白菜型油菜抗寒生理生化特性动态研究

采用大田自然越冬和室内分析相结合的方法,研究了自然越冬过程中,白菜型冬油菜冬前抗寒生理生化指标的变化动态特征.结果表明:冬前随着气温降低,5种白菜型油菜植株地上部避害型失绿枯萎的同时,主根不断增长、根颈逐渐加粗、单根干质量和单根鲜质量增加,且品种间差异极显著,越冬率品种间差异极显著,即‘天油2号’>‘876’>‘8728’>‘986’>‘813’.叶片含水量均逐渐下降,其中‘876’和‘天油2号’的含水量下降幅度较大,明显高于其他品种.叶片丙二醛(MDA)含量波动明显,总体呈上升趋势,油菜叶片内MDA含量在温度较低时急剧累积,而根系中MDA含量却逐渐下降,说明根系受低温伤害的程度低于地上部植株的受伤害程度.随冬前温度下降,油菜叶片和根系的可溶性糖和游离脯氨酸均呈增加趋势,当含水量降到最低时,二者含量均达到最高.‘876’和‘天油2号’体内积累较多的可溶性糖和脯氨酸,形态特征表现为植株匍匐、生长点下陷,说明2个品种更能适应低温寒害,具较强的抗寒性.

Dynamics study on cold hardiness and physiological and biochemical characteristics of Brasica carnpestris

In order to study cold hardiness and physiological and biochemical index dynamics characteristics of Brasica campestris,the experiments were carried out in field and laboratory during the natural overwintering.The results showed that main root become lengthen,root collar become overstriking,dry weight and fresh weight of single root increased while the five B.campestris overground part withering,and there were significant differences among the five species as same as the wintering rate.It arranged as 'Tianyou 2'>'876'>'8728'>'986'>'813' as the temperature decreased before overwintering.While leaves water content descending generally before overwinter,water contents in 'Tianyou 2' and '876' leave had a deeply extent than that of other three B.campestris.MDA content in leaves had a ascending trend generally but decreasing in roots,it was well seen roots suffered lightest injury lower the leaves suffered.However,soluble sugar and proline content of rape leaf and root showed an increasing trend,there were differences among varieties,when the water content fell to the lowest,leaf and root soluble sugar and proline content were the highest.'876' and the 'Tian you 2' accumulated more soluble sugar and proline content,combined with its prostrate and growing point subsidence of the morphological characteristics before overwintering,more adaptation to low temperature cold damage,showing a strong cold hardiness.Morphological and physiological features in the five B.campestris species leaves and roots reflected cooperating actions to resist environmental low temperature,it had an important significance on breeding and resistance against frost in B.campestris production.