Iron Deficiency Induced Changes in Chlorophyll and Ferric Reductase Activity in Asian Pear Rootstocks

The objective of this work was to study the induction of the root ferric-chelate reductase (FCR) activities, and to reveal differences in the tolerance to Fe-deficiency chlorosis among four Asian pear rootstock species (Pyrus spp.) grown in nutrient solution with or without Fe. Our re sult showed that the induction of root FCR activity was dependent on the root area. The highest FCR activity was found in lateral root tips. The FCR activity of root tips under Fe-deficiency stress significantly increased in four pear rootstocks, while the FCR activity of intact roots under Fe-deficiency stress slightly increased except Pyrus xerophila Yð, but no significant difference in both treatments with or without Fe. Under Fe-deficiency stress, Pyrus xerophila showed greater contents of leaf chlorophyll and•gactive•hiron, and higher FCR activity in roots tips than the other three pear rootstocks, Pyrus calleryana Decne, Pyrus betulaefolia Bunge and Pyrus pyrifolia Nakai. Our results suggested that Pyrus xerophila may be more tolerant to Fe-deficiency chlorosis than other three rootstocks. There was a strong induction of the FCR activity in root tips of all pear rootstocks. The measurement of FCR activity in root tips may be a suitable indicato