ISSN:
1573-5036
Keywords:
Helianthus annuus L.
;
Manganese accumulation
;
Manganese toxicity
;
Solution culture
;
Toxicity symptoms
;
Trichome
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary In comparison with other crop species, sunflower (Helianthus annuus L.) has been found to be very tolerant of high manganese (Mn) concentrations in nutrient solution. Furthermore, sunflower was able to accumulate high Mn concentrations in plant tops without apparent detrimental effect on growth. The first symptom of excess Mn supply (c. 30μM Mn in solution) was the appearance of small, dark-brown to black spots (〈0.5 mm in diameter) on lower stems and on petioles and blades of the lower leaves. The spots were not necrotic and were visibly associated with the trichomes on these plant parts. Electron microprobe techniques demonstrated an accumulation of Mn in and around the trichomes. A compartmentation mechanism is suggested whereby sunflower is able to tolerate high Mn concentrations in its tissues through localization of Mn in a metabolically inactive form. At Mn concentrations approximately 6 times higher than that required to produce the small, dark spots, the upper recently-expanded leaves developed a veinal chlorosis and severe leaf crinkling of the interveinal areas. Dark brown lesions (〉2 mm in size) developed on the lower leaves, especially along the veins. A concentration of 2205 μg Mn g−1 in the tops was associated with a 10% reduction in plant dry matter yield.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02181785
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