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The response to iron deficiency of two sensitive grapevine
cultivars grafted on a tolerant rootstock
M. A. Russo*, F. Sambuco and A. Belligno
Department of Agrochemistry,
University of Catania, Italy.
*Corresponding author.
E-mail:
marcoanton.russo@tiscali.it . Tel. +39 095 7580202. Fax
+39 095 7141581.
Accepted 22 December, 2009 |
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Two sensitive cultivars were
examined, Vittoria and Italia, grafted on a
tolerant rootstock (140 Ruggeri). Two levels of iron
chlorosis in scions were selected, initial and evident, and
compared to the healthy rootstock (control). The fractions
of extracellular and cytoplasmatic cations, chloroplastic
mobile, loosely linked, strongly linked and residual cations
as well as the active fraction were extracted from the fresh
matter. In the chlorotic the plant inability to use Fe2+
uptaken by the rootstock was highlighted, with a different
response from Vittoria and Italia, as
evidenced by the decrease in the available fraction of Fe2+,
particularly in the case of evident chlorosis. The increase
in leaf content of the active forms of K+ and Ca2+
resulted directly correlated to the intensity of iron
deficiency, since they bring about a higher pH and a
destabilization of membranes, respectively, both hindering
iron utilization. The modified response in terms of reduced
photosynthetic activity in chlorotic scions was evidenced
through the decrease in the active form of Mg2+
and consequently in chlorophyll content.
Key words:
Fe and nutrition unbalance, active Fe fraction, iron
chlorosis. |
