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rbalzer said:
it is nice to have other people share their coolest finds though. can't find what you want with google often, at least I can't

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Inocuole said:
You're not going to find a whole lot of sources that correlate with illegal mushrooms that almost nobody can get funding for studies on.

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Dboy said:
Hi so I'm interested in learning the science of mushroom cultivation.

I want to invite anyone to join the conversation, BUT PLEASE only share your knowledge if you can back it up with A SOURCE.


How do spores become mycelium?
i.e What is the mode of action that causes mycelial growth, and what is needed in this process?

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I also want to know more about hyphal knots, rhizomorphic growth, and metabolites

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Inocuole said:
Ohhhh PF says it's advanced Mycology. 

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Better than where u wanted to put it lol.

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PussyFart said:

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Inocuole said:
Ohhhh PF says it's advanced Mycology. 

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Better than where u wanted to put it lol.

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Shhh I didn't tell him where I really wanted to put it.

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Inocuole said:

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PussyFart said:

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Inocuole said:
Ohhhh PF says it's advanced Mycology. 

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Better than where u wanted to put it lol.

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Shhh I didn't tell him where I really wanted to put it.

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Inocuole said:
Well... Spores become mycelium by extending as single... monokaryotic strands, which clamp to compatible strands and form dikaryotic myceilum.  Hyphal knots are just the beginning of pins, can't really explain much on those, and rhizomorphic growth is just a phase of growth that occurs most often on low-nutrient substrates or media, but can also be genetic.  A healthy culture could go its whole life without showing rhizomorphs, so it's not critical feature.

That's all I've got for real answers.

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Well, i feel sufficiently educated now. thanks

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Dboy said:
Well, i feel sufficiently educated now. thanks

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I'm glad. It's good you feel that way

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Inocuole said:
That was a really lackluster explanation, even the people who've posted in here already should know more than me on that, I just picked up what I've learned here from some of the biologists and such that come through.

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Inocuole said:
That was a really lackluster explanation, even the people who've posted in here already should know more than me on that, I just picked up what I've learned here from some of the biologists and such that come through.

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Inocuole said:
They don't require high humidity, they require lots of water.  High humidity just keeps them from losing water, if there's a supply of water like a week long light rain, or someone misting them several times a day, they don't actually need the humidity to be high, they can actively transport water to where it's needed very well.

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Do you actually believe what you are saying there?

Why do you case? Why do you use perlite?

Why do they grow underground?

If humidity didn't matter you wouldn't do any of these things.

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A lot more would be available for reading without having to just be in the right place at the right time if this could get funding, like I said.  Most of what I know about this, I read in some thread whose topic wasn't even about the thing that I learned.  Sometimes people just come out of the woodwork and share gems when you lurk in certain places.

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micro said:
Do you actually believe what you are saying there?

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Inocuole said:
You just do this everywhere don't you?  You don't have any argument, you just want to discredit anything that doesn't fit into your paradigm.  This is coming from the guy who argued with Pasty and Mad Season about what constitutes "mist".

Have you ever fruited in open air?  Do you not understand?  Is your brain incapable?

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Inocuole said:
This is coming from the guy who argued with Pasty and Mad Season about what constitutes "mist".

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now that was funny.

everybody is so opposed to opposing views that they think everybody else is a troll.

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rbalzer said:
now that was funny.

everybody is so opposed to opposing views that they think everybody else is a troll.

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Youre buying this crap?

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Inocuole said:
If you did open air fruit you'd want a casing, and if you did fruit something uncased, you'd probably want a SGFC full of perlite, but that's besides the point.  Humidity isn't a need, it's a luxury.

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Inocuole said:
I get it, you have this shtick where you like to be the wrench in the cog, but I'm not trolling, I'm actually offering what I know to this guy's thread.  What are you doing other than stirring up shit?  You haven't reasonably disproved anything, you just keep trying the same old tired straw man shit.  You don't care about the topic, that much is clear.

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rbalzer said:
I'm sitting here thinking you're the troll. I have no clue what you're talking about

Talk about ruining a thread. Poor OP

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Inocuole said:
To be clear, this still creates humidity on the surface for the time it takes for any moisture to evaporate from the surface.

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Ambient humidity just isn't the end-all factor in whether a mushroom life cycle can complete.  Surface humidity will happen anyway when the substrate is properly hydrated.  It's not worth focusing on humidity as its own factor though.  It's not a measurement that tells you anything in particular about how well a grow will do.

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Inocuole said:
Now you're pulling shit out of context, seriously dude, stop.  If you were being tactful being a dick would be totally fine but you're just being retarded.  Perlite does provide humidity, I'm glad you know that, I can't imagine what that has to do with the biological needs of a fucking organism.

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Inocuole said:
If you did open air fruit you'd want a casing, and if you did fruit something uncased, you'd probably want a SGFC full of perlite, but that's besides the point.  Humidity isn't a need, it's a luxury.

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Gases take on both the shape and the volume of their container

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Inocuole said:
Definitely none of it hanging around the area that's producing it, that would be ludicrous.

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D. SPORE GERMINATION
Just as there are a variety of types of fungal spores, there are also different means of germination. It is not germane to the present treatment of spore germination to detail the many mechanisms of fungal spore germination, but we point out some general aspects of the topic.

Germination of spores may be affected by the physical feature of the spore; i.e., if the spore wall is thick as in chlamydospores or resistant sporangia, the spore may survive unfavorable conditions of temperature or desiccation, which would not be the case with thin-walled spores. Also, the contents of spores may vary. This includes water content, nutrients, and enzymatic capabilities.

1. Factors Affecting Germination

Whereas some spores will germinate immediately on being released from the parent structure if the environmental conditions are suitable, other species produce spores that remain dormant for a period of time. Dormancy is of two types - endogenous (constitutive) and exogenous.

Endogenous dormancy is imposed from within and may be due to the presence of low moisture content within the spore or the presence of inhibitors of germination. Thus, a wall that is relatively impermeable to water and a low water content of the spore will combine to keep the spore in the dormant stage, and this is a constitutive feature of the spores of certain species of fungi.

The inhibitors of germination may be volatile or nonvolatile substances, and these must be removed for germination to take place. In addition, there are compounds that stimulate germination, and one of the ways in which these stimulators act is by overcoming the effects of self inhibitors. Among the edible mushrooms there are some species in which breeding is difficult because of poor or inconsistent germination of basidiospores. The outstanding case in which this is true is that of Agaricus bisporus, but it is also true with Volvariella volvacea; and in a number of other species, the scientist is plagued by inconsistent germination. Because A. bisporus is the edible mushroom that is produced in greatest amounts and is the one for which the most advanced technology has been developed, much attention has been given to the study of spore germination in this species. Early observations indicated that isolated spores germinated very infrequently; but when many spores were close together, good germination occurred. A few spores germinated early and these seemed to stimulate the germination of other spores. These observations led to numerous experimental studies based on the premise that gaseous substances stimulated germination.

This was supported by the finding that spore germination increased when the spores were in the same gaseous environment as the living mycelium of A. bisporus, or other fungi. Numerous volatile organic acids were then tested for a possible effect on spore germination, and isovalerate, produced by the mycelium, has been implicated as the stimulator of germination in a number of studies. The mode of action that has been suggested is that germination of the spores is suppressed by the accumulation of carbon dioxide in the spores and that isovalerate is a direct precursor of a carbon dioxide acceptor methylcrotonyl coenzyme A. Thus, isovalerate acts by removing carbon dioxide from the spore. Essentially what this does is to take away the carbon dioxide that normally is fixed to form oxaloacetate, production of which in this manner suppresses the activity of the enzyme succinic dehydrogenase of the tricarboxylic acid cycle (TCA or Krebs cycle). That is, in the absence of isovalerate, carbon dioxide is used to produce oxaloacetate, slowing the respiratory activities of the TCA cycle in the spores and keeping them in a dormant stage. Isovalerate, by removing the carbon dioxide, prevents the formation of oxaloacetate from that carbon dioxide and thus activates the respiratory activity of the TCA cycle, which is required for germination.

Exogenous dormancy is imposed from without; i.e., it is environmentally controlled. In some species of fungi, nutrients are required for germination, but in other species the spore contains sufficient nutrients for germination if water and suitable environmental conditions exist. The environmental factors important in spore germination are the same as those for mycelial growth and fruiting body formation: temperature, pH, aeration, and light. The optimal values for these three different developmental stages of fungi (spore, mycelium, and fruiting body) will differ, although commonly within the same range of values.

The nutritional requirements for germination are difficult to generalize, because there are species, on the one hand, whose spores require nothing beyond water and an aerobic condition and, on the other hand, there are species that require inorganic salts and organic compounds such as glucose, or specific vitamins, or amino acids. Griffin points out that in several fungi, carbon dioxide has been shown to be a requirement for spore germination and growth and, more importantly, emphasizes that carbon dioxide may be a universal requirement.

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Spore germination and the orientation of
hyphal tip growth Fungi respond to many types of environmental signal, including signals that trigger spore germination (i.e. the production of a hyphal tip where none existed before– see Chapter 10) and signals that change the orientation of hyphal tip growth. Below we consider several examples of these processes.

Studies on germinating spores Some fungal spores, such as the uredospores of rust  fungi (Basidiomycota), have a fixed point of germination termed the germ pore, where the wall is conspicuously thinner than elsewhere. Similarly, the zoospores (motile, flagellate cells) of Chytridiomycota, Oomycota, and plasmodiophorids have a fixed point of germination, and they settle and adhere to receptive surfaces so that their future point of germ-tube outgrowth is located next to that surface (Chapter 10).

However, many spores seem to be able to germinate from any point on the cell periphery. The germination process often follows a common pattern (Fig. 4.7). Initially, the spore swells by hydration, then it swells further by an active metabolic process and new wall materials are incorporated over most or all of the cell surface – the phase termed nonpolar growth. Finally a germ-tube (a young hypha) emerges from a localized point on the cell surface, and all subsequent wall growth is localized to this region. The first sign that an apex will emerge is the localized development of an apical vesicle cluster. In the conidia of Aspergillus niger the transition from nonpolar to polarized growth is temperature-dependent (Fig. 4.7). At a normal temperature of about 30°C, the spore initially incorporates new wall material over the whole surface and then an apex is formed. However when the spores are incubated at 44°C they continue to swell for 24–48 hours, producing giant rounded cells up to 20–25 µm diameter (a 175-fold increase in cell volume) with walls up to 2 µm thick.

At this stage the cells stop growing. But if these “giant cells” are shifted down to 30°C before they stop growing they will respond by producing a hyphal apex, and this behaves in an unusual way: instead of forming a normal hypha it produces a small spore-bearing head (Fig. 4.7). These observations suggest two things. First, that the transition from nonpolar to polar growth in A. niger is temperature-dependent – it is blocked at the restrictive temperature (44°C). Second, that the fungus can still “mature” at the restrictive temperature: it reaches a developmental stage at which it is committed to sporulate, and it does so as soon as the temperature is lowered

The production of spores from germinating spores with a minimum of intervening growth is termed microcycle sporulation. It occurs naturally in some fungi, especially if they grow in water films in nutrient limited conditions.

For example, microcycle sporulation has been reported for some saprotrophs on leaf surfaces (e.g. Cladosporium, Alternaria spp., Chapter 11), some leaf infecting pathogens (e.g. Septoria nodorum), several vascular wilt pathogens that colonize xylem vessels (e.g. Fusarium oxysporum, Chapter 14), and the rhizosphere fungus Idriella bolleyi which is a biological control agent of root pathogens. All these fungi will germinate to form normal hyphae in nutrient-rich conditions, so their microcycling behavior in nutrient-poor conditions might be a means of spreading to new and potentially more favorable environments.

Spore germination tropisms

A tropism is defined as a directional growth response of an organism to an external stimulus. The spores of some fungi show this very markedly, a classic example being the yeast-like fungus Geotrichum candidum which is a common cause of spoilage of dairy products. The cylindrical spores of this
fungus germinate typically from one or other pole, but the site of germ-tube emergence is influenced strongly by the presence of neighboring spores when the spores are seeded densely on agar and covered with a coverslip. In these conditions the germ-tubes always emerge from the end furthest away from a touching spore – a phenomenon termed negative autotropism.

The causes of this behavior are still unclear. On the one hand, it has been suggested to involve the release of auto-inhibitors, which would accumulate maximally in the zone of contact of two spores but could diffuse away from the “free” ends, leading to germination there. On the other hand, oxygen depletion in the zone of spore contact could be a critical factor for G. candidum because the spores always germinate towards an oxygen source (a small hole in a plastic coverslip placed over the spore layer) and this positive tropism to oxygen could overcome the negative autotropism of touching spore pairs.

The spores of Idriella bolleyi (a mitosporic fungus) also show negative autotropism, but they show an even more spectacular response when placed in contact with cereal root hairs. The spores of Idriella always germinate away from living root hairs but towards dead root hairs and rapidly penetrate them.

This behavior seems to be ecologically relevant because I. bolleyi is a weak parasite of cereal and grass roots. It exploits the root cortical cells as they start to senesce naturally behind the growing root tip, and in doing so it competes with aggressive root pathogens that otherwise would use the dead cells as a food base for infection. Thus, the spore germination tropisms of I. bolleyi help to explain its role as a biological control agent of cereal root pathogens, similar to the role of nonpathogenic strains of the take-all fungus, discussed in Chapter 12. The tropic signals for I. bolleyi spores seem to be quite specific, because G. candidum and some other fungi tested in the same conditions showed quite different responses; for example, G. candidum germinated towards both living and dead root hairs (Allan et al. 1992).

Fungal spores can also show orientation responses to electrical fields of sufficiently high strength (5–20Vcm−1). For example, in one study the spores of Neurospora crassa and Mucor mucedo were found to germinate towards the anode, whereas spores of Emericella nidulans showed no significant orientation response. The somatic (older) hyphae of these and other fungi showed an array of orientation responses: Neurospora hyphae grew towards the anode and formed branches towards the anode; but hyphae of E. nidulans and M. mucedo grew and branched towards the cathode. In a more recent study (Lever et al. 1994) the galvanotropic responses of somatic hyphae were found to be pH- and calcium-dependent. Neurospora hyphae even changed from being strongly cathodotropic at pH 4.0 to strongly anodotropic at pH 7. Given the range of different responses to electrical fields it is difficult to summarize this topic, except to say that fungal hyphae can be responsive to electrical/ionic fields. Gow (2004)
recently reviewed this topic.

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-Fungal Biology 4 edition by Jim Deacon pg. 73-75

Spore germination mechanisms and requirements depend on the species AND the conditions so it is almost impossible to explain every little detail for the broad group of basidiomycota. The authors do give you a general idea of what is needed to support germination.

Here's some graphs for the metabolic cycle. Once again the species and conditions will alter how these pathways are specifically utilized by basidiomycetes. Most people generally agree that metabolites are produced for certain functions (mainly defense against competitors). Metabolites were previously believed to be waste-products before more data emerged on their functions.

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Nutrient-translocating organs

All fungi translocate nutrients in their hyphae, but some fungi produce conspicuous differentiated organs for bulk transport of nutrients across nutrient-free environments. Depending on their structure and mode of development, these translocating organs are termed mycelial cords or rhizomorphs. They are quite common among wood-rotting fungi, and also among the ectomycorrhizal fungi of tree roots, where carbohydrates are transported from the roots to the mycelium in soil, and mineral nutrients and water are translocated back towards the roots. Mycelial cords are also found at the bases of the larger mushrooms and toadstools, serving to channel nutrients for fruitbody development Mycelial cords.

Mycelial cords have been studied most intensively in Serpula lacrymans (Basidiomycota) which causes dry-rot of timbers in buildings (Chapter 7). Once this fungus is established in the timbers, it can spread several meters beneath plaster or brickwork to initiate new sites of decay. It spreads across non-nutritive surfaces as fans of hyphae, which draw nutrients forwards from an established site of decay. The hyphae differentiate into mycelial cords behind the colony margin.

The early stage of differentiation of mycelial cords occurs when branches emerge from the main hyphae and, instead of radiating, they branch immediately to form a T-shape and these branches grow backwards and forwards close to the parent hypha. The branches produce further branches that repeat this process, so the cord becomes progressively thicker, with many parallel hyphae. Consolidation occurs by intertwining and anastomosis of the branch hyphae and by secretion of an extracellular matrix which cements them together. Some of the main hyphae then develop into wide, thick-walled vessel hyphae with no living cytoplasm, while some of the narrower hyphae develop into fiber hyphae with thick walls and almost no lumen. Interspersed with these types of hyphae are normal, living hyphae rich in cytoplasmic contents. The cords of other fungi, such as the mycorrhizal species Leccinum scabrum, do not have fibre hyphae but otherwise show a similar pattern of development. In mature hyphal cords there is evidence of a large degree of degeneration of hyphal contents and of the deposition of large amounts of cementing material between the hyphae. The factors that control the development of mycelial cords are poorly understood, but studies on S. lacrymans suggest that the availability of nitrogen is a key factor.

Cords were found to develop on media containing
inorganic nitrogen (e.g. nitrate) but not on media containing amino acids. Also, cords growing from a mineral nutrient medium onto an organic nitrogen medium gave rise to normal, diverging hyphal branches. So it was suggested that cords develop when the parent hyphae leak organic nitrogen in nitrogen-poor conditions, causing branch hyphae to grow close to the parent hyphae in the nitrogen-rich zone. Regulatory control by nitrogen seems logical for wood-decay fungi, because wood has a very low nitrogen content and these fungi could have evolved special mechanisms for conserving and remobilizing their organic nitrogen (Chapter 11). This could apply also to the cords of ectomycorrhizal fungi, because these fungi have a significant role in degrading organic nitrogen in otherwise nitrogen-limiting soils (Chapter 13).

In terms of function, mycelial cords have been shown to translocate carbohydrates, organic nitrogen, and water over considerable distances between sources and sinks of these materials. The vessel hyphae seem to act like xylem vessels of plants, transporting water by osmotically driven mass flow (Chapter 7). The combination of their thick walls, the extensive extrahyphal matrix and reinforcement by fiber hyphae could enable vessel hyphae to withstand considerable hydrostatic pressure.

Rhizomorphs

Rhizomorphs serve similar functions to mycelial cords but have a more clearly defined organization. A notable example is the rhizomorph of Armillaria mellea, a major root-rot pathogen of broad-leaved trees. It spreads from tree to tree by growing as rhizomorphs through the soil, and it also spreads extensively up the trunks of dead trees by forming thick, black rhizomorphs beneath the bark. These rhizomorphs resemble boot laces, hence the common name for this fungus – the boot-lace fungus. The rhizomorph has a specially organized apex or growing point similar to a root tip, with a tightly packed sheath of hyphae over the apex, like a root cap. Behind the apex is a fringe of short hyphal branches. The main part of the rhizomorph has a fairly uniform thickness and is differentiated into zones: an outer cortex of thick-walled melanized cells in an extracellular matrix, a medulla of thinner-walled, parallel hyphae, and a central channel where the medulla has broken down, serving a role in gaseous diffusion. Rhizomorphs branch by producing new multicellular apices, either behind the tip or by bifurcation of the tip.

Rhizomorphs extend much more rapidly than the
undifferentiated hyphae of A. mellea, and they can grow for large distances through soil. However, they need to be attached to a food base because their growth depends on translocated nutrients, so one of the  traditional ways of preventing spread from tree to tree is by trenching of the soil to sever the rhizomorphs.

Almost nothing is known about the developmental triggers of rhizomorphs, except that ethanol and other small alcohols can induce them; similarly, almost nothing is known about their mode of development because they originate deep within an established colony in laboratory culture. However, the behavior of rhizomorphs is of considerable interest, as shown by the work of Smith & Griffin (1971) on Armillariella elegans (related to A. mellea). In this fungus, the rhizomorph apex will only grow if it remains hyaline, and this means that the partial pressure of oxygen at the surface of the apex must be 0.03 or less (compared with about 0.21 in air). Above this level, the apex rapidly becomes melanized, stopping its growth. Yet growth of the apex is strongly oxygen-dependent, and the fungus seems to resolve this dilemma by a combination of factors. A high respiration rate is maintained at thevapex, supported partly by diffusion of oxygen along the central channel, while the surface of the apex is covered by a water film which limits the rate of oxygen diffusion: at 20°C, oxygen diffuses about 10,000 times more slowly through water than through air. The dependence on a water film ensures that rhizomorphs grow naturally at a specific depth in soil, depending on the soil type and the climate. If a tip grows too close to the soil surface then the width of the water film is reduced and oxygen diffuses to the tip more rapidly, causing melanization. These tips near to the soil surface then break down to produce “breathing pores” connected to the central channel. Conversely, if the apex grows too deeply into moist soil then the water film increases and the rate of growth becomes oxygen-limited. Thus, the peculiar organization of a rhizomorph helps to regulate growth to specific zones in the soil, and these zones are where tree roots occur, maximizing the opportunities for infection.

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This was also from Fungal Biology 4 edition by Jim Deacon.

Hyphal knots.... Fuck I'm tired of typing.... They are a cylindrical matrix of mycelium that forms primordia, which eventually enlarge, mature, and sporulate. Basically a sexual rhizomorph that develops into a fruitbody.

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tyrosinase is a sex hormone :V

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Maybe? fungi are super freaky in terms of sexual reproduction. I honestly wouldn't know as I only dabble in life and that would involve a lot of effort to figure out

I've never heard of blast but it sounds useful.

Fungi are surprisingly forgotten like some mutant freak of nature nobody wishes to embrace. Eventually that will change though.

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rbalzer said:
can't thank you enough for that link!

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Thanks for the information.

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micro said:
textbooks rock

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