Effect of low-temperature hardening on activities of proteolytic enzymes and their inhibitors in the leaves of wheat and 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.

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Ultrastructural Changes in Chloroplasts of Cucumis sativus L. and Secale cereale L. during Low-Temperature Hardening

Russian Journal of Plant Physiology ◽

10.1134/s1021443721040130 ◽

2021 ◽

Vol 68 (4) ◽

pp. 678-687

Author(s):

V. N. Popov ◽

N. V. Astakhova

Keyword(s):

Low Temperature ◽

Cucumis Sativus ◽

Secale Cereale ◽

Ultrastructural Changes ◽

Cucumis Sativus L ◽

Secale Cereale L ◽

Temperature Hardening

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Activities of Hydrogen Peroxide-Scavenging Enzymes during Low-Temperature Hardening of Potato Plants Transformed by the desA Gene of Δ12-Acyl-Lipid Desaturase

Russian Journal of Plant Physiology ◽

10.1134/s1021443718040064 ◽

2018 ◽

Vol 65 (5) ◽

pp. 667-673 ◽

Cited By ~ 1

Author(s):

N. V. Naraikina ◽

M. S. Sin’kevich ◽

A. N. Deryabin ◽

T. I. Trunova

Keyword(s):

Hydrogen Peroxide ◽

Low Temperature ◽

Potato Plants ◽

Acyl Lipid ◽

Temperature Hardening ◽

Scavenging Enzymes ◽

Desa Gene

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A STUDY OF LOW TEMPERATURE HARDENING ON THIN FILM ASPHALT BINDER IN CONTACT WITH AGGREGATE SURFACE

Petroleum Science and Technology ◽

10.1080/10916469808949816 ◽

1998 ◽

Vol 16 (7-8) ◽

pp. 869-902

Author(s):

Shin-Che Huang ◽

Raymond E. Robertson ◽

John F. McKay ◽

Jan F. Branthaver

Keyword(s):

Thin Film ◽

Low Temperature ◽

Asphalt Binder ◽

Temperature Hardening

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STATUS OF THE RADAPPERTIZATION OF MEATS1

Journal of Milk and Food Technology ◽

10.4315/0022-2747-37.2.86 ◽

1974 ◽

Vol 37 (2) ◽

pp. 86-93 ◽

Cited By ~ 2

Author(s):

D. B. Rowley ◽

Abe Anellis ◽

E. Wierbicki ◽

A. W. Baker

Keyword(s):

Sodium Chloride ◽

Low Temperature ◽

Proteolytic Enzymes ◽

Model Systems ◽

Human Consumption ◽

Cured Meats ◽

Radiation Resistant ◽

Animal Feeding ◽

Resistant Strains ◽

Microbiological Data

Considerable progress has been made toward development of highly acceptable radappertized meats through application of a heat treatment to an internal temperature of 65–80 C to inactivate proteolytic enzymes before irradiation, low temperature (−30 ± 10 C) of the food during irradiation, and addition of low levels of tripolyphosphate and sodium chloride. To assure that radappertized meats are free of potential pathogens and spoilage microorganisms they are given a minimum radiation dose (MRD) computed to effect a 12 log cycle reduction in the most radiation resistant strains of Clostridium botulinum spores. Inoculated pack studies are carried out to obtain the specific microbiological data required for computing the MRD. Cured meats normally have a lower MRD than uncured meats. In model systems concentrations of sodium chloride (NaCl) up to 4.0% (w/v) present during irradiation had no effect on radiation resistance, but NaCl did inhibit recovery of irradiated spores. A mixture of salts (4.0% NaCl, 30 ppm NaNO2 500 ppm NaNO3) had essentially the same effect as NaCl alone. Of 11 genera of vegetative cells examined, Micrococcs radiodurans and Streptococcus faecium were shown to be the most resistant to low-temperature gamma irradiation. Before the radappertization process can be established commercially it is necessary to provide proof that products so treated are safe for human consumption. An intensive animal feeding study of radappertized (4.7–7.1 Mrads) beef was initiated in 1971 and is expected to be completed in 1976.

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