Plant growth, water relations and proline content of three vetch species under water‐limited conditions

Abstract

Vetch species (Vicia narbonensis, V. sativa and V. villosa) are widely used for fodder production in Tunisia. This study aims to investigate vetch strategies involved in drought resistance through morphological and physiological criteria. Plants were sown in pots and subjected to four soil‐water levels: 100% (control), 80, 60 and 40% of field capacity (FC). After 133 d of water treatment, and under well‐watered conditions, V. narbonensis showed the largest plant height and shoot and root dry matter and the highest leaf relative water content and water potential (Ψw), whereas V. sativa had the greatest leaf area (LA). At the 40% FC treatment, V. narbonensis showed smaller decreases in plant height and LA, and the greatest reduction in Ψw (140%). Thus, it shows better adaptation and a more equilibrated water balance, despite having accumulated less proline than the two other species. Vicia sativa and V. villosa showed a similar behaviour under water stress with a superiority of the latter. Vicia sativa was the species most affected in terms of its growth and water‐status parameters. Vetch species mainly used avoidance mechanisms to withstand drought, with V. narbonensis showing the highest tolerance.

Agronomic performances of three vetch species growing under different drought levels

“…Adjustment of these variables demonstrates the ability of this species to develop characters of adaptation to an imposed water shortage. Leaf water status parameters (relative water content, water potential, and stomatal conductance) demonstrated the superiority of V. narbonensis in comparison with the two other species (Haffani et al, 2014). Besides, it was characterized by a shorter growth cycle than V. sativa and V. villosa (data no shown), which allowed it to escape terminal drought.…”

“…Despite the high number of inflorescences, flowers and pods, V. villosa had low yields because of the small seed size. Moreover, water potential reductions under water stress were more pronounced than relative water content decreases indicating that the three vetch species involved avoidance strategies to retain water in their leaf tissues (Haffani et al, 2014). Seed yield was strongly related to leaf area (R 2 = 0.927) and to DM yield (R 2 = 0.841) ( Figure 5).…”

Growth and competition among understory plants varies with reclamation soil and fertilization

“…The fact that V. americana aboveground biomass did not change among soil type indicates that its aboveground growth may have been limited by something other than inorganic nitrogen, which is logical considering it is a nitrogen fixer. Water availability, which was restricted and held constant across all treatments, could be the limiting resource for V. americana, as is common in vetch species (Gallacher and Sprent 1978;Haffani et al 2014). In our study, V. americana also had the highest per gram water use, further supporting the importance of water availability for V. americana growth.…”

Fatty Acid Composition of the Seed Oils of SelectedViciaL. Taxa from Tunisia

“…and Vicia narbonensis L., are largely cultivated in different bioclimatic areas (semi-arid for V. sativa, sub-humid for V. villosa, and from sub-humid to arid for V. narbonensis), particularly in the North of the country and mainly in association with oats (Avena sativa L.), for food and fodder production (Hassen and Zoghlami, 2004;Haffani et al, 2013).…”