白菜型与甘蓝型冬油菜抗寒机理差异的研究

为探究白菜型与甘蓝型冬油菜抗寒机理差异的原因。以8个抗寒性不同的冬油菜品种为材料,采用大田试验和盆栽试验相结合的方法,待油菜长至5~6片真叶时,大田试验进行植物学形态,干物质积累量的测定,盆栽试验按24℃→10℃→5℃→0℃→-5℃→-10℃各48 h依次降温处理后测定生理生化指标。结果表明,白菜型冬油菜冬前生长点洼陷,幼苗匍匐生长,干物质积累主要集中在地下部分,其中白菜型冬油菜地下部鲜质量与地下部干质量较甘蓝型冬油菜平均增加了236.1%,263.0%,说明抗寒性强的冬油菜能够在营养生长阶段将光合有机产物优先运输到地下部,建立庞大的根系,为安全越冬提供代谢能量。随着温度的变化,不同类型冬油菜的生理生化活性有较大的差异,-5℃时陇油7号SOD活性较CK增加了10.7%,0℃时陇油7号CAT、POD活性较CK分别增加了24.7%,28.6%,而0℃时白菜型冬油菜SP含量较甘蓝型冬油菜平均增加了32.3%,-10℃时白菜型冬油菜的SS含量较甘蓝型冬油菜平均增加了71.4%,-10℃甘蓝型冬油菜MDA含量较白菜型冬油菜平均增加了52.8%,这说明抗寒性强的品种在低温条件下能够保护自身免受损伤,其中CAT、POD、SP是抵抗冷害的保护性物质,SOD、SS是抵御冻害的保护性物质。白菜型冬油菜比甘蓝型冬油菜在形态学及生理水平上都具有明显的优势,形态学上的优势使其有利于抵御极端低温天气,提供维持越冬及冬后返青所需的代谢能量;生理水平上,低温胁迫后保护性酶活性、调节性物质含量增加,能够有效地保护细胞膜结构,MDA含量减少,可以缓解低温对冬油菜叶片的伤害,从而保证高越冬率,为北方白菜型与甘蓝型冬油菜抗寒性研究提供理论依据。

Study of Difference in Mechanism of Cold Resistance of Winter Rapeseed of Brassica rape and Brassica napus

To explore the reasons for difference in mechanism of cold resistance of winter rapeseed of Brassica rape and Brassica napus.The method of combining field and pot culture was adopted,and using 8 different cold re-sistance of winter rapeseed varieties as materials,before wintering period with 5 to 6 true leaves,field experiments researched botanical morphology and accumulation of dry matter,the physiological characteristics were measured by pot experiment after the treatment of 24 ℃→10 ℃→5 ℃→0 ℃→ -5 ℃→ -10 ℃ 48 h.The results showed that winter Brassica rape was creeping growth,growth point was under the ground,accumulation of dry matter was mainly concentrated in the underground part,such as fresh matter of underground parts and dry matter of underground parts of winter Brassica rape had increased,which average increased 236.1%,263.0% than winter Brassica napus re-spectively.It was showed that the photosynthetic organic product of strong cold resistant varieties was preferentially allocated to the underground part during the vegetative growth stage,to establish a large root system to provide meta-bolic energy for the safe winter.With the change of temperature,the physiological and biochemical indexes of differ-ent varieties was vary greatly,SOD activity of Longyou 7 increased 10.7% than CK at low temperature of -5 ℃, CAT and POD activity of Longyou 7 increased 24.7%,28.6% than CK respectively at 0 ℃,SP content of winter Brassica rape average increased 32.3% than winter Brassica napus at 0 ℃,SS content of winter Brassica rape aver-age increased 71.4% than winter Brassica napus,and MDA content of winter Brassica napus average increased 52.8% than winter Brassica rape at low temperature of -10 ℃,this indicated that the strong cold resistant varieties could protect themselves from damage of low temperature condition,the CAT,POD,SP were protective substance of against chilling injury,but SOD,SS were protective substance of against freezing.Therefore,the winter Brassica rape had obvious advantages in the morphology and physiological level than winter Brassica napus,the morphological ad-vantages was that to withstand cold weather of extreme,to provide metabolic energy of during the wintering period and regreen next year;At physiological levels,the activities of protective enzyme and content of osmotic regulation of winter Brassica rape increased significantly at low temperature stress to protect the structure of cell membrane,and the accumulation of MDA was decreased,to alleviate hurt of winter rapeseed leaves at low temperature,so the over wintering was ensured highly,it was important to provide a theoretical basis for the research on the cold resistance of winter rapeseed of Brassica rape and Brassica napus in the North of China.