Physiological and Molecular Mechanisms of ABA and CaCl2 Regulating Chilling Tolerance of Cucumber Seedlings

Cold stress is a limiting factor to the growth and development of cucumber in the temperate regions; hence, improving the crop’s tolerance to low temperature is highly pertinent. The regulation of low-temperature tolerance with exogenous ABA and CaCl2 was investigated in the cucumber variety Zhongnong 26. Under low-temperature conditions (day/night 12/12 h at 5 °C), seedlings were sprayed with a single application of ABA, CaCl2, or a combination of both. Our analysis included a calculated chilling injury index, malondialdehyde (MDA) content, relative electrical conductivity, antioxidant enzyme activities (SOD, CAT, and APX), leaf tissue structure, and expression of cold-related genes by transcriptome sequencing. Compared with the water control treatment, the combined ABA + CaCl2 treatment significantly improved the superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) of the seedlings by 34.47%, 59.66%, and 118.80%, respectively (p < 0.05), and significantly reduced the chilling injury index, relative electrical conductivity, and MDA content, by 89.47%, 62.17%, and 44.55%, respectively (p < 0.05). Transcriptome analysis showed that compared with the water control treatment, 3442 genes were differentially expressed for the combined treatment, 3921 for the ABA treatment, and 1333 for the CaCl2 treatment. KEGG enrichment analysis for both the ABA and combined ABA + CaCl2 treatments (as compared to the water control) showed that it mainly involves genes of the photosynthesis pathway and metabolic pathways. Differentially expressed genes following the CaCl2 treatment were mainly involved in plant hormone signal transduction, plant–pathogen interaction, MAPK signaling pathway–plant, phenylpropanoid biosynthesis, and circadian rhythm–plant. qRT-PCR analysis and RNA-seq results showed a consistent trend in variation of differential gene expression. Overall, this study demonstrated that although all three treatments provided some protection, the combined treatment of ABA (35 mg/L) with CaCl2 (500 mg/L) afforded the best results. A combined ABA + CaCl2 treatment can effectively alleviate cold-stress damage to cucumber seedlings by inducing physiological changes in photosynthesis and metabolism, and provides a theoretical basis and technical support for the application of exogenous ABA and CaCl2 for low-temperature protection of cucumber seedlings.

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HARDENING PRETREATMENT BY DROUGHT AND LOW TEMPERATURE ENHANCED CHILLING STRESS TOLERANCE OF CUCUMBER SEEDLINGS

Acta Scientiarum Polonorum Hortorum Cultus ◽

10.24326/asphc.2019.2.4 ◽

2019 ◽

Vol 18 (2) ◽

pp. 29-37 ◽

Cited By ~ 1

Author(s):

Fardin Ghanbari ◽

Sajad Kordi

Keyword(s):

Low Temperature ◽

Chilling Stress ◽

Chilling Injury ◽

Warm Season ◽

Chilling Tolerance ◽

Limiting Factors ◽

Antioxidant Enzyme Activities ◽

Cucumber Seedlings ◽

Injury Index ◽

Randomized Design

Chilling stress is of major limiting factors influencing the growth and development of warm-season crops like cucumber. In this research, the possibility of chilling tolerance of cucumber seedlings was investigated through employing the drought and low-temperature pretreatments. The factorial experiment consisted of two factors including cucumber cultivars (i.e. ‘Super Dominos’ and ‘Super Star’) and hardening treatments (control, low temperatures at 10°C, and 15°C and drought simulated by 10% and 20% PEG) based on completely randomized design (CRD) in 3 replications. After applying treatments and providing them 48 h opportunity to be recovered, the seedlings were subjected to 3°C for a six-day period and 6 h for each day. All hardening treatments improved seedlings’ growth, chlorophyll content, total phenol (TP) and antioxidant enzyme activities, while reducing chilling injury index and malondialdehyde (MDA) content. Comparing to temperature hardening, the drought pretreatment showed to have a better effect on inducing the chilling tolerance into cultivars. Overall, the results of this experiment showed that employing drought and low-temperature pretreatments enabled cucumber seedlings to mitigate the harmful effects of chilling.

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H2O2 Functions as a Downstream Signal of IAA to Mediate H2S-Induced Chilling Tolerance in Cucumber

International Journal of Molecular Sciences ◽

10.3390/ijms222312910 ◽

2021 ◽

Vol 22 (23) ◽

pp. 12910

Author(s):

Xiaowei Zhang ◽

Yanyan Zhang ◽

Chenxiao Xu ◽

Kun Liu ◽

Huangai Bi ◽

...

Keyword(s):

Chilling Stress ◽

Chilling Injury ◽

Chilling Tolerance ◽

H2o2 Production ◽

Mrna Levels ◽

Sodium Hydrosulfide ◽

Polar Transport ◽

Cucumber Seedlings ◽

Injury Index ◽

Transport Inhibitor

Hydrogen sulfide (H2S) plays a crucial role in regulating chilling tolerance. However, the role of hydrogen peroxide (H2O2) and auxin in H2S-induced signal transduction in the chilling stress response of plants was unclear. In this study, 1.0 mM exogenous H2O2 and 75 μM indole-3-acetic acid (IAA) significantly improved the chilling tolerance of cucumber seedlings, as demonstrated by the mild plant chilling injury symptoms, lower chilling injury index (CI), electrolyte leakage (EL), and malondialdehyde content (MDA) as well as higher levels of photosynthesis and cold-responsive genes under chilling stress. IAA-induced chilling tolerance was weakened by N, N′-dimethylthiourea (DMTU, a scavenger of H2O2), but the polar transport inhibitor of IAA (1-naphthylphthalamic acid, NPA) did not affect H2O2-induced mitigation of chilling stress. IAA significantly enhanced endogenous H2O2 synthesis, but H2O2 had minimal effects on endogenous IAA content in cucumber seedlings. In addition, the H2O2 scavenger DMTU, inhibitor of H2O2 synthesis (diphenyleneiodonium chloride, DPI), and IAA polar transport inhibitor NPA reduced H2S-induced chilling tolerance. Sodium hydrosulfide (NaHS) increased H2O2 and IAA levels, flavin monooxygenase (FMO) activity, and respiratory burst oxidase homolog (RBOH1) and FMO-like protein (YUCCA2) mRNA levels in cucumber seedlings. DMTU, DPI, and NPA diminished NaHS-induced H2O2 production, but DMTU and DPI did not affect IAA levels induced by NaHS during chilling stress. Taken together, the present data indicate that H2O2 as a downstream signal of IAA mediates H2S-induced chilling tolerance in cucumber seedlings.

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Methyl jasmonate alleviates chilling injury and keeps intact pericarp structure of pomegranate during low temperature storage

Food Science and Technology International ◽

10.1177/1082013220921597 ◽

2020 ◽

Vol 27 (1) ◽

pp. 22-31

Author(s):

Lan Chen ◽

Yanfang Pan ◽

Haideng Li ◽

Xiaoyu Jia ◽

Yanli Guo ◽

...

Keyword(s):

Low Temperature ◽

Methyl Jasmonate ◽

Cell Structure ◽

Effective Means ◽

Chilling Injury ◽

Cell Membrane Permeability ◽

Total Phenol Content ◽

Injury Index ◽

Low Temperature Storage ◽

Temperature Storage

Pomegranate is a kind of fruit with low temperature sensitivity. Abnormal low temperature can easily lead to chilling injury, which negatively impacts the appearance of fruit, accelerates browning and deterioration, as well as seriously reduces the consumption quality and commodity value of pomegranate. This study was carried out to determine the effect of methyl jasmonate on chilling injury of pomegranate during low temperature storage. The result showed that methyl jasmonate treatment effectively maintained edible quality of pomegranate, suppressed the polyphenol oxidase activity and the development of chilling injury index, and inhibited the decline of total phenol content and the increase of malondialdehyde content and cell membrane permeability. In addition, methyl jasmonate could also enhance the disease resistance of fruit by increasing the content of soluble protein, and effectively maintain the integrity of epidermal cell structure and tissue structure. Overall, the conclusion of this paper is that methyl jasmonate can be used as an effective means to suppress chilling injury in postharvest storage of pomegranate.

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Comprehensive Evaluation for Cold Tolerance in Wucai (Brassica campestris L.) by the Performance Index on an Absorption Basis (PIabs)

Agronomy ◽

10.3390/agronomy9020061 ◽

2019 ◽

Vol 9 (2) ◽

pp. 61 ◽

Cited By ~ 5

Author(s):

Yun Dai ◽

Lingyun Yuan ◽

Shujiang Zhang ◽

Jie Wang ◽

Shilei Xie ◽

...

Keyword(s):

Low Temperature ◽

Cold Tolerance ◽

Performance Index ◽

Comprehensive Evaluation ◽

Chilling Injury ◽

Cell Ultrastructure ◽

Phenotypic Differences ◽

Injury Index ◽

Total Antioxidant ◽

Fluorescence Transients

Wucai is a biannual leafy vegetable that is more sensitive to cold than most Brassicaceae vegetables. Here, phenotypic differences in wucai were investigated to identify those genotypes with high cold tolerance at low temperature, which could allow their cultivation in cold climates. In all, on the basis of PIabs, 20 wucai genotypes (10 lower PIabs and 10 higher PIabs) were selected from a collection of 124 genotypes. Both W16-13 and SW-3 (higher PIabs) and the LS-6 and W15-16 (lower PIabs) were screened from the 20 wucai genotypes according to several key plant physiological traits: net photosynthetic rate, electrolyte leakage, chilling injury index, specific leaf area, malondialdehyde contents, and PIabs. To further verify the reliability of PIabs, four genotypes were grown under low temperature gradient conditions and their morphological indexes, chlorophyll content, total antioxidant capacity, fluorescence transients (OJIP transients), leaf cell ultrastructure, and gene expression were measured. These indicators strongly demonstrated that the W16-13 and SW-3, which had higher PIabs, possessed higher resistance to cold stress, while both LS-6 and W15-16 were sensitive to cold. As this study shows, the easily measured performance index, PIabs, could be applied to wucai genotypes to screen for one or more varieties characterized by higher cold tolerance.

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Change of Physiological Properties and Ion Distribution by Synergistic Effect of Ca2+ and Grafting under Salt Stress on Cucumber Seedlings

Agronomy ◽

10.3390/agronomy11050848 ◽

2021 ◽

Vol 11 (5) ◽

pp. 848

Author(s):

Xiaodong Wang ◽

Zhiqian Lan ◽

Lei Tian ◽

Jianshe Li ◽

Guankai Yang ◽

...

Keyword(s):

Salt Stress ◽

Synergistic Effect ◽

Control Treatment ◽

Stem Volume ◽

Ion Distribution ◽

Sod Activity ◽

Cucumber Seedlings ◽

Salt Damage ◽

Free Treatment ◽

Mda Content

Salinization is an important soil environmental problem, which severely restricts the sustainable production of cucumbers. Therefore, how to improve the salt tolerance of cucumbers is a global problem. Grafting improves the resistance of crops, and calcium ion (Ca2+) weakens the permeability of the plasma membrane. In this paper, grafting cucumber with NaCl-free treatment was the control treatment (CK). Under salt stress, grafting combined different concentrations of CaCl2 and non-grafted (NG) were considered as treatments. The synergistic effect of grafting and Ca2+ to relieve salt stress on cucumber seedlings was investigated. The results revealed that grafting (G), Ca2+, and their interaction significantly influenced plant growth, osmotic adjustment substances, enzyme activities, and iron distribution. Under salt stress, grafting increased the absorption of potassium ion (K+) and Ca2+ in cucumber stems and leaves, but compared with NG, it significantly reduced the accumulation of Na+ in those parts by 61.58–89.40%. Moreover, supplication suitable Ca2+ content had a similar effect. Supplemental Ca2+ promoted the shoot and root biomass. The 10 mM L−1 Ca2+ had the highest biomass, compared with CK and NG, an increase of 49.95% and 20.47%, respectively; the lowest sodium ion (Na+). The highest Ca2+ accumulation in cucumber stem and leaves was found in 10 mM L−1 Ca2+ treatment. Supplemental Ca2+ increased free proline (Pro) and decreased malondialdehyde (MDA) content during the entire salt stress period. At 11 days, compared with 0 mM L−1 Ca2+ treatment, pro content was increased by 4.70–25.31, and MDA content was decreased by 1.08–4.90 times, respectively. Superoxide dismutase (SOD) activity, relative growth rate of plant height (PH), and stem volume (SV), and K+/Na+ and K+/Ca2+ in cucumber leaves had significantly negative correlations with a salt damage score. The combination of grafting and supplemental 5–20 mM L−1 Ca2+ relieved salt damage to cucumber seedlings. The best synergistic effect was obtained with grafting and 10 mM L−1 Ca2+ treatment.

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Combined treatment of heat shock and low temperature conditioning reduces chilling injury in zucchini squash

Postharvest Biology and Technology ◽

10.1016/0925-5214(94)90008-6 ◽

1994 ◽

Vol 4 (1-2) ◽

pp. 65-73 ◽

Cited By ~ 36

Author(s):

Chien Yi Wang

Keyword(s):

Heat Shock ◽

Low Temperature ◽

Combined Treatment ◽

Chilling Injury

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Pengukusan untuk Menurunkan Gejala Chilling Injury dan Mempertahankan Mutu Buah Pisang Nipah

Jurnal Penelitian Pascapanen Pertanian ◽

10.21082/jpasca.v16n3.2019.116-122 ◽

2020 ◽

Vol 16 (3) ◽

pp. 116

Author(s):

Nurhayati Hamzah ◽

NFN Assrorudin

Keyword(s):

Low Temperature ◽

Chilling Injury ◽

Total Soluble Solid ◽

Injury Index ◽

Low Temperature Storage ◽

Climacteric Fruit ◽

Soluble Solid ◽

Index Weight ◽

Temperature Storage

Buah pisang nipah termasuk buah klimakterik yang pematangannya akan berlangsung cepat jika disimpan pada suhu ruang. Penyimpanan suhu rendah merupakan salah satu teknik memperpanjang umur simpan buah pisang namun dapat menyebabkan kerusakan berupa pencokelatan kulit buah yang dikenal sebagai salah satu gejala chilling injury. Penelitian ini bertujuan untuk mendapatkan informasi tentang pengaruh pengukusan dalam menurunkan gejala chilling injury serta mempertahankan mutu buah pisang nipah yang disimpan pada suhu rendah. Percobaan dilakukan menggunakan rancangan acak lengkap dengan empat perlakuan dan tiga ulangan. Perlakuan terdiri dari pengukusan pada suhu 42oC selama 15 menit, 48oC selama 10 menit, 100oC selama 30 detik dan tanpa pengukusan. Parameter pengamatan terdiri dari indeks chilling injury, susut bobot, kekerasan buah dan total padatan terlarut. Hasil penelitian menunjukkan perlakuan pengukusan dapat mengurangi gejala chilling injury dan dapat mempertahankan buah pisang selama 15 hari penyimpanan. Pengukusan pada suhu 100oC selama 30 detik merupakan perlakuan terbaik. Perlakuan pengukusan tidak menurunkan kandungan total padatan terlarut dan berpengaruh tidak nyata terhadap peningkatan susut bobot serta penurunan kekerasan buah pisang nipah. Steaming to Reduce the Symptoms of Chilling Injury and Maintaining Quality of Banana CV. NipahNipah banana is a kind of climacteric fruit which is the ripening can be faster if its storage at room temperature. Low temperature storage is a way to prolong shelf-life but can caused peel browning, known as chilling injury symptom. This study was aiming to get information about steaming decreased chilling injury symptom and maintaining nipah banana quality at low temperature. The experiment was arranged in a randomized complete design with 4 treatments and 3 replication. Nipah bananas were steamed at 42oC 15 minutes, 48oC 10 minutes, 100oC 30 seconds and unsteamed. Chilling injury index, weight lost, firmnes and total soluble solid were measured. The result showed that steaming treatments decreased chilling injury symptom and maintained Nipah banana until 15 days storage. Steaming on 100oC,30 seconds was more effective to alleviate chilling injury symptom than others. No significant effect were found on weight loss, firmness and total soluble solid.

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Commercial growth regulator has adverse effect over soybean seedlings under different cadmium levels

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2020181-15930 ◽

2020 ◽

Vol 18 (1) ◽

pp. e0301

Author(s):

Guilherme S. Francischini ◽

Hélida R. Sala ◽

Inaê Braga-Reis ◽

Adriana Lima-Moro ◽

Suzana C. Bertoli

Keyword(s):

Plant Growth ◽

Growth Regulator ◽

Control Treatment ◽

Enzymatic Antioxidants ◽

Water Control ◽

Exogenous Application ◽

Soybean Seedlings ◽

Mda Content ◽

Metabolic Activities ◽

Stressful Environments

Aim of study: Soils contaminated by heavy metals, such as cadmium, may reduce plant development. Exogenous application of plant growth regulators (PGR), are used for optimizing the crops production in stressful environments. The aim of this study was to evaluate the effects of Cd concentrations on the development of soybean seedlings under exogenous application of a commercial PGR.Area of study: Presidente Prudente, São Paulo, Brazil.Material and methods: Soybean seeds were pre-treated in distilled water (control treatment) and in solution with plant growth regulator (PGR treatment) and then germinated with distillated water. The germinated seeds were transferred to different levels of Cd (0, 100, 500 and 900 mg of Cd).Main results: Cd exposure at increasing concentrations, decreased root development, (area, length and volume of roots) and activity of enzymatic antioxidants (SOD, CAT and APX) and enhanced MDA. These responses were accentuated by the PGR exposition. The root morphology and activity of antioxidant enzymes presented "hormesis" responses until 500 mg L-1 of Cd, and the proline content may have played a fundamental role in the maintenance of metabolic activities and biomass.Research highlights: The results indicate that the use of PGR intensified the toxicity responses caused by exposure to increased Cd level. In addition, stress indicators such as MDA content and antioxidant activity in different organs (root and shoot) of soybean seedlings, responded differently according with the use of PGR under exposure of Cd.

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