Photosynthetic energy conversion under extreme conditions -: I:: important role of lipids as structural modulators and energy sink under N-limited growth in Antarctic sea ice diatoms

被引:88
作者
Mock, T
Kroon, BMA
机构
[1] Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany
[2] KroonAqa GmbH, D-27572 Bremerhaven, Germany
关键词
bacillariophyceae; carbohydrates; fatty acids; fluorescence; lipids; low temperature; nitrogen limitation; pigments; proteins; sea ice;
D O I
10.1016/S0031-9422(02)00216-9
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The availability of dissolved nutrients such as nitrate under extreme low temperatures is a strong determinant in the development and growth of ice diatoms. Consequently we investigated regulation of photosynthesis in a mixed culture of three diatom species, which grew in chemostats at -1 degreesC, 15 mumol photons m(-2) s(-1) under N-limitation. When nitrogen is limiting, pigment-protein complexes are one of the most affected structures under low-light conditions. The loss of integral polar thylakoid components destabilized the bilayer structure of the membrane with consequences for lipid composition and the degree of fatty acid desaturation. N-Limitation caused a decrease in monogalactosycliacylglycerol (MGDG) and a simultaneous increase in bilayer forming digalactosyldiacylglycerol (DGDG). Their ratio MGDG:DGDG decreased from 3.4 +/- 0.1 to 1.1 +/- 0.4, while 20:5 n-3 fatty acids of chloroplast related phospholipid classes such as phosphatidylglycerol (PG) increased under N-limitation. These data reveal that lipids are important components, required to sustain membrane structure under a deficiency of integral membrane bound proteins and pigments. Nonetheless, energy conversion at photosystem, H is still affected by N-limitation despite this structural regulation. Photosynthetic quantum yield (F-v/F-m) and electron transport rates decreased under N-limitation caused by an increasing amount of electron acceptors (second stable electron acceptor=Q(B)) which had slower reoxidation kinetics. The energy surplus under these conditions is stored in triacylglycerols, the main energy sink in Antarctic sea ice diatoms under N-limitation. (C) 2002 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:41 / 51
页数:11
相关论文
共 48 条
[1]   Impacts of chilling temperatures on photosynthesis in warm-climate plants [J].
Allen, DJ ;
Ort, DR .
TRENDS IN PLANT SCIENCE, 2001, 6 (01) :36-42
[2]   Primary production in Antarctic sea ice [J].
Arrigo, KR ;
Worthen, DL ;
Lizotte, MP ;
Dixon, P ;
Dieckmann, G .
SCIENCE, 1997, 276 (5311) :394-397
[3]  
BLOCK MA, 1983, J BIOL CHEM, V258, P3281
[4]   EFFECT OF ENVIRONMENTAL-CONDITIONS ON FATTY-ACID COMPOSITION OF THE RED ALGA PORPHYRIDIUM-CRUENTUM - CORRELATION TO GROWTH-RATE [J].
COHEN, Z ;
VONSHAK, A ;
RICHMOND, A .
JOURNAL OF PHYCOLOGY, 1988, 24 (03) :328-332
[5]   The topology of phosphatidylglycerol populations is essential for sustaining photosynthetic electron flow activities in thylakoid membranes [J].
Duchêne, S ;
Smutny, J ;
Siegenthaler, PA .
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES, 2000, 1463 (01) :115-120
[6]  
EICKEN H, 1992, POLAR BIOL, V12, P3
[7]   A MODEL FOR THE RELATIONSHIP BETWEEN LIGHT-INTENSITY AND THE RATE OF PHOTOSYNTHESIS IN PHYTOPLANKTON [J].
EILERS, PHC ;
PEETERS, JCH .
ECOLOGICAL MODELLING, 1988, 42 (3-4) :199-215
[8]   NITROGEN LIMITATION IN ISOCHRYSIS-GALBANA (HAPTOPHYCEAE) .2. RELATIVE ABUNDANCE OF CHLOROPLAST PROTEINS [J].
FALKOWSKI, PG ;
SUKENIK, A ;
HERZIG, R .
JOURNAL OF PHYCOLOGY, 1989, 25 (03) :471-478
[9]   LIGHT-TEMPERATURE INTERACTIONS ON THE GROWTH OF ANTARCTIC DIATOMS [J].
FIALA, M ;
ORIOL, L .
POLAR BIOLOGY, 1990, 10 (08) :629-636
[10]  
FOLCH J, 1957, J BIOL CHEM, V226, P497