyphae of G. caledonium. We showed t
hat G. rosea, when growing in axenic culture in the absence of the host, ce
ased growth within 8 days of germination and underwent a process of protopl
asm retraction from hyphal tips, leading to the formation of empty mycelial
segments. A process of resource reallocation was inferred in spores of G.
rosea showing multiple germination. Detailed developmental studies of livin
g hyphae by using microchambers could provide useful information on spatio-
temporal dimensions of cellular events occurring in arbuscular mycorrhizal
fungi.