• F T Last

      Articles written in Proceedings – Plant Sciences

    • Factors affecting the production of fruitbodies ofAmanita muscaria in plantations ofPinus patula

      F T Last P A Mason R Smith J Pelham K A Bhoja Shetty A M Mahmood Hussain

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      Monthly counts, in plantations ofPinus patula at Kodaikanal in southern India, during 1977 and 1978, indicate that fruitbody production byAmanita muscaria, a fungus forming sheathing (ecto-) mycorrhizas, was influenced by (i) the current month’s rainfall and (ii) the age of the plantation.

      Fruitbodies rarely appeared in the absence of rain. Average monthly numbers increased in rain-months from 11 to 320 per thousand trees when monthly rainfall increased from 40 to 640 mm.

      During a period of 11 months (February/December 1978) numbers of fruitbodies per 1000 trees ranged fromc. 150 to 10800 in plantations 5 and 16 years old respectively.

      After rainfall-thresholds for fruitbody production had been exceeded—they were less in old, than in young, plantations—young plantations, judged by the production ofA. muscaria fruitbodies, were more responsive to additional rainfall than older plantations.

    • Erratum to: Factors affecting the production of fruitbodies ofAmanita muscaria in plantations ofPinus patula

      F T Last P A Mason R Smith J Pelham K A Bhoja Shetty A M Mahmood Hussain

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    • Factors affecting the occurrence of fruitbodies of fungi forming sheathing (ecto-) mycorrhizas with roots of trees

      F T Last L V Fleming

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      The production of fruitbodies of fungi forming sheathing (ecto-) mycorrhizas with trees depends upon current supplies of host assimilates, upon host genotype and the age of the host tree, upon soil types and soil amendments, and weather.

      Fruitbodies are not produced by fungi on roots severed from their tree, nor are they produced when trees are naturally or artificially defoliated. As trees, planted in ‘new’ sites, increase in age a succession of fungi produce fruitbodies, most arranged in annuli (rings) but some are arranged linearly, seemingly along secondarily thickened roots. From the initial ‘focus’, a stem base, each ring progresses outwards at rates comparable to those of grassland fairy ring fungi (10–20 cm yr−1), the movement of different rings being spatially correlated. Around birch trees in brown earth soils, rings of early stage fungi (Hebeloma crustuliniforme andLaccaria tortproximalis) are followed by those ofLactarius pubescens, Cortinarius spp. andRussula grisea. This pattern of development is likely to be different when seedlings grow in soil permeated with mycorrhizal roots of old (living) trees as happens during natural regeneration.

      Whereas more fruitbodies ofInocybe petiginosa were produced in association with one clone ofBetula pubescens than with another, the reverse was true ofLaccaria tortilis. There is evidence to suggest that soil type may influence the types of early-stage fungi producing fruitbodies. Applying lime to a Scots pine plantation decreased the production of fruitbodies byPaxillus involutus andLactarius rufus; applying ammonium-N stimulated fruitbody production byPaxillus involutus but decreased that ofAmanita muscaria and some species ofRussula.

      Seasons favouring the production ofPaxillus involutus fruitbodies were different from those favouringLactarius rufus. Fruitbody production of the late stageAmanita muscaria, in plantations ofPinus patula, was directly proportional to amounts of rainfall after an initial threshold which was smaller in old, than in young, plantations.

    • Characteristics of some species ofLaccaria, a fungal genus of significance to forestry, temperate and tropical

      F Irving A Crossley P A Mason F T Last J Wilson K Natarajan

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      With an increasing interest in the use of selected fungi for the production of sheathing (ecto-) mycorrhizas by controlled inoculations, attempts were made to identify collections ofLaccaria fruitbodies from woodland and forest sites in central Scotland and at high altitudes in southern India.

      Although the sizes of individual fruitbodies within collections varied appreciably, it was nonetheless possible to sort the collections into 2 groups using mean sizes: one group with (i) stipes (stalks) about 7 mm long and 1 mm diam. and (ii) pilei (caps) 10 mm diam., and a second group with appreciably larger fruitbodies.

      The group of larger fruitbodies was found to contain collections with either 2- or 4-spored basidia; the basidia in the group of small fruitbodies were all 2-spored.

      Although of similar sizes, spores of the 4-spored specimens had different shapes as judged by the ratios (Q values) of spore length: spore width, separately assessed for each spore with its apiculus in view. They were either globose (Q=1·01) with 8·6 spines per 9 μm2, each spine being on average 1·01 μm tall—a description conforming toLaccaria laccata (Scop.: Fr.) Bk. and Br- or elliptical (Q=1·20) with 16·3 spines per 9 μm2, each spine being only 0·72 μm tall—a description conforming toLaccaria proxima (Boud.) Pat.

      The spores of the group of large fruitbodies with 2-spored basidia were globose, like those ofLaccaria laccata, but slightly larger and with more spines per unit area, 11·3 per 9 μm2, a description conforming toLaccaria ohiensis (Mont.) Sing. The spores of the group of small fruitbodies with 2-spored basidia were similarly globose but, in contrast, were appreciably larger, 10·1×9·6 μm (compared with 6·3×6·3 μm forL. laccata), with taller (1·91 μm) and fewer spines, 4·2 per 9 μm2, a description conforming toLaccaria tortilis (Bolt.) S. F. Gray.

      Laccaria laccata, Laccaria proxima andLaccaria tortilis were collected in Scotland;Laccaria proxima andLaccaria ohiensis in India. Contrary to expectationLaccaria laccata was found less frequently thanLaccaria proxima, the fruitbodies of both being sometimes outnumbered by those ofLaccaria tortilis in young stands ofBetula spp.

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