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