Studies on Screening Methods for Alkaline Tolerance at Germination Period and Early Seedling Stage in Rice

Using four different Na_2CO_3 concentration as simulating alkaline stress,the relative alkali damage rate(RADR) of rice germinative energy(GE) and germination rate(GR) at germination period,RADR of rice root length(RL),seedling height(SH) and root number(RN) at early seedling stage were looked as evaluation indexes,so the alkaline stress concentration for evaluation of alkaline tolerance at germination period and early seedling stage in rice was studied.The results showed that germinative energy(GE) was more sensitive to alkaline stress than germination rate(GR),RL was more sensitive to alkaline stress than SH and RN,early seedling stage was more sensitive to alkaline stress than germination period.The mean value,variance and range of variance for RADR of GE and GR under 0.15% or 0.20% Na_2CO_3 stress were larger and their distribution was more reasonable that was good condition for the evaluation of alkaline tolerance at germination period.The mean value,variance and range of variance for RADR of RB,RL,SH and total value at early seedling stage under 0.10% or 0.15% Na_2CO_3 stress were larger and their distribution was more reasonable,that was good condition for the evaluation of alkaline tolerance at early seedling stage.GE,GR,RN,RL and SH were negatively related to their RADR;RADR of GR was significantly associated with RADR of RN,RL and SH.Total RADR at germination period was significantly correlated with total RADR at early seedling stage.Therefore the alkaline tolerance at early seedling stage would indirectly evaluated by the alkaline tolerance at germination period.