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Pigment formation in potato tubers ( Solanum tuberosum ) exposed to light followed by darkness
Author(s) -
Virgin Hemming I.,
Sundqvist Christer
Publication year - 1992
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1992.tb02174.x
Subject(s) - darkness , pigment , etiolation , greening , blue light , solanum tuberosum , chlorophyll , botany , chlorophyll fluorescence , chlorophyll a , horticulture , biology , chemistry , materials science , biochemistry , ecology , optoelectronics , organic chemistry , enzyme
Potato tubers ( Solanum tubersoum cvs Bintje and King Edward). never exposed to light, lack chlorophyllous pigments. Continuous irradiation results in chlorophyll (Chl) formation and induces the ability for protochlorophyll (Pchl) formation when the tubers are brought back to darkness. Pigment synthesis takes place in both blue and red light, but blue light is more effective than red in starting the greening process. The pigment formation is strongest in the layers just below the periderm with a steep gradient inwards. Small amounts of Chl formed after irradiation. slowly fade away during extended darkness. However, the Chl formed after long time of irradiation is remarkably stable. Irradiated potatoes, placed in darkness, form Pchl with a fluorescence emission peak at 633 nm. A maximal level is reached after ca 7 days. Resolution of the Pchl spectrum suggests the presence of small amounts of a pigment with an emission maximum at around 642 nm. No sign of the Pchl with emission maximum at 657 nm, which dominates in etiolated leaves, is found. A faint Chl fluorescence indicates that some Pchl, probably the 642 nm form, is phototransformed into Chl in weak light. The Chl formation in the potato tuber is discussed in relation to that of roots and leaves.