剪根处理对不同秧龄杂交稻幼苗生长及生理特性的影响

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。

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

Supper hybrid rice F you 498 was used to investigate the effects of seedling age (25 days old and 40 days old) and root cutting (1/3, 2/3 and 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 of 40 day old seedling. In the views of root cutting ratio, 1/3 root 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 1/3 root 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 1/3 root cutting, and the above ground biomass, root length, nitrogen accumulation amount and nitrogen content were also higher than those of control 29 days after 1/3 root 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.