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1.
Microtuberization in potato (Solanum tuberosum L.) 总被引:7,自引:0,他引:7
Twenty-two genotypes of potato (Solanum tuberosum L.) were induced to form microtubers under six in vitro culture conditions. Cultures maintained under a short photoperiod
(10 h of 6–12 μmol m–2 s–1) and low temperatures (day 20°±2°C and night 18°±2°C) had both a higher yield (255 mg/plantlet) and a greater number (2/plantlet)
of microtubers than those maintained under long days (16 h of 38–50 μmol m–2 s–1) combined with high temperatures (day 28°±2°C and night 25°±2°C) (yield 207 mg/plantlet; microtuber number, 0.9/plantlet),
over a wide range of genotypes. After the plantlets had been cultured under long days for an initial period of 60 days, continuous
darkness advanced microtuberization by 2–3 months in various genotypes. Under short-day and low-temperature conditions the
addition of 6-benzylaminopurine increased microtuber yield from 255 mg/plantlet to 645 mg/plantlet and average microtuber
weight from 115 mg to 364 mg. A similar pattern was observed under conditions of long days and high temperature, and continuous
darkness and low-temperature. Microtubers produced under light had a greater number of eyes (maximum average: 5.96/microtuber)
than those produced in the dark (maximum average: 3.50/plantlet). The genotype × cultural conditions interactions were significant
indicating the importance of developing genotype-specific protocols to maximize microtuberization.
Received: 17 September 1997 / Revision received: 12 December 1997 / Accepted: 1 January 1998 相似文献
2.
Summary Calluses from five asparagus genotypes G14, G32, G171, G203, and G447 and hybrid Jersey Giant (JG) were incubated at three
temperature regimes (24, 27, and 30°C) on embryo induction medium to assess somatic embryo development and conversion to plantlets.
The calluses from three genotypes (G14, G32, and G171) were not responsive, failing to produce somatic embryos at any temperature
regime. For three responsive genotypes (G203, G447, and JG), both incubation temperature and genotype significantly affected
the numbers of somatic embryos produced. The calluses produced the most and the least numbers of total, bipolar, and globular
embryos when incubated at 27°C and 24°C, respectively. When incubated at 27°C, G203 produced the highest numbers of total
and globular embryos, 178 g−1 callus and 142 g−1 callus, respectively while G447 produced the highest number of bipolar embryos, 77 g−1 callus. Incubation temperature but not genotype significantly affected the conversion of somatic embryos to plantlets. The
somatic embryos recovered from the three responsive genotypes incubated at 27°C also converted to plantlets at the highest
frequencies, 60–63% of the bipolar embryos and 42–43% of the globular embryos converted to plantlets, while the somatic embryos
recovered from the calluses incubated at 24°C converted to plantlets at the lowest frequencies. 相似文献
3.
A community analysis of the mega-zooepibenthos at water depths between 99 and 1243 m was carried out for the Weddell and
Lazarev Seas (47°W 77°S–12°E 70°S). A total of 144,531 specimens were counted and 313 taxa were identified from 3,768 photographs
at 55 stations, which represented approximately 3,304 m2 of seafloor. The stations were classified into six groups according to their inventory of taxa although they represented
rather a gradient from a rich and diverse suspension feeder assemblage to a poorer assemblage. In the latter, the proportion
of deposit feeders was higher than in the former. A statistical comparison between biological and physical data showed that
the faunistic pattern could best be explained by a combination of water depth and a geographical gradient. A positive correlation
between the abundance of large sponges and the number of all other taxa was found.
Received: 16 September 1997 / Accepted: 11 April 1998 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.
Microviscosity of the highly purified plasma membranes isolated from the maturing goat caput, corpus and cauda epididymal
sperm, was measured using l,6-diphenyl-l,3,5-hexatriene as the lipophilic probe at varying temperatures (12–42°C). As shown
by the Arrhenius plot of the data each of the maturing sperm membranes had two distinct lipid phase transitions in the temperature
zones 19–25°C and 34–37°C. The low-temperature transitions for the immature caput- and mature cauda-sperm membranes were noted
at 19–20°C, and 24–25°C, respectively, whereas both these membranes showed high temperature transition at 36–37°C. The maturing
corpus-sperm membrane had phase transitions at 21–22°C and 35–36°C that were significantly different from those of the immature/mature
sperm membranes. The data implicate significant alteration of the sperm membrane structure during epididymal maturation. The
phase transition of the mature male gametes at 36–37°C may have a great impact on the subsequent events of the sperm life
cycle since the mature spermatozoa that are stored in the epididymis a few degrees below the body temperature, experience
higher temperature when ejaculated into the female reproductive tract. 相似文献
6.
Psychrotrophic bacteria are known to occur in temperate, constantly cold, and artificially cooled environments. This is the
first report of their occurrence in a constantly warm (ca. 24°–35°C) tropical environment. Soil samples taken from two sites
along the southeastern coastal zone of Jamaica yielded growth of psychotrophic bacteria after 3–4 weeks of enrichment culture
in 1/30 strength tryptic soy broth, 20 mg L−1 cycloheximide at 2°C. Growth of individual isolates at 2°C was confirmed. Isolates include aerobic and fermentative Gram-negative
rods and sporeforming (Bacillus sp.) and non-sporeforming (Aureobacterium sp.) Gram-positive rods. We determined the effect of temperature on growth rate in four isolates. Strain Y1 has an unusually
wide temperature range for growth, 2°–44°C, resembling that of Listeria monocytogenes. In strain R1 the optimum temperature for growth occurred unusually near the maximum temperature for growth. Strains R2 and
Y2 displayed cardinal temperatures typical of known psychotrophs but appear to have evolved enhanced growth potential near
the optimum temperature in response to a constantly warm environment.
Received: 30 April 1997 / Accepted: 9 August 1997 相似文献
7.
People adapt to thermal environments, such as the changing seasons, predominantly by controlling the amount of clothing insulation, usually in the form of the clothing that they wear. The aim of this study was to determine the actual daily clothing insulation on sedentary human subjects across the seasons. Thirteen females and seven males participated in experiments from January to December in a thermal chamber. Adjacent months were grouped in pairs to give six environmental conditions: (1) January/February = 5°C; (2) March/April = 14°C; (3) May/June = 25°C; (4) July/August = 29°C; (5) September/October = 23°C; (6) November/December = 8°C. Humidity(45 ± 5%) and air velocity(0.14 ± 0.01 m/s) were constant across all six experimental conditions. Participants put on their own clothing that allowed them to achieve thermal comfort for each air temperature, and sat for 60 min (1Met). The clothing insulation (clo) required by these participants had a significant relationship with air temperature: insulation was reduced as air temperature increased. The range of clothing insulation for each condition was 1.87–3.14 clo at 5°C(Jan/Feb), 1.62–2.63 clo at 14°C(Mar/Apr), 0.87–1.59 clo at 25°C(May/Jun), 0.4–1.01 clo at 29°C(Jul/Aug), 0.92–1.81 clo at 23°C (Sept/Oct), and 2.12–3.09 clo at 8°C(Nov/Dec) for females, and 1.84–2.90 clo at 5°C, 1.52–1.98 clo at 14°C, 1.04–1.23 clo at 25°C, 0.51–1.30 clo at 29°C, 0.82–1.45 clo at 23°C and 1.96–3.53 clo at 8°C for males. The hypothesis was that thermal insulation of free living clothing worn by sedentary Korean people would vary across seasons. For Korean people, a comfortable air temperature with clothing insulation of 1 clo was approximately 27°C. This is greater than the typical comfort temperature for 1 clo. It was also found that women clearly increased their clothing insulation level of their clothing as winter approached but did not decrease it by the same amount when spring came. 相似文献
8.
S. D. Kashenko 《Russian Journal of Marine Biology》2009,35(5):422-430
The combined effects of temperatures of 14, 17, 20, 22, and 25°C and salinities of 36–12‰ on embryos and larvae of the sand
dollar Scaphechinus mirabilis was studied. Embryonic development is the most sensitive stage in the early ontogenesis of S. mirabilis. It is completed at a temperature of 14–20°C in a salinity range of 36–24‰ and at temperature of 22°C to 26‰. The fertilization
proceeds in wider ranges of temperature and salinity. Among the swimming larvae, blastulae showed the greatest resistance
to variations of these environmental factors. All the larvae survived at a temperature of 14–22°C and a salinity of 36–20‰,
and more than 70% of them at 18‰. The pluteus I is the most vulnerable stage; probably this is related to the formation of
the larval skeleton and transition to phytoplankton feeding. The survival of larvae at the age of 20 days was 100% at 14–22°
C and a salinity of 36–24‰, most of them survived at 14–20°C and a salinity 18‰. The temperature 25 ° C is the most damaging
for early development of S. mirabilis. The duration of development of that species lasts 28.5–29 days at 20°C and a salinity of 32.2–32.6‰. At 20 and 22°C, the
larvae settled and completed metamorphosis more quickly if sand from the parental habitat was present. The larvae did not
settle during the experiment (14 days) at 14 ° C and in the absence of sand. 相似文献
9.
E. B. Vinogradova 《Entomological Review》2009,89(9):1019-1024
Three methods of short-term storage of the blowfly Calliphora vicina strains are considered based on the experimental study of 21 strains originating from different parts of the species range.
The colony can be preserved as diapausing adults at 6° and darkness for 2–3 months or more, depending on the geographical
origin of the population. During the first five days of adult life the flies should be kept at 12° and short day on a sugar
diet, after which they should be transferred into a refrigerator. During artificial hibernation the flies also require periodic
sugar feeding every 20 days (3–4 h at 20°C) to maintain their vital functions. The combination of temperatures of 20–23°C
and a protein diet terminates reproductive diapause, and oviposition starts in 10–17 days. The fly strain may be preserved
as reproductive females at 6°C and darkness with sugar feeding. Flies also require periodic sugar feeding at 20°C (3–4 hours).
In this case the flies start laying eggs 2–3 days after being transferred to 20–23°C. The preservation of diapausing larvae
is a more reliable method of prolonged strain storage. In this case the flies of maternal generation are maintained at 20–23°C
on sugar and protein diet. The egg rafts laid during 5–6 hours are then transferred into 12°C and short day until hatchment.
The hatched larvae should be immediately placed into a refrigerator (2–3 or 5–6°C), where they feed during 1–1.5 months and
enter diapause. For strain restoration, the diapausing larvae should be transferred into 20–25°C, where they pupariate in
3–5 days and the flies emerge in nearly 10 days. 相似文献
10.
The ability of a Bacillus subtilis strain to grow and produce biosurfactant on different carbon and nitrogen sources under thermophilic conditions (45°C) was
studied. The strain was able to reduce surface tension to 34 dynes cm−1 on 2% sucrose, and 32 dynes cm−1 on starch after 96 h of growth. The biosurfactant was stable at 100°C and within a wide pH range (3.0–11.0). Biosurfactant
formation at mesophilic conditions (30°C) was also studied. The organism was able to produce the maximum amount of biosurfactant
when nitrate ions were supplied as the nitrogen source. The potential application of the biosurfactant in oil recovery from
desert oil fields, acidic and alkaline environments is demonstrated. The biosurfactant was identical to surfactin as confirmed
by TLC and IR analysis.
Received 29 May 1997/ Accepted in revised form 03 October 1997 相似文献
11.
G. Sandoya R.A. Malvar R. Santiago A. Alvarez P. Revilla A. Butrón 《The Annals of applied biology》2010,156(3):377-386
A maize synthetic population was improved for resistance to the Mediterranean corn borer (MCB, Sesamia nonagrioides) while maintaining yield. The objectives of this research were to investigate whether yield and yield stability of the maize synthetic population named EPS12 were affected by selection for MCB resistance; also to determine which genotypic and environmental covariates could explain the genotype (G), environment (E) and genotype × environment (GE) effects for yield under corn borer infestation. Plants from three cycles of selection and their testcrosses to three inbred testers (A639, B93 and EP42) were evaluated at two locations in 2 years, under MCB and European corn borer infestations. After selection EPS12 was a more stable genotype. Hybrids derived from crosses between B93 and inbreds obtained from the initial cycles of selection could be recommended for cultivation in northern Spain. The yield of crosses between cycles of selection and testers increased when there were fewer days with temperatures >25°C and higher mean maximum temperatures. Differences in yield among these genotypes were mostly explained by resistance to corn borer attack. In general, among EPS12-derived materials, genetic characteristics that contribute to increased grain yield were also responsible for increased abiotic stress tolerance. 相似文献
12.
Chun-Min Lo Michael Glogauer Marisa Rossi J. Ferrier 《European biophysics journal : EBJ》1998,27(1):9-17
We measure the change in cell-substrate separation in response to an upward force by combining two relatively new techniques,
Electric Cell-substrate Impedance Sensing (ECIS) to measure average cell-substrate separation, and collagen-coated magnetic
beads to apply force to the top (dorsal) surface of cells. The collagen-coated ferric oxide beads attach to integrin receptors
in the dorsal surfaces of osteoblastlike ROS 17/2.8 cells. Magnetic force is controlled by the position and the number of
permanent magnets, applying an average 320 or 560 pN per cell. Comparing model calculations with experimental impedance data,
the junctional resistivity of the cell layer and the average distance between the lower (ventral) cell surface and substrate
can be determined. The ECIS analysis shows that these forces produce an increase in the distance between the ventral cell
surface and the substrate that is in the range of 10 to 25%. At temperatures of 4°, 22° and 37 °C, the measured cell surface-substrate
distances without magnetic beads are 84 ± 4, 45 ± 2 and 38 ± 2 nm. The force-induced changes at 22° are 11 ± 3 and 21 ± 3
nm for 320 and 560 pN, and at 37° they are 5 ± 2 and 9 ± 2 nm. The resulting cell-substrate spring constants at 22° and 37°
are thus about 28 and 63 pN nm–1 (dyne cm–1). Using a reasonable range for the number for individual integrin-ligand adhesion bonds gives a range for the spring constant
of the individual adhesion bond of from about 10–3 to 10–1 pN nm–1. These data also provide evidence that the number of adhesion bonds per cell increases with temperature.
Received: 20 June 1997 / Accepted: 24 August 1997 相似文献
13.
Stamp, P. 1987. Seedling development of adapted and exotic maizegenotypes at severe chilling stress.J. exp. Bot. 38:13361342. Four maize genotypes from North West Europe (NWE), tropicalhighlands (TH) and tropical lowlands (TL) were grown at 24°Cuntil full expansion of the second leaf. Seedlings were subjectedto 5°C during 2 d thereafter, with or without a previousconditioning phase at 10°C for 4 d. After stress, seedlingswere allowed to recover at 24°C for 5 d. All genotypes resumedhigh growth rates after stress, highest values were observedfor one TH genotype. Previous conditioning was most effectivein TL and least effective in TH genotypes. In spite of similaritiesbetween patterns of growth rates and rates of leaf expansionthe latter process was less promoted by previous conditioning.The green area of the second leaf was little impaired by 5°Cin most genotypes. But without conditioning the TL genotypelost about 40% green leaf area, mostly during the recovery phase.Conditioning did not prevent losses in relative turgidity ofsecond leaves during stress but it enabled sensitive genotypesto resume normal values during recovery. Losses in phosphofructokinaseactivity occurred in the TL genotype during stress and recovery,and in TH genotypes during recovery while the activity was stablein the NWE genotype. A close relationship between this enzymeactivity and growth rates was not observed. Although one THgenotype had the best chilling tolerance on the whole plantlevel the expression of some physiological and biochemical leaftraits was inferior to the adapted NWE genotype. Key words: Low temperature, exotic germplasm, phosphofructokinase activity 相似文献
14.
Daniel Delille Emilien Pelletier Arturo Rodriguez-Blanco Jean-Francois Ghiglione 《Polar Biology》2009,32(10):1521-1528
In an attempt to evaluate the potential of petroleum bioremediation at high latitudes environments, microcosm studies using
Antarctic coastal seawater contaminated with diesel or crude oil were conducted in Kerguelen Archipelago (49°22′S, 70°12′E).
Microcosms were incubated at three different temperatures (4, 10 and 20°C). During experiments, changes observed in microbial
assemblages (total direct count, heterotrophic cultivable microorganisms and hydrocarbon-degrading microorganisms) were generally
similar for all incubation temperatures, but chemical data showed only some slight changes in biodegradation indices [Σ(C12–C20)/Σ(C21–C32)
and C17/pristane]. The complete data set provided strong evidence of the presence of indigenous hydrocarbon-degrading bacteria
in Antarctic seawater and their high potential for hydrocarbon bioremediation. The rate of oil degradation could be increased
by the addition of a commercial fertilizer, but water temperature had little effects on biodegradation efficiency which is
in conflict with the typical temperature-related assumption predicting 50% rate reduction when temperature is reduced by 10°C.
Global warming of Antarctic seawater should not increase significantly the rate of oil biodegradation in these remote regions. 相似文献
15.
The effect of polyunsaturated fatty acids on photosynthesis and the growth of the marine cyanobacterium Synechococcus sp. PCC 7002 was examined using wild-type and Δ12 fatty acid desaturase mutant strains. Under a light intensity of 250 μmol
m−2 s−1, wild-type cells could grow exponentially in a temperature range of 20–38 °C, but growth was non-exponential below 20 °C
and ceased at 12 °C. The Δ12 desaturase mutant cells lacking polyunsaturated fatty acids had the same growth rate as wild-type
cells in a temperature range of 25–38 °C but grew slowly at 22 °C, and no cell growth took place below 18 °C. Under a very
high-light intensity of 2.5 mmol m−2 s−1, wild-type cells could grow exponentially in a temperature range of 30–38 °C, although the high-light grown cells became
chlorotic because of nitrogen limitation. The temperature sensitive phenotype in the Δ12 desaturase mutant was enhanced in
cells grown under high-light illumination; the mutant cells could grow at 38 °C, but were killed at 30 °C. The decrease of
oxygen evolution and nitrate consumption by whole cells as a function of temperature was similar in both wild type and the
Δ12 desaturase mutant. No differences were observed in either light-induced damage of oxygen evolution or recovery from this
damage. No inactivation of oxygen evolution took place at 22 °C under the normal light intensity of 250 μmol m−2 s−1. These results suggest that growth of the Δ12 desaturase mutant at low temperature is not directly limited by the inactivation
of photosynthesis, and raise new questions about the functions of polyunsaturated membrane lipids on low temperature acclimation
in cyanobacteria.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
Han Gil Choi Ki Hoon Lee Hyun Il Yoo Pil Jun Kang Young Sik Kim Ki Wan Nam 《Journal of applied phycology》2008,20(5):729-735
The effects of temperature, irradiance, and daylength on Sargassum horneri growth were examined at the germling and adult stages to discern their physiological differences. Temperature–irradiance
(10, 15, 20, 25, 30°C × 20, 40, 80 μmol photons m−2s−1) and daylength (8, 12, 16, 24 h) experiments were carried out. The germlings and blades of S. horneri grew over a wide range of temperatures (10–25°C), irradiances (20–80 μmol photons m−2s−1), and daylengths (8–24 h). At the optimal growth conditions, the relative growth rates (RGR) of the germlings were 21% day−1 (25°C, 20 μmol photons m−2s−1) and 13% day−1 (8 h daylength). In contrast, the RGRs of the blade weights were 4% day−1 (15°C, 20 μmol photons m−2s−1) and 5% day−1 (12 h daylength). Negative growth rates were found at 20 μmol photons m−2s−1 of 20°C and 25°C treatments after 12 days. This phenomenon coincides with the necrosis of S. horneri blades in field populations. In conclusion, we found physiological differences between S. horneri germlings and adults with respect to daylength and temperature optima. The growth of S. horneri germlings could be enhanced at 25°C, 20 μmol photons m−2s−1, and 8 h daylength for construction of Sargassum beds and restoration of barren areas. 相似文献
17.
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
18.
Temperature requirements for growth, reproduction and formation of macrothalli of a day-neutral strain ofScytosiphon lomentaria from the Gulf of Thessaloniki were experimentally determined and correlated with the geographic distribution in the North
Atlantic Ocean. The microthallus grew in a wider temperature interval and better at higher temperatures than did the macrothallus.
Germlings acclimated to 5 or 15°C grew sufficiently (>20% of maximum rate) and developed into macrothalli at 5–25°C and 5–27°C.
Macrothalli acclimated to 10 or 15°C grew sufficiently at 5–20°C. Macrothalli acclimated to 15°C survived at −1°C and reproduced
at 5 to 23°C. Regardless of the acclimation temperature, germlings and macrothalli grew optimally (>80% of maximum rate) at
15–25°C and at 10–15°C. The experimental data explain only the southern distribution boundary ofScytosiphon in the North Atlantic. This boundary is composite in nature: on the European coasts it is a growth boundary, whereas on the
American coasts it is a lethal one. 相似文献
19.
Effects of elevated temperature on bacterial community structure and function in bioreactors treating a synthetic wastewater 总被引:1,自引:0,他引:1
T M LaPara A Konopka C H Nakatsu J E Alleman 《Journal of industrial microbiology & biotechnology》2000,24(2):140-145
The impact of elevated temperature on bacterial community structure and function during aerobic biological wastewater treatment
was investigated. Continuous cultures, fed a complex growth medium containing gelatin and α-lactose as the principal carbon
and energy sources, supported mixed bacterial consortia at temperatures ranging from 25–65°C. These temperature- and substrate-acclimated
organisms were then used as inocula for batch growth experiments in which the kinetics of microbial growth and substrate utilization,
efficiency of substrate removal, and mechanism of substrate removal were compared as functions of temperature. Bacterial community
analysis by denaturing gradient gel electrophoresis (DGGE) revealed that distinct bacterial consortia were supported at each
temperature. The efficiency of substrate removal declined at elevated temperatures. Maximum specific growth rates and the
growth yield increased with temperature from 25–45°C, but then decreased with further elevations in temperature. Thus, maximum
specific substrate utilization rates did not vary significantly over the 40°C temperature range (0.64 ± 0.04 mg COD mg−1 dry cell mass h−1). A comparison of the degradation of the protein and carbohydrate portions of the feed medium revealed a lag in α-lactose
uptake at 55°C, whereas both components were utilized simultaneously at 25°C. Journal of Industrial Microbiology & Biotechnology (2000) 24, 140–145.
Received 09 August 1999/ Accepted in revised form 12 November 1999 相似文献
20.
Germination responses ofMallotus japonicus (Thumb). Muell. Arg. seeds to temperature revealed a gap-detecting mechanism in the seed germination of the species. Among
various constant and alternating temperatures examined in the range from 12–40°C, only very limited temperature regimes were
found to be favourable for seed germination, specifically, alternating temperatures between 18–32°C and 28–40°C. A single
several-hour higher-temperature (32–40°C) treatment could also induce the germination of seeds which had been imbibed for
several days at a constant temperature in the range of 20–26°C, suggesting that there is a process requiring higher temperature
among the overal germination processes. Seeds located at or near the surface of denuded soil would have a good chance of experiencing
such a temperature change when several rainy days are followed by fine weather, while seeds beneath close vegetation would
not. On the other hand, the pressence or absence of light or a simulated ‘canopy ligh’ had little effect on the germination.
Therefore, it was concluded that the seeds ofM. japonicus have a ‘gapdetecting mechanism’ in the form of a higher-temperature requirement of a certain process involved in the overall
germination processes. 相似文献