The French fibre sorghum network: First results

International audienc

French Program on Sorghum

International audienc

Nitrogen nutrition influences some biochemical responses to iron deficiency in tolerant and sensitive genotypes of Vitis

International audienceThe effects of nitrogen source on iron deficiency responses were investigated in two Vitis genotypes, one tolerant to limestone chlorosis Cabernet Sauvignon ( Vitis vinifera cv.) and the other susceptible Gloire de Montpellier ( Vitis riparia cv.). Plants were grown with or without Fe(III)- EDTA, and with NO3- alone or a mixture of NO3- and NH4+. Changes in pH of the nutrient solution and root ferric chelate reductase (FC-R) activity were monitored over one week. We carried out quantitative metabolic profiling ((HNMR)-H-1) and determined the activity of enzymes involved in organic acid metabolism in root tips. In iron free-solutions, with NO3- as the sole nitrogen source, the typical Fe-deficiency response reactions as acidification of the growth medium and enhanced FC-R activity in the roots were observed only in the tolerant genotype. Under the same nutritional conditions, organic acid accumulation ( mainly citrate and malate) was found for both genotypes. In the presence of NH4(+), the sensitive genotype displayed some decrease in pH of the growth medium and an increase in FC-R activity. For both genotypes, the presence of NH4+ ions decreased significantly the organic acid content of roots. Both Vitis genotypes were able to take up NH4+ from the nutrient solution, regardless of their sensitivity to iron deficiency. The presence of N-NH4+ modified typical Fe stress responses in tolerant and sensitive Vitis genotypes

How do grapevine rootstocks modify phosphorus concentration in the scion

Oral presentation. SEB’s Annuel Meeting, 2018 Jul 3-6, Florence, Ital

Phosphorus acquisition efficiency and phosphorus remobilization mediate genotype-specific differences in shoot phosphorus content in grapevine

Crop productivity is limited by phosphorus (P) and this will probably increase in the future. Rootstocks offer a means to increase the sustainability and nutrient efficiency of agriculture. It is known that rootstocks alter petiole P concentrations in grapevine. The objective of this work was to determine which functional processes are involved in genotype-specific differences in scion P content by quantifying P uptake, P remobilization from the reserves in the cutting and P allocation within the plant in three grapevine genotypes. Cuttings of two American rootstocks and one European scion variety were grown in sand and irrigated with a nutrient solution containing either high P (0.6 mM) or low P (0 mM). The high P solution was labelled with 32P throughout the experiment. The grapevine genotypes studied show variation in the inhibition of shoot and root biomass in response to low P supply, and P supply also affected shoot, but not root, P concentrations. Genotype-specific differences in total P content were related to differences in P acquisition and utilization efficiencies (PAE and PUE, respectively). Phosphorus allocation within the plant was not affected by genotype or P supply. The rootstock genotype known to confer high petiole P content in the vineyard was associated with a high PAE under high P, and a high PUE under low P. This suggests that the petiole P concentrations in the vineyard are related to genotype-specific differences in PAE and PUE, and that these traits could be used for rootstock selection programmes in the future

Two grapevine rootstocks used different strategies to control scion growth in response to nitrogen availability

Poster. 4th International Symposium on the Nitrogen Nutrition of Plants (ISNNP), 2019 Sept. 21-25, Nanjing, Chin

Rootstock effect on processes involved in phosphorus nutrition in grapevine

National audienc

Comment adapter la viticulture de demain?

Oral presentation. Festival Pint of Science, 2018 Apr. 14-16, Bordeaux, Franc