| Low temperature is an important abiotic stress factor affecting rice growth and development in Northeast China.Especially in rice seedling stage,its growth and development,physiological characteristics and metabolic response are very sensitive to low temperature.Wood vinegar is a natural organic liquid obtained by condensation and separation of gases produced by biomass during pyrolysis and carbonization.It has been widely used in agricul tural production.There are many studies on chilling injury of rice seedling stage and wood vinegar to promote the growth and development of rice and other plants,but there are few studies regarding the effect of wood vinegar on the cold resistance of rice seedling.In this experiment,rice seedling was taken as the research object.Firstly,the effects of different concentrations of wood vinegar on the growth status,cell membrane stability,chlorophyll content,osmotic regulators,protective enzymes and root activity of rice seedlings under low temperature stress and normal temperature recovery were studied to explore the effects of wood vinegar on cold resistance of rice seedlings,and to find the optimum concentration of wood vinegar to improve cold res istance of rice seedlings.Then the effects of wood vinegar extract after removal of acids,phenols,ketones and aldehydes on plant height,chlorophyll content,cell membrane stability,protective enzyme activity,osmotic regulators and root activity of rice seedlings under low temperature stress were studied to analyze the components of wood vinegar in improving cold resistance of rice seedlings,and to preliminarily explore the mechanism of wood vinegar to improve the cold resistance of rice seedlings.By studying the effect of wood vinegar on the cold resistance of rice seedlings,it provides a new idea and method for solving the problem of chilling injury of rice seedlings.The results of this experiment are as follows:(1)Spraying appropriate concentration of wood vinegar on leaves could increase the growth index of rice seedlings under low temperature stress,enhance SOD,POD,CAT activity and root activity of rice seedlings,promote the increase of chlorophyll content,soluble sugar content and proline content in leaves,and reduce the MDA content and electrolyte permeability of rice seedlings.The experiment also found that wood vinegar had dual effects on growth status,root activity,photosynthesis,antioxidant enzyme activity,cell membrane stability and osmotic regulation of rice seedlings under low temperature stress.Low concentration of wood vinegar sprayed on rice seedlings showed promoting effect,while high concentration of wood vinegar sprayed on rice seedlings showed inhibiting effect,among which 400 times of wood vinegar diluent had the best effect on improving cold resistance and restoring ability of rice seedlings after cold injury.(2)The cold resistance of rice seedlings treated with wood vinegar solution which removed acid and phenolic components was significantly lower than that treated with wood vinegar solution.Under low temperature stress,the activities of antioxidant enzymes,plant height,chlorophyll content,electrolyte permeability,MDA content,proline content,soluble suga r content and root activity of seedlings treated with wood vinegar solution which removed acids and phenols were significantly lower than those treated with wood vinegar solution.The results showed that the acid and phenolic components in wood vinegar were two important components in wood vinegar to improve cold resistance of rice seedlings.Acids in wood vinegar had the greatest effect on increasing plant height,chlorophyll content,root activity,cell membrane stability and osmotic regulation of rice seedlings under low temperature stress.The phenolic components in wood vinegar had the greatest effect on improving the antioxidant enzyme activity of rice seedlings under low temperature stress.The results showed that the cold resistance of rice seedlings treated with wood vinegar solution which removed aldehydes and ketones had no significant change compared with that treated with wood vinegar solution,indicating that the aldehydes and ketones in wood vinegar solution had no effect on the cold resistance of rice seedlings under low temperature stress.The effects of other components or elements in wood vinegar on plant related physiology and metabolism need further study. |
