← Back to reading

Spruce needles

In brief

A spruce needle is a leaf. Its narrow form changes how the organ presents a surface to light and air. Conifer needles illustrate a leaf form with reduced exposed surface and sunken stomata, features that help limit water loss. The needle dimensions below belong to Picea abies rather than every conifer. [6]

Evidence for this statement

Source-based explanation

Where to check this statement

biology59-leaves
Structure of a Typical Leaf; Leaf Structure and Function; Leaf Adaptations
Read the section →
Save, investigate and check this version

Editorial draft · human review pending

Ask about this material
On this page

A leaf in the shape of a needle

These dimensions belong to the Picea abies account in the European Atlas of Forest Tree Species. They should not be assigned to every spruce or used as the sole identification character.

[1]
Evidence for this statement

Source-based explanation

Compare leaf forms

A broad Arabidopsis leaf and a spruce needle offer two starting points for a question: how does a leaf receive light and exchange gases while retaining water? Compare organ shape, then follow each species source. A general leaf diagram helps locate structures, but does not prove identical tissue arrangements in the two species.

Evidence for this statement

EcoGenesis

    Starting with a needle

    Begin with a particular species and organ. The atlas measurements and four-sided needle description concern Picea abies. They connect an observation to the species article when the source and scope are retained. They are not a rule for all conifers.

    [1]
    Evidence for this statement

    Explanation of retained sources

    Description and measurement

    A species account and a measurement of one needle have different provenance. An atlas range describes the author’s account; a value for your specimen needs an organ, unit, method and conditions of its own. A missing value cannot be replaced by a value from the range and called a measurement.

    [1]
    Evidence for this statement

    Explanation of retained sources

    Continuing to a process

    The route “needle → leaf → photosynthesis” connects different types of explanation. Leaf is an anatomical concept and photosynthesis a process. The next step, photosystem II, is a molecular complex. This deepens a question without treating a process or protein as a taxon, or attributing all linked data to one photograph.

    [2] [4] [5]
    Evidence for this statement

    Explanation of retained sources

    Where to check this statement

    go-photosynthesis
    Captured GO ontology JSON: results[].id and definition.text
    go-photosystem2
    Captured GO ontology JSON: results[].id and definition.text

    Connected concepts

    Leaf

    A leaf is an organ of a vascular plant. Its structure can be explored from the whole leaf to tissue, cell and chloroplast.

    [2] [3]
    Evidence for this statement

    Source-based explanation

    Photosynthesis

    Photosynthesis synthesises organic compounds, including carbohydrates, from carbon dioxide using light energy. Gene Ontology identifies it as the biological process GO:0015979.

    [4] [5]
    Evidence for this statement

    Source-based explanation

    Where to check this statement

    go-photosynthesis
    Captured GO ontology JSON: results[].id and definition.text
    go-photosystem2
    Captured GO ontology JSON: results[].id and definition.text

    Continue with an organism

    The photographs and molecular record come from separate source materials.

    Norway spruce →Arabidopsis thaliana →

    Your research question

    Save the article to return to your question and this source version.

    Plan a test

    This is your research plan. Completing these fields does not confirm a hypothesis.

    Ask about this material

    Sources and versions

    Editorial draft · human review pending

    1. Caudullo, Tinner & de Rigo · Picea abies in Europe · p.114

      2026-09-06 · Reuse permission unverified

      Provenance and original
      Source version
      2016
    2. Plant Ontology · 2026-01-09

      2026-09-04 · CC-BY-4.0

      Provenance and original
      Source version
      2026-01-09 / f5e2a95d88fe08af22f49e522cc78481d990a0b0
    3. Arabidopsis thaliana basal leaf; photographed 14 April 2021

      Retrieval date unknown · CC BY-SA 4.0

      Provenance and original
      Original SHA-256
      4c0da1e60a566728712e6443d8dfa11d4f4cd0084a0ef454d1262a3cdf05fa39
      Processing
      Resized and encoded as WebP; original 5 mm scale retained.
    4. GO:0015979 · photosynthesis

      2026-09-09T01:17:01.233038+00:00 · CC-BY-4.0

      Provenance and original
      Original SHA-256
      8649763135938e40bdb112c62e870749510eea1b750ff5d230a3061be5a3e017
      Processing
      Unmodified provider response; article text is an attributed educational summary.
      Version details
      QuickGO response did not supply a native ontology release; retrieval time and exact response hash retained.

      View original JSON · Download original

    5. GO:0009523 · photosystem II

      2026-09-09T01:17:35.068503+00:00 · CC-BY-4.0

      Provenance and original
      Original SHA-256
      56537702684f4e6949eb9b16430a8830740bc9fd3369b21e7b5a9b711a341b4f
      Processing
      Unmodified provider response; article text is an attributed educational summary.
      Version details
      QuickGO response did not supply a native ontology release; retrieval time and exact response hash retained.

      View original JSON · Download original

    6. Clark, Douglas & Choi · Biology 2e · 30.4 Leaves

      2026-10-01 · Terms of use on source site

      Provenance and original
      Source version
      Selected web passages checked 2026-10-01; no immutable response edition asserted
      Source reading scope
      Named background passages only; not new experimental evidence.
      Location in the original source
      Structure of a Typical Leaf; Leaf Structure and Function; Leaf Adaptations
    Inspect structured data
    Content version
    9a2049705c622046f68438c757bb22463b225ef95ba8f43485316b1bbee107ad
    Source version
    knowledge-20260909.1
    Updated
    2026-10-01