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  • Author: H. Kheloufi x
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Morphological Characteristics and Seed Germination Improvement of Two Ecotypes of Astragalus armatus Willd. subsp. armatus in Algeria

Abstract

Astragalus armatus Willd. subsp. armatus is an endemic shrub of the Northern Africa. Its cultivation and domestication are very limited because of difficulty with seed germination and establishment. In this study, we investigated some plant morphological characteristics in real time and in situ (leaves, fruit and seeds) of different ecotypes of A. armatus, collected from two sites in Algeria (Arid Steppe of Aïn Naga and Condorcet Mountain), which elevation and climate data are very different. Moreover, the role played by the seed coat in seed dormancy of these two different populations was tested by the effects of the pretreatment and its duration on the performance of seed germination, by considering the final germination percentage (FGP) and the mean germination time (MGT). These parameters are estimated for 10 days in Petri dishes and stored in darkness at (25°C). Pre-sowing treatments included immersion in concentrated sulphuric acid for 30, 60 and 90 min, and immersion in hot water (100°C) for 10 min. Statistical analysis showed that the treatment and the ecotypes effects on both FGP and MGT were highly significant (p< 0.0001). Untreated seeds of both ecotypes of A. armatus failed to germinate (except for a few of Condorcet Mountain ecotypes). For both populations, the most effective treatment was immersion in sulphuric acid for 60 min for the ecotype of Arid Steppe of Aïn Naga, and only 30 min for Condorcet Mountain. An excellent germinative strength is characterized by a higher FGP and a reduced MGT. The morphological characteristic and seed germination could be attributed to intraspecific variations resulting from the natural selection of the same species.

Open access
Biological recovery the steppe of Hammada scoparia after enclosure in the region of Naama (Algeria)

Abstract

This work was being carried out in the steppe of remth (Hammada scoparia) in Oranian part of the Saharan Atlas (Tiout - south of Naama). The H. scoparia of Saharan group occupies the foothills south of the Saharan Atlas and glazes and hamadas of the northern part of the Sahara where it seems to find its optimum development. The objective of the study is the floristic and ecological characterisation of the steppe vegetation groups of H. scoparia after 4 years of enclosure grazing (Eg). For the past three decades, steppe of H. scoparia were completely overwhelmed, both in their structure and their operation by increasing the herd and the continued use of natural pastures using animal load significantly higher than the production potential of course, which is reflected by the reduction of their capacity for natural regeneration.

Intervention measures that address this alarming situation are to foster the inverse process of degradation reconstruction and rehabilitation of degraded steppe rangelands by the technique of the Eg. The methodology involves a device that is composed of a series of transects that constitute a grid and allow to scan the whole website for Eg and part of the neighbouring paths. The results emphasise the interest and constructive impact of the Eg on plant diversity and the fight against the factors of degradation and desertification. This review highlights the importance of the technique of Eg for the rehabilitation and restoration of steppe rangelands in arid bioclimate.

Open access