Under these experimental conditions, accessions 12 and 14 grafted onto cultivar alleviate the water stress effect. This effect may be attributed to enhanced osmotic adjustment because of active proline accumulation (asreflected by the lower reduction in RWC) which may protect leaves from excessive dehydration caused by damaged photosynthesis systems. In addition, the methods used in this work appear to besuitable for testing the water stress resistance of pepper root stocks.