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1.
P. Kakes 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,77(1):111-118
Summary The effect of the cyanogenic glucosides linamarin and lotaustralin and their hydrolyzing enzyme linamarase was studied in a B2 generation segregating for the genes Ac and Li. Plants containing the glucosides are protected against grazing by snails both in the seedling stage and as adult plants. In seedlings, however, there is a direct effect on survival, whereas in adult plants the leaf area of plants containing linamarin/lotaustralin is less reduced under intense grazing. Linamarase has no effect on grazing by snails, possibly as a result of the presence of -glucosidase activity in the gut of these animals. The genes Ac and Li, or genes tightly linked to them, have other effects as well: plants possessing one dominant Ac allele produce fewer flowers than homozygous ac plants. I compared this difference in flower production to the metabolic cost of producing the cyanogenic glucosides. The energy content of the difference in flower head production far exceeded the metabolic cost of cyanoglucoside production in Acac plants. It is possible that the cost of maintaining a certain level of cyanoglucosides is much more important for the plant than the initial cost of biosynthesis. The importance of the effects of Ac and Li in the maintenance of cyanogenic polymorphism in white clover is discussed. 相似文献
2.
Callus and cell suspension cultures were established from root and shoot tips of aseptically-grown seedlings of highly cyanogenic Phaseolus lunatus L. varieties. The content of cyanogenic glucosides in the explanted seedling sections decreased during storage, the derived callus cells were free of cyanogenic glycosides. In spite of the non-existence of cyanogenic glucosides, the cyanogen degrading linamarase, the cyanide detoxifying enzyme -cyanoalanine synthase and also hydroxynitrile lyase were still present in suspension cultures. The linamarase activity equalled the total -glucosidase activity, of which up to 80% was found in the culture medium. In contrast the -cyanoalanine synthase and the hydroxy nitrile lyase were entirely localized in the cell biomass.~Botanical Institute, Technical University Braunschweig 相似文献
3.
Cyanogenesis-the production of toxic hydrogen cyanide (HCN) by damaged tissue-inTrifolium repens L. (white clover), a type of most important pasture legume, has been studied at different elevations of Darjeeling Himalaya
(latitude-27° 2′ 57″ N, longitude-88° 15′ 45″ E). Release of HCN takes place due to reaction between cyanogenic glucosides
stored in vacuoles of the leaf cell and the corresponding enzyme β-glucosidase present in another compartment, often cell
wall. Cyanogenesis, a defense system in plant, protects the clover from herbivore and inhibits grazing. Biochemical analysis
showed the presence and absence of the cyanogenesis trait within the population in different proportions at different elevations.
Acyanogenic individuals also showed variations with respect to presence or absence of either cyanogenic glucosides or β-glucosidase
enzyme or both. The distribution of cyanogenic and acyanogenic plants was found in all places, but at lower altitudes (2084–2094
m) the dominating plants were cyanogenic whereas in higher altitude (2560 m) the dominating plants were acyanogenic. It was
observed that blister beetle (Mylabris pustalata Thunb.) and the mollusc (Macrochlamys tusgurium Benson.) were the most common consumer of leaflets ofT. repens. Six categories of damage on white clover leaf by these animals were recorded. Our results suggest that the two selective
factors or forces i.e. very cold temperature (harmful to cyanogenic plants) at higher altitude as well as indiscriminate but
preferential predation (harmful to acyanogenic plants) interact to affect the system of cyanogenesis and also to cause the
stable and protective polymorphism inT. repens rather than genotypic differences present among the plants. 相似文献
4.
In our previous studies, the yeast Endomyces fibuliger LU677 was found to degrade amygdalin in bitter apricot seeds. The present investigation shows that E. fibuliger LU677 produces extracellular β-glycosidase activity when grown in malt extract broth (MEB). Growth was very good at 25 °C
and 30 °C and slightly less at 35 °C. When grown in MEB of pH 5 and pH 6 with addition of 0, 10 or 100 ppm amygdalin, E. fibuliger produced only slightly more biomass at pH 5, and was only slightly inhibited in the presence of amygdalin. Approximately,
60% of the added amygdalin was degraded (fastest at 35 °C) during an incubation period of 5 days. Supernatants of cultures
grown at 25 °C and pH 6 for 5 days were tested for the effects of pH and temperature on activity (using amygdalin, linamarin
and prunasin as substrates). Prunase activity had two pH optima (pH 4 and pH 6), amygdalase and linamarase only one each at
pH 6 and pH 4–5 respectively. The linamarase activity evolved earlier than amygdalase (2 days and 4 days respectively). The
data thus indicate the presence of at least two different glycosidases having different pH optima and kinetics of excretion.
In the presence of amygdalin, lower glycosidase activities were generally produced. However, the amygdalin was degraded from
the start of the growth, strongly indicating an uptake of amygdalin by the cells. The temperature optimum for all activities
was at 40 °C. Activities of amygdalase (assayed at pH 4) and linamarase (at pH 6) evolving during the growth of E. fibuliger were generally higher in cultures grown at 25 °C and 30 °C. TLC analysis of amygdalin degradation products show a two-stage
sequential mechanism as follows: (1) amygdalin to prunasin and (2) prunasin to cyanohydrin.
Received: 16 September 1997 / Received revision: 6 October 1997 / Accepted: 14 October 1997 相似文献
5.
Whereas high activities of β-glucosidase occur in homogenates of leaves of Hevea brasiliensis Muell.-Arg., this enzyme, which is capable of splitting the cyanogenic monoglucoside linamarin (linamarase), is not present in intact protoplasts prepared from the corresponding leaves. Thus, in leaves of H. brasiliensis the entire linamarase is located in the apoplasmic space. By analyzing the vacuoles obtained from leaf protoplasts isolated from mesophyll and epidermal layers of H. brasiliensis leaves, it was shown that the cyanogenic glucoside linamarin is localized exclusively in the central vacuole. Analyses of apoplasmic fluids from leaves of six other cyanogenic species showed that significant linamarase activity is present in the apoplasm of all plants tested. In contrast, no activity of any diglucosidase capable of hydrolyzing the cyanogenic diglucoside linustatin (linustatinase) could be detected in these apoplasmic fluids. As described earlier, any translocation of cyanogenic glucosides involves the interaction of monoglucosidic and diglucosidic cyanogens with the corresponding glycosidases (Selmar, 1993a, Planta 191, 191–199). Based on this, the data on the compartmentation of cyanogenic glucosides and their degrading enzymes in Hevea are discussed with respect to the complex metabolism and the transport of cyanogenic glucosides. 相似文献
6.
As an adaptive mechanism, hypocotyl dormancy delays emergence of functional leaf until favorable season of growth in Podophyllum hexandrum, an endangered medicinal plant of the western Himalayas. However, upon exposure of the freshly germinated seedlings to favorable
temperature (25°C), functional leaves emerged within 20 days. Therefore, we examined regulation mechanisms of growth and development
of this alpine plant by temperature under laboratory conditions. The seedlings were exposed to (1) 25°C (temperature prevailing
at the time of maximum vegetative growth), (2) 4°C (mean temperature at the onset of winter in its natural habitat), and (3)
10°C (an intermediate temperature). Slackened growth at 4°C was followed by senescence of aerial parts and quiescence of roots
and predetermined leaf primordia. Rapid development of leaf primordia at 25°C was associated with increased starch hydrolysis.
This was evident from higher α-amylase activity and reducing sugars. These parameters decreased on sudden exposure to 4°C.
In contrast, the roots (perennating organs) showed a slight increase (1.36-fold) in α-amylase activity. Growth and development
in seedlings growing at 10°C (temperature less adverse than 4°C) were comparatively faster. The content of reducing sugars
and α-amylase activity were also higher in all the seedling parts at 10°C as compared to 4°C. This indicated larger requirements
for sugar by the seedlings at 10°C. Irrespective of temperature, maximum changes in nitrate and nitrate reductase occurred
during the initial 10 days, i.e., when the readily available form of sugars (reducing sugar) was highest. This indicated that
a temperature-dependent availability of carbon, but not temperature itself, was an important regulator of uptake and reduction
of nitrogen.
IHBT Publication number 508a. 相似文献
7.
The release of hydrogen cyanide (cyanogenesis) from damaged plant tissue depends upon the sequential action of a β-glucosidase and an α-hydroxynitrilase on cyanoglucosides. The non-isotopic digoxigenin labelling system was used to visualize the presence of cyanogenic β-glucosidase (linamarase) mRNA in cells of young leaves of Manihot esculenta Cranz (cassava). Strong hybridization to antisense riboprobes produced from the cDNA clone pCAS5, indicates localization of linamarase gene expression in laticifers (latex vessels). This is supported by the demonstration of linamarase mRNA in exuded latex. In contrast, in-situ localization of the control gene pGLF4, showed expression in all leaf mesophyll cells. High levels of linamarase activity were demonstrated in the latex of leaf petioles and this activity was shown to be dependent on the presence of attached leaflets. Assays of α-hydroxynitrilase activity in exuded latex and whole leaves shows that, unlike linamarase, this enzyme is present at very low levels in latex and must be located elsewhere in the leaf. 相似文献
8.
Jeong Seok Oh Hee Ho Park Tai Hyun Park 《Biotechnology and Bioprocess Engineering》2008,13(4):470-475
In a two-phase operation, E. coli containing λSNNU1 (Q
−
S
−) in the chromosome is typically cultured at 33°C and cloned gene expression is induced by elevating the temperature. At least
40°C is necessary for complete induction of cloned gene expression; however, temperatures above 40°C have been shown to inhibit
cloned gene expression. This suggests that a three-phase operation, which has an induction phase between the growth and production
phases, may result in higher gene expression. In this study, optimal temperature management strategies were investigated for
the three-phase operation of cloned gene expression in thermally inducible E. coli/bacteriophage systems. The optimal temperature for the induction phase was determined to be 40°C. When the temperature of
the production stage was 33°C, the optimal time period for the induction phase at 40°C was determined to be 60 min. In contrast,
when the temperature of the production phase was 37°C, the optimal period for the induction phase at 40°C was 20∼30 min. When
the three-phase temperature and temporal profile were set at a growth phase of 33°C, an induction phase at 40°C for 30 min,
and a production phase at 37°C, the highest level of cloned gene expression was achieved. 相似文献
9.
Taoka Y Nagano N Okita Y Izumida H Sugimoto S Hayashi M 《Marine biotechnology (New York, N.Y.)》2009,11(3):368-374
The growth, lipid content, and fatty acid composition of Aurantiochytrium sp. strain mh0186 at different temperatures were investigated. Strain mh0186 grew well at 15–30°C, but weakly at 10°C. The
biomass at 15–30°C was significantly higher than at 10 and 35°C, and the total lipid at 15–35°C was significantly higher than
that at 10°C. The amount of DHA in the total fatty acid was highest at 10°C and decreased in response to temperature increase.
The content of DHA (mg/g-dry cell weight) at 15–30°C were significantly higher than those at 35°C and those at 15–25°C were
significantly higher than those at 10 and 35°C. The DHA yield at 15–35°C was significantly higher than those at 10 and 35°C.
Unsaturation of fatty acid was regulated by temperature and was enhanced in response to temperature decrease. The ratio of
DHA to DPA varied at different temperatures. 相似文献
10.
The relationships between organogenesis of oil flax (Linum usitatissimum L., cv. ‘Szafir’) in vitro, cyanogenic potential (HCN-p) of these tissues and light were investigated. Shoot multiplication obtained on Murashige and Skoog medium containing 0.05 mg L?1 2,4-dichloro-phenoxyacetic acid and 1 mg L?1 6-benzyladenine (BA), was about twice higher in light-grown cultures than those in darkness. Light-grown explants showed also higher rate of roots regeneration (in medium containing 1 mg L?1 α-naphtaleneacetic acid and 0.05 mg L-1 BA) than dark-grown ones. The cyanogenic potential (expressed both as linamarin and lotaustralin content and linamarase activity) of flax cultured in vitro was tissue-specific and generally was higher under light conditions than in darkness. The highest concentration of linamarin and lotaustralin was detected in light-regenerated shoots, and its amount was twice as high as in roots, and about threefold higher than in callus tissue. The activities of linamarase and β-cyanoalanine synthase in light-regenerated organs were also higher than those in darkness. Thus, higher frequency of regeneration of light-grown cultures than dark-grown ones seems to be correlated with higher HCN-p of these tissues. We suggest that free HCN, released from cyanoglucosides potentially at higher level under light conditions, may be involved in some organogenetic processes which improve regeneration efficiency. 相似文献
11.
Lower induction temperature and polyoxyethylene sorbitan monolaurate (Tween-20) were successfully used to inhibit the aggregation
of recombinant human consensus interferon-α mutant (cIFN) during Pichia pastoris fermentation. When the induction temperature was decreased from 30 to 20°C, the cIFN secreted into the medium was in the form
of monomers instead of aggregates. The maximum specific activity at 20°C was 4.04 times as high as that at 30°C. There was
no obvious effect on the cell growth at 20°C, but the total protein level was decreased. Similar inhibition effect on cIFN
aggregation was observed when 0.2 g l−1 Tween-20 was added during induction. Furthermore, there was a synergistic effect found between induction temperature and
Tween-20 on the inhibition of cIFN aggregation. The maximum specific activity with Tween-20 at 20°C was 19.9-fold higher than
that without Tween-20 at 30°C. 相似文献
12.
Yuan Yuan Hongmei Qian Yidong Yu Fangqing Lian Dongqin Tang 《Acta Physiologiae Plantarum》2011,33(3):1001-1009
Followed a heat acclimation pretreatment, seedlings of Freesia hybrida ‘Shangnong Jinghuanghou’ were exposed to heat stress at 38°C for 6 h treatment and then recovered at 22°C for 72 h to study
the impact of heat acclimation (30°C) on thermotolerance under heat stress. The results showed that the pretreated seedlings
performed better under heat stress than control. Heat acclimation could slow down the decrease of chlorophyll contents under
heat stress and recover better. Higher levels of soluble sugar and proline and slight lower level of soluble protein were
observed in pretreated seedlings. After recovery, similar levels of proline and soluble protein were maintained in all seedlings.
However, a higher level of soluble sugar was maintained in pretreated seedlings. MDA content and EL showed a stable level
in pretreated seedlings while a significant increase in control, followed by a significant decrease after recovery. Significant
different responses of SOD, POD, CAT, and APX activities were observed in pretreated seedlings and control. Heat acclimation
led to higher activities of these enzymes and a significant response of antioxidant enzyme activities occurred in a time-dependent
manner under heat stress. Exposure to high temperature caused a significant increase in SOD and APX activity, and much higher
levels in SOD and APX activity were observed in pretreated seedlings compared to control during heat stress. A slight difference
in change pattern of POD and CAT activity was presented. The highest activities of POD and CAT were observed at 4 and 6 h
of heat stress in pretreated seedlings and control, respectively. After 72 h recovery, the activities of all tested enzymes
decreased to similar levels in all seedlings. 相似文献
13.
Progeny production increased and adult longevity decreased with rising temperature within the range 18°C to 30°C for the 3
mealybug parasitoidsAnagyrus pseudococci (Girault),Leptomastix dactylopii Howard andLeptomastidea abnormis (Girault). The Weibull distribution gave a good fit to survival curves for the 3 parasitoids and statistical comparison of
Weibullb andc parameters at different temperatures allowed changes in the scale and shape of the curves to be detected. In general, ♀♀
lived longer than ♂♂ for all 3 species, except at high temperature. FemaleL. abnormis attained their maximum progeny production at 24°C and maintained this level up to 34°C. They lived longer than the other
2 parasitoid species at 30°C and showed a type I survival curve throuhout the range of temperatures examined.A. pseudococci andL. dactylopii both required high temperatures (30°C) to attain their maximal progeny production, but werepseudococci tended towards type II, with a larger proportion of the population dying within the first few days.L. dactylopii lived longest at 26°C, with ♀♀ showing a type I survival curve at all temperatures and ♂ survival curves changing from type
I to type II at 30°C. The implications of these findings for the population dynamics of the different parasitoids are briefly
discussed.
相似文献
14.
Acclimation of chlorophyll biosynthetic reactions to temperature stress in cucumber (Cucumis sativus L.) 总被引:1,自引:0,他引:1
The adaptive responses of the greening process of plants to temperature stress were studied in cucumber (Cucumis sativus L. cv. Poinsette) seedlings grown at ambient (25 °C), low (7 °C) and high (42 °C) temperatures. Plastids isolated from these
seedlings were incubated at different temperatures and the net syntheses of various tetrapyrroles were monitored. In plastids
isolated from control seedlings grown at 25 °C, the optimum temperature for synthesis of Mg-protoporphyrin IX monoester or
protochlorophyllide was 35 °C. Temperature maxima for Mg-protoporphyrin IX monoester and protochlorophyllide syntheses were
shifted to 30 °C in chill-stressed seedlings. The net synthesis of total tetrapyrroles was severely reduced in heat-stressed
seedlings and the optimum temperature for Mg-protoporphyrin IX monoester or protochlorophyllide synthesis shifted slightly
towards higher temperatures, i.e. a broader peak was observed. To further study the temperature acclimation of seedlings with
respect to the greening process, tetrapyrrole biosynthesis was monitored at 25 °C after pre-heating the plastids (28–70 °C)
isolated from control, chill- and heat-stressed seedlings. In comparison to 28 °C-pre-heated plastids the percent inhibition
of protochlorophyllide synthesis in 40 °C-pre-heated plastids was higher than for the control (25 °C-grown) in chill-stressed
seedlings and lower than for the control in heat-stressed seedlings. Maximum synthesis of total tetrapyrroles and protoporphyrin
IX was observed when chloroplasts were heated at 50 °C, which was probably due to heat-induced activation of the enzymes involved
in protoporphyrin IX synthesis. Prominent shoulders towards lower or higher temperatures were seen in chill-stressed or heat-stressed
seedlings, respectively. The shift in optimum temperature for tetrapyrrole biosynthesis in chill- and heat-stressed seedlings
was probably due to acclimation of membranes possibly undergoing desaturation or saturation of membrane lipids. Proteins synthesized
in response to temperature-stress may also play an important role in conferring stress-tolerance in plants.
Received: 8 October 1998 / Accepted: 19 November 1998 相似文献
15.
RICHARD A. ENNOS 《Biological journal of the Linnean Society. Linnean Society of London》1981,15(1):75-82
Seed populations of white clover polymorphic for the presence/absence of both ovariogenic glucosides and the hydrolysing enzyme linamarase, were introduced into three natural populations. Over the first six months of life a significant increase in the frequency of linamarase containing individuals occurred. Estimated selection coefficients against plants lacking linamarase were in the region of 0.3. This result may have been due to selection at the enzyme locus alone, or to selection favouring cyanogenic individuals which possess both cyanogenic glucosides and enzyme. 相似文献
16.
Effects of exogenous abscisic acid (ABA) on cucumber seedling leaf carbohydrate metabolism under low temperature 总被引:2,自引:0,他引:2
Fan-Zhen Meng Li-Ping Hu Shao-Hui Wang Xiao-Lei Sui Li Wei Yu-Xia Wei Jian-Lei Sun Zhen-Xian Zhang 《Plant Growth Regulation》2008,56(3):233-244
Seedlings with four true leaves of cucumbers (Cucumis sativus L.), Guonong No.25 (a cold-tolerant cultivar) and Guonong No.41 (a cold sensitive cultivar), were grown under normal or low
temperature conditions: 25°C/18°C or 15°C/8°C (day/night). The seedlings of Guonong No.25 under low temperature were also
treated with or without exogenous ABA. The purpose of our study was to find out the effects of low temperature and exogenous
ABA application on the carbohydrate metabolism in the cucumber plants. Time course changes of carbohydrate contents and activities
of stachyose synthase and alkaline α-galactosidase in the seedling leaves were investigated after the treatment. Our results
show that compared to the seedlings under temperatures of 25°C/18°C, the seedlings of the both tested genotypes under 15°C/8°C
(day/night) have significantly higher contents of all measured soluble carbohydrates. Significant difference in stachyose
synthase activity is observed between the two genotypes under normal temperature or low temperature. Under normal temperature,
leaf stachyose synthase activity in Guonong No.41 is higher than that in Guonong No.25. The stachyose synthase activity of
Guonong No.41 decreases sharply under low temperature, but that of Guonong No.25 increases 3 days after treatment and then
decreases to the original level. In contrast, there is no significant genotypic difference in alkaline α-galactosidase activity.
Additionally, compared to the control seedlings treated with 0 μM ABA, the seedlings treated with 50 and 150 μM ABA accumulate
substantial amounts of all tested soluble carbohydrates except galactose whereas 250 μM ABA treated seedlings show decreased
levels of all these soluble carbohydrates. Stachyose synthase activity increases significantly upon 50 and 150 μM ABA treatments.
Fan-zhen Menga, Li-ping Hu, and Shao-hui Wang contributed equally to the paper. 相似文献
17.
M. Ceccarelli T. Giordani L. Natali A. Cavallini P. G. Cionini 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):309-315
Feulgen/DNA cytophotometric determinations were carried out on early prophases in the meristems of seedlings obtained by
germinating seeds of different accessions of Festuca arundinacea at 10°C, 20°C, or 30°C. Feulgen/DNA contents increased significantly with the increase in the temperature of seed germination.
In each accession, the greater the increase in absorption in seedlings obtained at 30°C, the lower the absorption in seedlings
obtained at 10°C. In contrast, Feulgen/DNA contents did not undergo changes when the temperature was altered at developmental
stages other than seed germination. The results of molecular hybridizations (slot blots) indicated that the redundancy of
repeated DNA sequences belonging to two families having Cot ranges of 0–2×10-1 and 2×10-1 −2×100, respectively, was significantly higher in the genome of seedlings obtained at 30°C than in that of seedlings obtained at
10°C. When centrifuged to equilibrium in CsCl density gradients, the DNA extracted from seedlings obtained at 30°C formed
a heavier and a lighter shoulder with buoyant densities of 1.707 g/ml and 1.692 g/ml, respectively, in addition to the main
band (1.701 g/ml). Only a less apparent shoulder banding at 1.706 g/ml was formed by the DNA extracted from seedlings obtained
at 10°C. After seed germination in the presence of [3H]-thymidine for 24 h at 30°C, most of radioactivity was found in the guanine + cytosine- or adenine+thymine-enriched DNA
fractions, which formed the two shoulders in the density profile. In contrast, only guanine+cytosine-enriched fractions, which
formed the heavier shoulder, were preferentially labelled in the DNA from seedlings obtained at 10°C. These results prove
that fluid domains do exist in the nuclear DNA of F. arundinacea. These DNA domains are capable of rapid, quantitative alterations, which represent the direct responses of the genome to
developmental and environmental stimuli. Seed germination appears to be a limited, specific period in development within which
the adaptive response to temperature variations can be put into effect.
Received: 9 August 1996 / Accepted: 23 August 1996 相似文献
18.
Properties of the extracellular amylase produced by the psychrotrophic bacterium, Arthrobacter psychrolactophilus, were determined for crude preparations and purified enzyme. The hydrolysis of soluble starch by concentrated crude preparations
was found to be a nonlinear function of time at 30 and 40 °C. Concentrates of supernatant fractions incubated without substrate
exhibited poor stability at 30, 40, or 50 °C, with 87% inactivation after 21 h at 30 °C, 45% inactivation after 40 min at
40 °C and 90% inactivation after 10 min at 50 °C. Proteases known to be present in crude preparations had a temperature optimum
of 50 °C, but accounted for a small fraction of thermal instability. Inactivation at 30, 40, or 50 °C was not slowed by adding
20 mg/ml bovine serum albumin or protease inhibitor cocktail to the preparations or the assays to protect against proteases.
Purified amylase preparations were almost as thermally sensitive in the absence of substrate as crude preparations. The temperature
optimum of the amylase in short incubations with Sigma Infinity Amylase Reagent was about 50 °C, and the amylase required
Ca+2 for activity. The optimal pH for activity was 5.0–9.0 on soluble starch (30 °C), and the amylase exhibited a K
m with 4-nitrophenyl-α-D-maltoheptaoside-4,6-O-ethylidene of 120 μM at 22 °C. The amylase in crude concentrates initially hydrolyzed raw starch at 30 °C at about the same
rate as an equal number of units of barley α-amylase, but lost most of its activity after only a few hours. 相似文献
19.
Lamia Trabelsi Hatem Ben Ouada Hassen Bacha Mohamed Ghoul 《Journal of applied phycology》2009,21(4):405-412
The effects of light intensity and temperature on Arthrospira platensis growth and production of extracellular polymeric substances (EPS) in batch culture were evaluated using a three-level, full-factorial
design and response surface methodology. Three levels were tested for each parameter (temperature: 30, 35, 40°C; light intensity:
50, 115, 180 μmol photons m−2 s−1). Both growth and EPS production are influenced mainly by the temperature factor but the interaction term temperature*light
intensity also had a significant effect. In addition, conditions optimising EPS production are different from those optimising
growth. The highest growth rate (0.414 ± 0.003 day−1) was found at the lowest temperature (30°C) and highest light intensity (180 μmol photons m−2 s−1) tested, no optima were detectable within the given test range. Obviously, optima for growth must be at a temperature lower
than 30°C and a light intensity higher than 180 μmol photons m−2 s−1. For EPS production, light intensity had a positive linear effect (optimum obviously higher than 180 μmol photons m−2 s−1), but for the temperature parameter a maximum effect was detectable at 35°C. 相似文献
20.
Ganka Chaneva Sevdalina Furnadzhieva Kaledona Minkova Jaromir Lukavsky 《Journal of applied phycology》2007,19(5):537-544
The effect of light intensity (50–300 μmol photons m−2 s−1) and temperature (15–50°C) on chlorophyll a, carotenoid and phycobiliprotein content in Arthronema africanum biomass was studied. Maximum growth rate was measured at 300 μmol photons m−2 s−1 and 36°C after 96 h of cultivation. The chlorophyll a content increased along with the increase in light intensity and temperature and reached 2.4% of dry weight at 150 μmol photons
m−2 s−1 and 36°C, but it decreased at higher temperatures. The level of carotenoids did not change significantly under temperature
changes at illumination of 50 and 100 μmol photons m−2 s−1. Carotenoids were about 1% of the dry weight at higher light intensities: 150 and 300 μmol photons m−2 s−1. Arthronema africanum contained C-phycocyanin and allophycocyanin but no phycoerythrin. The total phycobiliprotein content was extremely high,
more than 30% of the dry algal biomass, thus the cyanobacterium could be deemed an alternative producer of C-phycocyanin.
A highest total of phycobiliproteins was reached at light intensity of 150 μmol photons m−2 s−1 and temperature of 36°C, C-phycocyanin and allophycocyanin amounting, respectively, to 23% and 12% of the dry algal biomass.
Extremely low (<15°C) and high temperatures (>47°C) decreased phycobiliprotein content regardless of light intensity. 相似文献