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Lentil (Lens culinaris Medik.) is one of the most important food legumes in the world that can contribute to food security and sustainable farming. Drought tolerance is one of the major objectives of breeding programs. This research paper aimed at comparing genotypes with different genetic background (landraces, Lens orientalis wild accessions, and elite advanced lines) under 2 watering regimes (well-watered and progressive water deficit). Drought tolerance was assessed based on morphological and physiological parameters: relative water content and water loss rate of leaves, cell membrane stability, canopy temperature, root/shoot ratio, seedling vigor, wilting severity, and harvest index. The evaluation was carried out in a greenhouse pot experiment using 3 replications. Wild accessions were more drought tolerant than advanced lines and landraces. They had higher root/shoot ratios, relative water contents of leaves, canopy temperature depressions, and cell membrane stability, and lower wilting severity and water loss rate of leaves. In fact, discriminant factor analysis highlighted a clear genetic differentiation for drought tolerance between the 3 genetic groups. Different morpho-physiological responses of the studied genetic material have been observed corresponding to different drought tolerance mechanisms. Wild accessions, advanced lines, and new National Institute of Agricultural Research (INRA) of Morocco varieties A3, A4, A5, A6, and A7, as well as lentil of Zaer, a specific landrace with specific quality mark distinction known in the country, were identified as the most drought tolerant among the studied genetic material. These accessions could be used in genetic improvement programs from the perspective of developing drought tolerant varieties. [ABSTRACT FROM AUTHOR]

Lentil (Lens culinaris Medikus Subsp. culinaris) is grown as a rain-fed crop in Morocco mainly in moisture- deficient soils. Drought tolerance as well as high and stable seed yield are among the important traits of lentil cultivars preferred by Moroccan farmers. In order to determine terminal drought tolerance of some advanced lentil genotypes, an experiment was conducted in a greenhouse. The lines were planted in plastic pots (20 cm diameter and 40 cm height) in a randomized complete block with four replications and two treatments: well watered (applied 600 ml of water, three times per week) and water stressed condition (applied 180 ml of water, once a week). The results revealed that, for all the genotypes tested, drought stress reduced seed yield, seed weight, harvest index, total biomass and pod filling period by accelerating the maturity. Among the genotypes tested, the genotype F87-9 was the most susceptible. On the other hand the genotype F2003-7 was the most drought tolerant genotype because of its short cycle, a long pod filling period and less affected by water stress. This genotype was also characterized by a high harvest index, well developed root architecture (higher number of lateral roots and root length) and the capacity to maintain high leaf relative water content. Two other genotypes namely F00-24 and L8PS05-5-7 showed moderate level of drought tolerance characteristics. The susceptible genotype F87-9 had the lowest leaf relative water content. [ABSTRACT FROM AUTHOR]

Living and heat-killed bacterial cells of Rhizobium leguminosarum protected totally lentil plants against infection by the pathogen Fusarium oxysporum MR 84. Culture filtrate of this rhizobacterium was also able to protect the plants to a high degree. However, when they were inoculated separately of the pathogen, living bacterial cells did not protect the plants whereas culture filtrate and killed bacterial cells protected them. These results suggest that Rhizobium cannot protect lentil plants without interaction with the pathogen, but the culture filtrate and the killed bacterial cells can protect them even in the absence of this interaction. It seems that the culture filtrate and the killed bacterial cells contain signals able to induce plant resistance. Those signals would be suppressed once Rhizobium is in contact with the plant. To cite this article: H. Essalmani, H. Lahlou, C. R. Biologies 326 (2003). [Copyright &y& Elsevier]

Previous analysis showed that, in its initial phase, the geotropic response of Lens culinaris L. roots cannot be explained by a simple action by sliding, pressure or contact of amyloplasts on a sensitive surface located along the longitudinal wall. In this study another mode of action is tested by considering the following parameters as functions of the roots inclination: (1) the distance (d) which the amyloplasts move; (2) their number of contacts (...) with parietal cytoplasm; (3) the variable (sin α of the transversal component of the statolith weight (M̄ × g sin α). It is shown that the initial rate of curvature (V̄), at the various angles, is related to the sedimentation of the amyloplasts by the equation V̄ = a log b d̄c̄ sin α (where a and b are constants). The results obtained prove that the geotropic stimulation is dependent upon the sine of the angle (α) of the root inclination and explain the sine rule deviation. The role of statoliths is discussed in the light of recent literature on growth inhibitors which are involved in the geotropic reaction. [ABSTRACT FROM AUTHOR]

The content of acid-soluble sulfhydryl compounds (SH + S-S) is determined amperometrically in tissues of the Lens root. Two distinct zones are analysed: first the meristematic one (0 to 1.6 mm from the tip) and secondly the elongating one (1.6 to 3.7 mm). Measurements concerned the first 80 hours of the root growth. SH/S-S ratio is minimum in the meristematic zone. Connections seem to exist between the growth rate and the amount of SH compounds in the elongating zone. These facts suggest that the increase of cytoplasmic SH is associated with the reduction of protein-disulfur-bridges, which account for the intermicrofibrilar bindings in the cell wall. The effects of auxins (indoleacetic acid and naphtylacetic acid) treatments are also studied. They are strictly localized in the apical zone and their intensity depends upon the auxin concentration. SH-level is rising: this is due partially to a reduction of acid-soluble S-S. [ABSTRACT FROM AUTHOR]

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