TY  - JOUR
A1  - Balazadeh, Salma
A1  - Schildhauer, Joerg
A1  - Araujo, Wagner L.
A1  - Munne-Bosch, Sergi
A1  - Fernie, Alisdair R.
A1  - Proost, Sebastian
A1  - Humbeck, Klaus
A1  - Müller-Röber, Bernd
T1  - Reversal of senescence by N resupply to N-starved Arabidopsis thaliana: transcriptomic and metabolomic consequences
JF  - Journal of experimental botany
N2  - Leaf senescence is a developmentally controlled process, which is additionally modulated by a number of adverse environmental conditions. Nitrogen shortage is a well-known trigger of precocious senescence in many plant species including crops, generally limiting biomass and seed yield. However, leaf senescence induced by nitrogen starvation may be reversed when nitrogen is resupplied at the onset of senescence. Here, the transcriptomic, hormonal, and global metabolic rearrangements occurring during nitrogen resupply-induced reversal of senescence in Arabidopsis thaliana were analysed. The changes induced by senescence were essentially in keeping with those previously described; however, these could, by and large, be reversed. The data thus indicate that plants undergoing senescence retain the capacity to sense and respond to the availability of nitrogen nutrition. The combined data are discussed in the context of the reversibility of the senescence programme and the evolutionary benefit afforded thereby. Future prospects for understanding and manipulating this process in both Arabidopsis and crop plants are postulated.
KW  - Arabidopsis
KW  - gene expression
KW  - metabolomics
KW  - nitrogen limitation
KW  - senescence
KW  - transcriptome
Y1  - 2014
U6  - https://doi.org/10.1093/jxb/eru119
SN  - 0022-0957
SN  - 1460-2431
VL  - 65
IS  - 14
SP  - 3975
EP  - 3992
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Chorus, Ingrid
A1  - Spijkerman, Elly
T1  - What Colin Reynolds could tell us about nutrient limitation, N:P ratios and eutrophication control
JF  - Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica
N2  - Colin Reynolds exquisitely consolidated our understanding of driving forces shaping phytoplankton communities and those setting the upper limit to biomass yield, with limitation typically shifting from light in winter to phosphorus in spring. Nonetheless, co-limitation is frequently postulated from enhanced growth responses to enrichments with both N and P or from N:P ranging around the Redfield ratio, concluding a need to reduce both N and P in order to mitigate eutrophication. Here, we review the current understanding of limitation through N and P and of co-limitation. We conclude that Reynolds is still correct: (i) Liebig's law of the minimum holds and reducing P is sufficient, provided concentrations achieved are low enough; (ii) analyses of nutrient limitation need to exclude evidently non-limiting situations, i.e. where soluble P exceeds 3-10 mu g/l, dissolved N exceeds 100-130 mu g/l and total P and N support high biomass levels with self-shading causing light limitation; (iii) additionally decreasing N to limiting concentrations may be useful in specific situations (e.g. shallow waterbodies with high internal P and pronounced denitrification); (iv) management decisions require local, situation-specific assessments. The value of research on stoichiometry and co-limitation lies in promoting our understanding of phytoplankton ecophysiology and community ecology.
KW  - phytoplankton
KW  - nitrogen limitation
KW  - redfield ratio
KW  - co-limitation
KW  - enrichment experiments
Y1  - 2020
U6  - https://doi.org/10.1007/s10750-020-04377-w
SN  - 0018-8158
SN  - 1573-5117
VL  - 848
IS  - 1
SP  - 95
EP  - 111
PB  - Springer Nature
CY  - Berlin
ER  -