Haustoria contain nuclei and a concentrated number of mitochondria. The haustoria do not rupture the host cell protoplasmic membrane but invaginates itself into the cell thus greatly increasing the absorptive surface of the fungus. Reproduction of fungi is primarily by means of spores.
Spores are reproductive bodies that consist of one or a few cells. In function they are analogous to the seeds of green plants. Spores are produced by sexual and asexual reproduction. Sexual reproduction involves the union of two compatible nuclei as produced by meiosis. Sexually produced spores include oospores, zygospores, ascospores and basidiospores characteristic of the phyla Oomycota, Zygomycota, Ascomycota and Basidiomycota respectively. Asexual reproduction usually occurs by means of mitosis which produce mitotic spores, mycelial fragmentation, fission and budding.
With asexual reproduction the repeating cycles of infection can continue throughout the growing season. Asexual spores may be classified as oidia formed by fragmentation of hyphae into individual cells , conidia borne on tips or sides of specialized branches of hyphae and sporangiospores a nonmotile spore born in a sporangim or case.
There are many types and different characteristics of fruiting bodies, spores and mycelium. Fungi are both classified and identified by these features. The classification of pathogenic fungi is important for identifying and diagnosing plant disease. Each kingdom, phylum, class, order, genus and specie has its own identifying characteristics. Many of the diagnostic factors in identifying different fungi are very subtle and without proper lab equipment and skill are difficult to identify down to the species level.
Most often, we rely on visual signs and symptoms for diagnosis of fungal disease. Ascomycete fruiting bodies sexual. A - Apothecium, B - Cleistothecium, C - Perithecium The primary phyla dealt with in plant pathology and disease diagnosis are listed below. This outline is very brief and only includes a few of the more important pathogens and problems.
Also included are some of the more important characteristics of each phylum. For further clarification on fungal taxonomy, you can refer to any number of resources at the Extension office. Also, the internet is an excellent source of information on this subject. Fungal-like organisms lower fungi : Kingdom: Protozoa Phylum: Plasmodiophoromycota endoparasitic slim molds e. Simple pored nonseptate hyphae. Asexual spores - sporangiospores, motile and non- motile. Sexual spores — zoospores e.
Chrysanthemum White Rust, Phytophthora ssp. Phylum: Zygomycota saprophytes or parasites of plants, Humans and animals. No zoospores. Simple pored nonseptate Hyphae. Asexual spores - Sexual nonmotile sporangiospores. Rhizopus - bread molds, rots of fruits and vegetables. Phylum: Ascomycota the sac fungi - most have both teleomorphic sexual and anamorphic asexual stages.
Simple septate hyphae. Produce sexual spores ascospores or asexual spores conidia on free hyphae or in asexual fruiting bodies such as Cleistothecium, Perithecium, Apothecium and Pycnidium. This phylum is responsible for most of our phytopathogenic fungal diseases. Some important pathogens in this phylum: Peach leaf curl Taphrina sp. Powdery mildew Podosphaera, apple Microsphaera azalea etc. Incorrect about fruit bodies of sac fungi. Give the technical term for the fruiting bodies of: sac-fungi.
Compare the different types of fruiting bodies in fungi. Very Important Questions. If area of an equilateral triangle is then its height is a 3 cm b c 6 cm d. A twice differentiable function f x is defined for all real numbers and satisfies the following conditions. The function is defined by , where 'a' is any constant If. Find the value s of 'a'. The straw needs to be steamed for at least 8 hours. The straw has to be cooled down to 30 C before spawning. Good results, however, have been obtained by prolonged heating at this temperature when the substrate should be sterile.
Obviously the materials used should be able to withstand the temperatures. Insulation panels can keep energy costs down. After the heat treatment the substrate should be sterile. Large autoclaves require a high investment and may not be feasible for small and medium scale operations.
Alternatively, a layer of substrate can be topped with some spawn, layer by layer. Different types of bags can be used to hold the substrate. The bags should never be filled to more than 20 kg per bag. Holes need to be made in the bags to ensure complete aeration enough oxygen circulation throughout the substrate.
One type of bag used in China is made of cylindrical plastic, 20 cm in diameter, filled up to a height of 50cm, with a perforated pipe in the middle, right down to the bottom of the bag. The mouth of the bag is tied around the pipe, and aeration proceeds through the pipe.
The aeration pipe will also allow heat to dissipate, even if it is formed in the core of the substrate. Spawning is performed by lifting the plugs from the bags containing the substrate thus opening the bags and putting in a small amount of spawn. This is the moment at which contamination is most likely to occur. So ensure that the time the bags are open is as short as possible.
The hot bags need to be kept for cooling in a special room with UV lights without ventilation. The spawn run time is different for each species and depends on the size of the bag, amount of spawn, the strain used and the temperature. Depending on the strain and temperature the mycelium will colonize the substrate in two or three weeks e. If, however, the relative humidity is rather low, cutting away too much plastic results into drying out of the substrate and must be avoided.
Slashing and hanging the bags from the ceiling can also be used. Temperature, air movement, illumination and humidity should be controlled in the fruiting room. If the temperature is too high it can be regulated by spraying more water. Air movement and illumination can also be controlled by opening or closing windows and doors. Figure 12 Fruiting stage of mushroom development 3. Harvesting is performed by gently pulling or twisting the mushrooms from the substrate. Harvesting can continue as long as the mycelium remains white and firm.
In total, three or four flushes can be harvested. When the substrate becomes soft and colorless, it is time to remove it from the house. There is so much variability among strains and substrates used that it is difficult to give periods for fruiting.
Typically, it will take about one week before new primordia are formed, but much depends on the local climate conditions and the climate control in the growing rooms. Mushrooms can generally be compared with fish in their perishability. In order to avoid rapid deterioration, the fresh mushrooms should be marketed directly after harvesting. If this is not possible the mushrooms could be dried in a simple drying unit and marketed later.
Other preservation methods can also be used. Canning, brining and drying are the most common techniques of preserving mushrooms, but not all Preservation methods are equally suitable for all the different types mushrooms. Canned oyster mushrooms, for instance, taste horrible except for Pleurotus cystidiosus and P.
In some cases, the taste may become stronger after the preservation treatments. Oyster mushrooms and shiitake, for example, give off a specific fragrance after drying.
Among cultivated mushrooms, this conservation technique is mostly used for shiitake Lentinula. The shiitake mushrooms get tastier after the drying process. Oyster mushrooms Pleurotus also become tastier. Nevertheless, the market for dried oyster mushroom is smaller compared to the market for dried Shiitake. Wood ear mushrooms Auricularia can be dried as well and are often marketed in this way. Mushrooms do not have to be crisp to the touch after drying; they should still be slightly flexible.
As the mushrooms could become toasted at high temperatures, longer drying at low temperatures is safer than faster drying at high temperatures. However, if the fresh mushrooms are very wet, the starting temperature should not be low as they might start to rot. This is especially important for large whole mushrooms. Sun drying usually results in products of inferior quality having higher moisture and limited shelf life.
The success of these methods is dependent on the storage life required, type of mushroom and so on. Canning is less satisfactory specifically in shiitake, while irradiation with gamma rays has been successful for Agaricus mushrooms. Irradiation kills spoilage bacteria and inhibits respiration and significantly prolongs the storage life, although the sensory acceptance of irradiated mushrooms is not likely.
Controlled atmosphere packaging and storage was also observed to be effective method of prolonging the storage stability of agaricus mushrooms. Low O2 levels limited the activities of polyphenol oxidase which otherwise cause browning discoloration.
Other advanced technologies like freeze-drying can also successfully be employed in mushroom preservation. The packing material must be waterproof, airtight and insect-proof.
The dried products will only remain good if stored in such a way that they are dry and protected from insects. Normal plastic bags properly sealed will do for some time, but are not entirely gas and waterproof. A plastic bag of thicker quality polyethylene, 0. These can be closed tightly with a metal clip or with cellophane tape. It is also possible to use polymer-coated cellophane bags, which are waterproof and airtight. These can be sealed with a hot iron or a sealing machine where electricity is available.
Unfortunately this kind of plastic cannot be easily obtained and is not too strong either. It is reported that more than a thousand species of wild mushrooms are consumed in 85 countries, among which the black truffle Tuber melanosporum , boletes Boletus spp. The world production of cultivated mushrooms was estimated to be 6.
The world production of Lentinula edodes increased from More than 10 new mushroom species, including Agaricus blazei, Pleurotus eryngii, and Agrocybe aegerita, have been cultivated in recent years on a small commercial scale, and the potential for expansion is great.
However, it must be noted that the moisture content of mushrooms is affected by the time of cropping, watering conditions during cultivation, postharvest period, and temperature and relative humidity during growth. The specific moisture content of some fleshy edible mushroom species is presented in the Table 2 below.
The protein of edible mushrooms is comparatively rich in glutamic acid In some species, the lipid content may be as low as 2. Cultivated mushrooms are a good source of minerals, containing macro- elements such as calcium, magnesium, sodium, potassium, and phosphorus and microelements such as copper, iron, manganese, and zinc.
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