Record ID No. |
2011 |
Author(s) |
Specialized mycorrhizal colonization pattern in achlorophyllous Epirixanthes spp. (Polygalaceae) , 2007 |
Affiliation |
University of Marburg, Fachbereich Biol, D-35032 Marburg, GERMANY |
Title |
Specialized mycorrhizal colonization pattern in achlorophyllous Epirixanthes spp. (Polygalaceae) |
Source. Vol.(no):Page |
Plant Biology.9(6):786-792p. |
Categories |
Mycorrhiza General |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Organism |
n.a. |
Country |
GERMANY, Europe |
Abstracts |
Roots of the achlorophyllous Epirixanthes papunana and E elongata were sectioned
in complete series in order to reconstruct the three-dimensional mycorrhizal colonization pattern
within their tissues. Hyphal morphology, vesicles, as well as the exclusively intracellular mode
of colonization indicate a Paris-type of arbuscular mycorrhiza showing a hitherto unknown
colonization pattern: (1) the outer cortex is colonized by persistent straight-growing hyphae
which branch in a cascading manner, (2) a specific layer (called layer 2) is inhabited by
persistent hyphal coils, (3) in the cells of the anatomically distinct inner cortex parenchyma
layer (called layer 1) the hyphae immediately degenerate, and (4) the layer outside to layer 2
(called layer 3) is either transitional layer 2 when penetrated from the outer cortex or the
fungal material degenerates when colonized from the layer 2. This complex colonization pattern is
a reasonable adaptation to the particular demands of Epirixanthes as a myco-heterotrophic plant.
It not only allows a sustained benefit from the fungal symbiont but also provides a two-level
distribution system of hyphae within the roots. The outer cortex hyphae function as a permanent
intraradical resource of living fungi providing connection to the external mycelium as well as a
coarse distribution of hyphae within the root. Layer 2 represents the fine scale distribution of
hyphae, having access to all potentially digesting cells of the layers 1 and 3. Common structural
features of mycorrhizae in myco-heterotrophic plants are pointed out in order to find putative
prerequisites for their heterotrophic mode of life. |