of parasitic plants from the same genus exhibits a high level of variability [86]. We can speculate that for
some reason this sequence is a kind of “hot spot” that also occurs in the mitochondrial genome of these
plants. Because of the high copy number of mitochondrial chromosomes, a mitochodrial probe could be
an easy applicable tool in identifying Orobanchespecies.
E. Conserved Chloroplast Spots
It was already mentioned that the plastome of parasitic plants (and also that of Orobanche) is relatively
well studied. Its dynamic structure has already been shown [84,92,95,97,98]. It was tempting to compare
the three O. ramosagenotypes from these highly separated geographic isolates (North America, Bulgaria,
and Spain) and also the very closely related O. aegyptiacaandO. oxylobaby hybridization with chloro-
plast probes. However, the chloroplast probes we used did not show any differences in the hybridization
pattern. We have probably been investigating the regions within the inverted repeats considered most con-
served [84].
V. PHYSIOLOGIC RELATIONS WITH THE HOST PLANTS—A CASE
STUDYThe influence of two species of the parasitic angiosperm Orobanche,O. ramosaL. and O. aegyptiaca
Pers., on the physiology of its tomato host was studied in a trays-growth system.
796 MINKOV AND LJUBENOVAFigure 5 Southern blot of Orobanchesp. DNA digested by EcoRI, probed with the chloroplast probe pRp
7-1. 1, Lambda HindIII; 2,3, O. ramosa, Spain; 4,5, O. aegyptiaca, Egypt; 6,7, O. oxyloba, Egypt; 8,9, O.
ramosa, Bulgaria; 11, O. ramosa, North America; 12,13, L. esculentum.