Revue internationale d'écologie méditerranéenne International ...

Environmental control of germination
and dormancy of seeds of two cytotypes
of Lygeum spartum L.,
a perennial grass of semi-arid
and arid areas in Algeria
Influence des facteurs de l’environnement sur la germination
des semences de deux cytotypes de Lygeum spartum L.,
une Poacée vivace des zones semi-aride et aride d’Algérie
Abstract
Freshly harvested dispersal units of two cytotypes
of Lygeum spartum L. were dormant.
Their dormancy corresponded to a poor germination
at any temperature, including the optimal
one (20-25 o C), and to the inability to germinate
in a wide range of temperatures.
Germination did not occur at all below 10 o C
and above 30 o C. At the optimal temperature,
germination was markedly inhibited by continuous
white light and by decreasing water
potential of the medium to –1 MPa. Breaking of
dormancy for 12 months of dry storage at ambient
temperature resulted in a widening of the
temperature range within which a high rate of
germination occurred. However, the optimal
temperature remained similar to that of freshly
harvested dispersal units, i.e. 20-25 o C. The
lemma was mainly responsible for dormancy,
but the caryopsis itself also appeared to play a
role in photosensitivity of whole dispersal units.
The intensity of dormancy depended on the
Keywords: germination, Lygeum spartum,
temperature, light, water potential, after-ripening.
ecologia mediterranea – Vol. 36 (1) – 2010
A. DJABEUR1, 2 , M. KAID-HARCHE2 , D. CÔME1 and F. CORBINEAU1, *
1. Université Pierre et Marie Curie-Paris 6,
Germination et dormance des semences,
UR5, Boîte courrier 156, 4 place Jussieu,
75252 Paris cedex 05, France
2. Université des Sciences et de la Technologie d’Oran Mohamed Boudia,
Département de Biotechnologie, Faculté des Sciences,
BP 1505, El M’Naouar, Oran, Algeria
* Corresponding author: professeur Françoise Corbineau,
Université Pierre et Marie Curie-Paris 6,
Germination et dormance des semences,
UR5, Boîte courrier 156, 4, place Jussieu,
75252 Paris cedex 05, France
Tel: +33-1-44275987; Fax: +33-1-44275927
E-Mail: francoise.corbineau@upmc.fr
seed origin. It was deeper in seeds originated
from the semi-arid zone (polyploid cytotype, 2n
= 40) than in those collected in the arid highlands
(diploid cytotype, 2n = 16). The ecological
role of dormancy and after-ripening is discussed
in relation to the establishment of this species
in arid environment.
Résumé
Au moment de leur récolte, les unités de dispersion
de deux cytotypes de Lygeum spartum L.
sont dormantes. Cette dormance correspond à
une germination difficile à toutes les températures
ainsi qu’à l’optimum thermique (20-25 o C)
et à une impossibilité de germer dans une large
gamme de températures. Aucune semence ne
germe au-dessous de 10 o C et au-dessus de 30 o C.
À la température optimale, la germination est
fortement inhibée par la lumière blanche continue
et une réduction du potentiel hydrique du
Mots clés : germination, Lygeum spartum,
température, lumière, potentiel hydrique, postmaturation
au sec.
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