Lecture+2+-+Development%2C+Form+and+Function+of+Basidiomata+S25

Development of Basidiomata

  • The Problem

    • Transition from undifferentiated somatic feeding hyphae to organized, cooperative, differentiated hyphal systems in fruiting bodies.

    • Basidiomycete fruiting body: A three-dimensional, tissue-differentiated hyphal structure producing basidia and basidiospores. Known as basidioma or basidiocarp.

    • Developmental Sequence:

      • Somatic hyphae → Hyphal knot → Primordium → Mature basidioma.

    • Developmental processes: Highly coordinated, but less is understood regarding signaling chemicals (hormones) and environmental cues.

    • Importance of basidiomata:

      • Sites for basidiospore production (sexual reproduction).

      • Taxonomically informative; provides characteristics for classification.

Basidioma Expansion and Water Uptake

  • Primordium Development:

    • Differentiated tissue regions (cap, stem) exist at very small sizes (< 1mm).

    • Example: A primordium in Coprinus cinereus grows from ~1 mm (3% mature height) to a mature basidioma height of ~34 mm (34X growth).

    • Stipe circumference increases by 9X; pileus circumference increases by 15X.

    • Volume Expansion: Incredible 3000X increase in volume.

    • Basidiomata can exert such turgor pressure that they can burst through concrete.

Types of Basidioma Development in Agaricales

  • Development Types:

    • Gymnocarpic

    • Pseudoangiocarpic

    • Hemiangiocarpic

    • Angiocarpic

  • Key Terms:

    • Inner (partial) veil, universal veil, annulus, cortina, volva, volval fragments.

Basidioma Anatomy

  • Types of Mycelium:

    • 3˚ mycelium has a higher level of organization than 2˚ mycelium.

  • Agaric Fruiting Body Structure:

    • Longitudinal sections exhibit distinct hyphal regions:

      • Pileus cuticle (pileipellis)

      • Pileus trama

      • Hymenophoral trama and hymenium

      • Stipe cuticle (stipitipellis)

      • Stipe trama

      • Basal mycelium/rhizomorphs.

  • Lamella Cross Section:

    • Reveals:

      • Hymenophoral trama

      • Hymenium structures: subhymenium, basidioles, basidia, cystidia.

  • Hymenophore Types: Tubulose-poroid (e.g., Boletaceae) contains same components; variations in development types include aequi-hymeniferous vs. inaequihymeniferous.

  • Tramal Types:

    • Homoiomerous (single hyphal type) vs. heteromerous (multiple hyphal types).

    • In heteromerous trama: generative hyphae can combine with skeletal and/or binding hyphae.

  • Cystidia: Inflated, sterile structures important in taxonomy—functions include maintaining gill separation for spore dispersal and micro-climate management.

Ballistospory in Basidiomycota

  • Present in Hymenomycetes, jelly fungi, rusts; absent in gasteromycetes and smuts.

  • Ballistospory Process:

    • Mature spores are placed asymmetrically on the sterigma.

    • Before discharge, a droplet, known as Buller's drop, forms at the hilar appendix.

    • The plug formed seals the spore and the sterigma.

    • The droplet grows due to hygroscopic water buildup.

    • Spore can be shot off 1-1.5 mm, an optimal distance for dispersal.

    • The mechanism is debated; current understanding suggests accumulation of Buller's drop results in directional shifts and provides energy for discharge.

  • High-Speed Photography: Studies confirm surface tension catapult model for spore discharge, demonstrating the combined effects of droplet movement and spore prior launch movement.

References

  • Alexopolous, C.J., Mims, C.W., & Blackwell, M. (1996). Introductory Mycology. John Wiley: New York.

  • Buller, A.H.R. (1909-1934). Researches in Fungi (6 vols.). Longmans Green & Co.: London.

  • Ingold, C.T. (1965). Spore Liberation. Clarendon Press: Oxford.

  • Money, N.P. (1998). More g's than the Space Shuttle: ballistospore discharge. Mycologia, 90, 547-558.

  • Pringle, A., Patek, S.N., Fischer, M., Stolze, J., & Money, N.P. (2005). The captured launch of a basidiospore. Mycologia, 97, 866-871.

  • Stolze-Rybczynski et al. (2009). Adaptation of the spore discharge mechanism in the Basidiomycota. PLoS One, 4, e4163.

  • Webster, J., Davey, R.A., Duller, G.A., & Ingold, C.T. (1984). Ballistospore discharge in Intersonilia perplexans. Trans Br Mycol Soc, 82, 13-29.