Effects of High Temperature on Roots of Etiolated Maize Seedlings: Photosynthetic Activity and Chloroplast Ultra-Structure

1984 ◽  
pp. 271-274
Author(s):  
Marleen Caers ◽  
J. C. Vendrig
Keyword(s):  
High Temperature ◽  
Photosynthetic Activity ◽  
Maize Seedlings ◽  
Ultra Structure

scholarly journals Effects of temperature on the behaviour and metabolism of an intertidal foraminifera and consequences for benthic ecosystem functioning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noémie Deldicq ◽  
Dewi Langlet ◽  
Camille Delaeter ◽  
Grégory Beaugrand ◽  
Laurent Seuront ◽  
...  
Keyword(s):  
High Temperature ◽  
Ecosystem Functioning ◽  
Photosynthetic Activity ◽  
Species Traits ◽  
Biogeochemical Cycles ◽  
Variable Environment ◽  
Sediment Reworking ◽  
Temperature Regimes ◽  
Slow Moving ◽  
Effects Of Temperature

AbstractHeatwaves have increased in intensity, duration and frequency over the last decades due to climate change. Intertidal species, living in a highly variable environment, are likely to be exposed to such heatwaves since they can be emerged for more than 6 h during a tidal cycle. Little is known, however, on how temperature affects species traits (e.g. locomotion and behaviour) of slow-moving organisms such as benthic foraminifera (single-celled protists), which abound in marine sediments. Here, we examine how temperature influences motion-behaviour and metabolic traits of the dominant temperate foraminifera Haynesina germanica by exposing individuals to usual (6, 12, 18, 24, 30 °C) and extreme (high; i.e. 32, 34, 36 °C) temperature regimes. Our results show that individuals reduced their activity by up to 80% under high temperature regimes whereas they remained active under the temperatures they usually experience in the field. When exposed to a hyper-thermic stress (i.e. 36 °C), all individuals remained burrowed and the photosynthetic activity of their sequestered chloroplasts significantly decreased. Recovery experiments subsequently revealed that individuals initially exposed to a high thermal regime partially recovered when the hyper-thermic stress ceased. H. germanica contribution to surface sediment reworking substantially diminished from 10 mm3 indiv−1 day−1 (usual temperature) to 0 mm3 indiv−1 day−1 when individuals were exposed to high temperature regimes (i.e. above 32 °C). Given their role in sediment reworking and organic matter remineralisation, our results suggest that heatwaves may have profound long-lasting effects on the functioning of intertidal muddy ecosystems and some key biogeochemical cycles.

Stress memory gene FaHSP17.8-CII controls thermotolerance via remodeling PSII and ROS signaling in tall fescue

2021 ◽  
Author(s):  
Aoyue Bi ◽  
Tao Wang ◽  
Guangyang Wang ◽  
Liang Zhang ◽  
Misganaw Wassie ◽  
...  
Keyword(s):  
High Temperature ◽  
Tall Fescue ◽  
Limiting Factor ◽  
Cool Season ◽  
Stress Memory ◽  
Memory Response ◽  
Ultra Structure ◽  
Psii Activity ◽  
Ros Accumulation ◽  
Transcriptional Memory

Abstract High-temperature is the most limiting factor in the growth of cool-season turfgrass. To cope with high-temperature stress, grass often adopt a memory response by remembering one past recurring stress and preparing a quicker and more robust reaction to the next stress exposure. However, little is known about how stress memory genes regulate the thermomemory response in cool-season turfgrass. Here, we characterized a transcriptional memory gene, Fa-heat shock protein 17.8 Class II (FaHSP17.8-CII) in a cool-season turfgrass species, tall fescue (Festuca arundinacea Schreb.). The thermomemory of FaHSP17.8-CII continued for more than four days and was associated with a high H3K4me3 level in tall fescue under heat stress (HS). Furthermore, heat acclimation or priming (ACC)-induced reactive oxygen species (ROS) accumulation and photosystem II (PSII) electron transport were memorable, and this memory response was controlled by FaHSP17.8-CII. In the fahsp17.8-CII mutant generated using CRISPR/Cas9, ACC+HS did not substantially block the ROS accumulation, the degeneration of chloroplast ultra-structure and the inhibition of PSII activity compared to HS alone. However, overexpression of FaHSP17.8-CII in tall fescue reduced ROS accumulation and chloroplast ultra-structure damage, and improved chlorophyll content and PSII activity under ACC+HS compared with that HS alone. These findings unveil a FaHSP17.8-CII–PSII-ROS module regulating transcriptional memory to enhance thermotolerance in cool-season turfgrass.

scholarly journals GROWTH OF MAIZE SEEDLINGS AS AFFECTED BY GLUCOKININ AND INSULIN

1924 ◽  
Vol 6 (6) ◽  
pp. 653-670 ◽  
Author(s):  
W. H. Eyster ◽  
M. M. Ellis
Keyword(s):  
Root Growth ◽  
Photosynthetic Activity ◽  
Strong Solutions ◽  
The Other ◽  
Distilled Water ◽  
Maize Seedlings ◽  
Efficient Utilization ◽  
Primary Roots ◽  
Growth Promoting ◽  
Growth Of Seedlings

1. Solutions of glucokinin and insulin, particularly those from which the easily dialyzable substances had been removed, increased the growth of roots and tops of young maize seedlings, as shown by comparisons with untreated seedlings grown in distilled water. 2. Strong solutions of crude glucokinin or of crude insulin repressed growth. 3. Seedlings from which the tips of the primary roots had been removed just before placing the plants in the test solutions made greater gains in both top growth and root growth than seedlings with uncut roots treated with solutions of the same strength. Control experiments showed that this difference in growth was not the result of cutting the roots, and that crude glucokinin and crude insulin contained several substances some of which were more readily absorbed by the plant than others. 4. Purification of crude glucokinin and crude insulin by dialysis showed that the residue of relatively non-dialyzable substance was the growth-promoting fraction. 5. The dialysate of crude glucokinin contained at least three types of material, one of which repressed growth. 6. Ammonium sulfate, one of the possible impurities of glucokinin, repressed the growth of seedlings but did not produce the other changes in metabolism shown by seedlings treated with dialysate of onion glucokinin. 7. The endosperm of plants treated with growth-promoting solutions of purified insulin did not lose weight as rapidly as the endosperms of untreated plants, indicating that the treated plants made their greater gains in growth by more efficient utilization of the endosperm, or as a result of greater photosynthetic activity, or by a combination of these. 8. Experiments with albino seedlings suggested that the greater gain in weight made by plants treated with insulin was the result in part of increased photosynthetic activity.

High temperature effects on photosynthetic activity of two tomato cultivars with different heat susceptibility

2005 ◽  
Vol 162 (3) ◽  
pp. 281-289 ◽  
Author(s):  
Daymi Camejo ◽  
Pedro Rodríguez ◽  
Mª Angeles Morales ◽  
José Miguel Dell’Amico ◽  
Arturo Torrecillas ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Effects ◽  
Photosynthetic Activity ◽  
Tomato Cultivars

scholarly journals Efficacy of Root Zone Temperature Increase in Root and Shoot Development and Hormone Changes in Different Maize Genotypes

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 477
Author(s):  
Zhenqing Xia ◽  
Guixin Zhang ◽  
Shibo Zhang ◽  
Qi Wang ◽  
Yafang Fu ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
Root Zone ◽  
High Temperature Stress ◽  
Maize Seedling ◽  
Maize Seedlings ◽  
Adaptive Traits ◽  
Root Zone Temperature ◽  
Maize Type ◽  
Zone Temperature

In the context of global warming, the effects of warming in the root zone of crops on maize seedling characteristics deserve research attention. Previous studies on the adaptive traits of dryland maize have mainly focused on soil moisture and nutrients, rather than analyzing potential factors for the adaptive traits of root zone warming. This study was conducted to investigate the effects of different root zone warming ranges on the agronomic traits, hormones, and microstructures of maize seedling roots and leaves. The results showed that minor increases in the root zone temperature significantly enhanced maize seedling growth. However, when the temperature in the root zone was excessive, the stem diameter, root surface area, root volume, total root length, dry matter accumulation, and root/shoot biomass of maize seedlings sharply decreased. Under high temperature stress in the root zone, the root conduit area; root stele diameter; root content of trans-zeatin (ZT), gibberellin A3 (GA3), and indoleacetic acid (IAA); leaf thickness; upper and lower epidermis thickness; and leaf content of ZT and GA3 were significantly decreased. The hormone content and microstructure changes might be an important reason for root growth maldevelopment and nutrient absorption blockage, and they also affected the leaf growth of maize seedlings. Compared with the ‘senescent’ maize type Shaandan 902 (SD902), the plant microstructure of the ‘stay-green’ maize type Shaandan 609 (SD609) was less affected by increased temperatures, and the ability of the root system to absorb and transport water was stronger, which might explain its tolerance of high temperature stress in the root zone.

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