剪根处理对不同秧龄杂交稻幼苗生长及生理特性的影响

Effects of Root-cutting Treatment on Growth and Physiological Characteristics of Hybrid Rice at Different Seedling-ages

以超级杂交稻F优498为材料,采用旱育秧方式育苗,设置不同秧龄（25d和40d）和幼苗伤根处理（整株根系剪去1/3、2/3、全部,以不剪根为对照）,进行水培试验,研究根系损伤后（0~48h和1~29d）的生理响应、物质积累、根系形态及氮素吸收特性。结果表明,剪根后不同秧龄秧苗受影响的程度及反应速度不同,秧苗地上部脯氨酸和可溶性糖含量均出现了明显峰值,伤根程度越大,峰值越高,到达峰值的时间越早;25d秧龄的幼苗在剪根后的生理抗性及恢复能力均明显强于40d秧龄的幼苗。从剪根程度来看,不同秧龄下,剪根1/3处理对幼苗生长有一定促进作用,25d秧龄,剪根1/3处理在处理后22d,根系长度、根系表面积、地上部、根系干质量以及根冠比均大于对照,同时该处理氮素积累显著高于对照;40d秧龄,整个生育期根系表面积均随剪根程度的增大而减小,剪根1/3处理在处理后22d,根冠比显著大于对照,处理后29d,地上部、根系干质量、根系长度、氮素积累量以及含氮率均大于对照,而伤根程度较大不仅会导致水稻幼苗根系生长受阻,同时会严重抑制根系对养分的吸收,从而影响水稻幼苗的生长发育。

Supper hybrid rice F you 498 was used to investigate the effects of seedling-age（25days old and 40 days old）and root-cutting（1/3,2/3and the whole root were cut off with no root-cutting as control）on the root response 0-48 hours and 1-29 days after root cutting,as well as dynamics of biomass accumulation,root morphology and nitrogen（N）absorption in a hydroculture experiment.The results showed that rice seedlings at various seedling ages responsed diversely to root-cutting.The proline content and soluble sugar content of the above-ground part had a significant peak after root-cutting,which was higher and reached the peak value in shorter time with the increase of the root-cutting ratio.The physiological resistance and resilience after root-cutting of 25-day seedling-age were superior to that of40-day old seedling.In the views of root-cutting ratio,1/3root-cutting had positive effect on seedling growth.Compared to the control,the root length,root surface area,above-ground biomass,root biomass,nitrogen accumulation amount and root shoot ratio were higher 22 days after 1/3root-cutting for 25-day old seedling.However,the root surface area in the whole growth stage decreased with the increaing root-cutting ratio for 40-day old seedling.The root-shoot ratio was higher than that of control 22 days after 1/3root-cutting,and the above-ground biomass,root length,nitrogen accumulation amount and nitrogen content were also higher than those of control 29 days after 1/3root-cutting.Besides,the root damage might inhibite the seedling growth and restrain the absorption of nutrients,which could affect the growth and development of rice seedling.