Definition of stroma in US English:

stroma

noun

  • 1Anatomy Biology
    The supportive tissue of an epithelial organ, tumor, gonad, etc., consisting of connective tissues and blood vessels.

    ‘a loose stroma of connective tissue’
    mass noun ‘the virus caused necrosis of epithelium and stroma’
    • ‘Tumor cells were embedded in a loose collagenous stroma.’
    • ‘The stroma consists of fatty tissue and ligaments surrounding the ducts and lobules, blood vessels and lymphatic vessels.’
    • ‘The bland fibrous stroma is infiltrated by mature lymphocytes and plasma cells.’
    • ‘Loose connective tissue stroma predominated in the less cellular areas.’
    • ‘The deeper regions of the tumor showed hypocellularity and had an abundance of loose edematous stroma.’
    1. 1.1 The spongy framework of protein fibers in a red blood cell or platelet.
      • ‘The surrounding stroma was infiltrated by plasma cells and scattered aggregates of lymphocytes, forming follicles with germinal centres.’
      • ‘There is no cellular or architectural atypia of the lobules or stroma.’
      • ‘Typical plaques showed proliferation of myofibroblastic cells with myxoid stroma.’
      • ‘The endometrial stroma has a framework consisting of reticular fibers and stromal cells.’
      • ‘The results indicate that the stroma contains some rather fragile enzymes.’
    2. 1.2Botany The matrix of a chloroplast, in which the grana are embedded.
      • ‘There is characteristically a dense sparsely cellular fibrous stroma.’
      • ‘Chloroplast envelopes, stacked grana and unstacked stroma thylakoids were well-defined.’
      • ‘Granules of different sizes were noted in the chloroplast stroma in all treatments.’
      • ‘The relative amount of stroma thylakoids is also increased, while the portion of grana thylakoids is lowered.’
      • ‘Thylakoids of grana stacks are mostly abundant in PSII complexes, while PSI complexes are predominant in stroma lamellae.’
  • 2Botany
    A mass of fungal tissue that has spore-bearing structures either embedded in it or on its surface.

    ‘the fruiting body is tightly compressed and sessile on a stroma’
    • ‘A few times, dots are observed in the stroma of the amyloplasts.’
    • ‘This latter consisted of a few membranes irregularly distributed in the stroma or tightly pressed to form very electron-dense stacks.’
    • ‘Transport proteins in the inner plastid envelope membrane connect the metabolism of plastid stroma and surrounding cytoplasm.’
    • ‘During in vivo measurements, excitation light is incident upon the epithelium, and must travel through this tissue layer before reaching the stroma.’
    • ‘Very few dots are localized in the stroma of the amyloplasts.’

Origin

Mid 19th century: modern Latin, via late Latin from Greek strōma ‘coverlet’.

Pronunciation

stroma

/ˈstrōmə//ˈstroʊmə/