Evidence map›Paper›PMID 31942934›Full record

ArticleAnnals of botany2020

Structural basis for C4 photosynthesis without Kranz anatomy in leaves of the submerged freshwater plant Ottelia alismoides.

Shijuan Han, Stephen C Maberly, Brigitte Gontero, Zhenfei Xing, Wei Li, Hongsheng Jiang, Wenmin Huang

Open access · greenAbstract read
In one paragraph

Article in Annals of botany, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers.

0numbers the graph read from it
0cells of the map it votes in
11citing papers in PubMed
2.0field-weighted citation impact, top 13% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

11 citing papers in PubMed, 34 citations in OpenAlex.

  1. Review
  2. Review
  3. A novel single-cell NAD-ME CThe New phytologist · 2026
    Article
  4. Article
  5. Article
  6. Article
  7. Evolution of an intermediate CPhotosynthesis research · 2022
    Review
  8. Article
  9. Article
  10. Article
  11. Responses of Leaf Anatomy and COFrontiers in plant science · 2020
    Article
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

7 authors at 7 institutions in 3 countries.

Shijuan HanKey Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Stephen C MaberlyLake Ecosystems Group, UK Centre for Ecology & Hydrology, Lancaster Environment Centre, Bailrigg, Lancaster, UK.
Brigitte GonteroAix Marseille Univ CNRS, BIP UMR, IMM, FR, Chemin Joseph Aiguier, Marseille Cedex, France.
Zhenfei XingInstitute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
Wei LiKey Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Hongsheng JiangKey Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Wenmin HuangKey Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Aix-Marseille Université · FRBioénergétique et Ingénierie des Protéines · FRCentre National de la Recherche Scientifique · FRChinese Academy of Sciences · CNInstitute of Hydrobiology · CNSorbonne Université · FRWuhan Botanical Garden · CN

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

BACKGROUND AND

aimsOttelia alismoides (Hydrocharitaceae) is a freshwater macrophyte that, unusually, possesses three different CO2-concentrating mechanisms. Here we describe its leaf anatomy and chloroplast ultrastructure, how these are altered by CO2 concentration and how they may underlie C4 photosynthesis.

methodsLight and transmission electron microscopy were used to study the anatomy of mature leaves of O. alismoides grown at high and low CO2 concentrations. Diel acid change and the activity of phosphoenolpyruvate carboxylase were measured to confirm that CAM activity and C4 photosynthesis were present. KEY

resultsWhen O. alismoides was grown at low CO2, the leaves performed both C4 and CAM photosynthesis whereas at high CO2 leaves used C4 photosynthesis. The leaf comprised an upper and lower layer of epidermal cells separated by a large air space occupying about 22 % of the leaf transverse-section area, and by mesophyll cells connecting the two epidermal layers. Kranz anatomy was absent. At low CO2, chloroplasts in the mesophyll cells were filled with starch even at the start of the photoperiod, while epidermal chloroplasts contained small starch grains. The number of chloroplasts in the epidermis was greater than in the mesophyll cells. At high CO2, the structure was unchanged but the thicknesses of the two epidermal layers, the air space, mesophyll and the transverse-section area of cells and air space were greater.

conclusionsLeaves of O. alismoides have epidermal and mesophyll cells that contain chloroplasts and large air spaces but lack Kranz anatomy. The high starch content of mesophyll cells suggests they may benefit from an internal source of CO2, for example via C4 metabolism, and are also sites of starch storage. The air spaces may help in the recycling of decarboxylated or respired CO2. The structural similarity of leaves at low and high CO2 is consistent with the constitutive nature of bicarbonate and C4 photosynthesis. There is sufficient structural diversity within the leaf of O. alismoides to support dual-cell C4 photosynthesis even though Kranz anatomy is absent.

Indexed as

HydrocharitaceaePhotosynthesisCarbon CycleCarbon DioxideFresh WaterPlant LeavesCarbon DioxideAerenchymabicarbonate useCAMchloroplast ultrastructureCO2 acclimationCO2-concentrating mechanism (CCM)freshwater macrophyteHydrocharitaceae

Identifiers

PMID31942934
PMCPMC7218808
OpenAlexW3000550444

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.