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作者 Mangrich, Mary Elizabeth
書名 Effects of abiotic shocks on the induction of chilling tolerance in seedlings
國際標準書號 0599867310
book jacket
說明 94 p
附註 Source: Dissertation Abstracts International, Volume: 61-07, Section: B, page: 3457
Adviser: Mikal E. Saltveit
Thesis (Ph.D.)--University of California, Davis, 2000
Seedlings of cotton, cucumber, okra, rice, kenaf, and wheat were exposed to chilling temperatures for 0--5 days followed by 3 days at 25°C. Radicle length was used as an indicator of the severity of chilling injury. Exposure to chilling reduced radicle elongation in all species except wheat. When seedlings were heat-shocked at 45°C for 1--12 min before being chilled, radicles of okra, kenaf, cotton, and rice seedlings elongated more than those of seedlings not heat-shocked before chilling. The method of heat-shock application and the stringency (i.e., time x temperature) of the heat-shock and chilling treatments affected the response of the tissue
Seedlings were exposed to controlled atmospheres containing different levels of oxygen or carbon dioxide prior to and during chilling at 2.5°C. Effects of the controlled atmosphere exposures on chilling response were variable. Continuous exposure to reduced oxygen during chilling had a beneficial effect only at 0.0%; there was no beneficial effect of continuous exposure to any of the carbon dioxide treatments. Additionally, chilling tolerance of cucumber seedling radicles was also not increased by continuous exposure to solutions of 50 to 200 mM ethanol during chilling
Cucumber seedlings classified with different levels of vigor (i.e., different rates of growth) did not respond significantly different to chilling stress following heat shock treatments. Chilling-induced reduction in radicle growth was linear for 1 to 3 days of chilling at ∼10% per day of treatment, but then increased substantially until subsequent radicle growth was all but eliminated by 6 days of chilling. Heat shocks increased chilling tolerance such that 4 days of chilling caused only a 36% decrease in radicle growth compared to 66% for control seedlings. Heat shocks were only able to protect that part of radicle growth that was in excess of the linear decrease in radicle growth projected from 0 to 3 days. This data indicates that there may be two effects of chilling on radicle growth. The first inhibition of subsequent growth was linear and was not affected by heat shocks. The second inhibition was much more severe, appeared after 3 days, and could be prevented by heat shock
School code: 0029
DDC
Host Item Dissertation Abstracts International 61-07B
主題 Biology, Plant Physiology
0817
Alt Author University of California, Davis
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