JOURNAL ARTICLE

Metabolic responses in cucumber (Cucumis sativus L.) roots under Fe-deficiency: a 31P-nuclear magnetic resonance in-vivo study

L Espen, M Dell'Orto, P De Nisi, G Zocchi
Planta 2000, 210 (6): 985-92
10872232
The metabolic responses occurring in cucumber (Cucumis sativus L.) roots (a strategy-I plant) grown under iron-deficiency conditions were studied in-vivo using 31P-nuclear magnetic resonance spectroscopy. Iron starvation induced activation of metabolism leading to the consumption of stored carbohydrates to produce the NAD(P)H, ATP and phosphoenolpyruvate necessary to sustain the increased activity of the NAD(P)H:Fe(3+)-reductase, the H(+)-ATPase (EC 3.6.1.35) and phosphoenolpyruvate carboxylase (EC 4.1.1.31). Activation of catabolic pathways was supported by the enhancement of glycolytic enzymes and concentrations of the metabolites glucose-6-phosphate and fructose-6-phosphate, and by enhancement of the respiration rate. Moreover, Fe-deficiency induced a slight increase in the cytoplasmic (pHc) and vacuolar (pHv) pHs as well as a dramatic decrease in the vacuolar phosphate (Pi) concentration. A comparison was done using fusicoccin (FC), a fungal toxin which stimulates proton extrusion. Changes in pHc and pHv were measured after addition of FC. Under these conditions, a dramatic alkalinization of the pHv of -Fe roots was observed, as well as a concomitant Pi movement from the vacuole to the cytoplasm. These results showed that Fe starvation was indeed accompanied by the activation of metabolic processes useful for sustaining the typical responses occurring at the plasma-membrane level (i.e. increases in the NAD(P)H:Fe(3+)-reductase and H(+)-ATPase activities) as well as those involved in the homeostasis of pHc. The decrease in vacuolar Pi levels induced by Fe-deficiency and FC and movement of Pi from the vacuole to the cytoplasm suggest a possible involvement of this compound in the cellular pH-stat system.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
10872232
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"