Enzyme activity in the micropylar region of Melanoxylon brauna Schott seeds during germination under heat stress conditions

Abstract: Recent studies indicate that global temperatures will rise substantially in the 21st century, leading to the extinction of several plant species, as plant metabolism and germination are greatly affected by temperature. Melanoxylon brauna, a tree species native to the Atlantic Forest that occurs from northeastern to southeastern Brazil, is one of the many species threatened by global warming. Despite the economic and ecological importance of M. brauna, studies investigating the influence of heat stress on seed germination and biochemical responses are still incipient. This study aimed to evaluate enzyme activity in the micropylar region of M. brauna seeds during germination under heat stress conditions. Endo-β-mannanase, α-galactosidase, polygalacturonase, pectin methylesterase, pectin lyase, total cellulase, 1,3-β-glucosidase, and 1,4-β-glucosidase activities were determined in micropyles of seeds imbibed for 24, 48 and 72 h at 25, 35 and 45 °C. Seed germination was highest at 25 °C. Endo-β-mannanase activity was not detected under any of the experimental conditions, but imbibition temperature had a significant effect on the activity of all other enzymes.

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PSI-14 Feeding β-agonists under heat stress conditions in feedlot cattle

Journal of Animal Science ◽

10.1093/jas/skaa278.479 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 266-266

Author(s):

Pablo C Grijalva ◽

Rachel Reith ◽

Renae L Sieck ◽

Rebecca Swanson ◽

Ty B Schmidt ◽

...

Keyword(s):

Heat Stress ◽

Dry Matter ◽

Feedlot Cattle ◽

Stress Conditions ◽

Dry Matter Intake ◽

Environment Interaction ◽

Experimental Conditions ◽

Feedlot Steers ◽

Zilpaterol Hydrochloride ◽

Red Angus

Abstract Red Angus steers (n = 24; 260 ± 25 kg) were used to analyze the effects of supplementation of zilpaterol hydrochloride (ZH) under heat stress conditions on respiration rate (RR), rectal temperature (RT), growth performance (GP), and carcass traits (CT). Steers were randomly assigned to a 2 x 2 factorial treatment arrangement (n = 6/group) with factors including heat stress (HS; THI=71 to 83) or thermal neutral (TN; THI=27 to 39) conditions and with/without supplementation of ZH (0 or 8.38 mg/kg/d on 88% DM basis). Steers were provided 9 d to acclimate to tie stalls rooms under TN conditions before starting the study. TN steers were pair-fed to the average daily dry matter intake (DMI) of HS steers. Ad libitum water consumption (WC) was recorded daily. HS and TN steers were harvested on d 22 and 23, respectively. By design, DMI was not different between environments (P = 0.43). DMI also did not differ between supplement groups (P = 0.31). RT, RR, and WC were greater (P < 0.01) in HS steers compared to TN steers. There was a supplement by environment interaction (P = 0.02) for RT, as HS steers fed ZH had lower RT than HS control steers (39.1 vs 39.5 ℃). ADG was 20% higher (P = 0.04) in HS steers compared to TN steers. CT did not differ (P = >0.05) due to environment, treatment, or interactions between environment and ZH supplementation. Our results suggest that feedlot steers under our experimental conditions display some sensitivity to HS through GP, RR, and RT, however, this did not translate to an impact on CT. Furthermore, ZH supplementation under HS conditions appears to impact thermoregulatory responses positively, yet this did not impact GP or CT.

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The effect of heat stress on quinoa (cv. Titicaca) under controlled climatic conditions

The Journal of Agricultural Science ◽

10.1017/s0021859620000556 ◽

2020 ◽

Vol 158 (4) ◽

pp. 255-261

Author(s):

Jorge Alvar-Beltrán ◽

Leonardo Verdi ◽

Anna Dalla Marta ◽

Abdalla Dao ◽

Roberto Vivoli ◽

...

Keyword(s):

Heat Stress ◽

Seed Germination ◽

Seed Yield ◽

Abiotic Stresses ◽

Chenopodium Quinoa ◽

Heavy Precipitation ◽

Germination Percentage ◽

Climatic Conditions ◽

Stress Conditions ◽

African Region

AbstractQuinoa (Chenopodium quinoa Willd.) is capable of adapting to multiple environments and tolerating abiotic stresses including saline, drought and frost stress conditions. However, the introduction of quinoa into new environments has disclosed adaptation challenges. The principle factor affecting crop pollination is heat stress at flowering, which leads to sterile plants. To investigate the effect of high temperatures during the sensitive phenological phases, flowering and seed germination, a Danish-bred cultivar (cv. Titicaca) was grown in climatic chambers. Selection of the cv. Titicaca was based on the fact that it is the most extensively used cultivar in the Sahel and Middle East and North African region. The results of this research demonstrated that temperatures exceeding 38 °C hindered seed germination and pollination, and therefore, seed yield at harvest. At 38 °C, seed yield losses were 30%, whilst seed germination percentage declined below 50%. In addition, the results of the present research were compared with field observations from Burkina Faso in order to determine the spatiotemporal suitability of this crop with respect to temperature stress. Although many other abiotic stresses need to be considered when defining crop calendars (e.g. heavy precipitation in July and August), this research proposes the following growing periods to avoid heat-stress conditions at flowering: Sahel (July–September and November–February), Soudano–Sahel (June–February) and Soudanian zone (all year round).

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Endo-β-mannanase Activity in Tomato and Other Ripening Fruits

HortScience ◽

10.21273/hortsci.36.1.72 ◽

2001 ◽

Vol 36 (1) ◽

pp. 72-75 ◽

Cited By ~ 10

Author(s):

Richard Bourgault ◽

J. Derek Bewley ◽

Aurelia Alberici ◽

Delphine Decker

Keyword(s):

Molecular Weight ◽

Enzyme Activity ◽

Lycopersicon Esculentum ◽

Protease Inhibitor ◽

Cucumis Melo ◽

Citrullus Lanatus ◽

High Salt ◽

Tomato Seed ◽

Mannanase Activity ◽

The Many

High amounts of endo-β-mannanase (EC 3.2.1.78) activity were extracted from tomato (Lycopersicon esculentum Mill.) fruits when a high-salt-containing buffer was used. Two pI forms of the fruit enzyme were identified, one being much more basic than the many seed isoforms. The number of isoforms increased if a protease inhibitor was not used during extraction. The enzyme was found in the ripe fruits of many other species, and was particularly active in those of muskmelon (Cucumis melo L. Cantalupensis Group) and watermelon [Citrullus lanatus (Thunb.) Matsum. and Nak.]. In most fruits, enzyme activity was localized in the skin and the epidermal and subepidermal regions. The enzyme in several fruits had a molecular weight of ≈40,000 and reacted immunologically with the tomato seed endo-β-mannanase antibody.

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Cytosolic HSC70s repress heat stress tolerance and enhance seed germination under salt stress conditions

Plant Cell & Environment ◽

10.1111/pce.14009 ◽

2021 ◽

Author(s):

Huimei Zhao ◽

Asad Jan ◽

Naohiko Ohama ◽

Satoshi Kidokoro ◽

Fumiyuki Soma ◽

...

Keyword(s):

Salt Stress ◽

Heat Stress ◽

Seed Germination ◽

Stress Tolerance ◽

Stress Conditions ◽

Heat Stress Tolerance

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The Arabidopsis Phytocystatin AtCYS5 Enhances Seed Germination and Seedling Growth under Heat Stress Conditions

Molecules and Cells ◽

10.14348/molcells.2017.0075 ◽

2017 ◽

Vol 40 (8) ◽

pp. 577-586 ◽

Cited By ~ 7

Author(s):

Chieun Song ◽

Taeyoon Kim ◽

Woo Sik Chung ◽

Chae Oh Lim

Keyword(s):

Heat Stress ◽

Seed Germination ◽

Seedling Growth ◽

Stress Conditions

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Exploring Morpho-Physiological Variation for Heat Stress Tolerance in Tomato

Plants ◽

10.3390/plants10020347 ◽

2021 ◽

Vol 10 (2) ◽

pp. 347

Author(s):

Samikshya Bhattarai ◽

Joshua Harvey ◽

Desire Djidonou ◽

Daniel Leskovar

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Open Field ◽

Electrolyte Leakage ◽

Leaf Gas Exchange ◽

Total Yield ◽

Stress Conditions ◽

Heat Injury ◽

Injury Index ◽

Heat Tolerant

Texas tomato production is vulnerable to extreme heat in the spring-summer cropping period, which is exacerbated by the lack of superior genetic materials that can perform well in such environments. There is a dire need for selecting superior varieties that can adapt to warm environments and exhibit high yield stability under heat stress conditions. This research aimed at identifying heat-tolerant varieties under heat-stress conditions in controlled and open-field environments and was carried out in three stages. For the first experiment, 43 varieties were screened based on yield responses in natural open-field environment. From those, 18 varieties were chosen and exposed to control (greenhouse: 26/20 °C) and constant heat-stress (growth-chamber: 34/24 °C) conditions for three months. Measurements were done for chlorophyll fluorescence, chlorophyll content (SPAD), plant height, stem diameter and heat injury index (HII). The last experiment was conducted in an open field with a pool of varieties selected from the first and second experiments. Leaf gas exchange, leaf temperature, chlorophyll fluorescence, SPAD value, electrolyte leakage, heat injury index and yield were assessed. From the combined studies, we concluded that heat-tolerant genotypes selected by using chlorophyll fluorescence and HII in controlled heat-stress conditions also exhibited heat-tolerance in open-field environments. Electrolyte leakage and HII best distinguished tomato varieties in open-field environments as plants with low electrolyte leakage and HII had higher total yield. 'Heat Master,' 'New Girl,' 'HM-1823,' 'Rally,' 'Valley Girl,' 'Celebrity,' and 'Tribeca' were identified as high heat-tolerant varieties. Through trait correlation analysis we provide a better understanding of which traits could be useful for screening and breeding other heat-tolerant tomato varieties.

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