3.6 Fatty acid profile
The effect of water stress and PGPB treatment on the obtained fatty acid
profiles in gas chromatography is depicted in Table 5. Water stress
increased the main saturated fatty acids (SFA) content including
palmitic acid (C16:0) and stearic acid (C18:0) in no-inoculated and
inoculated plants, but the content of palmitic acid and stearic acid
decreased in all of the inoculated plants in comparison with the
no-inoculated plant. As illustrated in the Table 4 the highest palmitic
acid and stearic acid (9.99 and 3.69% respectively) in no-inoculated
plants were related to B0D2 and in inoculated plants, it was related to
B1D1which accounted 9.18 and 3.49% respectively for palmitic acid and
stearic acid content. The effect of water stress and PGPB on
monosaturated fatty acids (MUFA) were significant. Oleic acid (18:1),
eicoseonic acid (20:1) and erucic acid (22:1) content significantly
declined by 46, 22.5 and 45.9 % under water stress respectively. In
inoculated plants, the highest oleic acid and eicoseonic acid content
were seen in mild water stress (B1D1). In comparison with control, the
highest and the least erucic acid content is related to B1D0 and BD2
respectively. As the increase of erucic acid content coincided with the
increase of drought stress levels. The highest proportion of fatty acids
was related to polyunsaturated acid (PUFA) including linolenic acid
(C18:3) and linoleic acid (C18:2) content. The water-deficit stress in
particular (75% FC) increased linoleic acid content in both of the
inoculated and no-inoculated plants. The PGPB treatment significantly
decreased linoleic acid content. The linolenic acid content ranged from
33.40 to 43.44%. Both of the PGPB and water deficit treatment increased
the linolenic acid content. According to Table 5 linolenic acid (18:3)
content negatively correlated with linoleic acid (18:2) in the
inoculated plants. As the highest linolenic acid (43.44%) coincided
with the least linoleic acid (18.53%) content. In general,
water-deficit stress increased the total SFA content (6.04%) and total
PUFA (<0.1%) content. Adversely, a total MUFA reduced in
stressed plants, as the highest MUFA content (30.38%) related to B1D0.
The Fig 5 A-C showed the correlation between oil content with the total
content of SFA, MUFA, and PUFA in the all of treatments, as there was a
severely positive correlation between oil and MUFA and adversely for SFA
and PUFA content.