ENHANCED TOLERANCE TO LOW TEMPERATURE IN TOBACCO (NICOTIANA TABACUML.) SPRAYED WITH A LOW-TEMPERATURE-RESISTANT AGENT

SUMMARYLow-temperature stress is an important limiting factor to tobacco growth in early spring of south China. In this study, a low-temperature-resistant agent (LTRA) was employed to examine its ameliorating effect on the inhibition of tobacco growth triggered by low-temperature stress. Results indicated that low-temperature stress of 12 °C for 6 days reduced root number and biomass of tobacco seedling by 27.4% and 24.1%, while treatment with LTRA could recover the inhibitory effect of low-temperature stress on tobacco growth significantly. The content of ascorbic acid and the activities of superoxide dismutase and catalase at low-temperature stress were 65.2%, 53.5% and 32.1% of those at normal temperature condition (26 °C), while the corresponding values with LTRA treatment were 89.2%, 88.9% and 74.2%, suggesting that LTRA treatment could enhance the activity of antioxidant enzyme and the synthesis of antioxidant compounds. Low-temperature stress increased the membrane permeability by 84.8%, while LTRA treatment recovered it by 77.4%. Furthermore, LTRA treatment contributed to increase chlorophyll synthesis and maintain the integrity of tobacco leaf structure. Effective component analysis indicated that the complex of ammonium calcium nitrate and glycine betaine was the main effective component of LTRA in maintaining membrane integrity. Its effective concentration was 1.0 g L−1. The above results suggested that LTRA could enhance the synthesis of chlorophyll, activate the activity of antioxidant enzyme, maintain the integrity of cell membrane, and thus elevate the tolerance of tobacco seedlings to low-temperature stress.

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Exogenous application of 5-aminolevulinic acid improves low-temperature stress tolerance of maize seedlings

Crop and Pasture Science ◽

10.1071/cp17401 ◽

2018 ◽

Vol 69 (6) ◽

pp. 587 ◽

Cited By ~ 6

Author(s):

Yi Wang ◽

Jing Li ◽

Wanrong Gu ◽

Qian Zhang ◽

Lixin Tian ◽

...

Keyword(s):

Enzyme Activity ◽

Low Temperature ◽

Antioxidant Enzyme ◽

Temperature Stress ◽

Aminolevulinic Acid ◽

Photosynthetic Capacity ◽

Antioxidant Enzyme Activity ◽

Low Temperature Stress ◽

Temperature Sensitive ◽

Maize Seedlings

The important plant growth regulator 5-aminolevulinic acid (ALA) could promote low-temperature stress tolerance of many plants; however, the underlying mechanisms remain to be elucidated. We investigated the effects of exogenously applied ALA on seedling morphology, antioxidant enzyme activity and photosynthetic capacity of maize (Zea mays L.) seedlings under low-temperature stress. Two cultivars, low-temperature-sensitive cv. Suiyu 13 (SY13) and low-temperature-tolerant cv. Zhengdan 958 (ZD958), were subjected to four treatments: low-temperature without ALA treatment, low-temperature after ALA treatment, normal temperature without ALA treatment, and normal temperature after ALA treatment. Plant morphological growth, proline content, antioxidant enzyme activity and photosynthetic capacity were determined. ALA treatment significantly decreased the inhibitory effects of low-temperature stress on seedling dry weight and increased proline accumulation under low temperatures in ZD958. Pre-application of ALA significantly improved superoxide dismutase and catalase activities in SY13 under low-temperature stress. Furthermore, treating maize seedlings with ALA resulted in significant enhancement of ribulose-1,5-bisphosphate (RuBP) carboxylase activity under low-temperature stress in both cultivars. Pre-treatment with ALA relieved the damage caused by low-temperature stress to maize seedlings, particularly in the low-temperature-sensitive cultivar. Therefore, ALA at appropriate concentrations may be used to prevent reductions in maize crop yield due to low-temperature stress.

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24-Epibrassinolide Ameliorates Endogenous Hormone Levels to Enhance Low-Temperature Stress Tolerance in Cucumber Seedlings

International Journal of Molecular Sciences ◽

10.3390/ijms19092497 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2497 ◽

Cited By ~ 16

Author(s):

Ali Anwar ◽

Longqiang Bai ◽

Li Miao ◽

Yumei Liu ◽

Shuzhen Li ◽

...

Keyword(s):

Gene Expression ◽

Low Temperature ◽

Antioxidant Enzyme ◽

Temperature Stress ◽

Seedling Growth ◽

Photosynthetic Capacity ◽

Low Temperature Stress ◽

Endogenous Hormones ◽

Cucumber Seedling ◽

Biosynthesis Gene

Phytohormone biosynthesis and accumulation are essential for plant growth and development and stress responses. Here, we investigated the effects of 24-epibrassinolide (EBR) on physiological and biochemical mechanisms in cucumber leaves under low-temperature stress. The cucumber seedlings were exposed to treatments as follows: NT (normal temperature, 26 °C/18 °C day/night), and three low-temperature (12 °C/8 °C day/night) treatments: CK (low-temperature stress); EBR (low-temperature and 0.1 μM EBR); and BZR (low-temperature and 4 μM BZR, a specific EBR biosynthesis inhibitor). The results indicated that low-temperature stress proportionately decreased cucumber seedling growth and the strong seedling index, chlorophyll (Chl) content, photosynthetic capacity, and antioxidant enzyme activities, while increasing reactive oxygen species (ROS) and malondialdehyde (MDA) contents, hormone levels, and EBR biosynthesis gene expression level. However, EBR treatments significantly enhanced cucumber seedling growth and the strong seedling index, chlorophyll content, photosynthetic capacity, activities of antioxidant enzymes, the cell membrane stability, and endogenous hormones, and upregulated EBR biosynthesis gene expression level, while decreasing ROS and the MDA content. Based on these results, it can be concluded that exogenous EBR regulates endogenous hormones by activating at the transcript level EBR biosynthetic genes, which increases antioxidant enzyme capacity levels and reduces the overproduction of ROS and MDA, protecting chlorophyll and photosynthetic machinery, thus improving cucumber seedling growth.

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Cold tolerance in rice plants is partially controlled by root responses

10.1101/2020.01.25.919464 ◽

2020 ◽

Author(s):

Angie Geraldine Sierra Rativa ◽

Artur Teixeira de Araújo Junior ◽

Daniele da Silva Friedrich ◽

Rodrigo Gastmann ◽

Thainá Inês Lamb ◽

...

Keyword(s):

Low Temperature ◽

Cold Tolerance ◽

Temperature Stress ◽

Cold Treatment ◽

Membrane Integrity ◽

Root Hairs ◽

Acc Oxidase ◽

Dry Weight ◽

Low Temperature Stress ◽

Cold Tolerant

AbstractRice (Oryza sativa L.) ssp. indica is the most cultivated species in the South of Brazil. However, these plants face low temperature stress from September to November, which is the period of early sowing, affecting plant development during the initial stages of growth, and reducing rice productivity. This study aimed to characterize the root response to low temperature stress during the early vegetative stage of two rice genotypes contrasting in their cold tolerance (CT, cold-tolerant; and CS, cold-sensitive). Root dry weight and length, as well as number of root hairs, were higher in CT than CS when exposed to cold treatment. Histochemical analyses indicated that roots of CS genotype present higher levels of lipid peroxidation and H2O2 accumulation, along with lower levels of plasma membrane integrity than CT under low temperature stress. RNAseq analyses revealed that the contrasting genotypes present completely different molecular responses to cold stress. The number of over-represented functional categories was lower in CT than CS under cold condition, suggesting that CS genotype is more impacted by low temperature stress than CT. Several genes might contribute to rice cold tolerance, including the ones related with cell wall remodeling, cytoskeleton and growth, signaling, antioxidant system, lipid metabolism, and stress response. On the other hand, high expression of the genes SRC2 (defense), root architecture associated 1 (growth), ACC oxidase, ethylene-responsive transcription factor, and cytokinin-O-glucosyltransferase 2 (hormone-related) seems to be related with cold sensibility. Since these two genotypes have a similar genetic background (sister lines), the differentially expressed genes found here can be considered candidate genes for cold tolerance and could be used in future biotechnological approaches aiming to increase rice tolerance to low temperature.

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Arbuscular mycorrhizal fungi alleviate low-temperature stress and increase freezing resistance as a substitute for acclimation treatment in barley

Crop and Pasture Science ◽

10.1071/cp18385 ◽

2019 ◽

Vol 70 (3) ◽

pp. 218 ◽

Cited By ~ 6

Author(s):

Roghieh Hajiboland ◽

Arshad Joudmand ◽

Nasser Aliasgharzad ◽

Roser Tolrá ◽

Charlotte Poschenrieder

Keyword(s):

Survival Rate ◽

Low Temperature ◽

Arbuscular Mycorrhizal Fungi ◽

Temperature Stress ◽

Mycorrhizal Fungi ◽

Membrane Integrity ◽

Arbuscular Mycorrhizal ◽

Climatic Conditions ◽

Low Temperature Stress ◽

Acclimation Treatment

Barley (Hordeum vulgare L.) is cultivated globally under a wide range of climatic conditions and is subjected to chilling and freezing stresses under temperate and cold climatic conditions. As a mycorrhizal crop, barley may benefit from this association for increasing cold resistance. In order to investigate the effects of inoculation with arbuscular mycorrhizal fungi (AMF) on cold-stress resistance in barley plants, one winter and one spring cultivar were grown under control (25°C day, 17°C night) and low, non-freezing (LT: 5°C day, 3°C night) temperatures for 3 weeks in the absence (−AMF) or presence (+AMF) of two species of AMF, Glomus versiforme and Rhizophagus irregularis. In addition, the influence of LT (as an acclimation treatment) was studied on plant survival after a 2-day exposure to freezing temperature (FT: −5°C in dark). Biomass production, membrane integrity and survival rate of plants indicated that the winter cultivar was more tolerant than the spring cultivar. Inoculation with AMF resulted in improved growth, photosynthesis, osmotic and water homeostasis, and potassium uptake under both control and LT conditions, whereas the effect on membrane integrity, antioxidative defence and phenolics metabolism was mainly observed in LT plants. AMF inoculation substituted partially or completely for acclimation treatment and increased the survival rate of FT plants, with the highest survival achieved in a combination of AMF and LT. Mycorrhizal responsiveness was higher in LT plants. Despite the lower AMF colonisation, G. versiforme was often more effective than R. irregularis for the alleviation of low temperature stress in both cultivars, whereas R. irregularis was more effective in increasing the survival rate. Our data suggest that the right combination of fungus species and host-plant cultivar is important for successful utilisation of AMF under cold conditions.

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