affy_sunflower_2011_02-Effect of frost on sunflower. Helianthus annuus

affy_sunflower_2011_02 - affy_sunflower_2011_02 - The early sowing constitutes an alternative strategy to avoid drought occurring during flowering and post-flowering periods and responsible for decrease in sunflower production. In French cropping system, early sowing is associated to low temperature period and frost during first development stages in sunflower. Knowledge about metabolism of frost acclimation must be performed to supply tools for breeding programs in sunflower. The aim of our experiment is to unravel the transcriptional regulation underpinning frost tolerance in sunflower-5 genotypes of sunflower were grown in a growth chamber 1 (23°C day/18°C night, 63% air humidity, 14 hours day photoperiod). At the stage of 6 leaves well-developed, 12 plants of each genotype were subjected to cold acclimation (+4°C during 2 days) in another growth chamber 2. Then, these plants were subjected to 2 nights at -3°C (frost treatment). Chlorophylle fluorescence, Osmotic potential, Relative electrolyte leakage were then determined in the following conditions : - 6th October on 6 plants X 5 genotypes from growth chamber 1 (C1) - 6th October on 6 plants X 5 genotypes from growth chamber 2 (S1) - 11th October on 6 plants X 5 genotypes from growth chamber 1 (C2) - 11th October on 6 plants X 5 genotypes from growth chamber 1 (S2) Overall design: 12 arrays - SUNFLOWER; treated vs untreated comparison