Seed Germination Characteristics And Its Response To Maternal Environment Of Thlaspi Arvense

Seed dormancy and germination is the early stage of plant life history and the most vulnerable stage.Understanding weed seed dormancy,germination and their response to the environmental factors is extremely important to prevent and control weeds.In this study,the characteristics of seed dormancy and germination of different populations of Thlaspi arvense and their response to maternal environment were studied using a combination of indoor and pot experiments.The main results were as following:1.Seeds of two T.arvense populations both exhibit dormancy,but their dormancy degree was varied.Seed dormancy rate of Xiahe population was higher than those of Maqu population.2.GA₃,KNO₃ and stratification significantly affected seed germination of T.arvense,but the effect degree varied with populations.Both GA₃ and stratification significantly increased seed germination rate（P<0.05）,while the effect of KNO₃treatment on the seed germination rate was different in two populations（P<0.05）.With the increasing of GA₃ concentration,seed germination rate increased in the beginning,and then decreased.The highest germination rate was observed when the GA₃ concentration was 10 mmol/L.Besides,seed germination rate increased with the increasing of stratification time.3.Water had significant effects on plant height and biomass of T.arvense.The plant height and biomass under sufficient water supply condition were significantly higher than those under water stress（P<0.05）.Light also made significantly effects on the plant height and underground biomass of T.arvense.The plant height and underground biomass under shading condition were significantly higher than those under light.However,light showed no significant effect on aboveground biomass（P<0.05）.4.Water significantly affected pod biomass,reproductive branch,the number of pods per reproductive branch,the number of seeds per pod,seed size and seed yield of T.arvense.The above indexes under sufficient water supply condition were significantly higher than those under water stress（P<0.05）.Light also significantly affected the number of reproductive branches and pods per reproductive branch of T.arvense.Under shading condition,the number of reproductive branches was more than those under lighting condition,while the number of pods per reproductive branch varied with populations.The number of pods per reproductive branch in Maqu population under shading condition was significantly lower than those under lighting condition（P<0.05）,while Xiahe population was on the contrary.The results of path analysis on yield and yield components of T.arvense showed that the contribution rate of yield components varied with populations and degree of water stress.5.The maternal environment,GA₃ and temperature all had significantly effects on seed germination of the offspring of T.arvense.Seed germination rate decreased with the increasing of water stress,but the maternal light had no significant effect on seed germination of offspring.GA₃ treatment increased the seed germination rate of offspring of two populations with different degrees,and the effect was more significant in offspring of Xiahe population.