Localized, Cold-Induced Inhibition of Translocation in Mycelia and Strands of Serpula lacrimans

Thompson, W., Brownlee, C, Jennings, D. H. and Mortimer, A.M. 1987. Localized, cold-induce inhibition of translocationin mycelia and strands of Serpula lacrimans. —J. exp.Bot. 38: 889–899 The effect has been investigated of localized low temperatureon translocation of ³²P across myceliui of Serpula lacrimansusing two gas-flow detectors capable of recording radioactivitycontinuously. When the temperature of a band of mycelium wasreduced to 0 ? C, radioactivity ceased to accumulai and in factdeclined under the detector (number 2) separated from the sourceof radioactivity by tr cold-treated mycelium. In the myceliumbeneath the other detector (number 1), closest to the sourceradioactivity, the rate of accumulation of radioactivity increased.When the temperature was raised t 20 ?C, radioactivity beganto accumulate in the mycelium under detector 2 and, apart froma sma fluctuation, continued to accumulate at a uniform rate.In the mycelium under detector 1, the accumulation of radioactivitystopped for a short time but then recommenced at a rate similarto thi found at 0 ?C. In other experiments the distributionof radioactivity (¹⁴C) throughout the myceliui was measuredat the end in homogenized samples. In these experiments a bandof mycelium we subjected to 0 ?C or to 20 ?C for the whole experimentalperiod, or only after the mycelium had bee translocating radioactivityalready for 16 h. These experiments showed that the changesin the rate of accumulation of ³²P in living mycelium underthe two gas flow detectors used for in situ measurements werenot due to a reversal of the flow of translocation. The resultsare consistent with an hypothesis that a turgor-driven massflow of solution is the mechanism for translocation in thisfungus and are considered in relation to the results of similarexperiments on phloem translocation in higher plants. Key words: Serpula lacrimans, mycelium, translocation, low-temperature, phloem transport     

Internal Structure and Hydraulic Conductivity of Basidiomycete Translocating Organs

Eamus, D., Thompson, W., Cairney, J. W. G. and Jennings, D.H. 1985. Internal structure and hydraulic conductivity of basidiomycetetranslocating organs.–J. exp. Bot. 36: 1110–1116. The presence in rhizomorphs of Armillaria mellea and cords ofPhallus impudicus of wide diameter hyphae (5–20 {diaeresis}m),which run for considerable distances along these linear organs,has been demonstrated. The longitudinal hydraulic conductivityof these organs has been determined experimentally and similarvalues were obtained when the hydraulic conductivity was calculatedtheoretically on the basis that the vessel hyphae were the solechannel for water movement along these organs. The experimentaldata have been discussed in relation to other data for long-distancetranslocation in basidiomycete linear organs. It is concludedthat the vessel hyphae are the main channels for turgor-driventranslocation. Key words: -Basidiomycete fungi, translocation, hydraulic conductivity     

How New Guinea rainforest flower resources vary in time and space: Implications for nectarivorous birds

Abstract Variability in spatial and temporal patterning of flowering by populations of rainforest trees fed upon by honeyeaters and flower-visiting parrots was studied for 2 years in lowland tropical hill forest in Papua New Guinea. All 2200 trees in a 3 ha plot were tagged, identified, mapped and monitored monthly. Of 274 tree species present, 86 flowered during the course of the study; during any given month, approximately 20% of the species flowering that month were visited by nectarivorous birds. Results showed that overall flower resources (total number of species, and number of bird-pollinated species, individuals and flowers) fluctuated during the year, decreased during the dry season and increased during the wet season. In addition, there was a wide range of temporal variation within and among tree species in length and timing of flowering period, percentage of each conspecific population flowering from year to year, and degree of synchrony among flowering conspecifics. Spatial dispersion of tree populations also varied, from clumps to scattered single individuals. Resident bird species were correlated with synchronously flowering trees, whereas nomadic bird species were correlated with asynchronously flowering trees. Resident birds were also associated with smaller blooming displays per tree, whereas nomadic birds were associated with trees that bloomed massively. There was no correlation between avian nomadism and spatial dispersion of tree populations. Thus nomadic birds seem to range in search of rich but unpredictable resources; resident birds may rely more on predictable, but smaller resources.