Flooding tolerance and cell wall alterations in maize mesocotyl during hypoxia

This research aimed to characterize the tolerance to flooding and alteratio ns in pectic and hemicellulose fractions from mesocotyl of maize tolerant t o flooding when submitted to hypoxia. In order to characterize tolerance se eds from maize cultivars Saracura BRS-4154 and BR 107 tolerant and sensitiv e to low oxygen levels, respectively, were set to germinate. Plantlet survi val was evaluated during five days after having been submitted to hypoxia. After fractionation with ammonium oxalate 0.5% (w/v) and KOH 2M and 4M, Sar acura BRS-4154 cell wall was obtained from mesocotyl segments with differen t damage intensities caused by oxygen deficiency exposure. The cell wall fr actions were analyzed by gel filtration and gas chromatography, and also by Infrared Spectrum with Fourrier Transformation (FTIR). The hypoxia period lasting three days or longer caused cell lysis and in advanced stages plant death. The gelic profile from pectic, hemicellulose 2M and 4M fractions fr om samples with translucid and constriction zone showed the appearance of l ow molecular weight compounds, similar to glucose. The main neutral sugars in pectic and hemicellulose fractions were arabinose, xilose and mannose. T he FTIR spectrum showed a gradual decrease in pectic substances from mesoco tyl with normal to translucid and constriction appearance respectively.This research aimed to characterize the tolerance to flooding and alterations i n pectic and hemicellulose fractions from mesocotyl of maize tolerant to fl ooding when submitted to hypoxia. In order to characterize tolerance seeds from maize cultivars Saracura BRS-4154 and BR 107 tolerant and sensitive to low oxygen levels, respectively, were set to germinate. Plantlet survival was evaluated during five days after having been submitted to hypoxia. Afte r fractionation with ammonium oxalate 0.5% (w/v) and KOH 2M and 4M, Saracur a BRS-4154 cell wall was obtained from mesocotyl segments with different da mage intensities caused by oxygen deficiency exposure. The cell wall fracti ons were analyzed by gel filtration and gas chromatography, and also by Inf rared Spectrum with Fourrier Transformation (FTIR). The hypoxia period last ing three days or longer caused cell lysis and in advanced stages plant dea th. The gelic profile from pectic, hemicellulose 2M and 4M fractions from s amples with translucid and constriction zone showed the appearance of low m olecular weight compounds, similar to glucose. The main neutral sugars in p ectic and hemicellulose fractions were arabinose, xilose and mannose. The F TIR spectrum showed a gradual decrease in pectic substances from mesocotyl with normal to translucid and constriction appearance respectively.