scholarly journals Cytokinins are involved in drought tolerance of Pinus radiata plants originating from embryonal masses induced at high temperatures

2020 ◽  
Author(s):  
Ander Castander-Olarieta ◽  
Paloma Moncaleán ◽  
Catia Pereira ◽  
Aleš Pěnčík ◽  
Ivan Petřík ◽  
...  
Keyword(s):  
Somatic Embryogenesis ◽  
High Temperature ◽  
High Temperatures ◽  
Pinus Radiata ◽  
Temperature Regime ◽  
Zeatin Riboside ◽  
Embryogenic Cell ◽  
Temperature Regimes ◽  
Extreme High Temperature ◽  
Somatic Plants

Abstract Vegetative propagation through somatic embryogenesis is an effective method to produce elite varieties and can be applied as a tool to study the response of plants to different stresses. Several studies show that environmental changes during embryogenesis could determine future plant development. Moreover, we previously reported that physical and chemical conditions during somatic embryogenesis can determine the protein, hormone and metabolite profiles, as well as the micromorphological and ultrastructural organization of embryonal masses and somatic embryos. In this sense, phytohormones are key players throughout the somatic embryogenesis process as well as during numerous stress–adaptation responses. In this work, we first applied different high-temperature regimes (30 °C, 4 weeks; 40 °C, 4 days; 50 °C, 5 min) during induction of Pinus radiata D. Don somatic embryogenesis, together with control temperature (23 °C). Then, the somatic plants regenerated from initiated embryogenic cell lines and cultivated in greenhouse conditions were subjected to drought stress and control treatments to evaluate survival, growth and several physiological traits (relative water content, water potential, photosynthesis, stomatal conductance and transpiration). Based on those preliminary results, even more extreme high-temperature regimes were applied during induction (40 °C, 4 h; 50 °C, 30 min; 60 °C, 5 min) and the corresponding cytokinin profiles of initiated embryonal masses from different lines were analysed. The results showed that the temperature regime during induction had delayed negative effects on drought resilience of somatic plants as indicated by survival, photosynthetic activity and water- use efficiency. However, high temperatures for extended periods of time enhanced subsequent plant growth in well-watered conditions. High-temperature regime treatments induced significant differences in the profile of total cytokinin bases, N6-isopentenyladenine, cis-zeatin riboside and trans-zeatin riboside. We concluded that phytohormones could be potential regulators of stress-response processes during initial steps of somatic embryogenesis and that they may have delayed implications in further developmental processes, determining the performance of the generated plants.

scholarly journals Growth, flowering and fruiting in tomatoes in relation to temperature, cycocel and GA.

1970 ◽  
Vol 18 (2) ◽  
pp. 105-110
Author(s):  
A.A. Abdalla ◽  
K. Verkerk
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
High Temperatures ◽  
Root Development ◽  
Temperature Regime ◽  
Low Temperatures ◽  
Fruit Set ◽  
High Temperature Regime ◽  
Temperature Regimes ◽  
Dark Green

The effects were assessed of CCC and GA on tomatoes grown either under a high temperature regime (35 degrees day and 25 degrees C. night) or at normal temperatures (22 degrees and 18 degrees ). CCC (0.4%) was applied to the soil in the pots either 2 days after transplanting or at the start of flowering; G A was applied by dipping the first truss in GA (50 p.p.m.). CCC greatly retarded the growth rate of the stems of the plants under both temperature regimes; this effect persisted for about 17 and 24 days under the high and normal temperature regimes, respectively. With plants grown at high temperatures CCC applied at the start of flowering greatly reduced flower shedding and slightly increased the fruit set and fruit development of hand-pollinated flowers. With plants grown at normal temperatures, however, the effects of CCC were slight. CCC-treated plants were sturdy with dark-green leaves which remained green longer, especially under the high temperature regime. More N accumulated in the tissues of plants grown at high temperatures than at normal temperatures, and the N content of the latter plants was considerably increased by CCC treatment. The root development of the CCC-treated plants was much more extensive than that of the untreated plants. The numbers of seeds in the hand-pollinated fruit were not affected by CCC, but at high temperatures there were considerably less seeds than at low temperatures. GA enhanced fruit set of the high-temperature plants, but the fruits were small and seedless. GA also accelerated fruit ripening by 2 and 3 weeks in the plants grown at high and normal temperatures, respectively.-Agric. Univ., Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals How will the key marine calcifier <i>Emiliania huxleyi</i> respond to a warmer and more thermally variable ocean?

2019 ◽  
Vol 16 (22) ◽  
pp. 4393-4409
Author(s):  
Xinwei Wang ◽  
Feixue Fu ◽  
Pingping Qu ◽  
Joshua D. Kling ◽  
Haibo Jiang ◽  
...  
Keyword(s):  
High Temperatures ◽  
Variable Temperature ◽  
Thermal Fluctuations ◽  
Emiliania Huxleyi ◽  
Thermal Variation ◽  
Negative Effects ◽  
Surface Ocean ◽  
Temperature Regimes ◽  
Ocean Productivity ◽  
Extreme High Temperature

Abstract. Global warming will be combined with predicted increases in thermal variability in the future surface ocean, but how temperature dynamics will affect phytoplankton biology and biogeochemistry is largely unknown. Here, we examine the responses of the globally important marine coccolithophore Emiliania huxleyi to thermal variations at two frequencies (1 d and 2 d) at low (18.5 ∘C) and high (25.5 ∘C) mean temperatures. Elevated temperature and thermal variation decreased growth, calcification and physiological rates, both individually and interactively. The 1 d thermal variation frequencies were less inhibitory than 2 d variations under high temperatures, indicating that high-frequency thermal fluctuations may reduce heat-induced mortality and mitigate some impacts of extreme high-temperature events. Cellular elemental composition and calcification was significantly affected by both thermal variation treatments relative to each other and to the constant temperature controls. The negative effects of thermal variation on E. huxleyi growth rate and physiology are especially pronounced at high temperatures. These responses of the key marine calcifier E. huxleyi to warmer, more variable temperature regimes have potentially large implications for ocean productivity and marine biogeochemical cycles under a future changing climate.

The Effects of Extreme High Temperature Day-Off on Electricity Conservation

2021 ◽  
Author(s):  
Yu-Wen Su
Keyword(s):  
High Temperature ◽  
Human Health ◽  
High Temperatures ◽  
Power Grid ◽  
Electricity Consumption ◽  
New Normal ◽  
Space Cooling ◽  
Extreme High Temperature ◽  
Industrial Service ◽  
Electricity Conservation

AbstractThe continuously increasing temperatures worldwide indicate the frequently extreme heat in summer will become a new normal. The extreme high temperature (EHT) could be dangerous to human health, especially for outdoor workers or commuters, and increase the risk of grid collapse. Thus, the possibility of a day-off due to EHT has started to be discussed in Taiwan, based on the experience of typhoon day-off, but not yet concluded. In this study, the effects of the EHT day-off on electricity consumption in the industrial, service, and residential sectors was investigated through two determinants: First, high temperature would increase the electricity consumption in space cooling. Second, a day-off would change people’s behavior of electricity consumption from workday to non-workday modes. Combining the effects of cooling hours and non-workdays, the net influence of the EHT day-off on electricity consumption can be evaluated. Estimated results indicated that an EHT day-off can reduce aggregate electricity consumption by between 0.41% and 1.08%. The reduction of electricity consumption due to the off-day offsets the increase driven by high temperatures. Thus, an EHT day-off will mitigate the pressure of power grid and be of benefit to electricity conservation.

Cotton responses to different light–temperature regimes

1998 ◽  
Vol 131 (3) ◽  
pp. 277-283 ◽  
Author(s):  
D. ROUSSOPOULOS ◽  
A. LIAKATAS ◽  
W. J. WHITTINGTON
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Light Intensity ◽  
Leaf Area ◽  
Temperature Regime ◽  
Light Regime ◽  
High Light ◽  
Cultivar Differences ◽  
Low Light ◽  
Temperature Regimes

A series of experiments investigating the interactive effects of light and temperature on vegetative growth, earliness, fruiting, yield and fibre properties in three cultivars of cotton, was undertaken in growth rooms. Two constant day/night temperature regimes with a difference of 4 °C (30/20 and 26/16·5 °C) were used throughout the growing season in combination with two light intensities (75 and 52·5 W m−2).The results showed that significant interactions occurred for most of the characters studied. Although the development of leaf area was mainly temperature-dependent, plants at harvest had a larger leaf area when high temperature was combined with low rather than with high light intensity. Leaf area was least in the low temperature–low light regime. However, the plants grown under the high temperature–low light combination weighed the least.Variations in the number of nodes and internode length were largely dependent on temperature rather than light. Light did, however, affect the numbers of branches, sympodia and monopodia. The first two of these were highest in the high light–high temperature regime and the third in the low light–low temperature regime.All other characters, except time to certain developmental stages and fibre length, were reduced at the lower light intensity. Variation in temperature modified the light effect and vice versa, in a character-dependent manner. More specifically, square and boll dry weights, as well as seed cotton yield per plant, were highest in high light combined with low temperature, where the most and heaviest bolls were produced. But flower production was favoured by high light and high temperature, suggesting increased boll retention at low temperature, especially when combined with low light. Low temperature and high light also maximized lint percentage.Fibres were shortest in the high temperature–high light regime, where fibre strength, micronaire index and maturity ratio were at a maximum. However, the finest and the most uniform fibres were produced when high light was combined with low temperature.Cultivar differences were significant mainly in leaf area and dry matter production at flowering.

scholarly journals 907 PB 531 EFFECT OF HIGH TEMPERATURE ON SUCROSE METABOLISM IN SOURCE AND SINK TISSUES OF POTATO

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 564a-564
Author(s):  
Abbas M. Lafta ◽  
James H. Lorenzen
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Sucrose Synthase ◽  
Sucrose Phosphate Synthase ◽  
Sucrose Metabolism ◽  
Potato Plants ◽  
Temperature Regimes ◽  
Whole Plant ◽  
Young Leaves ◽  
Source And Sink

Potato plants are sensitive to heat stress, which reduces tuber yield and alters whole plant partitioning. This study was conducted to determine the effect of high temperature on activity of enzymes related to sucrose metabolism in source and sink tissues of potato plants. Potato plants were exposed to two temperature regimes (20 and 28 C) for 3 days. High temperatures resulted in an increase in sucrose synthase and acid and neutral invertase activities in young growing leaves (< 1.5 cm). However, there were no significant changes in these enzyme activities in stems or mature leaves. The results indicate that both sucrose synthase and invertases are involved in sucrose breakdown in young leaves. We will also discuss the role of sucrose phosphate synthase in mature source leaves and how it is affected by temperature and altered partitioning pattern. Activity of sucrose synthase was affected more than ADP-glucose pyrophosphorylase in small growing tubers exposed to high temperatures.

Effect of heat stress during seed development and maturation on wheat (Triticum durum) seed quality. II. Mitochondrial respiration and nucleotide pools during early germination

1995 ◽  
Vol 75 (4) ◽  
pp. 831-839 ◽  
Author(s):  
L. Grass ◽  
J. S. Burris
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Low Temperature ◽  
Oxygen Uptake ◽  
Temperature Regime ◽  
Seed Quality ◽  
Energy Levels ◽  
Medium Temperature ◽  
Mitochondrial Structure ◽  
Temperature Regimes

Marzak and Oum-rabia wheat seeds were produced under three temperature regimes (20:15, 28:21, 36:29 °C) starting 10 d after anthesis through harvest. Nucleotide levels and respiratory activity of mitochondria isolated from imbibing embryos were determined. Mitochondrial structure from the radicle meristem region of imbibed embryos was examined under electron microscopy. Embryos from low-temperature treatments showed rapid accumulation of adenosine triphosphate (ATP) and higher energy levels and rates of oxygen uptake than embryos from high-temperature treatments. Embryos from medium-temperature treatments exhibited intermediate values. Parallel to these metabolic changes during early seed germination, results from electron microscopy revealed visible differences in mitochondrial structure. Mitochondria from the low-temperature regime were well developed with visible membranes and cristae; those from the high-temperature regime were degenerating. These results provide clear evidence of the influence of parent temperature conditions on the seed metabolism during early stages of germination. Key words: Embryo, mitochondria, nucleotide, oxygen uptake, vigor, wheat

scholarly journals Somatic Embryogenesis and Plant Regeneration from Sugi (Japanese Cedar, Cryptomeria japonica D. Don, Cupressaceae) Seed Families by Marker Assisted Selection for the Male Sterility Allele ms1

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1029 ◽  
Author(s):  
Tsuyoshi E. Maruyama ◽  
Saneyoshi Ueno ◽  
Satoko Hirayama ◽  
Takumi Kaneeda ◽  
Yoshinari Moriguchi
Keyword(s):  
Somatic Embryogenesis ◽  
Male Sterility ◽  
Marker Assisted Selection ◽  
Cryptomeria Japonica ◽  
Public Health Problem ◽  
Efficient Production ◽  
Initial Growth ◽  
Male Sterile ◽  
Embryogenic Cell ◽  
Somatic Plants

One of the possible countermeasures for pollinosis caused by sugi (Cryptomeria japonica), a serious public health problem in Japan, is the use of male sterile plants (MSPs; pollen-free plants). However, the production efficiencies of MSPs raised by conventional methods are extremely poor, time consuming, and resulting in a high seedling cost. Here, we report the development of a novel technique for efficient production of MSPs, which combines marker-assisted selection (MAS) and somatic embryogenesis (SE). SE from four full sib seed families of sugi, carrying the male sterility gene MS1, was initiated using megagametophyte explants that originated from four seed collections taken at one-week intervals during the month of July 2017. Embryogenic cell lines (ECLs) were achieved in all families, with initiation rates varying from 0.6% to 59%. Somatic embryos were produced from genetic marker-selected male sterile ECLs on medium containing maltose, abscisic acid (ABA), polyethylene glycol (PEG), and activated charcoal (AC). Subsequently, high frequencies of germination and plant conversion (≥76%) were obtained on plant growth regulator-free medium. Regenerated plantlets were acclimatized successfully, and the initial growth of male sterile somatic plants was monitored in the field.

scholarly journals Induction of Radiata Pine Somatic Embryogenesis at High Temperatures Provokes a Long-Term Decrease in DNA Methylation/Hydroxymethylation and Differential Expression of Stress-Related Genes

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1762
Author(s):  
Ander Castander-Olarieta ◽  
Cátia Pereira ◽  
Ester Sales ◽  
Mónica Meijón ◽  
Isabel Arrillaga ◽  
...  
Keyword(s):  
Somatic Embryogenesis ◽  
High Temperatures ◽  
Stress Responses ◽  
Radiata Pine ◽  
Global Methylation ◽  
Protein Coding ◽  
Somatic Plants ◽  
Stress Related Genes ◽  
As Stress ◽  
Stress Mediators

Based on the hypothesis that embryo development is a crucial stage for the formation of stable epigenetic marks that could modulate the behaviour of the resulting plants, in this study, radiata pine somatic embryogenesis was induced at high temperatures (23 °C, eight weeks, control; 40 °C, 4 h; 60 °C, 5 min) and the global methylation and hydroxymethylation levels of emerging embryonal masses and somatic plants were analysed using LC-ESI-MS/ MS-MRM. In this context, the expression pattern of six genes previously described as stress-mediators was studied throughout the embryogenic process until plant level to assess whether the observed epigenetic changes could have provoked a sustained alteration of the transcriptome. Results indicated that the highest temperatures led to hypomethylation of both embryonal masses and somatic plants. Moreover, we detected for the first time in a pine species the presence of 5-hydroxymethylcytosine, and revealed its tissue specificity and potential involvement in heat-stress responses. Additionally, a heat shock protein-coding gene showed a down-regulation tendency along the process, with a special emphasis given to embryonal masses at first subculture and ex vitro somatic plants. Likewise, the transcripts of several proteins related with translation, oxidative stress response, and drought resilience were differentially expressed.

Number and weight of cotton lint fibres: variation due to high temperatures in the field

2006 ◽  
Vol 57 (5) ◽  
pp. 583 ◽  
Author(s):  
Hafeez-ur Rahman
Keyword(s):  
High Temperature ◽  
Surface Area ◽  
Temperature Regime ◽  
Combining Ability ◽  
General Combining Ability ◽  
Cotton Lint ◽  
Seed Surface ◽  
High Temperature Regime ◽  
Relative Contribution ◽  
Temperature Regimes

Seed surface area is the basic ground for lint production in cotton and, hence, a starting point for genetic improvement in lint yield. Experiments on upland cottons were carried out under 2 temperature regimes (April sown, high temperature regime; June sown, moderate regime) for 2 years in the field to study their modifying effect on phenotypic expression and combining ability of lint weight per seed (LW/S), lint weight per unit seed surface area (LW/SA), lint weight per unit fibre length (LW/FL), lint frequency (LF), number of spinnable fibres per seed (F/S), and number of spinnable fibres per unit seed surface area (F/SA). Variation among cultivars for relative decrease in the basic lint traits under high temperature regime indicated their differences in heat sensitivity. Genetic variation for all basic lint traits was low over environments but high within environments. Temperature regime was a stronger source of variation in basic lint traits than year. Temperature regimes modified phenotype, ranking among parents, and combining ability of basic lint traits. Relative contribution of specific combining ability to total variation decreased under high temperature regime for all the basic lint traits, except LW/FL, with a corresponding increase in general combining ability due to either female or male parents. Relative contribution of general combining ability due to female parents for LW/S and LW/SA, and that due to male parents for LW/SA, LF, F/S, and F/SA, increased substantially under high temperature regime. High temperature regime was favourable for the expression of additive genetic variability. From the breeding point of view, F/S and F/SA were more useful traits.

scholarly journals Effects of light and temperature on lettuce seedlings.

1973 ◽  
Vol 21 (2) ◽  
pp. 102-109 ◽  
Author(s):  
K. Verkerk ◽  
C.J.T. Spitters
Keyword(s):  
High Temperature ◽  
Light Intensity ◽  
Leaf Area ◽  
Temperature Regime ◽  
Natural Light ◽  
Light Conditions ◽  
Subsequent Growth ◽  
High Temperature Regime ◽  
Temperature Regimes ◽  
Effects Of Temperature

In the first of 2 experiments lettuces were grown either under natural light conditions in the glasshouse in December and January or under 8- or 16-h daylengths, with several temperature regimes, and the leaf area per plant was measured after 22 and 45 days. Under natural light growth during the first 22 days was slight but subsequent growth was greatest with a light/dark temperature regime of 13/13 deg C, followed by one of 17/17 deg . With an 8-h day growth with diurnally changing temperatures was much greater than with constant ones, the best results being obtained with a regime of 25/17 deg . With a 16-h day the effect of diurnal temperature was much less marked and a constant high temperature regime of 21/21 deg gave better results than one of 25/17 deg . In the second experiment the plants were grown for 4 weeks under the same temperature regimes with 8- or 16-h daylengths, but the light intensity was varied by placing the plants at 2 vertical distances from the overhead lamps and all plants receiving a 16-h daylength were shaded by cheesecloth. The best results were obtained with a 16-h daylength with the plants placed close to the lamps; the effects of temperature were not so marked, but regimes of 25/17, 21/13 or 17/17 deg were the most satisfactory. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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