scholarly journals Mechanisms of tolerance differences in cucumber seedlings grafted on rootstocks with different tolerance to low temperature and weak light stresses

2015 ◽  
Vol 39 ◽  
pp. 606-614 ◽  
Author(s):  
Yan LI ◽  
Xuemei TIAN ◽  
Min WEI ◽  
Qinghua SHI ◽  
Fengjuan YANG ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cucumber Seedlings ◽  
Weak Light

scholarly journals Substrate Application of 5-Aminolevulinic Acid Enhanced Low-temperature and Weak-light Stress Tolerance in Cucumber (Cucumis sativus L.)

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 472 ◽  
Author(s):  
Ali Anwar ◽  
Jun Wang ◽  
Xianchang Yu ◽  
Chaoxing He ◽  
Yansu Li
Keyword(s):  
Low Temperature ◽  
Stress Tolerance ◽  
Antioxidant Enzyme ◽  
Aminolevulinic Acid ◽  
Light Stress ◽  
Photochemical Quenching ◽  
Antioxidant Enzyme Activities ◽  
Cucumber Seedlings ◽  
Chl A ◽  
Weak Light

5-Aminolevulinic acid (ALA) is a type of nonprotein amino acid that promotes plant stress tolerance. However, the underlying physiological and biochemical mechanisms are not fully understood. We investigated the role of ALA in low-temperature and weak-light stress tolerance in cucumber seedlings. Seedlings grown in different ALA treatments (0, 10, 20, or 30 mg ALA·kg−1 added to substrate) were exposed to low temperature (16/8 ˚C light/dark) and weak light (180 μmol·m−2·s−1 photosynthetically active radiation) for two weeks. Treatment with ALA significantly alleviated the inhibition of plant growth, and enhanced leaf area, and fresh and dry weight of the seedlings under low-temperature and weak-light stress. Moreover, ALA increased chlorophyll (Chl) a, Chl b, and Chl a+b contents. Net photosynthesis rate, stomatal conductance, transpiration rate, photochemical quenching, non-photochemical quenching, actual photochemical efficiency of photosystem II, and electron transport rate were significantly increased in ALA-treated seedlings. In addition, ALA increased root activity and antioxidant enzyme (superoxide dismutase, peroxidase, and catalase) activities, and reduced reactive oxygen species (hydrogen peroxide and superoxide radical) and malondialdehyde accumulation in the root and leaf of cucumber seedlings. These findings suggested that ALA incorporation in the substrate alleviated the adverse effects of low-temperature and weak-light stress, and improved Chl contents, photosynthetic capacity, and antioxidant enzyme activities, and thus enhanced cucumber seedling growth.

scholarly journals Adaptation of cucumber seedlings to low temperature stress by reducing nitrate to ammonium during it’s transportation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yumei Liu ◽  
Longqiang Bai ◽  
Mintao Sun ◽  
Jun Wang ◽  
Shuzhen Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Stress ◽  
Root Hair ◽  
N Uptake ◽  
Low Temperature Stress ◽  
Shoot Tip ◽  
Lateral Vein ◽  
Vascular Bundles ◽  
Flux Rate ◽  
Cucumber Seedlings

Abstract Background Low temperature severely depresses the uptake, translocation from the root to the shoot, and metabolism of nitrate and ammonium in thermophilic plants such as cucumber (Cucumis sativus). Plant growth is inhibited accordingly. However, the availability of information on the effects of low temperature on nitrogen transport remains limited. Results Using non-invasive micro-test technology, the net nitrate (NO3−) and ammonium (NH4+) fluxes in the root hair zone and vascular bundles of the primary root, stem, petiole, midrib, lateral vein, and shoot tip of cucumber seedlings under normal temperature (NT; 26 °C) and low temperature (LT; 8 °C) treatment were analyzed. Under LT treatment, the net NO3− flux rate in the root hair zone and vascular bundles of cucumber seedlings decreased, whereas the net NH4+ flux rate in vascular bundles of the midrib, lateral vein, and shoot tip increased. Accordingly, the relative expression of CsNRT1.4a in the petiole and midrib was down-regulated, whereas the expression of CsAMT1.2a–1.2c in the midrib was up-regulated. The results of 15N isotope tracing showed that NO3−-N and NH4+-N uptake of the seedlings under LT treatment decreased significantly compared with that under NT treatment, and the concentration and proportion of both NO3−-N and NH4+-N distributed in the shoot decreased. Under LT treatment, the actual nitrate reductase activity (NRAact) in the root did not change significantly, whereas NRAact in the stem and petiole increased by 113.2 and 96.2%, respectively. Conclusions The higher net NH4+ flux rate in leaves and young tissues may reflect the higher NRAact in the stem and petiole, which may result in a higher proportion of NO3− being reduced to NH4+ during the upward transportation of NO3−. The results contribute to an improved understanding of the mechanism of changes in nitrate transportation in plants in response to low-temperature stress.

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

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2746
Author(s):  
Qian Feng ◽  
Sen Yang ◽  
Yijia Wang ◽  
Lu Lu ◽  
Mintao Sun ◽  
...  
Keyword(s):  
Low Temperature ◽  
Combined Treatment ◽  
Chilling Injury ◽  
Control Treatment ◽  
Water Control ◽  
Cucumber Seedlings ◽  
Injury Index ◽  
Mda Content ◽  
Cacl2 Treatment ◽  
Relative Electrical Conductivity

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.

Photoconductivity of InN grown by MOVPE: Low temperature and weak light illumination

2017 ◽  
Vol 110 (4) ◽  
pp. 042104 ◽  
Author(s):  
Ting-Ting Kang ◽  
Yuhui Zhang ◽  
Ping-Ping Chen ◽  
ZhiHai Wang ◽  
Akio Yamamoto
Keyword(s):  
Low Temperature ◽  
Light Illumination ◽  
Weak Light

ROOTSTOCK SCREENING FOR TOLERANCE TO LOW TEMPERATURE, WEAK LIGHT AND SALT STRESS IN CUCUMBER

2015 ◽  
pp. 167-176 ◽  
Author(s):  
Y. Li ◽  
X.M. Tian ◽  
M. Wei ◽  
X.F. Wang ◽  
Q.H. Shi ◽  
...  
Keyword(s):  
Salt Stress ◽  
Low Temperature ◽  
Weak Light

scholarly journals Adaptation of Cucumber Seedlings to Low Temperature Stress by Reducing Nitrate to Ammonium During It’s Transportation

2020 ◽  
Author(s):  
Yumei Liu ◽  
Longqiang Bai ◽  
Jun Wang ◽  
Mintao Sun ◽  
Shuzhen Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Root Hair ◽  
Reductase Activity ◽  
N Uptake ◽  
Vascular Bundles ◽  
Nitrogen Transport ◽  
Flux Rate ◽  
Cucumber Seedlings ◽  
Non Invasive ◽  
Test Technology

Abstract Background: Low temperature seriously depressed the uptake, translocation from root to shoot and metabolism of nitrate and ammonium in thermophilic plants such as cucumber, and the growth of plant was inhibited accordingly. However, there was no breakthrough in the effect of low temperature on nitrogen transport over the years. Results: By using the non-invasive micro-test technology the net NO3- and NH4+ fluxes rate in root hair zone and vascular bundles of main root, stem, petiole, midrib, lateral vein, and shoot tip of cucumber seedlings under normal temperature (NT) and low temperature (LT) treatment were tested, respectively. Under LT treatment, the net NO3- flux rate in root hair zone and vascular bundles of cucumber seedlings decreased, while the net NH4+ flux rate in vascular bundles of midribs, lateral veins and shoot tips increased. In accordance with this, the relative expression of CsNRT1.4a in petioles and midribs was down-regulated, while the expressions of CsAMT1.2a~1.2c in midribs were up-regulated. The results of 15N isotope tracing showed that compared with NT treatment, NO3--N and NH4+-N uptake of the seedlings under LT treatment decreased 78.1% and 58.8%, respectively, and the concentration and proportion of both NO3--N and NH4+-N distributed in the shoot decreased. Under LT treatment, the actual nitrate reductase activity (NRAact) in roots didn’t change significantly, while NRAact in stems and petioles of LT treatment increased by 113.2% and 96.2%, respectively.Conclusion: In summary, the higher net NH4+ flux rate in leaves and young tissues may be due to the higher NRact in stems and petioles, which could reduce more NO3- to NH4+ so as to reduce the energy consumption in nitrogen transportation under low temperature.

scholarly journals Responses of the Hybrid between Sphagneticola trilobata and Sphagneticola calendulacea to Low Temperature and Weak Light Characteristic in South China

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Zhongyu Sun ◽  
Yanqiao Chen ◽  
Valentin Schaefer ◽  
Huimiao Liang ◽  
Weihua Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
South China ◽  
Weak Light ◽  
Sphagneticola Calendulacea
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