Study of photosynthesis process in the presence of low concentrations of clomazone herbicide in tobacco (Nicotiana tabacum)

The effect of chemical residues of clomazone on photosynthetic processes has been studiedby using several low concentrations of the herbicide (0, 1, 0.1, 0.01, 0.001, 0.0001 and 0.00001) µM and seedlings of two varieties of tobacco (Nicotiana tabacum L. cv. Virginie vk51, Nicotiana tabacum, L. cv. Xanthi). The content of photosynthetic pigments, the parameters of the chlorophyll-a fluorescence and the JIP-test were performed on an adult leaf (AL) and a young leaf (YL), that gave a complementary designto know the action's mode of clomazone on the plant physiological processes. Clomazone reducedthe total chlorophyll (a+b), carotenoids pigments (reduction in size antenna pigments judged by an increase in the chlorophyll a/b ratio) in young leaves more than adults leaves. The maximal photochemical efficiency (Fv/Fm) of photosystem II (PSII) decreased significantly in youngleavescompared to adult leaves and in (Virginie) variety than (Xanthi) variety. Among the parameters calculated of the JIP-test most affected by the treatment, PIabs, 1-VJ, ABS/RC, DI0/RC, TR0/RC, ET0/RC, ET0/ABS, which indicated acomparable effects of clomazone(1μM, 0.1µM, 0.01µM) between the two types of leaves and the varieties used. More, the results showed that the concentration ( 1μM) was the most effective amongthe other low concentrations used and the (Virginie) variety ismore sensitive than the (Xanthi)variety. We conclude that clomazone has probably two combined functions (physiological, toxic) judged by the different behavior of both types of leaves in the presence of the herbicide

Health benefits of vitamins and secondary metabolites of fruits and vegetables and prospects to increase their concentrations by agronomic approaches

Fruits and vegetables (FAVs) are an important part of the human diet and a major source of biologically active substances such as vitamins and secondary metabolites. The consumption of FAVs remains globally insufficient, so it should be encouraged, and it may be useful to propose to consumers FAVs with enhanced concentrations in vitamins and secondary metabolites. There are basically two ways to reach this target: the genetic approach or the environmental approach. This paper provides a comprehensive review of the results that have been obtained so far through purely agronomic approaches and brings them into perspective by comparing them with the achievements of genetic approaches. Although agronomic approaches offer very good perspectives, the existence of variability of responses suggests that the current understanding of the way regulatory and metabolic pathways are controlled needs to be increased. For this purpose, more in-depth study of the interactions existing between factors (light and temperature, for instance, genetic factors x environmental factors), between processes (primary metabolism and ontogeny, for example), and between organs (as there is some evidence that photooxidative stress in leaves affects antioxidant metabolism in fruits) is proposed

Detection of dynamic QTLs for traits related to organoleptic quality during banana ripening

International audienceFruit quality traits are directly linked to consumer acceptability, and thus key targets for banana breeding programs. We explored the genetic control of three major organoleptic and ripening-related traits, namely pulp acidity (pH), firmness (PF) and dry matter content (DMC), over a 7-day ripening period and three production cycles in a banana segregating population genotyped by sequencing. Significant broad-sense heritabilities were estimated with 0.77, 0.46 and 0.81 values for pH, PF and DMC, respectively. QTL detection was first performed on the whole dataset to analyze their dynamics. In a second approach, per-cycle data were considered to evaluate the stability across production cycles. Finally, a meta-analysis was performed. Various QTLs were detected, as well as many QTL colocalizations, while 12 of these QTLs were more prominent as they were detected in several approaches and/or explained over 15.0% of the phenotypic variation. Candidate genes were proposed for 10 of these QTLs. The QTL with the largest contribution to pulp acidity (R-2 = 19.3-50.6%) was located on LG1_7 on the genetic map of Pisang Madu, i.e. a parent that is closely related to Cavendish, the world's most cultivated dessert banana cultivar group. This QTL is located on a chromosome derived from a reciprocal translocation that does not recombine in Pisang Madu, which is a favorable context for molecular marker monitoring. These first results will provide a relevant basis for marker-assisted selection in banana improvement programs

Inhibition of wound-induced ethylene does not prevent red discoloration in fresh-cut endive (Cichorium intybus L.)

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