Test the resistance to ultraviolet irradiation and low vacuum pressure on germination of some woody tree seeds [electronic resource].

Includes reference.

This study was carried Out in Laboratory of Rhizosphére biology in INRA- Versailles. France. from April 2005 to January 2006 in two experiments repeated under the same laboralory conditions. The objeclive of the study was to test the resistance of some woody tree seeds to condition found in space (Ultraviolet -C and low vacuum pressure). Seeds of four tree species. Acacia saligna. Leucaenia leucocephylla. as the hard coat seeds and Casuarina cunninghamiana and Eucalyptus cammaldulensis as the light coat seeds, were exposed to Ultraviolet ( λ= 254 nm.) and low vacuum pressure (1. 33x 10̄̄⁻¹ Pa) to study the efficts on seeds germination. The results indicated that, both the Ultraviolet and low vacuum pressure affected seed germination. Leucaenia leucoeephylla seeds were the most toterant to exposure to the Ultraviolet 254 nm irradiation. while the low sensitive ones were Acacia saligna and Casuarina cunninghamiana seeds. The lowest exposure period did not affect germination of the tree seeds hardly was 6 hours, while the most effective exposure period was 24 hours.

Summary in Arabic.

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