Revue internationale d'écologie méditerranéenne International ...

PHENOTYPIC AND PHENOLOGICAL BEHAVIOURS OF CLONES OF NATURAL POPULATIONS OF ATRIPLEX HALIMUS ◆
Table 7. Mean values and standard error
of phenotypic parameters (maximal height
(H max), the height per unit crown
diameters (Hmax / CWmax),
the maximum width crown diameters
(CW max), the minimum crown diameters
(CWmin), circumference (Cir)
and number of inflorescences (IN)).
Means followed by the same letter are not
different significantly at the 0.05 level.
of water. Irrigation improves in a highly significant way
the production of the number of male and female flowers,
the elongation of inflorescences and more ramifications of
an inflorescence. For the three studied populations, the
coastal Sidi Bouzid population showed more susceptibility
to water irrigation than the Idelssen Saharan population.
At the Sidi Bouzid population, in the non-irrigated
treatment, it is the formation of female flower which is
most affected as showed by much elevated floral sex ratio
(FM/FF). The variation of the floral sex ratio in relation to
water availability occurs in several species (Minina, 1952;
Hartmann & Panetsos, 1961; Freeman et al., 1981). The
variation of the floral sex ratio in response to water availability
is believed to be related to alteration of the endogenous
phytohormonal levels (Heslop-Harrison, 1972;
Pharis et al., 1975; Chailakhyan, 1979; Freeman et al.,
1980; Barker et al., 1982; Freeman & Vital, 1985) and the
reduction of the available resources (Freeman & Harper,
1980; Delph, 1990; Pendleton et al., 1992; Pendleton et al.,
2000), leading to a more male-biased floral sex ratio under
adverse conditions and a more female-biased floral sex
ratio under optimal conditions. In perennial species, the
ecologia mediterranea, tome 29, fascicule 2, 2003, p. 179-188
Growth parameters Populations
Treatment
Irrigated Non-irrigated
H max (cm)
CW max (cm)
CW min
H max/CW max
Cir (cm)
IN
Sidi Bouzid (Safi ) 90.4 ± 3.21bc 104.93 ± 16.07a
Marrakech 92.56 ± 2.28b 97.03 ± 3.02b
Idelssen (Ouarzazate) 87.72 ± 2.4bc 82.13 ± 2.22c
Sidi Bouzid (Safi ) 163.56 ± 3.06b 162.93 ± 2.72b
Marrakech 181.23 ± 4.5a 144.25 ± 4.52c
Idelssen (Ouarzazate) 180.79 ± 3.6a 159.96 ± 5.56b
Sidi Bouzid (Safi ) 134 ± 3.2b 132.66 ± 2.7b
Marrakech 153.23 ± 3.89a 128.80 ± 4.68b
Idelssen (Ouarzazate) 154.13 ± 2.56a 130.3 ± 4.17b
Sidi Bouzid (Safi ) 0.55 ± 0.016b 0.64 ± 0.013a
Marrakech 0.51 ± 0.016bc 0.68 ± 0.022a
Idelssen (Ouarzazate) 0.48 ± 0.011c 0.52 ± 0.012bc
Sidi Bouzid (Safi ) 459.46 ± 17.74b 435 ± 14.52b
Marrakech 509.63 ± 13.83a 411.22 ± 15b
Idelssen (Ouarzazate) 521.86 ± 9.31a 430.16 ± 16.79b
Sidi Bouzid (Safi ) 112.43 ± 9.81a 104.9 ± 8.06a
Marrakech 70.1 ± 6.26b 25.22 ± 2.87c
Idelssen (Ouarzazate) 70.31 ± 4.02b 28.46 ± 3.5c
reduction in the female sexual function in resource-limited
environments may be because of competition between
vegetative and reproductive growth. This last hypothesis
seems to be adapted to our study and may give an explanation
to the reduction of male and female flowers number
and the variation of the floral sex ratio (FM/FF) observed.
Flowering at Atriplex halimus occurs essentially during the
summery period (June, July and August) that coincides
with the dry seasons in the Mediterranean regions. In
these conditions, the competition between reproduction
and vegetative growth may be very important which will
probably affect the vegetative growth and the production
of flowers (males and female). Indeed, in the non-irrigated
treatment, the three studied populations showed a
reduction of the circumference and the crown diameters
in parallel to significant reduction of the numbers of
male and female flowers. However, the reduction of the
phenotypic features is more marked for the populations
of the arid regions (Marrakech and Idelssen) than those
of the less arid regions (Sidi Bouzid), reciprocally for the
reproductive traits. This makes sense when looking at life
history theory. The populations of the more arid zones
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