不同枫香种源对淹水胁迫的响应

采用随机区组试验设计,研究了人工模拟淹水胁迫对永康、邵武、南丹、南昌、泾县5个种源的枫香(Liquidambar formosana)2年生苗生长的影响。经过120 d的淹水处理,5个种源枫香的存活率均为100%,永康、泾县和南昌种源出现了少量不定根,而邵武和南丹种源未产生不定根。淹水抑制了枫香的干物质生产能力,其中对永康种源的抑制效应最明显,淹水胁迫下其干质量只有对照的64%;而对南昌种源干物质积累的影响最小,其生物量积累达对照的90%;同时发现,淹水胁迫下枫香种源地上部生物量积累和苗高生长变化不大,而根系生物量明显下降,导致根冠比下降,说明淹水胁迫对枫香地下部影响远远大于地上部,从而改变了干物质分配模式。随着淹水时间的延长,枫香叶绿素含量明显下降。淹水胁迫下不同种源枫香根系形态学参数也发生了变化,其中南丹种源的根系总长(TL)、根长密度(RLD)以及比根长(SRL)均有所增加,这可能是根系在缺氧环境下的一种适应性变化。根据5个种源在淹水胁迫下的生长状况和生物量积累,可以认为南昌和南丹种源较适合在低湿地推广。

Response to waterlogging stress of different five Liquidambar formosana provenances

The 2-year-old seedlings of 5 sweet gum(Liquidambar formosana Hance) provenances from Yongkang,Shaowu,Nandan,Nanchang,Jingxian were investigated under waterlogging stress.We studied the influence of the seedlings after the treatment of waterlogging.The results showed that,throughout the 120-day waterlogging period,the survival rates of seedlings of 5 formosan sweet gum provenances were 100 %.Seedlings from Yongkang,Jingxian and Shaowu developed adventitious roots at the stem base,whereas no adventitious root was observed in Nanchang and Nandan.The dry matter production of 5 formosan sweet gum provenances seedlings were greatly inhibited under waterlogging stress,seedlings from Yongkang produced only 64 % dry matter compared with that of CK,while little influence was found in seedlings from Nanchang,of which 90 % of dry matter were produced compared with that of CK.We also found the shoot biomass and seedling height changed very little,Whereas root biomass decreased significantly,which resulted obviously in decrement of root-shoot ratio.With the prolonging of waterlogging stress,chlorophyll content in leaves of 5 formosan sweet gum provenances decreased significantly.Root morphology indexes also changed under waterlogging stress,interestingly,the total length of root,root length density and specific root length of Nandan provenance increased under waterlogging stress,which would be considered as the adaptation of roots in conquering anoxic environment.According to the growth and biomass accumulation of 5 formosan sweet gum provenances under waterlogging stress,we can conclude gum species from Nanchang and Nandan provenances would be more suitable for planting in intermittent flooding areas.