低温胁迫及灌水对不同抗低温小麦品种根系生长和活性的影响

Impacts of Low Temperature Stress and Pre-Stress Irrigation on Root Traits of Wheat Varieties with Different Low Temperature Resistance

为了解春季低温胁迫下小麦根系形态性状和生理功能的变化及其与品种抗低温能力的关系,同时明确低温灾害来临前灌水对小麦根系伤害的缓解效应,采用室外盆栽方式,以强抗低温品种百农207和弱抗低温品种周麦18为材料,研究了不同抗低温小麦品种的根系生长发育特征及灌水对低温胁迫的缓解效应。结果表明,拔节期低温胁迫(T1)处理下,小麦单株总根长、根体积、根干重和根系活力随生育期的推进均呈先升后降的变化趋势,单株次生根数呈下降趋势;孕穗期T1处理下,单株总根长、根体积、次生根数和根干重均呈下降趋势,根系活力呈上升趋势。拔节期和孕穗期T1处理下,强抗低温品种百农207的根系性状变化幅度较小,单株次生根数、根系活力和产量均显著高于弱抗低温品种周麦18。相对于T1处理,灌水+低温胁迫(T2)处理下单株次生根数增加,其中弱抗低温品种周麦18变化显著。经相关分析、多元逐步回归和通径分析,春季T1处理下,抗低温品种具有较高的单株次生根数和根系活力,其中拔节期和孕穗期的T1处理下孕穗期根系活力、开花期单株根干重及孕穗期单株次生根数对产量贡献较大,T2处理下孕穗期和蜡熟期的单株次生根数贡献较大。综合来看,春季低温胁迫下,较高的根系活力和单株次生根数对小麦产量具有重要作用,而低温胁迫前灌水主要通过提高小麦生育后期的单株次生根数而增加产量。

In order to understand the changes in morphological traits and physiological functions of wheat roots under low temperature stress in spring and their relationship with the low temperature resistance of varieties,and to clarify the alleviating effect of irrigation before low temperature stress on wheat root damage,outdoor potted cultivation was adopted,using a strong cold resistance variety Bainong 207 and a weak cold resistance variety Zhoumai 18 as materials.The root growth and development characteristics of different cold resistant wheat varieties and the alleviating effect of irrigation on low temperature stress were studied.The results showed that under low temperature stress(T1)at jointing stage,the total root length,root volume,root dry weight,and root vigor of wheat plants all showed an increasing and then decreasing trend with the advancement of the growth period,while the number of secondary roots per plant showed a decreasing trend.Under T1 treatment at the booting stage,the total root length,root volume,number of secondary roots,and root dry weight per plant all showed a decreasing trend,while the root vigor showed an increasing trend.Under T1 treatment at jointing and booting stages,the root traits of the strong cold resistant variety Bainong 207 showed relatively small changes.The number of secondary roots per plant,root vigor,and yield were significantly higher than those of the weak cold resistant variety Zhoumai 18.Compared to T1 treatment,the number of secondary roots per plant increased under irrigation and low temperature stress(T2)treatment,with a significant change observed in the weak cold resistant variety Zhoumai 18.The results of correlation analysis,multiple stepwise regression,and path analysis showed that under the T1 treatment in spring,cold resistant varieties had higher secondary root numbers and root vifor per plant.Among them,under the T1 treatment at jointing and booting stages,root vigor at booting stage,dry weight of root per plant at flowering stage,and secondary root numbers per plant at booting stage contributed significantly to yield,while under the T2 treatment,the secondary root numbers per plant at booting and maturity stages contributed significantly.In summary,under low temperature stress in spring,higher root vigor and the number of secondary roots per plant play an important role in wheat yield,while irrigation before low temperature stress mainly increases yield by increasing the number of secondary roots per plant in the later stage of growth.