scholarly journals Metabolic and Ultrastructural Changes in Winter Wheat during Ice Encasement Under Field Conditions

1978 ◽  
Vol 61 (5) ◽  
pp. 806-811 ◽  
Author(s):  
M. Keith Pomeroy ◽  
Christopher J. Andrews
1978 ◽  
Vol 56 (7) ◽  
pp. 786-794 ◽  
Author(s):  
M. Keith Pomeroy ◽  
Chris J. Andrews

The decline in viability of cold-hardy Kharkov winter wheat (Triticum aestivum L.) seedlings during ice encasement at −1 °C was accompanied by characteristic ultrastructural changes. A dramatic increase in endoplasmic reticulum was observed within a few days. This proliferation of endoplasmic reticulum often resulted in the formation of an elaborate series of parallel membranes, either dispersed randomly throughout the cytoplasm or in the form of concentric whorls. However, the structural integrity of many cellular organelles was largely unaffected even by prolonged ice encasement resulting in death of the plants. In contrast, exposure of cold-hardy seedlings to near lethal, subfreezing temperature resulted in severe disorganization of cellular organelles. Ice encasement of nonhardened seedlings resulted in complete kill within 4 h. After 16 h ice encasement, occasional concentric whorls of endoplasmic reticulum and copious amounts of osmiophilic material were observed in the cytoplasm. Upon removal of the ice encasement stress, the accumulated endoplasmic reticulum disappeared rapidly during recovery at either2 or20 °C.


2010 ◽  
Vol 158 (12) ◽  
pp. 3539-3545 ◽  
Author(s):  
Zhaozhong Feng ◽  
Jing Pang ◽  
Isamu Nouchi ◽  
Kazuhiko Kobayashi ◽  
Takashi Yamakawa ◽  
...  

2018 ◽  
Vol 0 (1) ◽  
pp. 71-73
Author(s):  
Володимир Іванович Дубовий ◽  
Марьяна Германівна Табакаєва

1990 ◽  
Vol 70 (2) ◽  
pp. 443-454 ◽  
Author(s):  
P. RICHARD HETHERINGTON ◽  
BRYAN D. McKERSIE ◽  
LISA C. KEELER

Two winter wheat (Triticum aestivum L.) cultivars, Fredrick and Norstar, which differ in their winterhardiness potential, were compared with regard to the effects of nitrogen (N), phosphorus (P) and potassium (K) application, during acclimation, on the expression of four traits associated with winterhardiness — freezing, ice-encasement, and low temperature flooding tolerances and crown moisture content. Modified Hoagland’s nutrient solutions containing five levels of each nutrient were applied to the seedlings during a 5-wk acclimation period at 2 °C, and subsequently the crowns were tested for their ability to survive varying intensities of the stress treatments. Increasing the level of applied N from 0, caused a reduction in the level of all stress tolerances. Increased P did not significantly alter the expression of freezing tolerance, but tended to increase tolerance of the anaerobic stresses, icing and low temperature flooding, to an optimum. Increased K had minimal effects on stress tolerance at the levels tested. Increased levels of each nutrient increased crown moisture content. The cultivar Norstar was consistently more tolerant of freezing and icing stress than Fredrick and this relative ranking was not influenced by mineral nutrition. However, the relative ranking for low temperature flooding tolerance varied depending on the nutrients provided to the seedlings. The results suggest that environmental and growth regulatory factors which influence the uptake of mineral nutrients would be expected to influence crown moisture content, and the expression of stress tolerance.Key words: Freezing, ice-encasement, flooding


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