الفهرس 
Ecological StudiesOnly 14 pages are availabe for public view
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Abstract
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1. The Yemen Arab Republic lies between latitudes lao 40t,
17° a6’ north and longitude 4ao JO’, 46° Jl’ east and
bordered by Saudi Arabia in north, the Peoples Democratic
Republic of Yemen in the south and south east
and Red Sea in the west. However, the eastern botmdaries
are rather il1defined.
2. Yemen i: ~ocated in the northern stretchs of the tropical
zone with Vwo rainfall maxima: one in April-
May, the other in July-September and a long dry, almost
rainless period of four to five months during the late
autumn and winter.
J. An ecological survey of a part of Sanata-Taiz road
waB made. The plant cover may be classified in relation
to land-form into:
(a) Vegetation of table land, (b) Vegetation of rocky hill
countries or ridges and (c) Vegetation of slopes of
mountains. The vegetation of various geomorphological
units was subdivided into communities. The most prominant
feature observed was the repetition of the
plant communities with the repetition of habitats.
The phytochemical screening of ten species representing
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different ~ami1ies revealed variations in their constituenta
according to the characteristics of their
families.
~. The species concerned, Rumex nervosus, inhabits various
habitats ranging from moist land to vertically cutcliff
mainly of barren rock. Three different habitats
namely: (a) level habitat, (b) slope habitat, and
(c) 5umara mountain at elevation of )000 m were selected
for the study of the behaviour of Rumex nervosuS.
The behaviour of the root system was described in the
different habitats which may be vertical, horizontal,
forming rhizomatous sucker, or turn up and screw
according to the nature o~ the substratum.
6. 50il texture, water holding capacity, moisture equivalent
are among the physical factors affecting the
life of the plant. The pH of the soil was found to
be moderate alkaline (8.~to 8.8).The electrical
conductivity for all samples were less than 1 mm hosl
cm indicating that there was no development for alkalinity
or salinity in the soil supporting Rumex
nervosus in the three different habitats. The organic
matter content, calcium carbonate content and soluble
cations and anions were also determined.
The soil and plant moisture contents showed monthly
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fluctuations owing to the seasona~ity of rainfall and
other climatic factors.
7. With variation in time of flowering and fruiting, the
phenological behaviour of the plant was the same in
the three different habitats. The plant does not pass
a pronounced dormancy.
The enlarged perianth around the fruits of the plant
• was characterised by its pink colour which apparently
started to appear after fertilization. The colour
intensity uhich depends upon the degree of exposure
to direct light was attributed to the presence 01’
anthocyanin pigments.
8. The study of seed germination under the influence of
some factors revealed that the water extract obtained
from soaking of seeds with the two enlarged sheathes
inhibited the germination of wheat grains. This might be
due ’to ei.’ther’to i;he etfect of ’tN’nins on enzymatic activity,
or to the presence of growth inhibiting substances in
the outermost sheath of the seed.
9. The study of the community type of Rumex nervosus was
carried out by means of studying the analytical as
well as the synthetic characters. The similarity between
the communities in the three different habitats
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was ca1cu1a~ed according ~o simi1ari~y quo~ien~
(Sorensen, 19~8).
10. Concerning the phy~ochemica1 inves~iga~ion of ~he p1an~
i~ was fO\L~d~ha~ ~he va1ues ~f ~o~a1 ash con~en~,
wa~er so1ub1e ash, acid inso1ub1e ash, crude fibre
con~en~ and ascrobic acid con~en~ were higher in ~he
shoo~s ~han in ~he frui~s in bo~h habi~a~s name~y
Sumara moun~ain and ~ab1e 1and. Frui~s showed higher
va1ues of tota1 ni~rogen con~en~, crude pro~ein con-
~ent and to~a1 1ipid content than shoots in the bo~h
mentioned habi~ats.
11. The data of extraction with successive se1ective
organic solvents revea1ed ~hat the fruits yie1ded a
higher percentage of ~he tota1 residue being ~8.07%.
12. The pre1iminary phytochemica1 screening of each p1ant
organ inc1uded the tests for carbohydrates and/or
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g1ycosides, stero1es, terpenes, tannins, saponins,
f1avonoids, a1ka1oids, muci1age, resin, ch10rides
and su1phates. The resu1ts obtained indicated tha~
terpenes and saponins were absent in the fruits whi1e
-the a1ka1oids were absent in both shoots and fruits.
1). Chromatographic ana1ysis of mucilage hydro1ysates revea1ed
the presence of D_g1ucose and D-g1ucouronic
acid in both fruits and shoots.
. By chromatographic analysis of free and combined sugars.
glucose, galactose, sucrose and tructose were the ,.
deteoted free sugars while gluoose, galactose, fruc-
,!, tose, arabinose and rhamnose were the deteoted combined
sugars.
j 15. The tree and protein amino acids w~re identified
chromatographically and the results revealed the
presence of twelve free amino acids and eleven protein
amino acids namely, histidine,arginine, glycine,
iI glutamic acid, threonine, tryptophane, isoleucine,
’\ alanine, valine, leucine, and lycine.
16. Alcoholic extracts of both fruits and shoots contained
citric, tartaric, and succinic acids.
17. The percentage of gallotannins in fruits and shoots
of Rumex nervosus were tound to be 10.45% and 15.60%
respectively. Chromatographic analysi~ ot acid hydrolysates
ot gallotannins indicated that it consisted
of gallic acid and glucose.
18. The flavonoid contents were studied using paper, thin
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layer, and column chromatographic techniques which
revealed the presence of rutin glycosides. By means
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ot acid hydrolysis (5% H2S0~) ot the separated rutin
tollowed by ethyl acetate extraction, the sugar part
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(glycone) was identified as glucose and rhamnose,
while t~e nonsugar part (aglycone) was identioal to
quercetin. Some properties of the separated flavonoids
were studied.
19. Anthocyanin of the coloured fruits of the plant was .
extracted by l~ HC1 in methanol. The method was based
on partial purification of the extract using paper
• chromatographic technique. The aglycone part was isolated
from glycone one by means of hydrolysis at 97°C
followed by extraction with ethyl acetate.
20. The saponins present in the shoot of the plant were
extracted by means of 80% ethyl alcohol and investigated
chromatographically and by means of IR spectrometry.
On hydrolysis of the isolated saponin, xylose
and galactose were detected in sugar moiety. The
aglycone part of saponin had a m.p. of 162°C. The IR
spectrum and other properties were studied.
21. The physical and chemical properties of the oil in
the fruits and shoots of Rumex nervosuS were studied.
Thin layer chromatography of the unsaponifiable fraotion
of the oil revealed the presence of four steroidal
compounds. The main sterol was isolated by meanS of
column chromatography and crystallized from chloroformmethanol.
The isolated crys~al. had a melting point
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of 1)90C which did not show any depression upon mixing With
an authentic sample of B-sitosterol.
Chromatographic separation of the saponifiable fraction
of the oil revealed the presence of the unsaturated
fatty acid, linolenic acid, while the saturated ones
wore identical with stearic and palmitic acids.
22. A crystalline principle was isolated from petroleum
ether extract by using two different methods. It was
soluble in ether, chloroform and ethyl acetate with
m.p. 7)-7qOC. The UV and IR spectra were’also determined.
The microanalysis of the isolated compound
indicated that it consisted of C, 8).); H, 5.5, 0, 11.2
with an emp1ri.cal formula of C10H80. SuJ.phur, mtrogen
and halogens were completely absent.