Low temperature acclimation of guard cell chloroplasts by the arctic plantSaxifraga cernuaL.
作者:
B. T. MAWSON,
W. R. CUMMINS,
期刊:
Plant, Cell&Environment
(WILEY Available online 1991)
卷期:
Volume 14,
issue 6
页码: 569-576
ISSN:0140-7791
年代: 1991
DOI:10.1111/j.1365-3040.1991.tb01527.x
出版商: Blackwell Publishing Ltd
关键词: Saxifraga cernua;stomatathermal acclimation;guard cell chloroplast;fluorescence
数据来源: WILEY
摘要:
Abstract.The potential for thermal acclimation of photosynthetic electron transport by guard cell chloropiasts (GC ch) was assessed in epidermal peels taken from the abaxial side ofSaxifraga cernualeaves grown at 20°C and 10°C. Chlorophyllafluorescence induction kinetics measured in pairs of guard cells in individual stomata from tissue grown at 10 °C demonstrated a rise in the fluorescence to a maximum and a larger amplitude in variable fluorescence when measured at temperatures below 18°C than was seen in GC ch from tissue grown at 20°C. The rates of fluorescence quenching in 10°C‐grown tissue were also faster than in 20°C‐grown tissue when measured at temperatures below 18°C. State 1‐State 2 transitions by GC ch were measured at selected temperatures between 5 and 25 °C as changes in the magnitude of the fluorescence emission maxima at 685, 695 and 730nm (F685, F695 and F730) measured at 77K. At measuring temperatures of 5 and 10°C, GC ch in tissue grown at 10 °C showed a greater transition to State 2 (a larger F730/F695 ratio) than did GC ch in tissue grown at 20 °C. At measuring temperatures of 20 and 25 °C, there was no difference in either the kinetics or the magnitude of the State 1 to State 2 transition in the two tissues. The ultrastructure of GC ch from tissues grown at 10 and 20 °C was also examined using transmission electron microscopy. Less than half (48%) of the grana from the higher temperature grown tissue had more than nine thylakoids/grana. Grana in GC ch which had developed at 10 °C showed a dramatic reduction in stacking, such that 85% of the grana contained no more than two thylakoids. The reduction in grana stacking was also accompanied by a decrease in the degree of appression of thylakoid membranes. The results demonstrate a capacity for thermal acclimation of GC ch function to low temperatures. This acclimation is associated with alterations in the chloro
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