الفهرس 
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Abstract
The present study was undertaken to discriminate among nine growth forms of
Haplophyllurn tuberculaturn collected from six natural sites along the Mediterranean
coastal desert of Egypt. Three approaches were suggested to study the diversity among H
tuberculaturn growth forms using macro-and micromorphological characters, molecular
markers and allelopathy as a chemical marker.
The current implications suggested that ECT7 collected from Abo- Tamr village
was apart from the other growth forms by using macro-and micro morphological
characters. However seed protein electrophoresis as a molecular marker separated ECT3
and ECT4 collected from El-Karma village and El-Gophera village from the other
ecotypes, but Random Amplified Polymorphic DNA Analysis (RAPD) separated ECT6
and ECT7 collected from Abo- Tamr village from the other growth forms. Although, each
type of data separately offers different sort of aggregation for the ecotypes. By using
morphological and molecular characters collectively, H tuberculatum can be
discriminated into two ecotypes. The first ecotype was ECT7 which characterized by
presence of fused filaments while the other ecotypes have free filaments. H tuberculaturn
are morphologically similar to H blanchei and H buxbaumii. They are the species with
the most widespread distribution within Haplophyllum and with the highest level of intra-
specific morphological variability. H tuberculatum and H buxbaumii exhibited the same
character states for many morphoiogical characters so to determine this taxonomic rank
need to gain a deeper understanding and expand the current infra-specific sampling and
perform more detailed molecular and morphological analyses of both H buxbaumii and
H blanchei.
The allelopathic potential of the aqueous extracts of H tuberculaturn growth
forms on germination efficiency and growth parameters of Lepidium sativum and
Raphanus sativus seeds (as bioassay materials) were completely studied. At the full-
strength concentration (l 00%), GF3 and GF5 exert the highest allelopathic effect on the
germination percentage (GP), inhibition percentage (JP), the time taken for 50%
germination (Tso), mean germination time (MGT) , germination energy (GE) and seed
germination index (SGJ) of Lepidium sativum and Raphanus sativus seeds, respectively.
In the two investigated species hypocotyl length ’was more sensitive than radicle length
under aqueous extract of H tuberculaturn growth forms (HT AE). It was obvious that the
alIelopathic effect was prominent in L. sativum compared with R. sativus indicating the
resistance of the latter to the allelochemicals extracted from H tuberculaturn aqueous
extract (HTAE) growth forms. Using allelopathy as a chemical marker differentiated
between three different growth forms (GF3, GF5 and the rest of the studied growth
forms) need further studies using more highly specific techniques for separation and
isolation of a variety of allelochemicals.