GIBBERELLIN METABOLISM DURING STEM ELONGATION STIMULATED BY HIGH TEMPERATURE IN LETTUCE

2012 ◽  
pp. 259-264 ◽  
Author(s):  
M. Fukuda ◽  
S. Matsuo ◽  
K. Kikuchi ◽  
W. Mitsuhashi ◽  
T. Toyomasu ◽  
...  
Keyword(s):  
High Temperature ◽  
Stem Elongation ◽  
Gibberellin Metabolism

Thermodormancy in Seedlings of Eucalyptus obliqua L'herit

1976 ◽  
Vol 3 (2) ◽  
pp. 269 ◽  
Author(s):  
TJ Blake
Keyword(s):  
High Temperature ◽  
Respiration Rate ◽  
Respiratory Quotient ◽  
Stem Elongation ◽  
Temperature Treatment ◽  
Height Growth ◽  
High Temperature Treatment ◽  
Total Polyphenols ◽  
Terminal Buds

High (30°C) day and night temperatures reduced mainstem elongation in E. obliqua seedlings resulting in a temporary quiescence in height growth after 8 days of high temperature treatment; rapid stem elongation did not recommence when seedlings were returned to conditions usually favourable to growth. Associated with the onset of quiescence were: an increase in the respiratory quotient and a decrease in the respiration rate of upper terminal buds; an accumulation of inhibitory substances; and an increase in total polyphenols in the stem.

Promotion of flowering in potted Piceaengelmannii (Perry) grafts: effects of heat, drought, gibberellin A4/7, and their timing

1985 ◽  
Vol 15 (4) ◽  
pp. 618-624 ◽  
Author(s):  
Stephen D. Ross
Keyword(s):  
High Temperature ◽  
Shoot Growth ◽  
Critical Time ◽  
Shoot Elongation ◽  
The Other ◽  
Severe Drought ◽  
Lateral Shoot ◽  
Gibberellin Metabolism ◽  
Genetically Improved ◽  
Needle Water Potential

Young, potted grafts ofPiceaengelmannii were moved into a 30:20 °C (day:night) heated polyethylene house at different stages of lateral shoot elongation; and there they were subjected to low, moderate, or severe drought stress with and without branch applications of gibberellin A4/7 (GA4/7). The critical time for promoting flowering by high temperature was the late stage of slow shoot elongation, whereas for drought it was during early and rapid shoot growth. Each treatment inhibited flowering at the time the other was maximally effective and the effective treatment period for GA4/7 appeared to include that both for high temperature and drought. In contrast to drought, optimally timed heat treatment did not retard shoot elongation, nor did it result in a decreased needle water potential relative to well-watered grafts outdoors. It appears that heat and drought promote flowering through different mechanisms, albeit mechanisms which may be mediated, at least in part, through their influence on gibberellin metabolism. Advantages of indoor-potted orchards over conventional soil-based orchards for accelerating the breeding and production of genetically improved P. engelmannii seeds are discussed.

scholarly journals Difference Between Day and Night Temperatures Affects Stem Elongation in Tomato (Solanum lycopersicum) Seedlings via Regulation of Gibberellin and Auxin Synthesis

2020 ◽  
Vol 11 ◽  
Author(s):  
Kinuka Ohtaka ◽  
Akiko Yoshida ◽  
Yusuke Kakei ◽  
Kosuke Fukui ◽  
Mikiko Kojima ◽  
...  
Keyword(s):  
High Temperature ◽  
Solanum Lycopersicum ◽  
Growth Regulation ◽  
Stem Elongation ◽  
Stem Length ◽  
Control Temperature ◽  
Tomato Seedlings ◽  
Auxin Synthesis ◽  
The Difference ◽  
C 30

Temperature is a critical environmental factor governing plant growth and development. The difference between day temperature (DT) and night temperature (NT), abbreviated as DIF, influences plant architecture. Subjecting plants to artificial DIF treatments is an effective strategy in ornamental horticulture. For example, negative DIF (when DT – NT < 0) generally inhibits stem elongation, resulting in dwarf plants. However, the mechanisms underlying stem growth regulation by DIF remains to be completely elucidated. In this study, we aimed to analyze the growth, transcriptome, and phytohormone profiles of tomato (Solanum lycopersicum) seedlings grown under different DIF treatments. Under positive DIF (when DT – NT > 0), in contrast to the control temperature (25°C/20°C, DT/NT), high temperature (30°C/25°C) increased stem length and thickness, as well as the number of xylem vessels. Conversely, compared with the positive high temperature DIF treatment (30°C/25°C), under negative DIF treatment (25°C/30°C) stem elongation was inhibited, but stem thickness and the number of xylem vessels were not affected. The negative DIF treatment decreased the expression of gibberellin (GA)-, auxin-, and cell wall-related genes in the epicotyl, as well as the concentrations of GAs and indole-3-acetic acid (IAA). The expression of these genes and concentrations of these hormones increased under high temperature compared to those under the control temperature positive DIF. Our results suggest that stem length in tomato seedlings is controlled by changes in GA and IAA biosynthesis in response to varying day and night temperatures.

scholarly journals Gibberellin Metabolism and Signaling: Targets for Improving Agronomic Performance of Crops

2020 ◽  
Vol 61 (11) ◽  
pp. 1902-1911 ◽  
Author(s):  
Shaopei Gao ◽  
Chengcai Chu
Keyword(s):  
Stem Elongation ◽  
Crop Improvement ◽  
Green Revolution ◽  
Crop Productivity ◽  
Primary Objective ◽  
Fine Tuning ◽  
Breeding Programs ◽  
Pollen Maturation ◽  
Gibberellin Metabolism ◽  
Increase Productivity

Abstract Gibberellins (GAs) are a class of tetracyclic diterpenoid phytohormones that regulate many aspects of plant development, including seed germination, stem elongation, leaf expansion, pollen maturation, and the development of flowers, fruits and seeds. During the past decades, the primary objective of crop breeding programs has been to increase productivity or yields. ‘Green Revolution’ genes that can produce semidwarf, high-yielding crops were identified as GA synthesis or response genes, confirming the value of research on GAs in improving crop productivity. The manipulation of GA status either by genetic alteration or by exogenous application of GA or GA biosynthesis inhibitors is often used to optimize plant growth and yields. In this review, we summarize the roles of GAs in major aspects of crop growth and development and present the possible targets for the fine-tuning of GA metabolism and signaling as a promising strategy for crop improvement.

The endogenous level of GA1 is upregulated by high temperature during stem elongation in lettuce through LsGA3ox1 expression

2009 ◽  
Vol 166 (18) ◽  
pp. 2077-2084 ◽  
Author(s):  
Machiko Fukuda ◽  
Satoshi Matsuo ◽  
Kaori Kikuchi ◽  
Wataru Mitsuhashi ◽  
Tomonobu Toyomasu ◽  
...  
Keyword(s):  
High Temperature ◽  
Stem Elongation ◽  
Endogenous Level

Sensitivity of Broccoli Inflorescence Development to High Temperature

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 885E-885
Author(s):  
Thomas Bjorkman ◽  
Karen Pearson
Keyword(s):  
High Temperature ◽  
Developmental Stages ◽  
Stem Elongation ◽  
Sensitive Period ◽  
Small Range ◽  
Scanning Electron Micrographs ◽  
Inflorescence Development ◽  
Stage Of Development ◽  
Temperature Exposure ◽  
Bud Initiation

Production of broccoli in areas where summer temperatures exceed 30C is difficult because the head may not form properly. The high temperature causes an unevenness in the head due to widely differing sizes of buds. The sensitive stage of development was determined for the early maturing variety `Galaxy' by exposing it to 1-week at 36C at varying developmental stages, and subsequently analyzing the head structure. The injury is a cessation of bud enlargement during the high-temperature exposure. There is no corresponding cessation of bud initiation at the apex. The patter of injury is consistent with susceptibility over a relatively small range of bud development: even with a 1-week exposure, only about 1/3 of the buds will be affected. The plant's most developmental stage at this sensitive period still appears vegetative, but the youngest leaves are just beginning to reorient as a consequence of the reduced stem elongation rate. The meristem is less than 1 mm wide, and scanning electron micrographs show floral primordia just forming, still subtended by leaf primordia. The injury is fully expressed when the head is first exposed (≈10 mm wide), though it becomes more apparent as the head matures. The buds that were delayed in development by the high temperature developed into fertile flowers, albeit about a week late.

scholarly journals Expression of Gibberellin Metabolism Genes and Signalling Components in Dwarf Phenotype of Breadfruit (Artocarpus altilis) Plants Growing on Marang (Artocarpus odoratissimus) Rootstocks

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 634
Author(s):  
Yuchan Zhou ◽  
Steven J. R. Underhill
Keyword(s):  
Stem Elongation ◽  
Biosynthetic Gene ◽  
Dwarf Phenotype ◽  
Artocarpus Altilis ◽  
Della Proteins ◽  
Gibberellin Metabolism ◽  
Catabolic Genes ◽  
The Tropics ◽  
Insight Into ◽  
Size Controlling

Breadfruit (Artocarpus altilis) is a traditional staple tree crop throughout the tropics. The species is an evergreen tree 15–20 m; there are currently no size-controlling rootstocks within the species. Through interspecific grafting, a dwarf phenotype was identified in breadfruit plants growing on Marang (Artocarpus odoratissimus) rootstocks, which displayed ~60% reduction in plant height with ~80% shorter internodes. To gain insight into the molecular mechanism underlying rootstock-induced dwarfing, we investigated the involvement of gibberellin (GA) in reduction of stem elongation. Expression of GA metabolism genes was analysed in the period from 18 to 24 months after grafting. In comparison to self-graft and non-graft, scion stems on marang rootstocks displayed decrease in expression of a GA biosynthetic gene, AaGA20ox3, and increase in expression of a GA catabolic genes, AaGA2ox1, in the tested 6-month period. Increased accumulation of DELLA proteins (GA-signalling repressors) was found in scion stems growing on marang rootstocks, together with an increased expression of a DELLA gene, AaDELLA1. Exogenous GA treatment was able to restore the stem elongation rate and the internode length of scions growing on marang rootstocks. The possibility that GA deficiency forms a component of the mechanism underlying rootstock-induced breadfruit dwarfing is discussed.

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