We rehydrated potted grapevines at 07.00 h after a water stress period of ten days, in order to study i) the temporal coordination of conductance recovery in different plant organs and ii) the related gene expression changes in at a genomic scale. During the subsequent 24 hours we measured leaf water potential, and hydraulic conductance of leaves, petioles, and shoot and root segments. Degree of embolism was determined by comparing the initial conductance of plant organs to the maximum conductance after removal of air emboli after transient flushings of degassed water by HPFM technique. Gene expression was assessed using microarrays spotted with 14562 70mer probes representing transcripts obtained from the TIGR Grape Gene Index, release 3. As expected, leaf water potential decreased following water stress. Leaf water potential quickly recovered after rehydration: 85% in the first two hours, and further 15% before 12.00 h (5 hours after rewatering). Leaf transpiration of recovering plants was about half of irrigated controls. It was maximum in the afternoon (at 16.00 h), while maximum transpiration for irrigated plants was at middle morning. Percentage loss of hydraulic conductivity (PLC), an indicator of the extent of embolisation, decreased during the day of rehydration from 85% to 55% in petioles and from 48% to 20% in shoots segments. In irrigated plants time course of PLC was parallel to that of transpiration, and quite symmetrical to that of leaf water potential. Also in recovering plants PLC reduction during the day was interrupted by a PLC increase in central hours of the day caused by diurnal embolism formation. Only in shoots 24 hours were sufficient to recover embolisms caused by the imposed water stress. The expression of 380 genes was significantly affected by stress over irrigated control, 222 being upregulated by water stress. Rehydration significantly affected expression of 496 genes over irrigated controls, 217 being upregulated by rehydration. Among these are representatives of genes involved in metabolism, cellular transport, transcription, signal transduction and protein synthesis.
Ecophysiological and molecular changes during recovery from water stress of grapevine plants
LOVISOLO, Claudio;PERRONE, Irene;PAGLIARANI, CHIARA;SCHUBERT, Andrea
2007-01-01
Abstract
We rehydrated potted grapevines at 07.00 h after a water stress period of ten days, in order to study i) the temporal coordination of conductance recovery in different plant organs and ii) the related gene expression changes in at a genomic scale. During the subsequent 24 hours we measured leaf water potential, and hydraulic conductance of leaves, petioles, and shoot and root segments. Degree of embolism was determined by comparing the initial conductance of plant organs to the maximum conductance after removal of air emboli after transient flushings of degassed water by HPFM technique. Gene expression was assessed using microarrays spotted with 14562 70mer probes representing transcripts obtained from the TIGR Grape Gene Index, release 3. As expected, leaf water potential decreased following water stress. Leaf water potential quickly recovered after rehydration: 85% in the first two hours, and further 15% before 12.00 h (5 hours after rewatering). Leaf transpiration of recovering plants was about half of irrigated controls. It was maximum in the afternoon (at 16.00 h), while maximum transpiration for irrigated plants was at middle morning. Percentage loss of hydraulic conductivity (PLC), an indicator of the extent of embolisation, decreased during the day of rehydration from 85% to 55% in petioles and from 48% to 20% in shoots segments. In irrigated plants time course of PLC was parallel to that of transpiration, and quite symmetrical to that of leaf water potential. Also in recovering plants PLC reduction during the day was interrupted by a PLC increase in central hours of the day caused by diurnal embolism formation. Only in shoots 24 hours were sufficient to recover embolisms caused by the imposed water stress. The expression of 380 genes was significantly affected by stress over irrigated control, 222 being upregulated by water stress. Rehydration significantly affected expression of 496 genes over irrigated controls, 217 being upregulated by rehydration. Among these are representatives of genes involved in metabolism, cellular transport, transcription, signal transduction and protein synthesis.
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