RELATIVE SUSCEPTIBILITY OF SOME PRUNUS ROOTSTOCKS IN HYDROPONICS TO IRON DEFICIENCY

Abstract

The susceptibility of eleven Prunus rootstocks to iron (Fe) deficiency was studied in hydroponics by growing them with 20 μM Fe, 0 μM Fe or 3 μM Fe+10 mM sodium bicarbonate. Based on the intensity of leaf chlorosis, the peach-almonds PR 204/84, Stylianidis K and KID2, produced at the Pomology Institute of Naoussa (Greece), showed the same or even greater tolerance than GF 677, the Greek peach-almond Retsou x Nemaguard, the plum-almond Myrandier 617 and the peaches GF 305, IDS 37, Greek wild peach seedling the greatest susceptibility whereas the plums St. Julien GF655/2 and Myrobalan 29C intermediate. Rootstocks without Fe presented significantly lower nitrogen and Fe whereas with bicarbonate significantly lower nitrogen, phosphorus, Fe and zinc. Root ferric chelate reductase activity was significantly increased in −Fe rootstocks but negatively correlated with their tolerance; physiological and morphological changes were observed along a zone of a few centimeters length, 1–2 mm behind the root tip.

Keywords:

• lime-induced chlorosis
• peach
• nutrient element interactions
• ferric chelate reductase activity
• root ultrastructure

ACKNOWLEDGMENTS

We would like to thank the Pomology Institute of Naoussa (N.AG.RE.F.) and particularly Dr. C. G. Tsipouridis for offering the plant material and for his valuable advice, as well as I. A. Rodger for English corrections.