Mechanisms of resistance to water stress at plant and cellular levels in Atriplex halimus L
(2001)
Files
MartinezCastillo.pdf
Restricted Access - Adobe PDF
- 6.48 MB
Details
- Authors
- Supervisors
- Abstract
- (en) ater stress is the main factor limiting crop production in Mediterranean areas. In these areas rain is scarce, irregularly distributed and variable from year to year. Atriplex halimus of the Chenopodiaceae family is one the main fodder in these areas, because it is a xerophyte-halophyte plant particularly well adapted to arid and salt-affected régions. The genetic improvement may be an effective way to look for génotypes with a good productivity and favourable phenological and physiological characteristics which could improve the water stress résistance in this species. In A.halimus, the physiological study of water stress-resistance is important for a better understanding of the mechanisms associated to its control. The effects of water stress were studied in A. halimus at the whole plant and callus levels. At the whole plant level, water déficit was applied by withholding water for 22 days in pots or by polyethylene glycol-induced water stress for 6 days in nutritive solution. In the first case, two provenances of A. halimus from North Africa (Kairouan, Tunisia and Tensift, Morocco) were used. At the callus level, water déficit was applied by polyethylene glycol addition in solid culture medium for 50 days. Two callus Unes were also selected for sensitivity and résistance to water stress. Morphological and physiological parameters (growth, water status, organic and inorganic contents, water use efficiency, membrane permeability, etc) were determined. Several factors influenced the response to water stress such as the organization level (callus or plant) and the intensity and rapidity of stress. At the whole, Kairouan presented a lower mean growth and a greater osmotic adjustment compared with Tensift. Water use efficiency was greater in Tensift than in Kairouan. In both provenances, Na* and K* uptake was increased, the increase being less évident for K* in Kairouan. These results suggest that the osmotic adjustment was partially associated with water stress résistance. However, Na* and K* uptake and their distribution in the plant could be related to the résistance mechanisms to water stress. At the callus level, the growth was less reduced in the résistant than in the sensitive calli. Both callus lines exhibited a comparable capacity of osmotic adjustment in response to polyethylene glycol stress; however the Na* accumulation and electrolyte leakage appear to be associated with the cellular résistance. At this level, the characters of sensitivity and résistance were more clearly established than at the whole plant level
- Affiliations
Citations
Martínez Castillo, J. P. (2001). Mechanisms of resistance to water stress at plant and cellular levels in Atriplex halimus L. https://hdl.handle.net/2078.5/124347