Nitrogen nutrition influences some biochemical responses to iron deficiency in tolerant and sensitive genotypes of Vitis

Elemental 2-D mapping and changes in leaf iron and chlorophyll in response to iron re-supply in iron-deficient GF 677 peach-almond hybrid

“…These Fe concentrations do not correlate with leaf Chl, and this has been called the "Fe-chlorosis paradox" (Morales et al 1998;Römheld 2000). Iron deficiency has been reported to decrease shoot growth in several species, including grapevine (Gruber and Kosegarten 2002;Jiménez et al 2007), peach (Shi et al 1993;Alcántara et al 2000) and the GF 677 peach × almond hybrid (this work), and Fe deficiency may prevent nuclear and cellular division by inhibiting key metabolic enzymes such as ribonucleotide reductase (Kosegarten and Koyro 2001) and impair meristematic growth (Mengel 1994). Reductions in leaf growth would produce apparently high Fe concentrations, when expressed on a dry matter basis (Römheld 2000).…”

“…Leaf P increased with Fe chlorosis (Jiménez 2006), and this might indicate that the accumulated Fe could be precipitated as insoluble Fe-phosphate or other Fe-and P-containing compound such as phytate. In seeds and roots, K, Mg, Cu, Zn, Fe and Ca are stored in association with phytate (Becker et al 1995, and references therein), and in rice grain P, Fe, Zn, Cu and Mn concentrations also correlate with phytate (Stangoulis et al 2007).…”

Differential responses in pear and quince genotypes induced by Fe deficiency and bicarbonate

“…Woody plant species differ with regard to their susceptibility to Fe chlorosis, and many studies (Brancadoro et al, 1995;Cinelli, 1995;De la Guardia et al, 1995;Vizzotto et al, 1999;Jiménez et al, 2007;Ksouri et al, 2007) have reported that some tolerant genotypes are able to improve Fe acquisition through enzymatic Fe 3+ reduction and acidification of the root apoplast, associated with the increase of a Fe 3+ -chelate reductase (FC-R) and H + -ATPase activity, respectively, similarly to herbaceous dicots (Strategy I plants).…”

“…In fact, a good relationship has been found between FC-R activity and resistance to Fe deficiency in apple trees (Ao et al, 1985), in peach rootstocks or cultivars (Romera et al, 1991;Egilla et al, 1994), in grapevine (Brancadoro et al, 1995;Jiménez et al, 2007), in kiwi (Vizzotto et al, 1999) and in two quince rootstocks (Cinelli, 1995). However, no increase in Fe 3+ reductase activity under iron deprivation has been found either in mangoes (Shenker et al, 1991), or in several quince and pear rootstocks (Tagliavini et al, 1995).…”

Grapevine rootstock effects on abiotic stress tolerance

“…Grapevines upon iron deficiency stress enhance the activity of Fe-reductase enzyme and increase the release of protons and organic compounds in roots. This result in a lower pH and higher solubility of Fe (III) and is known as strategy I (Jiménez, Gogorcena, Hévin, Rombolà, & Ollat, 2007). In this context bicarbonate concentration is particularly important, indeed bicarbonate is one of the main factors causing Fe chlorosis in strategy I plants but mechanisms of its involvement in this stress are still not clear (Covarrubias and Rombolà, 2013).…”