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Biochemical composition and photosynthetic activity of chloroplasts from Striga hermonthica and Striga aspera , root parasites of field‐grown cereals
Author(s) -
Tuquet Christiane,
Farineau Nicole,
Salé Georges
Publication year - 1990
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.1399-3054.1990.tb05244.x
Subject(s) - striga , striga hermonthica , biology , photosynthesis , chloroplast , botany , parasitic plant , chlorophyll , germination , host (biology) , ecology , biochemistry , gene
Striga hermonthica (Del.) Benth. and Striga aspera (Willd.) Benth. are root parasites causing dramatic losses in field‐grown cereals in semi‐and tropics. Being achlorophyllous and obligate parasites during their underground development, upon emergence from the soil, they become green leafy plants; but, despite the presence of chlorophyll, they exhibit only low rates of photosynthesis. To investigate if deficiency in the photosynthetic apparatus could account for the low rates of photosynthesis, chloroplasts were isolated from S. hermonthica parasitizing sorghum [Sorghum bicolor (L.) Moench cv. Tiemarifing] and from S. aspera parasitizing maize ( Zea mays L. cv. Tiémantié ) grown under greenhouse conditions or in their natural surroundings. Isolated chloroplasts exhibited the characteristics of chloroplasts from C 3 plants but displayed low levels of chlorophyll and polar lipids, while the protein content was less reduced. Main changes occurred in polar lipid composition, with decreases in monogalactosyldiacylglycerol and digalactosyldiacylglycerol. All polar lipids showed a decrease in the degree of unsaturation of fatly acids. All these changes were particularly pronounced in chloroplasts from plants that experienced heavy drought in Africa. On a chlorophyll basis, chloroplasts did not display a dramatic decrease in photosynthetic activities. These results are discussed in relation to parasitism and drought adaptation.