Infection of cucumber seedling roots by Pseudomonas amygdali pv. lachrymans following artificial substrate inoculation

Chilling injury can be a serious problem during field germination of sensitive crop species. Because heat shock has been shown to induce chilling tolerance of germinating cucumber seeds, an experiment was initiated to determine the effectiveness of other treatments. Cucumber seeds germinated 20 to 24 h were either heat-shocked at 50C for 2 min or treated with ABA or salicylic acid for 4 h. Following treatment, the germinated seeds were chilled at 2C for 96, 120, or 144 h and then incubated at 25C to determine growth effects on the developing root. All treatments induced chilling tolerance compared to the controls, with ABA and heat shock being most effective after chilling. There did not appear to be an additive response when heat shock was used in combination with ABA. The evidence for different treatment mechanisms will be discussed.

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The Effect of Heat Shock on the Induction of Chilling Tolerance in Cucumber Seedling Roots

HortScience ◽

10.21273/hortsci.30.4.851f ◽

1995 ◽

Vol 30 (4) ◽

pp. 851F-851 ◽

Cited By ~ 1

Author(s):

Hua Zhang ◽

Paul H. Jennings

Keyword(s):

Molecular Weight ◽

Heat Shock ◽

Protein Profile ◽

Chilling Tolerance ◽

Low Molecular Weight ◽

Cucumber Seedling ◽

Sds Page ◽

Seedling Roots ◽

Shock Proteins ◽

Heat Shock Induction

Heat shock was applied to 32-h-old cucumber seedlings before chilling at 2.5C. Two cultivars, `Poinsett 76' and `Ashley', with different chilling tolerances, were tested. Using root growth after chilling as a measure of chilling tolerance, three heat shock regimes were found to induce chilling tolerance in both cultivars, with the most effective and uniform induction by heat shock at 40C for 3 h. `Ashley', the more chilling tolerant cultivar, exhibited a greater response to heat shock induction of chilling tolerance than `Poinsett 76'. Protein samples from roots were subjected to SDS-PAGE. Three low molecular weight heat shock proteins accumulated to a greater extent in the protein profile of heat-shocked `Ashley' roots. No such increase was found in the `Poinsett 76' roots. The induction of low molecular weight HSPs are discussed in relation to the heat-shock induction of chilling tolerance.

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Involvement of HSP Synthesis and Protease Inhibitors in Heat Shock-induced Cucumber Seedling Chilling Tolerance

HortScience ◽

10.21273/hortsci.30.4.775f ◽

1995 ◽

Vol 30 (4) ◽

pp. 775F-775

Author(s):

Paul H. Jennings ◽

Ann Fitzpatrick

Keyword(s):

Protein Synthesis ◽

Heat Shock ◽

Protease Inhibitors ◽

Actinomycin D ◽

Chilling Tolerance ◽

Cucumber Seedling ◽

Shock Effect ◽

Seedling Roots ◽

Germinating Seeds ◽

Heat Shock Induction

Heat shock induction of chilling tolerance in cucumber seedlings is not blocked by inhibitors of protein synthesis. Treatment of germinating seeds with cycloheximide and actinomycin-D, prior to heat shock and chilling, does not block the heat shock induction of chilling tolerance, while the inhibitors alone promote chilling tolerance of seedling roots. To test whether the heat shock effect might be acting on proteases, two protease inhibitors (bestatin and PMSF) were tested for their ability to induce chilling tolerance. Although PMSF slowed germination, it still provided protection against chilling, but bestatin was much more effective.

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Effects of 24-Epibrassinolide on Antioxidant System in Cucumber Seedling Roots Under Hypoxia Stress

Agricultural Sciences in China ◽

10.1016/s1671-2927(07)60046-7 ◽

2007 ◽

Vol 6 (3) ◽

pp. 281-289 ◽

Cited By ~ 8

Author(s):

Yun-yan KANG ◽

Shi-rong GUO ◽

Juan LI ◽

Jiu-ju DUAN

Keyword(s):

Antioxidant System ◽

Cucumber Seedling ◽

Hypoxia Stress ◽

Seedling Roots

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Effects of di-n-butyl phthalate on the physiology and ultrastructure of cucumber seedling roots

Environmental Science and Pollution Research ◽

10.1007/s11356-014-2580-x ◽

2014 ◽

Vol 21 (10) ◽

pp. 6662-6670 ◽

Cited By ~ 13

Author(s):

Ying Zhang ◽

Yue Tao ◽

Guoqiang Sun ◽

Lei Wang

Keyword(s):

Cucumber Seedling ◽

Seedling Roots ◽

Butyl Phthalate

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Microscopic Examination of Chilling Injury Symptoms in Ethanol-treated Cucumber Seedling Roots

HortScience ◽

10.21273/hortsci.33.3.454e ◽

1998 ◽

Vol 33 (3) ◽

pp. 454e-454

Author(s):

Windy A. Boyd ◽

Paul H. Jennings

Keyword(s):

Electron Microscopy ◽

Cell Walls ◽

Chilling Injury ◽

Light And Electron Microscopy ◽

Ethanol Solution ◽

Root Tip ◽

Cucumber Seedling ◽

Cortical Cells ◽

Before And After ◽

Seedling Roots

Cucumber seedlings were germinated for 24 h at 25 °C and half were immersed in a 500 mM ethanol solution for 2 h. After rinsing, seedlings were chilled for 96 h at 2 °C. Control and ethanol-treated samples were taken for light and electron microscopy immediately before and after chilling, and after re-warming for 24 and 72 h. Preliminary experiments revealed visual chilling symptoms such as pinching of the root in a region just above the root tip. This region was excised under a microscope, fixed, and mounted for microscopic observations. The cortical cells of ethanol-treated seedlings before chilling appeared to be irregular in shape with irregular edges, and some epidermal damage was evident. Chilling caused much more epidermal damage in the control seedlings when compared to the ethanol-treated seedlings. After chilling, cortical cells in the control seedlings were observed to be irregularly shaped while those treated with ethanol had round cells. Upon re-warming, control seedlings exhibited increasing epidermal damage with broken cell walls, while ethanol-treated seedlings exhibited more differentiation in the stele.

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Effects of Chilling, Ethanol, and Heat Shock on Enzyme Expression in Cucumber Seedling Roots

HortScience ◽

10.21273/hortsci.30.4.912d ◽

1995 ◽

Vol 30 (4) ◽

pp. 912D-912

Author(s):

Windy A. Boyd ◽

Paul H. Jennings

Keyword(s):

Heat Shock ◽

Catalase Activity ◽

Chilling Tolerance ◽

Activity Levels ◽

Cucumber Seedling ◽

Enzyme Expression ◽

Cucumber Seedlings ◽

Before And After ◽

Seedling Roots ◽

Chilling Period

Chilling-sensitive cucumber seedlings that are treated with ethanol or heat-shocked have shown an increase in chilling tolerance. The mechanisms that regulate this response have not been identified. Cucumber seeds were germinated for 24 h and then treated with 500 mM ethanol for 2 h or heat-shocked at 40C for 3 h. Immediately after treatment, roots were excised and catalase activity was assayed. Another set of control and treated seeds were chilled for 72 h and catalase was assayed at the end of the chilling period. Comparisons will be presented between catalase activity levels before and after chilling, as well as between the control and treated groups. Treatments of ethanol and heat shock resulted in an increase in catalase activity when compared to controls.

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