Abstract
Sesuvium sesuvioides (Sesuvioideae, Aizoaceae) is a perennial, salt-tolerant herb distributed in flats, depressions, or disturbed habitats of southern Africa and the Cape Verdes. Based on carbon isotope values, it is considered a C 4 species, despite a relatively high ratio of mesophyll to bundle sheath cells (2.7:1) in the portulacelloid leaf anatomy. Using leaf anatomy, immunocytochemistry, gas exchange measurements, and enzyme activity assays, we sought to identify the biochemical subtype of C 4 photosynthesis used by S. sesuvioides and to explore the anatomical, physiological, and biochemical traits of young, mature, and senescing leaves, with the aim to elucidate the plasticity and possible limitations of the photosynthetic efficiency in this species. Assays indicated that S. sesuvioides employs the NADP-malic enzyme as the major decarboxylating enzyme. The activity of C 4 enzymes, however, declined as leaves aged, and the proportion of water storage tissue increased while air space decreased. These changes suggest a functional shift from photosynthesis to water storage in older leaves. Interestingly, S. sesuvioides demonstrated CO 2 compensation points ranging between C 4 and C 3-C 4 intermediate values, and immunocytochemistry revealed labeling of the Rubisco large subunit in mesophyll cells. We hypothesize that S. sesuvioides represents a young C 4 lineage with C 4-like photosynthesis in which C 3 and C 4 cycles are running simultaneously in the mesophyll.
| Original language | English |
|---|---|
| Pages (from-to) | 1553-1565 |
| Number of pages | 14 |
| Journal | Journal of Experimental Botany |
| Volume | 70 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 15 Feb 2019 |
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C 4-like photosynthesis and the effects of leaf senescence on C 4-like physiology in Sesuvium sesuvioides (Aizoaceae). / Bohley, Katharina; Schröder, Till; Kesselmeier, Jürgen; Ludwig, Martha; Kadereit, Gudrun.
In: Journal of Experimental Botany, Vol. 70, No. 5, 15.02.2019, p. 1553-1565.Research output: Contribution to journal › Article
TY - JOUR
T1 - C 4-like photosynthesis and the effects of leaf senescence on C 4-like physiology in Sesuvium sesuvioides (Aizoaceae)
AU - Bohley, Katharina
AU - Schröder, Till
AU - Kesselmeier, Jürgen
AU - Ludwig, Martha
AU - Kadereit, Gudrun
PY - 2019/2/15
Y1 - 2019/2/15
N2 - Sesuvium sesuvioides (Sesuvioideae, Aizoaceae) is a perennial, salt-tolerant herb distributed in flats, depressions, or disturbed habitats of southern Africa and the Cape Verdes. Based on carbon isotope values, it is considered a C 4 species, despite a relatively high ratio of mesophyll to bundle sheath cells (2.7:1) in the portulacelloid leaf anatomy. Using leaf anatomy, immunocytochemistry, gas exchange measurements, and enzyme activity assays, we sought to identify the biochemical subtype of C 4 photosynthesis used by S. sesuvioides and to explore the anatomical, physiological, and biochemical traits of young, mature, and senescing leaves, with the aim to elucidate the plasticity and possible limitations of the photosynthetic efficiency in this species. Assays indicated that S. sesuvioides employs the NADP-malic enzyme as the major decarboxylating enzyme. The activity of C 4 enzymes, however, declined as leaves aged, and the proportion of water storage tissue increased while air space decreased. These changes suggest a functional shift from photosynthesis to water storage in older leaves. Interestingly, S. sesuvioides demonstrated CO 2 compensation points ranging between C 4 and C 3-C 4 intermediate values, and immunocytochemistry revealed labeling of the Rubisco large subunit in mesophyll cells. We hypothesize that S. sesuvioides represents a young C 4 lineage with C 4-like photosynthesis in which C 3 and C 4 cycles are running simultaneously in the mesophyll.
AB - Sesuvium sesuvioides (Sesuvioideae, Aizoaceae) is a perennial, salt-tolerant herb distributed in flats, depressions, or disturbed habitats of southern Africa and the Cape Verdes. Based on carbon isotope values, it is considered a C 4 species, despite a relatively high ratio of mesophyll to bundle sheath cells (2.7:1) in the portulacelloid leaf anatomy. Using leaf anatomy, immunocytochemistry, gas exchange measurements, and enzyme activity assays, we sought to identify the biochemical subtype of C 4 photosynthesis used by S. sesuvioides and to explore the anatomical, physiological, and biochemical traits of young, mature, and senescing leaves, with the aim to elucidate the plasticity and possible limitations of the photosynthetic efficiency in this species. Assays indicated that S. sesuvioides employs the NADP-malic enzyme as the major decarboxylating enzyme. The activity of C 4 enzymes, however, declined as leaves aged, and the proportion of water storage tissue increased while air space decreased. These changes suggest a functional shift from photosynthesis to water storage in older leaves. Interestingly, S. sesuvioides demonstrated CO 2 compensation points ranging between C 4 and C 3-C 4 intermediate values, and immunocytochemistry revealed labeling of the Rubisco large subunit in mesophyll cells. We hypothesize that S. sesuvioides represents a young C 4 lineage with C 4-like photosynthesis in which C 3 and C 4 cycles are running simultaneously in the mesophyll.
KW - Aizoaceae
KW - C 4 photosynthesis
KW - C 4-like
KW - carbon isotope values
KW - immunolocalization of Rubisco and PEPC
KW - portulacelloid leaf anatomy
UR - http://www.scopus.com/inward/record.url?scp=85062835173&partnerID=8YFLogxK
U2 - 10.1093/jxb/erz011
DO - 10.1093/jxb/erz011
M3 - Article
VL - 70
SP - 1553
EP - 1565
JO - Journal of Experimental Botany
JF - Journal of Experimental Botany
SN - 0022-0957
IS - 5
ER -