Climate change is increasingly impacting the water deficit over the world. Because of drought and the high pressure of the rising human population, water is becoming a scarce and expensive commodity, especially in developing countries. The identification of crops presenting a higher acclimation to drought stress is thus an important objective in agriculture. The present investigation aimed to assess the adaptation of three Vicia faba genotypes, Aguadulce (AD), Luz d’Otonio (LO) and Reina Mora (RM) to water deficit. Multiple physiological and biochemical parameters were used to analyse the response of the three genotypes to two soil water contents (80% and 40% of field capacity). A significant lower decrease in shoot, root and nodule dry weight was observed for AD compared to LO and RM. The better growth performance of AD was correlated to higher carbon and nitrogen content than in LO and RM under water deficit. Leaf parameters such as relative water content, mass area, efficiency of photosystem II and chlorophyll and carotenoid content were significantly less affected in AD than in LO and RM. Significantly higher accumulation of proline was correlated to the higher performance of AD compared to LO and RM. Additionally, the better growth of AD genotype was related to an important mobilisation of antioxidant enzyme activities such as ascorbate peroxidase and catalase. Taken together, these results allow us to suggest that AD is a water deficit tolerant genotype compared to LO and RM. Our multiple physiological and biochemical analyses show that nitrogen content, leaf proline accumulation, reduced leaf hydrogen peroxide accumulation and leaf antioxidant enzymatic activities (ascorbate peroxidase, guaiacol peroxidase, catalase and polyphenol oxidase) are potential biological markers useful to screen for water deficit resistant Vicia faba genotypes.

Doi:10.3906/tar-1305-52 Growth and nodulation of alfalfa-rhizobia symbiosis under salinity: electrolyte leakage, stomatal conductance, and chlorophyll fluorescenc

The effects of water deficit on growth, nodulation, and several physiological and biochemical processes in six symbiotic combinations involving three Moroccan alfalfa (Medicago sativa L.) populations (Tafilalet1, Adis-Tata and Demnate2), an American Moapa variety and two rhizobial strains (RhL9 and RhL10) were studied. The experiment was conducted under greenhouse conditions. Seedlings were separately inoculated with the suspension of two rhizobial strains and grown under two irrigation regimes: 80% of field capacity (optimal irrigation) and 40% of field capacity (water deficit). The water stress was applied for five weeks and the agro-physiological and biochemical parameters related to water deficit tolerance were assessed. The results showed that the water deficit had significantly reduced the height of the plants, the dry biomass and nodulation. This constraint also negatively affected the relative water content of leaves, the membrane permeability, the stomatal conductance, the maximum quantum yield of photosystem II, the time to reach maximum fluorescence, the total chlorophyll content and the total nitrogen content. Comparison among the tested symbiotic combinations showed that their behaviors were significantly different. Under drought, oasis populations Ad and Ta maintained high PS II efficiency, membrane stability, relative water content, chlorophyll and nitrogen content in comparison to the mountain one Dm2 and the American Moapa variety. These parameters were maintained at adequate levels in the plants inoculated with the rhizobial strain RhL9 that showed a tolerance to water deficit conditions.