To cite photosynthesis in publications use:

  Stinziano JR, D Gamble, BK Murphy, PJ Hudson, CD Muir. (2021).
  Principles of resilient coding for plant ecophysiologists. AoB PLANTS
  13: plab059.

A BibTeX entry for LaTeX users is

  @Article{,
    author = {Joseph R Stinziano and Cassaundra Roback and Demi Gamble and Bridget K Murphy and Patrick J Hudson and Christopher D Muir},
    title = {Principles of resilient coding for plant ecophysiologists},
    journal = {AoB PLANTS},
    volume = {13},
    number = {5},
    year = {2021},
    month = {10},
    issn = {2041-2851},
    doi = {10.1093/aobpla/plab059},
    url = {https://doi.org/10.1093/aobpla/plab059},
    note = {plab059},
  }

  Stinziano JR, Roback C, Gamble D, Murphy B, Hudson P, Muir CD.
  (2023). photosynthesis: tools for plant ecophysiology & modeling. R
  package version 2.1.4.
  https://CRAN.R-project.org/package=photosynthesis.

A BibTeX entry for LaTeX users is

  @Misc{,
    title = {photosynthesis: tools for plant ecophysiology & modeling},
    author = {Joseph R Stinziano and Cassaundra Roback and Demi Gamble and Bridget K Murphy and Patrick J Hudson and Christopher D Muir},
    note = {R package version 2.1.4},
    year = {2023},
    url = {https://CRAN.R-project.org/package=photosynthesis},
  }