778 PB 392 AXILLARY BUD DEVELOPMENT OF `RED SAILS' POINSETTIA IS INHIBITED BY HIGH DAY TEMPERATURES

Poor lateral branching sometimes occurs when certain poinsettia (Euphorbia pulcherrima) cultivars are pinched. Two experiments were conducted to determine the effect of high temperatures on axillary bud development. In Expt. 1, `Red Sails' plants were grown in a high-temperature environment (HTE) of 27°C at night (8 hr) and 30°C (3 hr), 33°C (10 hr), and 30°C (3 hr) in the day for two months, then transferred to a 20°C environment. In Expt. 2, plants grown at 20°C were transferred into the same HTE described above for 0, 2, 4, 8, 16, or 32 days and were then moved back into the 20°C environment. Axillary buds were examined for viability at the end of each experiment. In Expt. 1, only 8% of the lateral buds forming in the HTE were viable, while 80% of the buds forming in leaf axils of leaves unfolding after the plants were transferred to the 20°C environment were viable. In Expt. 2, 80% of buds produced in axils of the first four leaves to unfold after the start of the experiment were viable in all the treatments. However, the percentage of viable buds in the axils of leaf numbers 5 to 8 was 100, 100, 100, 96, 56, and 0 for the plants placed in the HTE for 0, 2, 4, 8, 16, and 32 days, respectively. These data indicate day temperatures of 30 to 33°C adversely affect lateral shoot development of `Red Sails' poinsettia.

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Axillary Bud Development of Poinsettia `Eckespoint Lilo' and `Eckespoint Red Sails' (Euphorbia pulcherrima Willd.) Is Inhibited by High Temperatures

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.121.5.920 ◽

1996 ◽

Vol 121 (5) ◽

pp. 920-926 ◽

Cited By ~ 3

Author(s):

James E. Faust ◽

Royal D. Heins

Keyword(s):

High Temperature ◽

High Temperatures ◽

Axillary Buds ◽

Axillary Bud ◽

Effect Of Temperature ◽

High Temperature Treatment ◽

Euphorbia Pulcherrima ◽

Lateral Shoot ◽

Bud Development ◽

Lateral Shoots

The effect of temperature on axillary bud and lateral shoot development of poinsettia (Euphorbia pulcherrima Willd.) `Eckespoint Lilo' and `Eckespoint Red Sails' was examined. Rooted `Eckespoint Lilo' cuttings were transplanted and placed into growth chambers maintained at 21, 24, 27, or 30 °C for 2 weeks before apex removal. The percentage of nodes developing lateral shoots after apex removal was 68%, 69%, 73%, or 76% at 21, 24, 27, or 30 °C, respectively. Cuttings were removed from the lateral shoots, rooted, and placed into a 21 °C greenhouse, and the apices were removed. The percentage of nodes developing into lateral shoots on cuttings taken from plants held at 21, 24, 27, and 30 °C were 74%, 65%, 66%, and 21%, respectively. Of the cuttings in the 30 °C treatment, 83% of the nodes not producing a lateral shoot had poorly developed axillary buds or no visible axillary bud development. Visual rating of axillary bud viability decreased from 100% to 0% when `Eckespoint Red Sails' plants were transferred from a 21 °C greenhouse to a greenhouse maintained at 27 °C night temperature and 30 °C for 3 hours followed by 33 °C for 10 hours and 30 °C for 3 hours during the 16-hour day. Transfer from the high-temperature greenhouse to a 21 °C greenhouse increased axillary bud viability from 0% to 95%. Axillary buds of leaves not yet unfolded were sensitive to high temperatures, whereas those of unfolded leaves (i.e., fully developed correlatively inhibited buds) were not. Sixteen consecutive days in the high-temperature treatment were required for axillary bud development of `Eckespoint Red Sails' to be inhibited.

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Investigation of Impact Compressive Mechanical Properties of Sandstone After as well as Under High Temperature

High Temperature Materials and Processes ◽

10.1515/htmp-2013-0125 ◽

2014 ◽

Vol 33 (6) ◽

pp. 585-591 ◽

Cited By ~ 3

Author(s):

Shi Liu ◽

Jinyu Xu

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Critical Temperature ◽

High Temperatures ◽

Experimental Studies ◽

Practical Significance ◽

Temperature Environment ◽

Shpb Test ◽

The Impact ◽

High Temperature Environment

AbstractConducting experimental studies on the impact compressive mechanical properties of rock under the high temperature environment is of both theoretical value and practical significance to understanding the relationship between the rock under the effect of impact loads and the high temperature environment. Based on the Φ100 mm SHPB and the self-developed Φ100 mm high-temperature SHPB test devices, the impact compressive tests on the sandstone, whether cooling after high temperatures or under real-time high temperatures are carried out. As the test results indicate that since the two high-temperature ways of loading are different from each other, the impact compressive properties of sandstone, after as well as under high temperatures, show different variations along with changes in temperature. Under the effect of the same impact loading rate, there exists a clear critical temperature range in the impact compressive mechanical properties of sandstone after high temperature, and, near the critical temperature, there occurs a significant mutation in the impact compressive mechanical properties. Under high temperatures, however, the impact compressive mechanical properties follow an overall continuity of change except that there are slight fluctuations at individual temperatures.

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A High Temperature Environment Regulates the Olive Oil Biosynthesis Network

Plants ◽

10.3390/plants9091135 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1135

Author(s):

Yael Nissim ◽

Maya Shlosberg ◽

Iris Biton ◽

Yair Many ◽

Adi Doron-Faigenboim ◽

...

Keyword(s):

Heat Stress ◽

High Temperature ◽

Olive Oil ◽

High Temperatures ◽

Fruit Development ◽

Biosynthesis Pathway ◽

Oil Biosynthesis ◽

Yield And Quality ◽

Temperature Environment ◽

High Temperature Environment

Climate change has been shown to have a substantial impact on agriculture and high temperatures and heat stress are known to have many negative effects on the vegetative and reproductive phases of plants. In a previous study, we addressed the effects of high temperature environments on olive oil yield and quality, by comparing the fruit development and oil accumulation and quality of five olive cultivars placed in high temperature and moderate temperature environments. The aim of the current study was to explore the molecular mechanism resulting in the negative effect of a high temperature environment on oil quantity and quality. We analyzed the transcriptome of two extreme cultivars, ‘Barnea’, which is tolerant to high temperatures in regard to quantity of oil production, but sensitive regarding its quality, and ‘Souri’, which is heat sensitive regarding quantity of oil produced, but relatively tolerant regarding its quality. Transcriptome analyses have been carried out at three different time points during fruit development, focusing on the genes involved in the oil biosynthesis pathway. We found that heat-shock protein expression was induced by the high temperature environment, but the degree of induction was cultivar dependent. The ‘Barnea’ cultivar, whose oil production showed greater tolerance to high temperatures, exhibited a larger degree of induction than the heat sensitive ‘Souri’. On the other hand, many genes involved in olive oil biosynthesis were found to be repressed as a response to high temperatures. OePDCT as well as OeFAD2 genes showed cultivar dependent expression patterns according to their heat tolerance characteristics. The transcription factors OeDof4.3, OeWRI1.1, OeDof4.4 and OeWRI1.2 were identified as key factors in regulating the oil biosynthesis pathway in response to heat stress, based on their co-expression characteristics with other genes involved in this pathway. Our results may contribute to identifying or developing a more heat tolerant cultivar, which will be able to produce high yield and quality oil in a future characterized by global warming.

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(74) Effect of Temperature on Axillary Bud Formation and Polyamine Contents of Nonbranching Chrysanthemum

HortScience ◽

10.21273/hortsci.40.4.1014c ◽

2005 ◽

Vol 40 (4) ◽

pp. 1014C-1014 ◽

Cited By ~ 1

Author(s):

Yeun Joo Huh ◽

Seoung Youl Choi ◽

Hak Ki Shin ◽

Chun Ho Pak

Keyword(s):

High Temperature ◽

Low Temperature ◽

Shoot Development ◽

Axillary Buds ◽

Axillary Bud ◽

Effect Of Temperature ◽

Lateral Shoot ◽

Bud Formation ◽

Polyamine Content

Nonbranching chrysanthemums [Dendranthema × grandiflorum (Ramat.) Kitamura] are preferred because they require less labor in disbudding. High temperature is responsible for this phenotype of not having axillary buds or poor lateral shoot development. This study attempted to find out the effect of temperature and identify the involvement of endogenous polyamine contents in axillary bud formation of nonbranching chrysanthemum cv. Iwanohakusen. Plants were treated at 22, 26, 30, 34, and 38 °C for 9 hours midday for 2 months. Polyamine content [putrescine (Put), spermidine (Spd), spermine (Spm)] was analyzed 1 month after treatment and axillary buds were counted when the flowers opened. Results revealed that viable axillary buds decreased remarkably at 30 and 34°C. It was also found out that not only low temperature, but also the excessively high temperature of 38 °C induced axillary bud formation. Exposure to 38 °C increased the Put contents and resulted in high Put/(Spd + Spm) ratio as 22 °C, 26 °C. Temperature of 30, 34 °C lowered Put/(Spd + Spm) ratio. Results further showed that not polyamine contents, but polyamine ratio (Put/Spd + Spm) or transformation of Put to Spd and Spm may be involved in the axillary bud formation in nonbranching chrysanthemum.

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Changes in Chrysanthemum Meristem and Lateral Bud Development at Elevated Temperatures

HortScience ◽

10.21273/hortsci.30.4.760c ◽

1995 ◽

Vol 30 (4) ◽

pp. 760C-760

Author(s):

Richard K. Schoellhorn ◽

James E. Barrett ◽

Terril A. Nell

Keyword(s):

High Temperature ◽

Low Temperature ◽

High Temperatures ◽

Elevated Temperatures ◽

Wall Material ◽

Temperature Sensitive ◽

Bud Development ◽

Lateral Buds ◽

Temperature Loss ◽

Lateral Bud

`Improved Mefo' chrysanthemums were grown at 22C/18C and 34C/28C day/night temperature regimes to evaluate the failure of lateral bud development following pinching of this temperature sensitive cultivar. The number of viable buds on plants at the high temperatures was 40% of number at low temperature. Loss of bud viability was categorized as those buds that were: 1) absent, or 2) those in which growth was present, but inhibited. Inhibited buds were visible swellings surrounded by dense masses of secondary cell wall material. Anatomical studies were completed to verify the absence of lateral buds and determine what cellular changes imposed inhibition on those buds that did develop. A second group of experiments demonstrated that moving low-temperature plants to the high temperature caused production of viable buds to decline. Plants were moved from high temperatures to low, and reciprocally to high from low temperature. Anatomical sampling of apical meristems began at time of shift and at 1, 2, 4, and 8 days after temperature shift. High-temperature meristems possessed predominantly non-viable lateral buds, with few viable buds present.

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