Spring frost can severely damage or even kill rapeseed/canola(Brassica napus L.) seedlings. A protocol for large scale screening of rapeseed germplasm under frost-simulating conditions has not yet been developed. Acco...Spring frost can severely damage or even kill rapeseed/canola(Brassica napus L.) seedlings. A protocol for large scale screening of rapeseed germplasm under frost-simulating conditions has not yet been developed. Accordingly, the present study was conducted to develop a protocol for screening rapeseed germplasm under artificial frost-simulation conditions in a plant growth chamber and in a greenhouse. Nine rapeseed varieties, including three commercial hybrids, three spring types, and three winter types were used. Cold acclimation at 4 °C was applied for 0, 7, or 14 days to two-week old seedlings. The seedlings were treated with four freezing temperatures(- 4 °C,- 8 °C,- 12 °C, and- 16 °C). The length of the freezing period was 16 h, including the ramping of temperature down from 4 °C and up from the respective freezing temperature to 4 °C. Plants were allowed to recover at 4 °C for24 h before they were moved back to the greenhouse. Frost damage was scored on a 0–5scale, where 0 denotes completely dead and 5 denotes no damage. Seedling survival from the freezing treatment increased from the non-acclimation to the cold acclimation treatment. However, no significant differences(P < 0.05) were found between 7 and14 days of acclimation. Frost treatment at- 4 °C resulted in significant differences in seedling damage relative to the other three temperatures, with the- 16 °C treatment resulting in the highest overall seedling damage. Significant differences were found between the spring type and the other two types(hybrid and winter). However, no significant differences were found between the hybrid and winter types. The suggested protocol for the assessment of frost tolerance is acclimation of two-week old seedlings for7 days at 4 °C followed by frost treatment at- 4 °C for 16 h.展开更多
This paper set up a series of comprehensive targets based on the concept of＇anti-freeze filler＇, which include reasonable water retention rate, frost heave characteristics, and compaction characteristics of filling ...This paper set up a series of comprehensive targets based on the concept of＇anti-freeze filler＇, which include reasonable water retention rate, frost heave characteristics, and compaction characteristics of filling material. Then, a type of permeable graded gravel is proposed, suitable for high-speed railway subgrade. A series of in-door water retention, permeability, and frost heave tests were performed under different graded conditions. Water retention, permeability, and frost heave characteristic of dif- ferent graded filling materials can be determined, in order to define the gradation range of permeable graded gravel. Relying on the frost-heave monitoring record of high speed railway in Northeast China, a series of experimental studies were per- formed, which included on-site filler production, compaction test, and the anti-frost effect test, in order to improve the pro- duction and compaction techniques of permeable graded gravel. From the research of this paper, the use of permeable graded gravel subgrade as the anti-frost structure for the high-speed railway subgrade in cold areas is feasible.展开更多
基金funded by the Northern Canola Growers Association under grant number NCGA-2013-10
文摘Spring frost can severely damage or even kill rapeseed/canola(Brassica napus L.) seedlings. A protocol for large scale screening of rapeseed germplasm under frost-simulating conditions has not yet been developed. Accordingly, the present study was conducted to develop a protocol for screening rapeseed germplasm under artificial frost-simulation conditions in a plant growth chamber and in a greenhouse. Nine rapeseed varieties, including three commercial hybrids, three spring types, and three winter types were used. Cold acclimation at 4 °C was applied for 0, 7, or 14 days to two-week old seedlings. The seedlings were treated with four freezing temperatures(- 4 °C,- 8 °C,- 12 °C, and- 16 °C). The length of the freezing period was 16 h, including the ramping of temperature down from 4 °C and up from the respective freezing temperature to 4 °C. Plants were allowed to recover at 4 °C for24 h before they were moved back to the greenhouse. Frost damage was scored on a 0–5scale, where 0 denotes completely dead and 5 denotes no damage. Seedling survival from the freezing treatment increased from the non-acclimation to the cold acclimation treatment. However, no significant differences(P < 0.05) were found between 7 and14 days of acclimation. Frost treatment at- 4 °C resulted in significant differences in seedling damage relative to the other three temperatures, with the- 16 °C treatment resulting in the highest overall seedling damage. Significant differences were found between the spring type and the other two types(hybrid and winter). However, no significant differences were found between the hybrid and winter types. The suggested protocol for the assessment of frost tolerance is acclimation of two-week old seedlings for7 days at 4 °C followed by frost treatment at- 4 °C for 16 h.
基金supported by the China Railways Corporation research projects entitled"The technical tests for the high speed railway subgrade frost heave prevention in the alpine"(Project No.Z2013-038)The long term observation of frost-heave technology for Ha-Da high-speed railway during the operation(Project No.Z2012-062)+2 种基金Optimal design for high-speed railway subgrade structure under different grade and environment(Project No.2014G003-A)from the Railway Scientific and Technological Research and Development Center called"The mechanism and evolution rule of the graded gravel under freeze and thawing cycles for the high speed railway"(Project No.J2014G003)The disease control technology and equipment of gradating gravel in surface layer of subgrade bed(Project No.2013YJ032)
文摘This paper set up a series of comprehensive targets based on the concept of＇anti-freeze filler＇, which include reasonable water retention rate, frost heave characteristics, and compaction characteristics of filling material. Then, a type of permeable graded gravel is proposed, suitable for high-speed railway subgrade. A series of in-door water retention, permeability, and frost heave tests were performed under different graded conditions. Water retention, permeability, and frost heave characteristic of dif- ferent graded filling materials can be determined, in order to define the gradation range of permeable graded gravel. Relying on the frost-heave monitoring record of high speed railway in Northeast China, a series of experimental studies were per- formed, which included on-site filler production, compaction test, and the anti-frost effect test, in order to improve the pro- duction and compaction techniques of permeable graded gravel. From the research of this paper, the use of permeable graded gravel subgrade as the anti-frost structure for the high-speed railway subgrade in cold areas is feasible.
