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1.
G. Richard Strimbeck Trygve D. Kjellsen Paul G. Schaberg Paula F. Murakami 《Trees - Structure and Function》2007,21(5):557-567
Because they maintain green foliage throughout the winter season, evergreen conifers may face special physiological challenges
in a warming world. We assessed the midwinter low-temperature (LT) tolerance of foliage from eight temperate and boreal species
in each of the genera Abies, Picea, and Pinus growing in an arboretum in Trondheim, Norway, using relative electrolyte leakage (REL) as an index of cell injury. Relatively
LT sensitive species came from temperate coastal and Mediterranean environments and displayed a well-defined sigmoidal response
to LT stress, with LT50 ranging from −27 to −38°C. Species originating from boreal regions were not lethally stressed by slow freezing to temperatures
as low as −80°C, while species from temperate mountains and continental interiors displayed intermediate responses, with LT50s
ranging from −33 to −44°C. Further evaluation of one sensitive and one insensitive species in each genus showed that boreal
species can survive quenching in liquid nitrogen at −196°C provided they are first slowly cooled to −30°C or lower. Quantitative
image analysis of color changes resulting from LT stress followed by exposure to light showed that foliage from nonlethally
stressed boreal species developed mild to moderate chlorosis while more sensitive species developed a mixture of chlorosis
and necrosis, with significant necrosis occurring mainly at temperatures resulting in REL of 50% or more. Sensitive and insensitive
trees differed significantly in total raffinose, sucrose, and total sugar concentrations, and raffinose and sucrose correlated
significantly with LT50 within the sensitive group.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Hayashi M Wharton DA 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(3):335-342
The cold tolerance abilities of only a few nematode species have been determined. This study shows that the oatmeal nematode,
Panagrellus redivivus, has modest cold tolerance with a 50% survival temperature (S
50) of −2.5°C after cooling at 0.5°C min−1 and freezing for 1 h. It can survive low temperatures by freezing tolerance and cryoprotective dehydration; although freezing
tolerance appears to be the dominant strategy. Freezing survival is enhanced by low temperature acclimation (7 days at 5°C),
with the S
50 being lowered by a small but significant amount (0.42°C). There is no cold shock or rapid cold hardening response under the
conditions tested. Cryoprotective dehydration enhances the ability to survive freezing (the S
50 is lowered by 0.55°C, compared to the control, after 4 h freezing at −1°C) and this effect is in addition to that produced
by acclimation. Breeding from survivors of a freezing stress did not enhance the ability to survive freezing. The cold tolerance
abilities of this nematode are modest, but sufficient to enable it to survive in the cold temperate environments it inhabits. 相似文献
3.
Three species of Arctic to cold-temperate amphi-Atlantic algae, all occurring also in the North Pacific, were tested for growth
and/or survival at temperatures of −20 to 30°C. When isolates from both western and eastern Atlantic shores were tested side-by-side,
it was found that thermal ecotypes may occur in such Arctic algae.Chaetomorpha melagonium was the most eurythermal of the 3 species. Isolates of this alga were alike in temperature tolerance and growth rate but
Icelandic plants were more sensitive to the lethal temperature of 25°C than were more southerly isolates from both east and
west. With regard toDevaleraea ramentacea, one Canadian isolate grew extraordinarily well at −2 and 0°C, and all tolerated temperatures 2–3°C higher than the lethal
limit (18–20°C) of isolates from Europe. ConcerningPhycodrys rubens, both eastern and western isolates died at 20°C but European plants tolerated the lethal high temperature longer, were more
sensitive to freezing, and attained more rapid growth at optimal temperatures. The intertidal species,C. melagonium andD. ramentacea, both survived freezing at −5 and −20°C, at least for short time periods.C. melagonium was more susceptible thanD. ramentacea to desiccation. Patterns of thermal tolerance may provide insight into the evolutionary history of seaweed species. 相似文献
4.
Variation of total soluble seminal root proteins of tetraploid wild and cultivated wheat induced at cold acclimation and freezing 总被引:2,自引:0,他引:2
The relationship between total soluble seminal root proteins induced at cold acclimation and freezing tolerance in tetraploid
wild wheat Aegilops L. (Ae. biuncialis, Ae. cylindrica) and cultivated wheat Triticum turgitum L. (Firat-93, Harran-95) was investigated. Cold acclimation was performed at 0 °C for 7 days. Freezing tolerance was determined
with survived roots after freezing treatments at −5 and/or −7 °C for 3, 6, 12 and 24 h. At −5°C, all tetraploid genotypes
showed over 60% tolerance for 3 h. This effect was also present in wild wheat for 6 h, but was decreased in cultivated wheat
to 30–35% tolerance for 6 h. Only Ae. biuncialis was able to show 52% tolerance just for 3 h freezing period at −7 °C. However, all the genotypes were not survived at −7
°C, for 6, 12 and 24 h. Cold acclimation induced greater amounts of new soluble seminal root proteins in tolerant Ae. biuncialis (29–104 kDa, pI 5.4–7.4) than in sensitive Harran-95 (29–66 kDa, pI 6.1–8.3). Synthesis and accumulation of these proteins
may be related to degree of freezing tolerance of these genotypes. 相似文献
5.
Josef Elster Peter Degma Ľubomír Kováčik Lucia Valentová Katarína Šramková Antonio Batista Pereira 《Biologia》2008,63(6):843-851
The freezing and desiccation tolerance of 12 Klebsormidium strains, isolated from various habitats (aeroterrestrial, terrestrial, and hydro-terrestrial) from distinct geographical
regions (Antarctic — South Shetlands, King George Island, Arctic — Ellesmere Island, Svalbard, Central Europe — Slovakia)
were studied. Each strain was exposed to several freezing (−4°C, −40°C, −196°C) and desiccation (+4°C and + 20°C) regimes,
simulating both natural and semi-natural freeze-thaw and desiccation cycles. The level of resistance (or the survival capacity)
was evaluated by chlorophyll a content, viability, and chlorophyll fluorescence evaluations. No statistical differences (Kruskal-Wallis tests) between strains
originating from different regions were observed. All strains tested were highly resistant to both freezing and desiccation
injuries. Freezing down to −196°C was the most harmful regime for all studied strains. Freezing at −4°C did not influence
the survival of studied strains. Further, freezing down to −40°C (at a speed of 4°C/min) was not fatal for most of the strains.
RDA analysis showed that certain Antarctic and Arctic strains did not survive desiccation at +4°C; however, freezing at −40°C,
as well as desiccation at +20°C was not fatal to them. On the other hand, other strains from the Antarctic, the Arctic, and
Central Europe (Slovakia) survived desiccation at temperatures of +4°C, and freezing down to −40°C. It appears that species
of Klebsormidium which occupy an environment where both seasonal and diurnal variations of water availability prevail, are well adapted to
freezing and desiccation injuries. Freezing and desiccation tolerance is not species-specific nor is the resilience only found
in polar strains as it is also a feature of temperate strains.
Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.
This paper is dedicated to the memory of the late Dr. Bohuslav Fott (1908–1976), Professor of Botany at the Charles University
in Prague, to mark the centenary of his birth. 相似文献
6.
Influence of autoclaved saprotrophic fungal mycelia on proteolytic activity in ectomycorrhizal fungi
The production of proteolytic enzymes by several strains of ectomycorrhizal fungi i.e., Amanita muscaria (16-3), Laccaria laccata (9-12), L. laccata (9-1), Suillus bovinus (15-4), Suillus bovinus (15-3), Suillus luteus (14-7) on mycelia of Trichoderma harzianum, Trichoderma virens and Mucor hiemalis and sodium caseinate, yeast extract was evaluated. The strains of A. muscaria (16-3) and L. laccata (9-12) were characterized by the highest activity of the acidic and neutral proteases. Taking the mycelia of saprotrophic
fungi into consideration, the mycelium of M. hiemalis was the best inductor for proteolytic activity. The examined ectomycorrhizal fungi exhibited higher activity of acidic proteases
than neutral ones on the mycelia of saprotrophic fungi, which may imply the participation of acidic proteases in nutrition. 相似文献
7.
Cold tolerance and dehydration in Enchytraeidae from Svalbard 总被引:4,自引:1,他引:3
L. Sømme T. Birkemoe 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(4):264-269
When cooled in contact with moisture, eight species of arctic Enchytraeidae from Svalbard were killed by freezing within
minutes or hours at −3 and −5 °C; an exception was Enchytraeus kincaidi which survived for up to 2 days. When the temperature approached 0 °C the enchytraeids apparently tried to escape from the
moist soil. The supercooling capacity of the enchytraeids was relatively low, with mean supercooling points of −5 to −8 °C.
In contrast, specimens of several species were extracted from soil cores that had been frozen in their intact state at −15 °C
for up to 71 days. Compared to freezing in a moist environment, higher survival rates were obtained during cooling at freezing
temperatures in dry soil. Survival was recorded in species kept at −3 °C for up to 35 days, and in some species kept at −6 °C
for up to 17 days. Slow warming greatly increased survival rates at −6 °C . The results strongly suggest that arctic enchytraeids
avoid freezing by dehydration at subzero temperatures. In agreement with this, weight losses of up to ca. 42% of fresh weight
were recorded in Mesenchytraeus spp. and of up to 55% in Enchytraeus kincaidi at water vapour pressures above ice at −3 to −6 °C. All specimens survived dehydration under these conditions.
Accepted: 12 December 1997 相似文献
8.
Voituron Y Paaschburg L Holmstrup M Barré H Ramløv H 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(2):223-230
Freeze tolerance and changes in metabolism during freezing were investigated in the moor frog (Rana arvalis) under laboratory conditions. The data show for the first time a well-developed freeze tolerance in juveniles of a European
frog capable of surviving a freezing exposure of about 72 h with a final body temperature of −3°C. A biochemical analysis
showed an increase in liver and muscle glucose in response to freezing (respectively, 14-fold and 4-fold between 4 and −1°C).
Lactate accumulation was only observed in the liver (4.1 ± 0.8 against 16.6 ± 2.4 μmol g−1 fresh weight (FW) between 4 and −1°C). The quantification of the respiratory metabolism of frozen frogs showed that the aerobic
metabolism persists under freezing conditions (1.4 ± 0.7 μl O2 g−1 FW h−1 at −4°C) and decreases with body temperature. After thawing, the oxygen consumption rose rapidly during the first hour (6-fold
to 16-fold) and continued to increase for 24 h, but at a lower rate. In early winter, juvenile R. arvalis held in an outdoor enclosure were observed to emerge from ponds and hibernate in the upper soil and litter layers. Temperature
recordings in the substratum of the enclosure suggested that the hibernacula of these juvenile frogs provided sheltering from
sub-zero air temperatures and reduced the time spent in a frozen state corresponding well with the observed freeze tolerance
of the juveniles. This study strongly suggests that freeze tolerance of R. arvalis is an adaptive trait necessary for winter survival. 相似文献
9.
Wen-Jun Wang Fei-Jiu Wang Jian-Yi Zhu Xiu-Tao Sun Chun-Yan Yao Pu Xu 《Journal of applied phycology》2011,23(6):1017-1022
In January and February 2010, heavy sea ice formed along the coast of the Bohai Sea and the northern Yellow Sea, China. Intertidal
organisms were subjected to serious freezing stress. In this study, we investigated the freezing tolerance of the upper intertidal
economic seaweed Porphyra yezoensis. The maximum photochemical efficiency of PS II (F
v/F
m) in undehydrated thalli remained high after 24 h at −2°C and that in dehydrated thalli decreased in a proportion to thallial
water loss. F
v/F
m dropped sharply after 24 h at −20°C, regardless of absolute cellular water content (AWC). The F
v/F
m in frozen thalli recovered rapidly at 0–20°C. A wide range of water loss in the thalli enhanced their tolerance to freezing.
F
v/F
m values in undehydrated thalli dropped sharply after 3 d at −2°C or 10 d at −20°C while those in dehydrated thalli (20–53%
AWCs) remained at high levels after 9 d at −2°C or 30 d at −20°C. These results indicate that P. yezoensis has high freezing tolerance by means of dehydration during the ebb tide and rapid recovery of F
v/F
m from freezing. A strategy of P. yezoensis industry to avoid heavy loss during freezing season is discussed based on these findings. 相似文献
10.
The production of enzymes involved in mycoparasitism by several strains of ectomycorrhizal fungi: Amanita muscaria (16-3), Laccaria laccata (9-12), L. laccata (9-1), Suillus bovinus (15-4), S. bovinus (15-3), S. luteus (14-7) on different substrates such as colloidal chitin, mycelia of Trichoderma harzianum, T. virens and Mucor hiemalis was examined. Chitinases and β-1,3-glucanases were assayed spectrophotometrically by measuring the amount of reducing sugars
releasing from suitable substrate by means of Miller’s method. β-glucosidases were determined by measuring the amount of p-nitrophenol released from p-nitrophenyl-β-D-glucopyranoside. It was observed that A. muscaria (16-3) and L. laccata (9-12) biosynthesized the highest activity of enzymes in contrast to the strains of S. bovinus and S. luteus. The mycelium of T. harzianum turned out to be the best substrate for the induction of β-1,3-glucanases and β-glucosidases for both strains of L. laccata, although the difference in the induction of chitinases in the presence of mycelia of different species of Trichoderma was not indicated. 相似文献
11.
12.
The adaptive fitness of a freeze-tolerant insect may be mediated by both endogenous and exogenous interactions. The aim of
the study presented here was to characterize the freeze tolerance of alpine Tiger moth caterpillars (Metacrias huttoni) and highlight two poorly explored indices of the potential attrition of fitness: (1) downstream development and reproduction;
(2) parasitism. Caterpillars survived temperatures as low as −16°C and demonstrated >90% 72-h survival after exposures to
−10°C. Two-week acclimations at 5, 10, and 20°C had no effect on body water content, haemolymph osmolality or survival of
equilibrium freezing, but there was a significant elevation of the temperature of crystallization (T
c) in those caterpillars acclimated to 5°C. Cell viability of fat body tissue was resilient to freezing (−10 to −16°C), but
midgut and tracheal cells showed significant degradation. Pupation and eclosion were unaffected by freezing at −5 or −10°C.
Likewise, there were no significant differences in egg production or the proportion of eggs that hatched between control and
frozen insects. By contrast, the ability of tachinid larvae to survive freezing within their hosts means that parasitism plays
an important role in regulating population size. Mean parasitism of caterpillars by tachinids was 33.3 ± 7.2%. Pupation and
imago emergence of tachinids after host ‘endo-nucleation’ was >75%. Eclosed adult tachinids showed a non-significant increase
in the incidence of wing abnormalities in relation to low temperature exposure. 相似文献
13.
Hydromedion sparsutum is a locally abundant herbivorous beetle on the sub-Antarctic island of South Georgia, often living in close association
with the tussock grass Parodiochloa flabellata. Over a 4-day period in mid-summer when the air temperature varied from 0 to 20°C, the temperature in the leaf litter 5–10 cm
deep at the base of tussock plants (the microhabitat of H. sparsutum) was consistently within the range of 5–7.5°C. Experiments were carried out to assess the ability of H. sparsutum larvae collected from this thermally stable environment to acclimate when maintained at lower (0°C) and higher (15°C) temperatures.
The mean supercooling points (freezing temperature) of larvae collected in January and acclimated at 0°C for 3 and 6 weeks
and 15°C for 3 weeks were all within the range of −2.6 to −4.6°C. Larvae in all treatment groups were freeze tolerant. Acclimation
at 0°C significantly increased survival in a 15-min exposure at −8°C (from 27 to 96%) and −10°C (from 0 to 63%) compared with
the field-fresh and 15°C-treated larvae. Similarly, survival of 0°C-acclimated larvae in a 72-h exposure at −6°C increased
from 20 to 83%. Extending the acclimation period at 0°C to 6 weeks did not produce any further increase in cold tolerance.
The concentrations of glucose and trehalose in larval body fluids increased significantly with low temperature acclimation.
Larvae maintained at 15°C for 3 weeks (none survived for 6 weeks) were less able to survive 1-h exposures between 30 and 35°C
than the 0°C-treated samples. Whilst vegetation and snow cover are an effective buffer against low winter temperatures in
many polar insects, the inability of H. sparsutum larvae to acclimate or survive at 15°C suggests that protection against high summer temperatures is equally important for
this species.
Accepted: 2 August 1999 相似文献
14.
Tapani Repo Anna Korhonen Tarja Lehto Raimo Silvennoinen 《Trees - Structure and Function》2016,30(2):483-495
Key message
A novel non-destructive method is presented for studying the frost hardiness of roots. Principal component analysis from the electrical impedance spectra revealed differences between freezing temperatures, but no clear differences between the mycorrhizal treatments as regards freezing stress.Abstract
We present a novel non-destructive method for the classification of root systems with different degrees of freezing injuries based on the measurement of electrical impedance spectra (EIS). Roots of Scots pine (Pinus sylvestris L.) seedlings, raised in perlite with nutrient solution, were colonized by Hebeloma sp. or Suillus luteus or left non-mycorrhizal, and exposed to a series of low temperatures (5, ?5, ?12 and ?18 °C) after cultivation with and without cold acclimation regimes. In EIS measurements, we ran a small-amplitude electric current to the root system at 44 frequencies between 5 Hz and 100 kHz through electrodes set in the stem and in perlite at the bottom of the container. The normalized (Euclidian) electrical impedance spectra were classified using the CLAFIC-method (CLAss-Featuring Information Compression) that is based on a subspace method with two variants where the longest projection vector defines the sample class. The current delivery through the root system was affected by freezing injuries in the roots. The most remarkable change, indicating the threshold for cold tolerance, took place between ?5 and ?12 °C for non-acclimated and between ?12 and ?18 °C for cold acclimated roots. No difference was found between the mycorrhizal treatments in the response to the freezing temperatures. The results on the effects of both the low-temperature exposure and mycorrhizas agree with freezing damage assessments done by other methods.15.
Antarctic wetlands are characterized by the presence of liquid water during short austral summer. Filamentous cyanobacteria are often dominant there and are exposed to severe conditions, of which the changes in the desiccation–rehydration and freeze–thaw cycles are two of the most stressful. Vigor, after freezing and desiccation, was laboratory tested in cyanobacterial and algal strains from wetland habitats collected in maritime and continental Antarctica. Whereas minor sub-zero temperatures (−4°C), demonstrating summer diurnal freeze–thaws did not cause significant damage on either cyanobacteria or algae, low sub-zero temperatures (−40, −100, −196°C), demonstrating annual winter freeze, caused little harm to cyanobacteria, but was fatal for more than 50% of the population of algae. Freezing and desiccation tolerance of these strains was compared using multiregression methods: cyanobacteria from continental Antarctica were significantly more tolerant to low sub-zero temperatures than similar strains from maritime Antarctica (P = 0.026; F = 3.66); and cyanobacteria from seepages habitat were less tolerant to freezing and desiccation than cyanobacteria from other wetlands (P = 0.002; F = 5.69). 相似文献
16.
The predatory mirid Dicyphus hesperus Knight (Hemiptera: Miridae) is native to North America. The species has been used for the control of glasshouse whitefly
on aubergine in the Netherlands, and is currently being evaluated for continued and wider release in Europe. Field and laboratory
studies were conducted on a population collected from southern California, USA, to assess the cold tolerance and potential
for outdoor establishment under prevailing northern European climates. The supercooling points (whole animal freezing temperatures)
of nymphal and adult insects were around −20°C. The lethal temperatures (LTemp50) of non-diapausing nymphs and adults and diapausing adults were close to their respective freezing temperatures at −17.6,
−17.6 and −19.2°C. At 5°C, the LTime50 was 54, 101.7 and 117.5 days for fed nymphs, non-diapausing and diapausing adults respectively. When first instar nymphs
were placed in the field in winter, starved samples died out after 70 days, but 5% of the fed nymphs survived until the end
of winter (140 days) and developed to adult on return to the laboratory. After a similar 5-month field exposure, 50% of fed
diapausing adults and 15% of fed non-diapausing adults were still alive at the end of winter, whereas starved diapausing adults
died after 140 days. On return to the laboratory after 5 months in the field, both diapausing and non-diapausing adults mated
and laid eggs, forming viable populations. Overall, the field and laboratory experiments indicate that this population of
D. hesperus is able to enter diapause and that winter temperatures are not a barrier to establishment in northern Europe. 相似文献
17.
Maturation to adulthood and successful reproduction in the Antarctic fairy shrimp, Branchinecta
gaini, must be completed within a physiologically challenging temporal window of ca. 2.5 months in the southern Antarctic Peninsula.
Although adults show considerable metabolic opportunism at positive temperatures, little is known of their tolerance of two
physiological insults potentially typical to pool life in the maritime Antarctic: sub-zero temperatures and salinity. B. gaini are freeze-avoiding crustaceans with temperatures of crystallisation (T
cs) of −5°C. No antifreeze proteins were detected in the haemolymph. Adults osmoregulate in relation to temperature, but rapid
mortality in saline solutions of even low concentration, indicate they cannot osmoregulate in relation to salinity. Survival
of ice encasement at temperatures above their T
c was found to be pressure but not time dependent: at severe inoculative ice pressures, there was little immediate survival
and none survived after 48 h below −2°C; at mild inoculative ice pressures, immediate survival was ca. 100% at −3°C, but <20%
after 48 h. There was no significant difference in survival after 1 and 6 h encasement at −3°C. Observations of ventilation
suggest that it is not low temperature per se, but ice that represents the primary cryo-stress, with ventilatory appendages
physically handcuffed below the freezing point of pool water. Both sub-zero temperatures and salinity represent real physiological
constraints on adult fairy shrimp. 相似文献
18.
Identification of quantitative trait loci and associated candidate genes for low-temperature tolerance in cold-hardy winter wheat 总被引:4,自引:0,他引:4
Båga M Chodaparambil SV Limin AE Pecar M Fowler DB Chibbar RN 《Functional & integrative genomics》2007,7(1):53-68
Low-temperature (LT) tolerance is an important economic trait in winter wheat (Triticum aestivum L.) that determines the plants’ ability to cope with below freezing temperatures. Essential elements of the LT tolerance mechanism are associated with the winter growth habit controlled by the vernalization loci (Vrn-1) on the group 5 chromosomes. To identify genomic regions, which in addition to vrn-1 determine the level of LT tolerance in hexaploid wheat, two doubled haploid (DH) mapping populations were produced using parents with winter growth habit (vrn-A1, vrn-B1, and vrn-D1) but showing different LT tolerance levels. A total of 107 DH lines were analyzed by genetic mapping to produce a consensus map of 2,873 cM. The LT tolerance levels for the Norstar (LT50=−20.7°C) × Winter Manitou (LT50=−14.3°C) mapping population ranged from −12.0 to −22.0°C. Single marker analysis and interval mapping of phenotyped lines revealed a major quantitative trait locus (QTL) on chromosome 5A and a weaker QTL on chromosome 1D. The 5A QTL located 46 cM proximal to the vrn-A1 locus explained 40% of the LT tolerance variance. Two C-repeat Binding Factor (CBF) genes expressed during cold acclimation in Norstar were located at the peak of the 5A QTL. 相似文献
19.
Mucha J 《Antonie van Leeuwenhoek》2011,100(1):155-160
Patterns of phenoloxidase activity can be used to characterize fungi of different life styles, and changes in phenoloxidase
synthesis were suspected to play a role in the interaction between ectomycorrhizal and two species of Trichoderma. Confrontation between the ectomycorrhizal fungi Amanita muscaria and Laccaria laccata with species of Trichoderma resulted in induction of laccase synthesis, and the laccase enzyme was bound to mycelia of ectomycorrhizal fungi. Tyrosinase
release was noted only during interaction of L. laccata strains with Trichoderma harzianum and T. virens. Ectomycorrhizal fungi, especially strains of Suillus bovinus and S. luteus, inhibited growth of Trichoderma species and caused morphological changes in its colonies in the zone of interaction. In contrast, hyphal changes occurred
less often in the ectomycorrhizal fungi tested. Species of Suillus are suggested to present a different mechanism in their interaction with other fungi than A. muscaria and L. laccata. 相似文献
20.
Colauto Nelson Barros da Eira Augusto Ferreira Linde Giani Andrea 《World journal of microbiology & biotechnology》2011,27(12):3015-3018
The preservation of Agaricus blazei is generally done by mycelial subculturing, but this technique may cause genetic degenerations. Despite this, there is not
an efficient protocol established to preserve this fungus and cryopreservation could be an alternative. This study aimed to
evaluate two freezing protocols for cryopreservation at −80°C of A. blazei strains. Five fungus strains grown on rice grains with husk and were transferred to glycerol (10%) in cryovials. Next, the
cryovials were submitted to two freezing temperature protocols: (1) cryopreservation starting at 25°C, then at 8°C for 30 min
and kept at −80°C; (2) cryopreservation starting at 25°C, then 8°C for 30 min, −196°C for 15 min and kept at −80°C. After
1 year of cryopreservation, the cryovials were thawed in a water bath at 30°C for 15 min and transferred to malt extract agar
medium. It was concluded that the one-year cryopreservation process of A. blazei, grown on rice grains and cryopreserved at −80°C in glycerol 10%, is viable. The slow freezing, from 8 to −80°C, is effective
whereas the fast freezing, from 8 to −196°C and then to −80°C, is ineffective. The different genetic characteristics among
the strains of this fungus do not interfere in the cryopreservation process. 相似文献