Differential responses in growth and water relationship of<br>Medicago sativa (L.) cv. Gabès and Astragalus gombiformis (Pom.)<br>under water-limited conditions

Abstract

Abstract:This study aims to compare the growth attributes and water relationship of two-forage legume plants: a crop plant, Medicago sativa (L.) cv. Gabès, and a wild plant, Astragalus gombiformis (Pom.), under drought-stress conditions. Water deficit stress was imposed at 40% and 70% of field capacity (FC) from 60 to 90 days after sowing, while the control pots were maintained at 100% FC throughout the period of entire growth. The results showed that the high potentialities of growth in both species were recorded for control plants. Water deficit reduced growth (whole plant biomass, leaf number, stem elongation rate and shoot relative growth rate) and decreased shoot/root ratio. After 30 days of water deficit stress, the leaf relative water content (RWC) and the water potential (Ψ w ) evolved in such a way and decreased significantly as water stress was intensified. The lowest level of transpiration rate of the most stressed plants may be explained by the lowering of leaf RWC. Under such conditions, the water use efficiency of wild plants was more pronounced than alfalfa plants. It can be concluded that A. gombiformis manifested the best morpho-physiological traits of adaptation to moisture stress when compared to M. sativa. This wild plant appears to be more tolerance to water stress than that cultivated, therefore a possibility of exploitation of this species.

Effects of Biotic and Abiotic Environmental Stimuli on the Morphology and Biomass Allocation of Mimosa pigra L.

“…However, in this experiment, as the plants received low water volume, the stems grew faster. These results were contrary to those of the studies from Gorai et al (2010) and Shao et al (2008), which suggested that water deficit caused height reduction in stressed plants. This may suggest that different species have different responses to water stress.…”

Major Transcriptome Reprogramming Underlies Floral Mimicry Induced by the Rust Fungus Puccinia monoica in Boechera stricta

“…Plants under water deficit show decreased stem elongation [47] and restricted formation and number of leaves due to increased leaf senescence [48]. To help prevent water loss under stressful conditions some plants secrete and accumulate waxes in the surface of the leaves [49].…”

Agronomic performances of three vetch species growing under different drought levels

“…Many previous studies have observed that WUE declines under water stress conditions and sustained that the species employed a water-use strategy (Hu et al, 2006;Gorai et al, 2010). Blum (2005) considered lower WUE as an avoidance strategy.…”

“…First, according to Wu et al (2008), WUE decrease may be attributed to a low biomass production under severe water deficit conditions. Secondly, Gorai et al (2010) sustained that WUE reduction under drought is due to an optimal water use by plants. Thirdly, Moreno et al (2008) claimed that this behavior is caused by the predominance of non stomatal limitation to photosynthesis and by the fact that stomata are less sensitive to water deficit.…”

“…These reductions confirm previous findings on annual clovers (Iannucci et al, 2002) and faba bean (Ghassemi-Golezani et al, 2009). According to Gorai et al (2010), lowering production constitutes an adaptive mechanism which reduces plant's water needs in Medicago sativa L. and Astragalus gombiformis (Pom. ), respectively.…”