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Tapani Repo - One of the best experts on this subject based on the ideXlab platform.
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whole plant frost hardiness of mycorrhizal hebeloma sp or suillus luteus and non mycorrhizal scots pine seedlings
Tree Physiology, 2019Co-Authors: Anna Korhonen, Tarja Lehto, Jaakko Heinonen, Tapani RepoAbstract:Ectomycorrhizal trees are common in the cold regions of the world, yet the role of the mycorrhizal symbiosis in plant cold tolerance is poorly known. Moreover, the standard methods for testing plant frost hardiness may not be adequate for roots and mycorrhizas. The aims of this study were to compare the frost hardiness of mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings and to test the use of reverse-flow root hydraulic conductance (Kr) measurement for root frost hardiness determination. Mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal seedlings were grown in controlled-environment chambers for 13 weeks. After this, half of the plants were allotted to a non-hardening treatment (long day and high temperature, same as during the preceding growing season) and the other half to a hardening (short day and low temperature) 'autumn' treatment for 4 weeks. The intact seedlings were exposed to whole-plant freezing tests and the needle frost hardiness was measured by relative electrolyte leakage (REL) method. The seedlings were grown for three more weeks for visual damage assessment and Kr measurements using a high-pressure flow meter (HPFM). Mycorrhizas did not affect the frost hardiness of seedlings in either hardening treatment. The effect of the hardening treatment on frost hardiness was shown by REL and visual assessment of the aboveground parts as well as Kr of roots. Non-mycorrhizal plants were larger than mycorrhizal ones while nitrogen and phosphorus contents (per unit dry mass) were similar in all mycorrhiza treatments. In plants with no frost exposure, the non-mycorrhizal treatment had higher Kr. There was no mycorrhizal effect on plant frost hardiness when nutritional effects were excluded. Further studies are needed on the role of mycorrhizas especially in the recovery of growth and nutrient uptake in cold soils in the spring. The HPFM is useful novel method for assessment of root damage.
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Frost hardiness of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine roots
Mycorrhiza, 2013Co-Authors: Anna Korhonen, Tarja Lehto, Tapani RepoAbstract:The frost hardiness (FH) of mycorrhizal [ectomycorrhizal (ECM)] and non-mycorrhizal (NM) Scots pine ( Pinus sylvestris ) seedlings was studied to assess whether mycorrhizal symbiosis affected the roots’ tolerance of below-zero temperatures. ECM ( Hebeloma sp.) and NM seedlings were cultivated in a growth chamber for 18 weeks. After 13 weeks’ growth in long-day and high-temperature (LDHT) conditions, a half of the ECM and NM seedlings were moved into a chamber with short-day and low-temperature (SDLT) conditions to cold acclimate. After exposures to a range of below-zero temperatures, the FH of the roots was assessed by means of the relative electrolyte leakage test. The FH was determined as the inflection point of the temperature-response curve. No significant difference was found between the FH of mycorrhizal and non-mycorrhizal roots in LDHT (−8.9 and −9.8 °C) or SDLT (−7.5 and −6.8 °C). The mycorrhizal treatment had no significant effect on the total dry mass, the allocation of dry mass among the roots and needles or nutrient accumulation. The mycorrhizal treatment with Hebeloma sp. did not affect the FH of Scots pine in this experimental setup. More information is needed on the extent to which mycorrhizas tolerate low temperatures, especially with different nutrient contents and different mycorrhiza fungi.
Anna Korhonen - One of the best experts on this subject based on the ideXlab platform.
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whole plant frost hardiness of mycorrhizal hebeloma sp or suillus luteus and non mycorrhizal scots pine seedlings
Tree Physiology, 2019Co-Authors: Anna Korhonen, Tarja Lehto, Jaakko Heinonen, Tapani RepoAbstract:Ectomycorrhizal trees are common in the cold regions of the world, yet the role of the mycorrhizal symbiosis in plant cold tolerance is poorly known. Moreover, the standard methods for testing plant frost hardiness may not be adequate for roots and mycorrhizas. The aims of this study were to compare the frost hardiness of mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings and to test the use of reverse-flow root hydraulic conductance (Kr) measurement for root frost hardiness determination. Mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal seedlings were grown in controlled-environment chambers for 13 weeks. After this, half of the plants were allotted to a non-hardening treatment (long day and high temperature, same as during the preceding growing season) and the other half to a hardening (short day and low temperature) 'autumn' treatment for 4 weeks. The intact seedlings were exposed to whole-plant freezing tests and the needle frost hardiness was measured by relative electrolyte leakage (REL) method. The seedlings were grown for three more weeks for visual damage assessment and Kr measurements using a high-pressure flow meter (HPFM). Mycorrhizas did not affect the frost hardiness of seedlings in either hardening treatment. The effect of the hardening treatment on frost hardiness was shown by REL and visual assessment of the aboveground parts as well as Kr of roots. Non-mycorrhizal plants were larger than mycorrhizal ones while nitrogen and phosphorus contents (per unit dry mass) were similar in all mycorrhiza treatments. In plants with no frost exposure, the non-mycorrhizal treatment had higher Kr. There was no mycorrhizal effect on plant frost hardiness when nutritional effects were excluded. Further studies are needed on the role of mycorrhizas especially in the recovery of growth and nutrient uptake in cold soils in the spring. The HPFM is useful novel method for assessment of root damage.
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Frost hardiness of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine roots
Mycorrhiza, 2013Co-Authors: Anna Korhonen, Tarja Lehto, Tapani RepoAbstract:The frost hardiness (FH) of mycorrhizal [ectomycorrhizal (ECM)] and non-mycorrhizal (NM) Scots pine ( Pinus sylvestris ) seedlings was studied to assess whether mycorrhizal symbiosis affected the roots’ tolerance of below-zero temperatures. ECM ( Hebeloma sp.) and NM seedlings were cultivated in a growth chamber for 18 weeks. After 13 weeks’ growth in long-day and high-temperature (LDHT) conditions, a half of the ECM and NM seedlings were moved into a chamber with short-day and low-temperature (SDLT) conditions to cold acclimate. After exposures to a range of below-zero temperatures, the FH of the roots was assessed by means of the relative electrolyte leakage test. The FH was determined as the inflection point of the temperature-response curve. No significant difference was found between the FH of mycorrhizal and non-mycorrhizal roots in LDHT (−8.9 and −9.8 °C) or SDLT (−7.5 and −6.8 °C). The mycorrhizal treatment had no significant effect on the total dry mass, the allocation of dry mass among the roots and needles or nutrient accumulation. The mycorrhizal treatment with Hebeloma sp. did not affect the FH of Scots pine in this experimental setup. More information is needed on the extent to which mycorrhizas tolerate low temperatures, especially with different nutrient contents and different mycorrhiza fungi.
Tarja Lehto - One of the best experts on this subject based on the ideXlab platform.
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whole plant frost hardiness of mycorrhizal hebeloma sp or suillus luteus and non mycorrhizal scots pine seedlings
Tree Physiology, 2019Co-Authors: Anna Korhonen, Tarja Lehto, Jaakko Heinonen, Tapani RepoAbstract:Ectomycorrhizal trees are common in the cold regions of the world, yet the role of the mycorrhizal symbiosis in plant cold tolerance is poorly known. Moreover, the standard methods for testing plant frost hardiness may not be adequate for roots and mycorrhizas. The aims of this study were to compare the frost hardiness of mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings and to test the use of reverse-flow root hydraulic conductance (Kr) measurement for root frost hardiness determination. Mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal seedlings were grown in controlled-environment chambers for 13 weeks. After this, half of the plants were allotted to a non-hardening treatment (long day and high temperature, same as during the preceding growing season) and the other half to a hardening (short day and low temperature) 'autumn' treatment for 4 weeks. The intact seedlings were exposed to whole-plant freezing tests and the needle frost hardiness was measured by relative electrolyte leakage (REL) method. The seedlings were grown for three more weeks for visual damage assessment and Kr measurements using a high-pressure flow meter (HPFM). Mycorrhizas did not affect the frost hardiness of seedlings in either hardening treatment. The effect of the hardening treatment on frost hardiness was shown by REL and visual assessment of the aboveground parts as well as Kr of roots. Non-mycorrhizal plants were larger than mycorrhizal ones while nitrogen and phosphorus contents (per unit dry mass) were similar in all mycorrhiza treatments. In plants with no frost exposure, the non-mycorrhizal treatment had higher Kr. There was no mycorrhizal effect on plant frost hardiness when nutritional effects were excluded. Further studies are needed on the role of mycorrhizas especially in the recovery of growth and nutrient uptake in cold soils in the spring. The HPFM is useful novel method for assessment of root damage.
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Frost hardiness of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine roots
Mycorrhiza, 2013Co-Authors: Anna Korhonen, Tarja Lehto, Tapani RepoAbstract:The frost hardiness (FH) of mycorrhizal [ectomycorrhizal (ECM)] and non-mycorrhizal (NM) Scots pine ( Pinus sylvestris ) seedlings was studied to assess whether mycorrhizal symbiosis affected the roots’ tolerance of below-zero temperatures. ECM ( Hebeloma sp.) and NM seedlings were cultivated in a growth chamber for 18 weeks. After 13 weeks’ growth in long-day and high-temperature (LDHT) conditions, a half of the ECM and NM seedlings were moved into a chamber with short-day and low-temperature (SDLT) conditions to cold acclimate. After exposures to a range of below-zero temperatures, the FH of the roots was assessed by means of the relative electrolyte leakage test. The FH was determined as the inflection point of the temperature-response curve. No significant difference was found between the FH of mycorrhizal and non-mycorrhizal roots in LDHT (−8.9 and −9.8 °C) or SDLT (−7.5 and −6.8 °C). The mycorrhizal treatment had no significant effect on the total dry mass, the allocation of dry mass among the roots and needles or nutrient accumulation. The mycorrhizal treatment with Hebeloma sp. did not affect the FH of Scots pine in this experimental setup. More information is needed on the extent to which mycorrhizas tolerate low temperatures, especially with different nutrient contents and different mycorrhiza fungi.
Mario Honrubia - One of the best experts on this subject based on the ideXlab platform.
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Using common mycorrhizal networks for controlled inoculation of Quercus spp. with Tuber melanosporum: the nurse plant method.
Mycorrhiza, 2013Co-Authors: Guillermo Pereira, Götz Palfner, Daniel Chávez, Laura M. Suz, Ángela Machuca, Mario HonrubiaAbstract:The high cost and restricted availability of black truffle spore inoculum for controlled mycorrhiza formation of host trees produced for truffle orchards worldwide encourage the search for more efficient and sustainable inoculation methods that can be applied globally. In this study, we evaluated the potential of the nurse plant method for the controlled inoculation of Quercus cerris and Quercus robur with Tuber melanosporum by mycorrhizal networks in pot cultures. Pine bark compost, adjusted to pH 7.8 by liming, was used as substrate for all assays. Initially, Q. robur seedlings were inoculated with truffle spores and cultured for 12 months. After this period, the plants presenting 74 % mycorrhizal fine roots were transferred to larger containers. Nurse plants were used for two treatments of two different nursling species: five sterilized acorns or five 45-day-old, axenically grown Q. robur or Q. cerris seedlings, planted in containers around the nurse plant. After 6 months, colonized nursling plant root tips showed that mycorrhiza formation by T. melanosporum was higher than 45 % in the seedlings tested, with the most successful nursling combination being Q. cerris seedlings, reaching 81 % colonization. Bulk identification of T. melanosporum Mycorrhizae was based on morphological and anatomical features and confirmed by sequencing of the internal transcribed spacer region of the ribosomal DNA of selected root tips. Our results show that the nurse plant method yields attractive rates of mycorrhiza formation by the Perigord black truffle and suggest that establishing and maintaining common mycorrhizal networks in pot cultures enables sustained use of the initial spore inoculum.
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Morphological characterization of the mycorrhiza formed by Helianthemum almeriense Pau with Terfezia claveryi Chatin and Picoa lefebvrei (Pat.) Maire
Mycorrhiza, 2003Co-Authors: A. Gutiérrez, A. Morte, Mario HonrubiaAbstract:This work presents the first anatomical description of the mycorrhizal systems of Helianthemum almeriense, and of the structure and ultrastructure of the Mycorrhizae formed by this plant species with the ascomycetes Terfezia claveryi and Picoa lefebvrei . Four different mycorrhizal systems are described, the club-shaped mycorrhiza being the most abundant. The type of mycorrhiza formed depended on the mycorrhiza culture conditions, but not on the fungal species. For both fungal species, H. almeriense formed an endomycorrhiza in natural field conditions, an ecto- and ectendomycorrhiza without a sheath in pot cultures, and an ectomycorrhiza with a characteristic sheath and Hartig net in in vitro cultures. This is the first report of a typical sheath in Helianthemum -desert truffle mycorrhizal associations. The results support the idea that culture conditions can induce changes in mycorrhiza morphology and that there is no clear barrier between the two main types of mycorrhiza organization in Helianthemum species. The ultrastructural study confirmed the regular presence of T. claveryi intracellular hyphae in direct contact with the host wall, a localization which seems to be a characteristic of the T. claveryi mycorrhiza organization. The P. lefebvrei mycorrhiza organization was characterized by intracellular hyphae with large amounts of electron-dense globules, probably with a lipidic content, and a warty ornamentation on the wall of the root external hyphae.
J W G Cairney - One of the best experts on this subject based on the ideXlab platform.
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a study of ageing of spruce picea sitchensis bong carr ectomycorrhizas i morphological and cellular changes in mycorrhizas formed by tylospora fibrillosa burt donk and paxillus involutus batsch ex fr fr
New Phytologist, 1992Co-Authors: G M Downes, Ian J. Alexander, J W G CairneyAbstract:summary An age sequence of mycorrhizas formed by Paxillus involutus (Batsch. ex Fr.) Fr. and Tylospora fibrillosa (Burt.) Donk was sampled from 6–9-month-old seedlings of Picea sitchensis (Bong.) Carr. grown on peat in root observation chambers. Information about the ageing process was obtained from co-ordinated studies of mycorrhizal morphology, anatomy, ultrastructure and cell vitality (indicated by FDA-staining). Newly produced mycorrhizas were pale and turgid over most of their length with obvious extramatrical mycelium. Most mycorrhizas over 50 d old had a light turgid apical portion and a darkened wrinkled proximal portion: extramatrical mycelium was less obvious. Many remained in this state until the sampling stopped at day 142, but some were completely darkened before day 50. The morphological appearance of a mycorrhiza was not a good indicator of its chronological age. Most mycorrhizas displayed periodic busts of growth which added portions of young turgid cortex to an ageing axis. The percentage of cortical cells showing nuclei in 1 μm sections of the apical 1 mm declined from 40–50 % in mycorrhizas < 25 d old to 5–15 % in mycorrhizas 110–140 d old. Cortical cells became more vacuolate as they aged and the number of organelles appeared to decline. Senescence proceeded from the outer to the inner cortex and from proximal to distal regions. Degenerate cortical cells were present in the Hartig net zone of mycorrhizas over 25 days old. Cortical cell degeneration preceded, but was closely followed by, degeneration of adjacent Hartig net. The FDA study supported the general pattern and timing of cell death interpreted from the morphological and ultrastructural study. Cortical/Hartig net fluorescence declined markedly in mycorrhizas over 70–85 d old. The stele was the last tissue in the mycorrhiza to degenerate. It is suggested that a mycorrhiza ceases to function in nutrient and water uptake when no living cortical/Hartig net interface remains. In this study a few mycorrhizas became non-functional by day 31. For most mycorrhizas the major decline in function took place after 85 days. This estimate is in broad agreement with the estimates of mycorrhizal life span obtained from biomass studies in the field.
